Abnormal Sensory Nerve Conduction Research Articles

Characteristics of Sensory Neuron Dysfunction in Amyotrophic Lateral Sclerosis (ALS): Potential for ALS Therapy.

Amyotrophic lateral sclerosis (ALS) is a devastating neurodegenerative disorder characterised by the progressive degeneration of motor neurons, resulting in muscle weakness, paralysis, and, ultimately, death. Presently, no effective treatment for ALS has been established. Although motor neuron dysfunction is a hallmark of ALS, emerging evidence suggests that sensory neurons are also involved in the disease. In clinical research, 30% of patients with ALS had sensory symptoms and abnormal sensory nerve conduction studies in the lower extremities. Peroneal nerve biopsies show histological abnormalities in 90% of the patients. Preclinical research has reported several genetic abnormalities in the sensory neurons of animal models of ALS, as well as in motor neurons. Furthermore, the aggregation of misfolded proteins like TAR DNA-binding protein 43 has been reported in sensory neurons. This review aims to provide a comprehensive description of ALS-related sensory neuron dysfunction, focusing on its clinical changes and underlying mechanisms. Sensory neuron abnormalities in ALS are not limited to somatosensory issues; proprioceptive sensory neurons, such as MesV and DRG neurons, have been reported to form networks with motor neurons and may be involved in motor control. Despite receiving limited attention, sensory neuron abnormalities in ALS hold potential for new therapies targeting proprioceptive sensory neurons.

A multicenter, randomized, double blind, placebo-controlled clinical trial of dl-3-butylphthalide in treatment of amyotrophic lateral sclerosis.

A multicenter, randomized, double blind, placebo-controlled clinical trial of dl-3-butylphthalide in treatment of amyotrophic lateral sclerosis.

Correlations between Electro-Diagnostic Findings, the Severity of Initial Infection, and the Rehabilitation Outcomes among COVID-19 Patients.

Simple SummaryPatients with Coronavirus-2019 (COVID-19) often have reduced muscle strength and loss of sensory function. We examined several properties of the function of the nerve located at the arm and leg of 19 COVID-19 hospitalized patients before and after their rehabilitation period. We also evaluated the severity of their illness, their gait, muscle strength, and level of disability. We isolated several factors in the function of their nerves, which can be used to predict their prognosis and rehabilitation outcomes. Our findings are important since clinicians can use examinations of nerve function at early stages of the illness in order to devise an optimal treatment plan for the patient, thereby reducing the hospitalization period and promoting patient’s independence.Patients with Coronavirus-2019 (COVID-19) manifest many neuromuscular complications. We evaluated the correlations between electromyography and nerve conduction measurements among COVID-19 patients and the severity of the initial infection, as well as the rehabilitation outcomes, and searched for the factors which best predict the rehabilitation outcomes. A total of 19 COVID-19 patients (16 men; mean ± SD age 59.1 ± 10.4), with WHO clinical progression scale of 6.8 ± 2.3, received rehabilitation for 3.9 ± 2.5 months. The Functional Independence Measure (FIM), the 10 m walk test, the 6 minute walk test, and grip force were collected before and after the rehabilitation period. Motor Nerve Conduction (MNC), Sensory Nerve Conduction (SNC) and electromyographic abnormalities were measured. All of the MNC measures of the median nerve correlated with the WHO clinical progression scale and duration of acute hospitalization. The MNC and SNC measures correlated with the rehabilitation duration and with FIM at discharge. The MNC distal latency of the median and the peroneal nerves and the MNC velocity of the median and tibial nerves predicted 91.6% of the variance of the motor FIM at discharge. We conclude that nerve conduction measurements, especially in COVID-19 patients with severe illness, are important in order to predict prognosis and rehabilitation outcomes.

