Inter-ocular asymmetry of retinal parameters in Caucasian healthy children and young adults measured with optical coherence tomography

AIM: To evaluate retinal parameters in a sample of healthy young Caucasian adults to define the normal or physiological range of inter-ocular asymmetry in this particular age and ethnic group. METHODS: Study sample consisted of 37 Caucasian children and young adults aged between 12 and 23y (spherical equivalent from -3.00 D to +4.00 D, anisometropia <0.5 D and axial length differences <0.3 mm). Normal inter-ocular asymmetry values were determined and 95% inter-ocular difference tolerance values were obtained. RESULTS: Statistically significant inter-ocular differences were found in mean (P=0.003) and superior (P=0.008) retinal nerve fiber layer (RNFL) thickness, as well as in central macular thickness (P=0.039), with larger values in the left eye in all instances, and with tolerance limits of inter-ocular asymmetry of -9.00 μm to 6.00 μm, -28.00 μm to 9 μm and -39.00 μm to 29.00 μm, respectively. In addition, statistically significant differences were found between males and females in mean thickness of the RNFL in the right eye (P=0.020). CONCLUSION: The exploration of the normal asymmetries of the retina may be an effective approach to further understand myopia onset and progression, which is particularly relevant in this age group. Differences in instrumentation and sample characteristics compromise direct comparison with published research and warrant the need for further studies.     

Exploring the potential application of dental pulp stem cells in neuroregenerative medicine

The trigeminal nerve and its peripheral branches are susceptible to injury in the dental practice due to surgical removal of impacted third molars and placement of dental implants.Although peripheral trigeminal nerve injuries can undergo spontaneous regeneration,some injuries may be permanent with varying degrees of continued sensory impairment and neuropathic pain ranging from mild numbness to complete anaesthesia(Tay and Zuniga,2007).Adult neurons require continued neurotrophic support from surrounding cells to sustain neural viability,inhibit death-inducing pathways activating a variety of cell survival pathways(Zheng and Quirion,2004).     

From regenerative strategies to pharmacological approaches:can we fine-tune treatment for Parkinson's disease?

Parkinson's disease is the second most prevalent neurodegenerative disorder worldwide.Clinically,it is characterized by severe motor complications caused by progressive degeneration of dopaminergic neurons.Current treatment is focused on mitigating the symptoms through the administration of levodopa,rather than on preventing dopaminergic neuronal damage.Therefore,the use and development of neuroprotective/disease-modifying strategies is an absolute need that can lead to promising gains on translational research of Parkinson's disease.For instance,N-acetylcysteine,a natural compound with strong antioxidant effects,has been shown to modulate oxidative stress,preventing dopamine-induced cell death.Despite the evidence of neuroprotective and modulatory effects of this drug,as far as we know,it does not induce per se any regenerative process.Therefore,it would be of interest to combine the latter with innovative therapies that induce dopaminergic neurons repair or even differentiation,as stem cell-based strategies.Stem cells secretome has been proposed as a promising therapeutic approach for Parkinson's disease,given its ability to modulate cell viability/preservation of dopaminergic neurons.Such approach represents a shift in the paradigm,showing that cell-transplantation free therapies based on the use of stem cells secretome may represent a potential alternative for regenerative medicine of Parkinson's disease.Thus,in this review,we address the current understanding of the potential combination of stem cell free-based strategies and neuroprotective/disease-modifying strategies as a new paradigm for the treatment of central nervous system neurodegenerative diseases,like Parkinson's disease.     

Cryogel scaffolds: soft and easy to use tools for neural tissue culture

The mammalian central nervous system(CNS)is highly complex,with a vast array of processes and interactions occurring in a dynamic and often transient manner.How these processes are combined to regulate our behavior remains poorly understood.This has in turn led to a lack of understanding of how these processes have gone awry in the many disorders of the nervous system.In order to address this,researchers need a controlled way to manipulate the nervous system in in vitro and ex vivo cultures,in both a specific area and for a specific period of time to start to pick apart these interactions.To date,this has been technically challenging,especially when modeling focal injury to the CNS or when working with human brain tissue.     

Propagation of TDP-43 proteinopathy in neurodegenerative disorders

Neurodegenerative disorders are characterized by disruptions to neuronal function and circuitry,leading to a variety of clinical syndromes depending on the affected neuroanatomic regions(Geula,1998).Many proteinopathies implicated in neurodegenerative diseases are characterized by the pathologic accumulation of proteins into inclusions that are initially deposited in specific areas of the brain and spread widely with disease progression.     

