Kei Fukada

The efficacy of trientine or ascorbate alone compared to that of the combined treatment with these two agents in familial amyotrophic lateral sclerosis model mice

One of the hypotheses regarding the pathogenesis of familial ALS (FALS) is a copper-mediated oxidative toxicity derived from the mutant Cu, Zn-superoxide dismutase (SOD1). We have previously demonstrated the efficacy of the combined treatment with a copper chelator (trientine) and an antioxidant (ascorbate) on the disease expression of the FALS-linked mutated SOD1 transgenic mice. Here, we investigated the efficacy of trientine or ascorbate alone on FALS mice when administered before or after the onset of the disease. The mice with a high dose of trientine or ascorbate administered before the onset survived significantly longer than the control. In the combined treatment with a high dose of trientine and ascorbate initiated before the onset, survival lengthened and the motor function of the mice remained more significantly than the control. None of the treatments affected the mean age of the onset, and none of the agents administered after the onset prolonged survival. These findings suggest that better outcomes may be expected by the administration of these agents at the preonset stage of the disease, and the combination of the agents acting on different sites might be useful in preserving the motor performance in FALS.

Stabilization of mutant Cu/Zn superoxide dismutase (SOD1) protein by coexpressed wild SOD1 protein accelerates the disease progression in familial amyotrophic lateral sclerosis mice

Transgenic mice carrying familial amyotrophic lateral sclerosis (FALS)‐linked mutant Cu/Zn superoxide dismutase (SOD1) genes such as G93A (G93A‐mice) and G85R (G85R‐mice) genes develop limb paresis. Introduction of human wild type SOD1 (hWT‐SOD1) gene, which does not cause motor impairment by itself, into different FALS mice resulted in different effects on their clinical courses, from no effect in G85R‐mice to acceleration of disease progression in G93A‐mice. However, the molecular mechanism which causes the observed difference, has not been clarified. We hypothesized that the difference might be caused by the stability of mutant SOD1 proteins. Using a combination of mass spectrometry and enzyme‐linked immunosorbent assay, we found that the concentration of G93A‐SOD1 protein was markedly elevated in tissues of transgenic mice carrying both G93A‐ and hWT‐SOD1 genes (G93A/hWT‐mice) compared to that in G93A‐mice, and also found that the concentration of G93A‐SOD1 protein had a close relation to the disease duration. The concentration of metallothionein‐I/II in the spinal cord, reflecting the degree of copper‐mediated oxidative stress, was highest in G93A/hWT‐mice, second in G93A‐mice, and normal in the mice carrying hWT‐SOD1 gene. These results indicated that the increase of G93A‐SOD1 protein was responsible for the increase of oxidative stress and disease acceleration in G93A/hWT‐mice. We speculate that coexpression of hWT‐SOD1 protein is deleterious to transgenic mice carrying a stable mutant such as G93A‐SOD1, because this mutant protein is stabilized by hWT‐SOD1 protein, but not to transgenic mice carrying an unstable mutant such as G85R‐SOD1, because this mutant protein is not stabilized by hWT‐SOD1.

Rapid disease progression correlates with instability of mutant SOD1 in familial ALS.

Studies on the clinical course of familial ALS suggest that the duration of illness is relatively consistent for each mutation but variable among the different mutations. The authors analyzed the relative amount of mutant compared with normal SOD1 protein in the erythrocytes from 29 patients with ALS with 22 different mutations. Turnover of mutant SOD1 correlated with a shorter disease survival time.

Identification of two novel mutations in the Cu/Zn superoxide dismutase gene with familial amyotrophic lateral sclerosis: mass spectrometric and genomic analyses.

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disorder affecting motor neurons. The majority of patients are sporadic cases, while 5-10% of the patients have a family history of ALS (fALS). Mutations in the gene that encodes cytoplasmic Cu/Zn superoxide dismutase (SOD1) have been identified in about 25% of fALS cases. Although the precise pathogenesis of ALS is still unknown, experimental studies including animal models suggest that fALS is caused by the toxic gain-of-function of the SOD1 mutant. We have analyzed not only SOD1 gene mutation by genomic sequencing, but also SOD1 mutant protein by liquid chromatography-electrospray ionization-mass spectrometry (LC-ESI-MS). We analyzed 33 fALS patients and found 10 mutations in SOD1 gene, in which two were novel: Asp101His substitution in exon 4 and Gly141Glu substitution in exon 5. Here, we present their mass spectrometric protein analyses and clinical features.