CANVAS: A New Genetic Entity in the Otorhinolaryngologist’s Differential Diagnosis

The biallelic inheritance of an expanded intronic pentamer (AAGGG)exp in the gene encoding replication factor C subunit 1 (RFC1) has been found to be a cause of cerebellar ataxia, neuropathy, and vestibular areflexia syndrome (CANVAS). This study describes clinical and genetic features of our patients with clinical suspicion of the syndrome. A retrospective descriptive study from an ataxia database comprising 500 patients. The study was performed at the Otorhinolaryngology Department of a hospital in the north of Spain. Specific genetic testing for CANVAS was performed in 13 patients with clinical suspicion of complete or incomplete syndrome. The clinical diagnosis was supported by quantitative vestibular hypofunction, cerebellar atrophy, and abnormal sensory nerve conduction testing. Nine of 13 (69%) patients met clinical diagnostic criteria for definite CANVAS disease. The first manifestation of the syndrome was lower limb dysesthesia in 8 of 13 patients and gait imbalance in 5 of 13. Eleven of 13 (85%) patients were carriers of the biallelic (AAGGG)exp in RFC1. A genetic cause of CANVAS has recently been discovered. We propose genetic screening for biallelic expansions of the AAGGG pentamer of RFC1 in all patients with clinical suspicion of CANVAS, since accurate early diagnosis could improve the quality of life of these patients.

Study of Sensory Nerve Conduction Abnormalities in Hypothyroid Patients

Study of Sensory Nerve Conduction Abnormalities in Hypothyroid Patients

Overexpression of Sirtuin 1 protein in neurons prevents and reverses experimental diabetic neuropathy.

In diabetic neuropathy, there is activation of axonal and sensory neuronal degeneration pathways leading to distal axonopathy. The nicotinamide-adenine dinucleotide (NAD+)-dependent deacetylase enzyme, Sirtuin 1 (SIRT1), can prevent activation of these pathways and promote axonal regeneration. In this study, we tested whether increased expression of SIRT1 protein in sensory neurons prevents and reverses experimental diabetic neuropathy induced by a high fat diet (HFD). We generated a transgenic mouse that is inducible and overexpresses SIRT1 protein in neurons (nSIRT1OE Tg). Higher levels of SIRT1 protein were localized to cortical and hippocampal neuronal nuclei in the brain and in nuclei and cytoplasm of small to medium sized neurons in dorsal root ganglia. Wild-type and nSIRT1OE Tg mice were fed with either control diet (6.2% fat) or a HFD (36% fat) for 2 months. HFD-fed wild-type mice developed neuropathy as determined by abnormal motor and sensory nerve conduction velocity, mechanical allodynia, and loss of intraepidermal nerve fibres. In contrast, nSIRT1OE prevented a HFD-induced neuropathy despite the animals remaining hyperglycaemic. To test if nSIRT1OE would reverse HFD-induced neuropathy, nSIRT1OE was activated after mice developed peripheral neuropathy on a HFD. Two months after nSIRT1OE, we observed reversal of neuropathy and an increase in intraepidermal nerve fibre. Cultured adult dorsal root ganglion neurons from nSIRT1OE mice, maintained at high (30 mM) total glucose, showed higher basal and maximal respiratory capacity when compared to adult dorsal root ganglion neurons from wild-type mice. In dorsal root ganglion protein extracts from nSIRT1OE mice, the NAD+-consuming enzyme PARP1 was deactivated and the major deacetylated protein was identified to be an E3 protein ligase, NEDD4-1, a protein required for axonal growth, regeneration and proteostasis in neurodegenerative diseases. Our results indicate that nSIRT1OE prevents and reverses neuropathy. Increased mitochondrial respiratory capacity and NEDD4 activation was associated with increased axonal growth driven by neuronal overexpression of SIRT1. Therapies that regulate NAD+ and thereby target sirtuins may be beneficial in human diabetic sensory polyneuropathy.

