Central motor conduction time reveals upper motor neuron involvement masked by lower motor neuron impairment in a significant portion of patients with amyotrophic lateral sclerosis

ObjectiveWe retrospectively investigated the utility of the central motor conduction time (CMCT) in detecting upper motor neuron (UMN) involvements in patients with amyotrophic lateral sclerosis (ALS).MethodsFifty-two ALS patients and 12 disease control patients participated in this study. Surface electromyograms were recorded from the first dorsal interosseous (FDI) and tibialis anterior (TA) muscles. We stimulated the motor cortex, brainstem, and spinal nerve using transcranial magnetic stimulation (TMS) in order to measure the cortical, brainstem, and spinal latencies. We divided the ALS patients into 2 subgroups (with UMN impairment vs. without UMN impairment) and calculated the rates of abnormal CMCT prolongation judged by their comparison with the normal ranges obtained by the measurement in the control patients.ResultsThe CMCTs in the FDI and TA were abnormally prolonged in over 40% of the ALS patients with UMN impairment and in nearly 30% of those without UMN impairment.ConclusionsCMCT shows UMN dysfunction in ALS patients without clinical UMN impairment.SignificanceTMS still has diagnostic utility in a significant portion of ALS patients.     

鼻咽癌放疗导致海马损伤及认知功能障碍研究进展

放射性认知功能障碍是鼻咽癌患者放疗后常见并发症,主要与神经发生障碍、胶质细胞损伤、血管损伤和细胞因子表达异常有关。随着医学的进步,功能磁共振可以提示认知障碍的早期病变,屏蔽海马及药物治疗(美金刚、多奈哌齐、贝伐单抗等)等方法可改善放射性认知障碍。本文总结了放射性认知障碍的发病机制、影像学、放疗剂量学和治疗方法。     

Exendin-4 attenuates pain-induced cognitive impairment by alleviating hippocampal neuroinflammation in a rat model of spinal nerve ligation

Glucagon-like peptide-1 receptor has anti-apoptotic,anti-inflammatory,and neuroprotective effects.It is now recognized that the occurrence and development of chronic pain are strongly associated with anti-inflammatory responses;however,it is not clear whether glucagon-like peptide-1 receptor regulates chronic pain via anti-inflammatory mechanisms.We explored the effects of glucagon-like peptide-1 receptor on nociception,cognition,and neuroinflammation in chronic pain.A rat model of chronic pain was established using left L5 spinal nerve ligation.The glucagon-like peptide-1 receptor agonist exendin-4 was intrathecally injected into rats from 10 to 21 days after spinal nerve ligation.Electrophysiological examinations showed that,after treatment with exendin-4,paw withdrawal frequency of the left limb was significantly reduced,and pain was relieved.In addition,in the Morris water maze test,escape latency increased and the time to reach the platform decreased following exendin-4 treatment.Immunohistochemical staining and western blot assays revealed an increase in the numbers of activated microglia and astrocytes in the dentate gyrus of rat hippocampus,as well as an increase in the expression of tumor necrosis factor alpha,interleukin 1 beta,and interleukin 6.All of these effects could be reversed by exendin-4 treatment.These findings suggest that exendin-4 can alleviate pain-induced neuroinflammatory responses and promote the recovery of cognitive function via the glucagon-like peptide-1 receptor pathway.All experimental procedures and protocols were approved by the Experimental Animal Ethics Committee of Renmin Hospital of Wuhan University of China(approval No.WDRM 20171214)on September 22,2017.     

Finite Neuron Method and Convergence Analysis

We study a family of $H^m$-conforming piecewise polynomials based on the artificial neural network, referred to as the finite neuron method (FNM), for numerical solution of $2m$-th-order partial differential equations in$\mathbb{R}^d$ for any $m,d≥1$ and then provide convergence analysis for this method. Given a general domain Ω$⊂\mathbb{R}^d$ and a partition$\mathcal{T}_h$ of Ω, it is still an open problem in general how to construct a conforming finite element subspace of $H^m$(Ω) that has adequate approximation properties. By using techniques from artificial neural networks, we construct a family of $H^m$-conforming functions consisting of piecewise polynomials of degree $k$ for any $k≥m$ and we further obtain the error estimate when they are applied to solve the elliptic boundary value problem of any order in any dimension. For example, the error estimates that $‖u−u_N‖_{H^m(\rm{Ω})}=\mathcal{O}(N^{−\frac{1}{2}−\frac{1}{d}})$ is obtained for the error between the exact solution $u$ and the finite neuron approximation $u_N$. A discussion is also provided on the difference and relationship between the finite neuron method and finite element methods (FEM). For example, for the finite neuron method, the underlying finite element grids are not given a priori and the discrete solution can be obtained by only solving a non-linear and non-convex optimization problem. Despite the many desirable theoretical properties of the finite neuron method analyzed in the paper, its practical value requires further investigation as the aforementioned underlying non-linear and non-convex optimization problem can be expensive and challenging to solve. For completeness and the convenience of the reader, some basic known results and their proofs are introduced.     

