Application of Pop-off Method to Bone Marrow and Peripheral Blood Specimens for Purposes of Electron Microscopy

In this paper, we describe a pop-off method applicable to the hematological field. Bone marrow or peripheral blood specimens from patients were placed on a clean glass slide and fixed immediately in 2% glutaraldehyde solution for 10 minutes. For the DAB reaction, the slide was immersed in the DAB reagent for 30 minutes, and post fixed with 1 % OsO₄ solution for 1 hour. Specimens on the slide were washed with buffer solution, dehydrated and polymerized directly on the slide. A gelatin capsule filled with Epon mixed monomer was then reversed over the specimen. After polymerization was completed, the specimen was popped off from the slide to the capsule and trimmed carefully to prepare for ultrathin sectioning. This method allows the entire sequence of tissue preparation to be carried out on the slide, from fixation to embedding, and even, especially in scanty specimens, including the DAB reaction. Electron microscopic findings in specimens prepared by this technique show excellent preservation and the absence of specific artifacts.     

Primary dural lymphoma: A novel concept of heterogeneous disease

Spinal primary dural lymphoma (PDL) is uncommon with a total of 37 previous well‐documented cases reported, including one diagnosed in the authors' institution. More recently we encountered an additional case of spinal PDL that, similarly to our previous case, was grade 1–2 follicular B‐cell PDL. Our two cases were diagnosed over a 3‐year interval in a 72‐year‐old female and a 74‐year‐old male, respectively. An exhaustive literature review on PDL was performed consequently to reveal that: (i) spinal and cerebral sites of involvement by PDL are constantly mutually exclusive; and (ii) unlike cerebral PDL, which is usually of marginal zone B‐cell type, only two of the 38 cases of spinal PDL were diagnosed as such, diffuse large B‐cell lymphoma being the most commonly encountered type in the spine. This divergence infers that, in contrast to the prevailing concept that PDL is a unique disease group, PDL appears to be rather heterogeneous with a difference in predilection of lymphoma type for the anatomical site of dural involvement. Such a site‐specific lymphoma‐type predilection phenomenon, well‐recognized in other organ systems, has not been acknowledged in PDL. This report brings new insights into PDL, and may contribute to a better understanding of nervous system pathophysiology and lymphoma classification.     

Disruption of ROCK1 gene attenuates cardiac dilation and improves contractile function in pathological cardiac hypertrophy

The development of left ventricular cardiomyocyte hypertrophy in response to increased hemodynamic load and neurohormonal stress is initially a compensatory response. However, persistent stress eventually leads to dilated heart failure, which is a common cause of heart failure in human hypertensive and valvular heart disease. We have recently reported that Rho-associated coiled-coil containing protein kinase 1 (ROCK1) homozygous knockout mice exhibited reduced cardiac fibrosis and cardiomyocyte apoptosis, while displaying a preserved compensatory hypertrophic response to pressure overload. In this study, we have tested the effects of ROCK1 deficiency on cardiac hypertrophy, dilation, and dysfunction. We have shown that ROCK1 deletion attenuated left ventricular dilation and contractile dysfunction, but not hypertrophy, in a transgenic model of Gαq overexpression-induced hypertrophy which represents a well-characterized and highly relevant genetic mouse model of pathological hypertrophy. Although the development of cardiomyocyte hypertrophy was not affected, ROCK1 deletion in Gαq mice resulted in a concentric hypertrophic phenotype associated with reduced induction of hypertrophic markers indicating that ROCK1 deletion could favorably modify hypertrophy without inhibiting it. Furthermore, ROCK1 deletion also improved contractile response to β-adrenergic stimulation in Gαq transgenic mice. Consistent with this observation, ROCK1 deletion prevented down-regulation of type V/VI adenylyl cyclase expression, which is associated with the impaired β-adrenergic signaling in Gαq mice. The present study establishes for the first time a role for ROCK1 in cardiac dilation and contractile dysfunction.     

Acute fulminant hemolysis after transcatheter mitral valve replacement for mitral annular calcification

Transcatheter mitral valve replacement (TMVR) is emerging as an alternative treatment strategy to surgery for patients with severe mitral annular calcification (MAC) who are not candidates for traditional mitral valve surgery. Paravalvular leak (PVL) is common following TMVR for severe MAC and can lead to heart failure symptoms and/or intravascular hemolysis, the latter of which usually is clinically stable. We report the case of a 67‐year‐old woman with symptomatic severe aortic stenosis and mitral stenosis with MAC in the setting of prior chest irradiation who was treated initially with transcatheter aortic valve replacement followed by TMVR at a later date (Sapien S3 system; Edwards Lifesciences). Immediately following TMVR, she developed acute profound hemolysis which manifested with hemoglobinuria, transfusion‐dependent anemia, and acute renal failure requiring renal replacement therapy. She was treated with post‐dilation balloon valvuloplasty after failed transcatheter PVL closure 10 days following TMVR with resulting improvement in the PVL. The hemolytic anemia resolved and renal function recovered without the need for continued hemodialysis 2 months later and stabilization of glomerular filtration rate at 6 months. This case highlights a potential severe complication of TMVR in MAC and suggests that improvement in hemolysis and late recovery of renal function may occur following treatment of PVL.     

Predictive mathematical models of cancer signalling pathways

Complex intracellular signalling networks integrate extracellular signals and convert them into cellular responses. In cancer cells, the tightly regulated and fine-tuned dynamics of information processing in signalling networks is altered, leading to uncontrolled cell proliferation, survival and migration. Systems biology combines mathematical modelling with comprehensive, quantitative, time-resolved data and is most advanced in addressing dynamic properties of intracellular signalling networks. Here, we introduce different modelling approaches and their application to medical systems biology, focusing on the identifiability of parameters in ordinary differential equation models and their importance in network modelling to predict cellular decisions. Two related examples are given, which include processing of ligand-encoded information and dual feedback regulation in erythropoietin (Epo) receptor signalling. Finally, we review the current understanding of how systems biology could foster the development of new treatment strategies in the context of lung cancer and anaemia.     

运动负荷超声评价主动脉瓣置换术后左心室收缩功能储备

目的:应用二维超声斑点追踪技术,评价主动脉瓣置换术后运动负荷试验中的左心室收缩功能储备。方法:21例因重度主动脉瓣狭窄进行瓣膜置换术的患者(左心室射血分数>50%)行运动负荷超声心动图检查,应用二维超声斑点追踪技术测量运动负荷试验中静息状态下及峰值负荷时的左心室收缩期长轴整体应变率(GLSRs),同时记录峰值负荷时的心肌摄氧量(pVO2)。结果与21例正常健康对照者进行比较。结果:静息状态下,病例组与对照组超声指标无明显差异。峰值负荷时,病例组pVO2低于正常组(P<0.05);GLSRs及二尖瓣环心肌收缩速度(Sm)均明显低于正常组(P<0.001)且与pVO2呈正相关(GLSRs:r=0.60,P=0.0007;Sm:r=0.65,P=0.002)。多重线性回归分析,病例组峰值负荷时的左心室收缩期应变率为pVO2的唯一影响因素。结论:主动脉瓣狭窄患者瓣膜置换术后,尽管静息状态下左心室功能正常,但运动负荷试验后,左心室收缩功能储备仍然低于正常。