Clinical characteristics analyses of multiple myeloma with peripheral neuropathy

Objective To investigate the clinical manifestations and nerve electrophysiological abnormalities of the patients with multiple myeloma peripheral neuropathy (MMPN). Methods The clinical data of 35 patients with MMPN diagnosed in Shanxi Provincial People's Hospital from March 2010 to June 2018 were retrospectively analyzed. All patients received nerve electrophysiology examination, including nerve conductive velocity (NCV) and skin sympathetic response (SSR). Results The most common symptoms of peripheral nerve involvement for MMPN patients were sensory abnormalities (25 cases, 71%), including root pains (3 cases, 9%), pain ablation of the upper or lower limbs (18 cases, 51%), dyskinesia (15 cases, 43%), disappeared or reduced knee or ankle reflex (13 cases, 37%) and automatic sympathetic disorders (20 cases, 57%). Nerve electrophysiological tests showed 29 cases (83%) were involved in abnormal sensory nerve conduction velocity (SCV) or motor nerve conduction velocity (MCV), including 13 cases of upper limb abnormality in NCV, 5 cases of prolonged incubation in upper limb, and 10 cases of decreased amplitude; 8 cases of lower limb abnormality in NCV, 6 cases of prolonged incubation in lower limb, and 4 cases of decreased amplitude. SSR test showed abnormalities were found in 17 patients (49%), including 8 cases of upper limb abnormality in SRR, 2 cases of prolonged incubation in upper limb, and 7 cases of decreased amplitude, 1 case of disappeared waveform; 6 cases of lower limb abnormality in SRR, 1 case of prolonged incubation in lower limb, and 4 cases of decreased amplitude, 2 cases of disappeared waveform; 3 cases of abnormal upper and lower limbs. Conclusions The most common peripheral nerve damages of MM are sock and glove-like sensory ablation, accompanied with the involvement of automatic nerve damage. NCV is the major method to diagnose MMPN, and SSR plays an important role in the detection of sympathetic nerve damage of MMPN. Key words: Multiple myeloma; Peripheral nervous system diseases; Electromyography; Neural conduction; Electrophysiology

Endoscopic carpal tunnel release surgery: a case study in Vietnam

BackgroundThis study aims at investigating the outcome and electrophysiologic recovery of 150 carpal tunnel syndrome hands after single-portal endoscopic surgery.MethodsPatients with the cross-sectional area of the median nerve being 13–15 mm2 on ultrasound or abnormal sensory nerve conduction velocity on EMG are assigned to endoscopic surgery that cuts the decompressing transverse ligament to avoid the emergence of severe symptoms, such as muscular atrophy and loss of hand function.ResultsSingle-portal endoscopic release is a safe and efficacious option for carpal tunnel release. The findings demonstrate encouraging results.ConclusionThe endoscopic carpal tunnel release with the placement of a MicroAire system is a safe and effective method for treating carpal tunnel syndrome.

Neuroelectrophysiological characteristics of peripheral neuropathy in primary Sjögren's syndrome: study protocol for a prospective case series and pre-preliminary results