Reviving through human hippocampal newborn neurons

Recent contradictory data has renewed discussion regarding the existence of adult hippocampal neurogenesis (AHN) in humans, i.e., the continued production of new neurons in the brain after birth. The present review revisits the debate of AHN in humans from a historical point of view in the face of contradictory evidence, analyzing the methods employed to investigate this phenomenon. Thus, to date, of the 57 studies performed in humans that we reviewed, 84% (48) concluded in favor of the presence of newborn neurons in the human adult hippocampus. Besides quality of the tissue (such as postmortem intervals below 26 hours as well as tissue conservation and fixation), considerations for assessing and quantify AHN in the human brain require the use of stereology and toxicological analyses of clinical data of the patient.     

New insights into Wnt signaling alterations in amyotrophic lateral sclerosis: a potential therapeutic target?

Amyotrophic lateral sclerosis is a fatal neurodegenerative disorder characterized by upper and lower motor neuron degeneration, which leads to progressive paralysis of skeletal muscles and, ultimately, respiratory failure between 2–5 years after symptom onset. Unfortunately, currently accepted treatments for amyotrophic lateral sclerosis are extremely scarce and only provide modest benefit. As a consequence, a great effort is being done by the scientific community in order to achieve a better understanding of the different molecular and cellular processes that influence the progression and/or outcome of this neuropathological condition and, therefore, unravel new potential targets for therapeutic intervention. Interestingly, a growing number of experimental evidences have recently shown that, besides its well-known physiological roles in the developing and adult central nervous system, the Wnt family of proteins is involved in different neuropathologica conditions, including amyotrophic lateral sclerosis. These proteins are able to modulate, at least, three different signaling pathways, usually known as canonical(β-catenin dependent) and non-canonical(β-catenin independent) signaling pathways. In the present review, we aim to provide a general overview of the current knowledge that supports the relationship between the Wnt family of proteins and its associated signaling pathways and amyotrophic lateral sclerosis pathology, as well as their possible mechanisms of action. Altogether, the currently available knowledge suggests that Wnt signaling modulation might be a promising therapeutic approach to ameliorate the histopathological and functional deficits associated to amyotrophic lateral sclerosis, and thus improve the progression and outcome of this neuropathology.     

癫痫持续状态后小鼠海马组织神经元中微管蛋白和内体-溶酶体系统表达的变化及其意义

目的：探讨癫痫持续状态（SE）后小鼠海马组织神经元中微管蛋白β-tubulin和内体-溶酶体系统表达的变化，阐明神经元迟发性死亡过程中微管和内体-溶酶体系统的变化规律。方法：40只雄性ICR小鼠分为对照组（n=7，给予生理盐水）和实验组（n=33，给予匹鲁卡品），实验组中达到SE标准的SE小鼠根据SE后时间分为SE1d、SE2d、SE3d和SE7d组（n=5）。Nissl和Fluoro-Jade B （F-JB）染色检测各组小鼠海马组织神经元损伤情况，免疫荧光法检测各组小鼠海马组织神经元中微管蛋白β-tubulin、内体蛋白Rab5和溶酶体结构蛋白LAMP1表达强度及β-tubulin、Rab5和LAMP1阳性面积百分比；双重荧光法检测各组小鼠海马组织CA1区β-tubulin与Rab5和LAMP1表达的关系。结果：与对照组比较，SE1d组小鼠海马CA1和CA3区神经元数减少（P<0.01），F-JB阳性细胞数增加（P<0.01）；SE2d、SE3d和SE7d组小鼠海马组织中Nissl阳性神经元数明显减少（P<0.01）。与对照组比较，SE2d、SE3d和SE7d组小鼠海马组织中F-JB阳性神经元数增加（P<0.01）。与对照组比较，SE2d、SE3d和SE7d组小鼠海马CA1和CA3区神经元树突中β-tubulin阳性面积百分比明显降低（P<0.05），其变化趋势与神经元损伤相似。与对照组比较，SE1d、SE 2d、SE 3d和SE 7d组小鼠海马组织神经元中Rab5和LAMP1表达强度随着时间延长呈下降趋势；Rab5阳性面积百分比明显降低（P<0.05或P<0.01）；LAMP1阳性面积百分比在SE后第1天出现一过性增多，之后逐渐减少（P<0.05或P<0.01）。双重荧光染色检测，SE后1 d是早期内体减少和溶酶体一过性增多的关键点，并与神经元微管损伤的出现时间极为一致。结论：SE引起神经元迟发性死亡的同时神经元微管骨架受损，内体-溶酶体系统的定位和功能也发生异常改变。