Acute hyperglycemia attenuates nerve conduction velocity and nerve blood flow in male Sprague–Dawley rats: reversal by adenosine

Hyperglycemia is implicated to play a major role in development of diabetic neuropathy. Since most of the diabetics are hyperglycemic much before they develop full-blown diabetes, we felt, it would be very important to know the effects of acute hyperglycemia on nerve function so that early pathophysiological events could be understood and appropriate therapeutic intervention can be made. Moreover, effect of acute hyperglycemia on motor nerve conduction velocity (MNCV) and nerve blood flow (NBF) is not known. Hence, we studied the effects of acute hyperglycemia on sciatic MNCV and sciatic NBF in healthy male Sprague-Dawley (SD) rats. Three different animal models of acute hyperglycemia (50% glucose (3 g kg(-1), i.v. (intra-venous) or i.p. (intra-peritoneally)) or 24 h post-streptozotocin (STZ) injected rats were used. Acute hyperglycemia but not mannitol or sucrose significantly attenuated MNCV and NBF. Adenosine (10 mg kg(-1), i.p.) prevented the acute hyperglycemia-induced attenuation of MNCV and NBF in all the three rat models of acute hyperglycemia. Adenosine effects were blocked by theophylline (50 mg kg(-1), i.p.) suggesting the role of adenosinergic receptor mediated mechanisms in acute hyperglycemia-induced neuropathy. Acute glucose administration in 8 weeks, STZ diabetic rats did not further affect MNCV or NBF. Adenosine (10 mg kg(-1), i.p.) did not produce any adverse effects on the blood pressure and heart rate. From the results, we conclude that acute hyperglycemia attenuates MNCV and NBF via an adenosinergic receptor-dependent mechanism.     

血糖控制情况对糖尿病周围神经病变(DPN)患者下肢神经减压术疗效的影响

目的 探讨糖尿病周围神经病变(diabetic peripheral neuropathy,DPN)患者的血糖控制情况对周围神经减压手术疗效的影响。方法 2014年12月至2016年6月在复旦大学附属中山医院接受单侧下肢神经减压术的DPN患者共计40例,以HbA1c=8%为标准分为血糖控制尚可组和血糖控制不佳组。在术前1天和术后6个月,测量视觉模拟评分(visual analogue scale,VAS)、两点辨别觉(two point discrimination,TPD)和10 g单丝测验,比较两组患者的手术疗效。结果 所有患者术后VAS、TPD和10 g单丝测验结果均较术前均明显改善。血糖控制尚可的患者术后VAS、TPD和10 g单丝测验结果均优于血糖控制不佳的患者。结论 良好的血糖控制对DPN患者下肢神经减压术后疼痛的缓解和肢体感觉的恢复具有积极作用,血糖控制尚可的患者手术疗效明显优于血糖控制不佳的患者。     

视神经损伤后视觉功能重塑的研究进展

青光眼或其他原因导致的视神经损伤,以及颅脑损伤导致的视觉损伤通常被认为是不可逆的。然而,近年来的研究发现,神经系统具有明显的神经可塑性(neuroplasticity)。人们尝试对神经的可塑性作用机制进行阐明,并通过视觉经验、电流刺激、代偿性眼球运动训练及压力疏导等方法来激活或活化“休眠”细胞及视觉传递,并构建自组织映射模型对视觉重塑效果进行预估。     

Pupillomotor campimetry in normals

The pupillary light reaction is closely related to retinal function and the integrity of the visual pathway. Thus, pupil perimetry may be a useful tool to objectively assess a patient’s visual field function. To judge a patient’s ‘pupil field’ as pathological, it is necessary to know if there are any asymmetries in the pupil field of a normal. To cope with stray light problems, we presented stimuli of low intensity on a dim computer monitor. Within the central 20° field, we performed computerized infrared pupil campimetry in 43 normal subjects. Stimuli were presented on a monitor at a distance of 30 cm. We ran four trials using a grid with 15 test spots for each eye. Stimulus luminance was 54 cd/m 2 in low mesopic conditions, spot size was 2° to 3° (depending on the individual sensitivity), and stimulus duration was 200 ms. Pupillomotor sensitivity decreased from the central retina to the periphery. The nasal retina gave larger amplitudes than the temporal retina. The inferior retina was more sensitive than the superior retina. These asymmetries were subtle, but significant. The nasal inferior retina was the most sensitive area, the temporal superior retina the least sensitive. We obtained reliable results in pupillomotor campimetry using a low stimulus intensity. There are asymmetries in the pupillomotor sensitivity of the normal central retina which must be considered when pupil perimetry is performed in patients.     

The pathological diagnosis of nerve biopsies: a practical approach

The approach to the neuropathological assessment of nerve biopsies is the main focus of this review. Nerve biopsies are invasive diagnostic procedures resulting in a permanent neurological deficit, and are therefore carried out only following an in-depth clinical assessment including laboratory, imaging, electrophysiological, and where appropriate also genetic studies. This review will outline the key diagnostic approaches and will discuss neuropathies relevant in clinical practice, caused by vasculitis, inflammatory demyelination, dysproteinaemic, amyloid, toxic agents, and neuropathies due to genetic conditions.     

Chronic inflammatory demyelinating polyradiculoneuropathy: A role for haematopoietic stem cell transplantation?

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is a clinical syndrome of a chronic progressive or relapsing and remitting, symmetrical, sensory and motor radiculoneuropathy. The immune reaction in CIDP is characterised by selective inflammation of peripheral nerves and is probably due to the interaction of cellular and humoral responses. Only three treatments for CIDP have demonstrated benefit in randomised studies, corticosteroids, plasma exchange and intravenous immunoglobulin. 25% of patients fail to respond or do not respond adequately to these treatments. Experimental data in animal models have shown that several autoimmune disorders, either congenital or acquired, can be transferred and/or treated by the transplantation of bone marrow stem cells. Haematopoietic stem cell transplantation (HSCT) has been performed with varying success in over 700 patients with autoimmune disorders throughout Europe. The experience in CIDP is very limited. This article will review current understanding of CIDP and experience of the use of HSCT in refractory CIDP.     

Stavudine extended release (once-daily,Bristol-Myers Squibb) for the treatment of HIV/AIDS

Exenatide is a glucagon-like peptide 1 receptor agonist, which has recently received FDA approval in the US for the treatment of Type 2 diabetes. Exenatide is an incretin mimetic that improves glycaemic control in patients with diabetes through acute mechanisms, such as glucose-dependent stimulation of insulin secretion, suppression of inappropriate glucagon secretion and slowing of gastric emptying, as well as chronic mechanisms that include enhancement of β-cell mass in rodent studies and weight loss and inhibition of food intake in humans. This article reviews the mechanisms of exenatide action, as well as its efficacy in the treatment of Type 2 diabetes.