Background and objectives: Sjogren's syndrome (SS) is a chronic progressive autoimmune disease. The incidence of peripheral nervous system damage in patients with primary SS (pSS) is 10–30%. Previous studies have shown that there are multiple electrophysiological manifestations in pSS patients presenting with peripheral neuropathy. However, there is no consensus on its neuroelectrophysiological manifestations. Peripheral neuropathy associated with pSS is easily confused with peripheral neuropathy of other etiologies. We hope to observe the neuroelectrophysiological manifestations of peripheral neuropathy associated with pSS to assist in the diagnosis of the disease. Design: A prospective case series. Methods: A total of 100 pSS patients with peripheral neuropathy receiving treatment in the Department of Neurology, First Affiliated Hospital of Kunming Medical University, China will be included in this study. Fifty-two patients presenting with peripheral neuropathy associated with pSS have been included in a preliminary investigation. Outcome measures and preliminary results: The primary outcome measure is the incidence of abnormal motor nerve conduction velocity in these patients. The secondary outcome measures are the incidences of abnormalities in terminal motor latencies, compound muscle action potential amplitudes, sensory nerve conduction velocities, sensory nerve action potential amplitudes, F waves, and sympathetic skin responses. The results of 52 patients included in the preliminary study showed that the incidences of each electrophysiological index was similar between the upper and lower extremities. Abnormal motor nerve conduction velocity occurred more frequently than abnormal compound muscle action potential amplitude. Abnormal sensory nerve conduction velocity was observed significantly more often than abnormal sensory nerve action potential amplitude. Abnormal motor nerve conduction velocity had a similar incidence to abnormal sensory nerve conduction velocity. Abnormal compound muscle action potential amplitude had a similar incidence to abnormal sensory nerve action potential amplitude. Abnormal F waves were observed significantly less frequently than abnormal motor nerve conduction study. Abnormal sympathetic skin response was seen with a similar incidence to abnormal motor nerve conduction study. Discussion: The results of this study, as indicated by the preliminary investigation, will reveal the neuroelectrophysiological abnormalities in peripheral neuropathy associated with pSS, which will aid diagnosis of the disease. Ethics and dissemination: This study was approved by Medical Ethics Committee of Kunming Medical University of China on October 14 th , 2005 (approval No. 20051014). The study protocol was designed in September 2016 and registered in April 2018. The study protocol received ethics approval from Medical Ethics Committee of Kunming Medical University of China on October 14 th , 2016 (approval No. 2016101411). Patient recuritment for the preliminary study was performed during January to October 2017. Patient recuritment for this study will begin in June 2018. Data collection will end in December 2020. The current study will be performed from June 2018 to December 2020. Results will be disseminated through presentations at scientific meetings and/or by publication in a peer-reviewed journal. Anonymized trial data will be published at www.figshare.com . Trial registration: This trial was registered with the Chinese Clinical Trial Registry (registration number: ChiCTR1800015669).

Analysis of the clinical and electrophysiological characteristics of multifocal motor neuropathy

Ten patients diagnosed with multifocal motor neuropathy (MMN) were recruited in the Department of Neurology at Chinese PLA General Hospital from January 1, 2009 to August 31, 2015. The clinical and electrophysiological features were analyzed retrospectively. All patients complained of progressive asymmetric limb weakness, which was more severe in distal than in proximal. Five presented muscle atrophy. None had sensory disturbances. All suffered diminished or disappeared tendon reflex, whereas Babinski signs were negative. Multi-focal conduction block (CB) was confirmed by nerve conduction studies (NCS) in all patients and 7 showed spontaneous potentials in needle electrode electromyography. Abnormal sensory nerve conduction was seen in 3 patients. Laboratory test revealed anti-ganglioside GM1 antibody in cerebrospinal fluid (CSF) in 6 cases and elevated CSF protein in 7 cases. Limb weakness alleviated greatly in 9 cases after intravenous immunoglobulin (IVIg) treatment. But the other one reported poor response, who had long course of disease, serious limb weakness and obvious muscle atrophy. Motor nerve damage is the most important manifestation of MMN and sensory nerve damage may also appear. NCS is essential to the diagnosis of this disease, with CB as the characteristic electrophysiological feature. IVIg is an effective treatment.

An analysis of characteristics of nerve conduction in 154 cases of amyotrophic lateral sclerosis

Objective: To analyze the features of nerve conduction in patients with amyotrophic lateral sclerosis (ALS), and explore the correlation between compound muscle action potential (CMAP) amplitude and disease duration and revised amyotrophic lateral sclerosis functional rating scale (ALSFRS-R). Methods: Standard motor and sensory nerve conduction studies were performed in 154 patients with ALS. The following parameters were collected including CMAP amplitude, distal motor latency (DML), motor conduction velocity, sensory conduction velocity and sensory nerve action potential amplitude. Regression study was done to explore the correlation between CMAP amplitude and disease duration and ALSFRS-R. Results: Motor nerve conduction abnormalities were presented in a majority of the patients with prolonged DML in the tibial nerve, median nerve and ulnar nerve as the most common form (61.06%-81.42%), followed by decreased CMAP amplitude (30.12%-53.98%), decreased MCV (12.05%-16.81%) and absence of CMAP (2.65%-9.73%). Sensory nerve conduction abnormalities were detected in a small proportion of patients and the decreased SCV, decreased SNAP amplitude and absence of SNAP in the sural nerve, median nerve and ulnar nerve were found in 1.22%-2.73%, 0-1.82% and 0-1.22% patients respectively. No correlation was found between CMAP of the common peroneal nerve, tibial nerve, median nerve and ulnar nerve and the disease duration (P>0.05), while significant positive correlation was established between CMAP amplitude of the median nerve and ulnar nerve and ALSFRS-R (r=0.273, P=0.016; r=0.357, P=0.001). Conclusions: Motor nerve conduction is abnormal in a majority of ALS patients with prolonged DML as the most common form, while abnormal sensory nerve conduction is only found in a few of ALS patients. CMAP amplitude of the median nerve and ulnar nerve might be of certain clinical value in evaluating the severity of ALS.