Progress in perisynaptic Schwann cell and neuromuscular junction research

The neuromuscular junction(NMJ)is widely studied for its utility in investigating synaptic properties and processes and neuromuscular changes in response to injury,aging,and disease.The NMJ consists of three essential anatomic components,the pre-synaptic motor axon terminal,the post-synaptic nicotinic acetylcholine receptors(AchRs)on the muscle,and the perisynaptic Schwann cell(PSC),also known as the terminal Schwann cell,that caps the synapse(Figure 1A).     

使用棱镜重新定位双侧中心暗点患者视网膜物像的预试验

目的 本研究使用激光扫描检眼镜(SLO)评价双侧中央暗点患者使用棱镜后的眼球运动反应.方法 本预试验共招募6例有双侧中央暗点的年龄相关性黄斑变性(AMD)患者以及6例正常视力的志愿者.首先用Nidek MP-1微视野仪确认患者的中央暗点和优选视网膜注视点(PRL),然后用Rodenstock SLO,在将视标投射在优选视网膜注视点时拍下实时视网膜像,接着在受检者眼前加入6～8 PD的棱镜,要求受检者保持注视视标,这时通过视网膜标记来测量视网膜像的移位量,以及随后发生的优选视网膜注视点的再次注视.过程中平均移位量和再次注视时间通过图像软件(ImageJ software)来计算.结果 实验组再次注视时的移位量在3个像素点或11.66个弧分之内(x轴:2.90±3.92,y轴:2.53±4.18).对照组再次注视时的移位会准确些(x轴:0.33±1.15,y轴:0.89±2.50),但与实验组差异无统计学意义(tx=1.32,Px＞0.05;ty=0.80,Py＞0.05).对照组再次注视时间(0.98±0.19)s较实验组(2.83±1.63)s要短,差距有统计学意义(t=5.03,P＜0.01).其中有1例实验组受检者没有发生再次注视,其结果被排除并单独分析.结论 研究发现,双眼中央暗点患者对棱镜物像转移后的再注视反应与正常人接近,但实验组再注视明显较对照组慢,并有1例受检者没有发生再注视.该数据说明双侧中央暗点患者无论眼前有没有棱镜,都会利用相同的视网膜位置视物,因此,通过棱镜物像再定位的意义不大.     

Alpha-synuclein as a biomarker in Parkinson's disease: focus on neural derived extracelluar vesicles

The prevalence of Parkinson’s disease(PD)is rapidly increasing,and more than 12 million people are expected to suffer from PD by 2040.PD is a highly invalidating neurodegenerative condition that arises from the progressive degeneration of dopaminergic neurons in the substantia nigra pars compacta.The main cause for such degeneration is the formation of cytoplasmic inclusions known as Lewy bodies.     

Forge AHEAD with stricter criteria in future trials of embolic stroke of undetermined source

What lurks within the crypt?With more than 200 known causes of is chemic stroke(Saver,2016),what should be the minimum work up?Many centers offer high-resolution brain imaging and vessel studies,telemetry monitoring for atrial fibrillation(AF),trans-thoracic and transesophageal echocardiography.     

Interchangeability of corneal curvature and asphericity measurements provided by three different devices

AIM: To evaluate the interchangeability of keratometric and asphericity measurements provided by three measurement systems based on different optical principles. METHODS: A total of 40 eyes of 40 patients with a mean age of 34.1y were included. In all cases, a corneal curvature analysis was performed with IOL-Master (IOLM), iDesign 2 (ID2), and Sirius systems (SIR). Differences between instruments for flattest (K1) and steepest (K2) keratometric readings, as well as for magnitude and axis of corneal astigmatism were analyzed. Likewise, differences in asphericity (Q) between SIR and ID2 were also evaluated. RESULTS: Mean differences between devices for K1 were 0.20±0.21 (P<0.001), -0.12±0.36 (P=0.046) and -0.32±0.36 D (P<0.001) for the comparisons IOLM-SIR, IOLM-ID2 and SIR-ID2, respectively. The ranges of agreement for these comparisons between instruments were 0.41, 0.70, and 0.70 D. For K2, mean differences were 0.31±0.33 (P<0.001), -0.08±0.43 (P=0.265) and -0.39±0.38 D (P<0.001), with ranges of agreement of 0.65, 0.84, and 0.74 D. Concerning magnitude of astigmatism, ranges of agreement were in the limit of clinical relevance (0.49 D, P=0.011; 0.55 D, P=0.386; 0.43 D, P=0.05). In contrast, ranges of agreement were clinically relevant for astigmatic axis (26.68o, 33.83o and 18.37o, P≥0.121) and for Q between SIR and ID2 (0.16, P<0.001). CONCLUSION: The keratometric corneal power, astigmatic axis and asphericity measurements provide by the three systems evaluated cannot be considered as interchangeable, whereas measurements of corneal astigmatism obtained with SIR and ID2 can be considered as interchangeable for clinical purposes.