1-P-D-5. Anti-GT1a antibody characteristics in Miller Fisher syndrome with or without sensory nerve conduction abnormalities

To clarify the immunological and clinical features, the antibody specificities were analyzed in Miller Fisher syndrome (MFS) with and without sensory nerve conduction abnormalities. Anti-ganglioside antibodies and anti-ganglioside complex (GSC) antibodies coordinated with GT1a were analyzed in 17 MFS patients. Clinical features including the nerve conduction study results were also reviewed. All 17 MFS patients (median age, 52 years [10 men and 7 women]) had ophthalmoparesis, ataxia, and decreased tendon reflexes. 9 of 17 of the patients presented one or more nerves with abnormal sensory conduction in the median, ulnar or sural nerves. Anti-GQ1b and anti-GT1a antibodies were detected in 13 and 10 patients, respectively. Anti-GSC antibodies were detected in 8. All of 9 patients with abnormal sensory conduction had anti-GQ1b or -GT1a antibodies. In 8 patients with normal sensory conduction, 5 had anti-GQ1b or -GT1a antibodies. Anti-GT1a/GA1 complex antibody was frequent in patients with normal sensory conduction compared with the patients with abnormal sensory conduction. In 9 of 10 patients with anti-GT1a antibody, the activity of the antibodies to GT1a was higher than those to GSC. In MFS, the antibody with strong specificity to GT1a can be correlated with sensory nerve conduction abnormalities.

An electrophysiological classification associated with Guillain-Barré syndrome outcomes.

Guillain-Barré syndrome (GBS) is an acute, post-infectious, inflammatory, autoimmune peripheral neuropathy with a highly diverse clinical course and outcome. We classified GBS on the basis of patients' first nerve conduction and validated this system to be associated with outcome on the basis of electrophysiological characteristics during the acute phase of GBS. We retrospectively evaluated 40 GBS patients who underwent their first electrophysiological study within 14 days of onset and classified GBS into four patterns: (1) acute inflammatory demyelinating polyneuropathy (AIDP) pattern with sensory nerve conduction abnormalities (motor-sensory AIDP: MS-AIDP), (2) AIDP pattern without sensory nerve conduction abnormalities (motor AIDP: M-AIDP), (3) acute motor axonal neuropathy (AMAN) pattern, and (4) minor abnormalities pattern. We compared the clinical, electrophysiological, and laboratory findings between groups and determined subgroups associated with poor outcome. The MS-AIDP and AMAN patterns more frequently exhibited prolonged recovery compared with the M-AIDP and minor abnormalities patterns and were associated with prolonged recovery (specificity, 100%; sensitivity, 73%; P < 0.001). The period of inability to walk independently was significantly longer in the MS-AIDP and AMAN patterns than in the M-AIDP and minor abnormalities patterns (median 85 vs. 10 days; P < 0.001). In conclusion, our classification of GBS using a single nerve conduction study in the early phase of disease is associated with outcomes. This classification can be used to counsel individual patients and guide decision-making with respect to treatment.

Antidromic sensory nerve conduction study of the digital branches of the medial plantar nerve: A novel method to detect early diabetic sensory axonal polyneuropathy

Distal sensory neuropathy is the most common form of diabetic neuropathy. We developed a novel antidromic technique for assessment of distal nerve function for early diagnosis of diabetic neuropathy. Diabetic and control groups underwent standard and more distal sensory nerve conduction studies (NCS); sensory nerve action potentials (SNAPs) of the proper digital branches of the medial plantar nerve were recorded with our method after stimulation at the sole and recording from digits I and II. Comparison between controls and diabetics showed a statistically significant difference in mean SNAP amplitudes for all nerves tested. A higher percentage of abnormal SNAPs was obtained with our technique than with either conventional or more distal NCS in all patients. As compared with clinical evaluation and other NCS, our antidromic stimulation was the most sensitive method to detect abnormal sensory nerve conduction in symptomatic and asymptomatic diabetic patients.

Second lumbrical-interossei nerve test predicts clinical severity and surgical outcome of carpal tunnel syndrome

The purpose of this study was to examine the utility of the second lumbrical-interossei nerve (2L-IN) test in the diagnosis of carpal tunnel syndrome (CTS). We examined 65 patients with suspected unilateral CTS using the 2L–IN test, in addition to the standard electrophysiological test. The operative cases were divided into three classes of severity based on Padua’s neurophysiological classification: extreme CTS (absence of median motor and sensory response); severe CTS (absence of sensory response, abnormal distal motor latency [DML]); and moderate CTS (abnormal sensory nerve conduction velocity, abnormal DML). With the 2L-IN test, the extreme CTS group could be further subdivided into extreme CTS-A (both abductor pollicis brevis [APB]- compound muscle action potential [CMAP] and 2L-CMAP not recordable) and extreme CTS-B (2L-CMAP recordable, APB-CMAP not recordable). Patients with extreme CTS and severe CTS were older, had chronic symptoms, and poorer outcome compared with the moderate CTS patients. Patients of the moderate CTS group were almost all satisfied with the results of surgery. The electrodiagnostic severity correlated with the clinical outcome. Severe strangulation of the thenar muscle branch was identified in patients in the extreme CTS-B group, requiring decompression of the thenar muscle branch rather than conventional simple transverse ligament detachment.

Patterns of sensory nerve conduction abnormalities in Fisher syndrome: More predominant involvement of group Ia afferents than skin afferents

ObjectiveTo elucidate the features of sensory nerve involvement in Fisher syndrome (FS), this study extensively investigated sensory electrophysiology. MethodsIn 47 consecutive FS patients, results of sensory nerve conduction studies in the median, ulnar and sural nerves, soleus H-reflexes, and median or tibial somatosensory-evoked potentials (SEP) were reviewed. Because of the large effects of age on amplitude of sensory nerve action potentials (SNAP), we strictly defined reduction of SNAP amplitudes by using a nomogram which age and amplitude obtained from 87normal subjects. ResultsIn routine nerve conduction studies, SNAP amplitude was reduced only in 32% of the patients, and conduction velocity was decreased in 2%. In contrast, soleus H-reflexes were frequently absent or reduced (67%). SEPs were abnormal only in 17%. ConclusionsIn FS, absent soleus H-reflexes are the most frequent electrophysiologic abnormalities, whereas SNAPs amplitudes are rarely affected. The pattern is characterized by predominant involvement of group Ia afferents with relatively preserved cutaneous afferents without evidence suggestive of demyelination. SignificanceThe major targets of immune attack by anti-GQ1b antibodies in FS appear to be group Ia neurons in the dorsal root ganglia, and this is presumably responsible for ataxia and areflexia in FS.

Neuropathies associated with oxaliplatin therapy

Neuropathies associated with oxaliplatin therapy

An analysis of the electrophysiological characteristics of entrapment neuropathy

Objective To investigate the electrophysiological characteristics of carpal tunnel syndrome (CTS) and CTS-associated cervical spondylotic radiculopathy (CSR),and to examine the relationship between CTS and CSR. Methods The clinical characteristics and electrodiagnostic features of 81 patients with CTS and 20 patients with both CTS and CSR (the double crush,DC) were analyzed and compared.The data were analyzed according to the severity of the deficit in median nerve conduction using electromyography. Results The 81 patients with CTS had 123 median nerves with abnormal conduction (39 cases with unilateral abnormalities and 42 cases with bilateral abnormalities).The 20 patients with DC had 31 median nerves with abnormal conduction (9 cases with unilateral abnormalities and 11 cases with bilateral abnormalities).The rate of abnormal sensory nerve conduction velocity (SCV) was 100％ in C6 and C7 level radiculopathies.The rate of abnormal distal motor latency (DML) was 92.31％ in C5 level radiculopathies.There was a statistically significant difference between CTS and DC in the rate of abnormal SCV from the middle finger to the wrist.The other electrodiagnostic data were not significantly different between the CTS and DC patients.Neurophysiological tests were used to grade CTS into categories according to the American Association of Electrodiagnostic Medicine's criteria,but there was no statistically significant difference between CTS and DC. Conclusions CSR lesions on a proximal nerve root may cause the nerve to be more susceptible to distal injury and increase the risk of CTS.The findings support the DC hypothesis,but DC on a median nerve did not result in more severe injury than a single crush. Key words: Carpal tunnel syndrome; Cervical spondylotic radiculopathy; Double crushing; Electromyography

Wld S protects against peripheral neuropathy and retinopathy in an experimental model of diabetes in mice

We aimed to evaluate the effect of the mutant Wld(S) (slow Wallerian degeneration; also known as Wld) gene in experimental diabetes on early experimental peripheral diabetic neuropathy and diabetic retinopathy. The experiments were performed in four groups of mice: wild-type (WT), streptozotocin (STZ)-induced diabetic WT, C57BL/Wld(S) and STZ-induced diabetic C57BL/Wld(S). In each group, intraperitoneal glucose and insulin tolerance tests were performed; blood glucose, glycated haemoglobin and serum insulin were monitored. These mice were also subjected to the following behavioural tests: grasping test, hot-plate test and von Frey aesthesiometer test. For some animals, sciatic-tibial motor nerve conduction velocity, tail sensory nerve conduction velocity and eye pattern electroretinogram were measured. At the end of the experiments, islets were isolated to detect glucose-stimulated insulin secretion, ATP content and extent of apoptosis. The NAD/NADH ratio in islets and retinas was evaluated. Surviving retinal ganglion cells were estimated by immunohistochemistry. We found that the Wld(S) gene is expressed in islets and protects beta cells against multiple low doses of STZ by increasing the NAD/NADH ratio, maintaining the ATP concentration, and reducing apoptosis. Consistently, significantly higher insulin concentrations, lower blood glucose concentrations, and better glucose tolerance were observed in Wld(S) mice compared with WT mice after STZ treatment. Furthermore, Wld(S) alleviated abnormal sensory responses, nerve conduction, retina dysfunction and reduction of surviving retinal ganglion cells in STZ-induced diabetic models. We provide the first evidence that expression of the Wld(S) gene decreases beta cell destruction and preserves islet function in STZ-induced diabetes, thus revealing a novel protective strategy for diabetic models.

Motor Root Conduction Block in the Lewis-Sumner Syndrome

The Lewis-Sumner syndrome (LSS) is a rare immune-mediated peripheral nerve disorder presenting with asymmetric upper limb sensory complaints and motor weakness. Asian patients with LSS have not been reported in the English literature. Three Asian patients with features of LSS were prospectively studied. Our patients tended to older, female, and have involvement of the upper limbs exclusively than those in the West. They have a markedly longer disease duration before a diagnosis was made, which could also be the result of difficulty in eliciting motor root conduction block as a sign of proximal demyelination as observed in every patient. Pain is a universal feature as is sensory nerve conduction abnormality. None responded to immunotherapy, but disease stabilization was observed over the chronic course. Although rare, these unique observations in Asian patients with LSS differ from those reported in Western literature. The presence of motor root conduction block demonstrated for the first time is instrumental in establishing a diagnosis.