Exome sequencing reveals a novel MRE11 mutation in a patient with progressive myoclonic ataxia

Progressive myoclonic ataxia (PMA) is a clinical syndrome defined as progressive ataxia and myoclonus and infrequent seizures in the absence of progressive dementia. Due to the extremely heterogeneous nature of PMA, a large proportion of PMA cases remain molecularly undiagnosed. The aim of this study was to clarify the molecular etiology of PMA. The patient was a 52-year-old female from consanguineous parents. She developed a jerking neck movement at age 9, which gradually expanded to her entire body. On physical examination at age 47, she exhibited generalized, spontaneous myoclonus that occurred continuously. She also presented with mild limb and truncal ataxia. An electroencephalogram revealed no abnormalities. A brain MRI displayed no atrophy of the cerebellum. Electrophysiological studies suggested myoclonus of a subcortical origin. For further evaluation, we performed exome sequencing, and we identified a novel homozygous missense mutation in the MRE11 gene (NM_005590:c.140C>T:p.A47V). Subsequently, we analyzed the expression of MRE11 and related proteins (RAD50 and NBS1) via Western blot, and they were markedly decreased compared to a healthy control. Mutations in the MRE11 gene have been known to cause an ataxia-telangiectasia-like (ATLD) disorder. Accumulating evidence has indicated that its wide phenotypic variations in ATLD correspond to genotypic differences. Interestingly, our case exhibited a relatively mild decrease in NBS1 compared to previously reported cases of a homozygous missense mutation, which may account for the milder phenotype in this patient. Moreover, together with a recently reported case of an MRE11 mutation, it is suggested that MRE11 mutations can present as PMA.

A quantitative characterization of postural sway during human quiet standing using a thin pressure distribution measurement system

The accuracy of the center of pressure (CoP) measurement during human quiet standing using an ultra-thin film pressure measurement system (Tekscan, I-Scan) was examined. To this end, CoP sway was measured simultaneously by I-Scan and a force platform (FP) to quantify differences in CoP obtained by the two methods. The sway amplitudes of I-Scan were slightly smaller than those of FP. The differences were systematic, allowing us to identify a filter that could bring every CoP trajectory of I-Scan close to that of FP. We concluded that, with the use of the filter, I-Scan could be used for accurate measurement of CoP sway during quiet standing.

Porphyria with double errots in the heme biosynthetic pathway

Sirs: We report a patient with a rare combination of hereditary coproporphyria (HCP) and a partial δ-aminolevulinate dehydratase (ALAD) deficiency who developed an acute attack of porphyria during the course of viral encephalitis. A 21-year-old woman began to suffer from headache and fever up to 38°C. Six days later she developed generalized tonic-clonic seizures. Cranial computed tomography revealed generalized oedema, and electroencephalography showed intermittent spikes mainly in the right temporal region. She was treated with diazepam and phenobarbital but continued to have seizures for 2 days and lapsed into generalized status epilepticus. Cerebrospinal fluid revealed a mild pleocytosis and an increase in the herpes simplex type 1 virus antibody titre. As the treatment with acyclovir, phenytoin and glycerol did not control her seizures, continuous injection of anaethetics under controlled mechanical ventilation was adopted for 2 months. After waning from general anaesthesia, frequent generalized seizures persisted in spite of the treatment with several anticonvulsants (sodium valproate 800 mg, carbamazepine 800 mg, and phenytoin75 mg daily). When transferred to our hospital 1 year after the onset of encephalitis, she was hypertensive (154/120 mmHg), tachycardiac (104/min), and had tetraparesis and hyper-reflexia with severe muscle weakness and pains in the distal part of the lower legs. She showed poor verbal response and emotional lability. Complex partial seizures occurred at least once a day. A nerve conduction study indicated the presence of motor-dominant peripheral polyneuropathy. Laboratory blood tests showed hepatic dysfunction. Porphyria was suspected from her clinical manifestations and unusual responses to anticonvulsants at the previous hospitals. We tested both urine and faeces for porphyrins, and the results were positive. Although intravenous heme treatment and newer types of anticonvulsants including gabapentin and vigabatrin [4] were considered, these treatments are not authorized by the Japanese health insurance system. We therefore tried discontinuation of phenytoin, reduction in carbamazepine, and initiation of clonazepam. The modification in the regimen caused a decline in the frequency of her seizures and marked improvement in her mental state. The gastrointestinal symptoms, leg pain, hypertension, tachycardia, and liver dysfunction disappeared. Further family analyses for porphyria were carried out according to the well established methods (Tables 1, 2) [6, 7, 10, 13]. In brief, porphyrins were extracted from urine, faeces and erythrocytes, and separated into isomeric types by reverse-phase high-performance liquid chromatography (HPLC). The ALAD activity in erythrocytes was measured in the presence and absence of dithiothreitol [10] to assess the inhibition of the enzyme by intrinsic chemicals that can be completely reactivated by the addition of dithiothreitol. Porphobilinogen deaminase activity was LETTER TO THE EDITORS

The Motor Unit Number Index of Subclinical Abnormality in Amyotrophic Lateral Sclerosis

Purpose: Diagnosis of amyotrophic lateral sclerosis (ALS) at an early stage is challenging, thus making the enrollment of these patients in clinical trials infeasible. In this study, we investigated the potential usability of motor unit number index (MUNIX) to detect denervation of clinically intact muscles of ALS patients. Methods: Thirty-two first dorsal interosseous muscles of 26 ALS patients were evaluated with both MUNIX and needle electromyography. Results: The mean MUNIX value of first dorsal interosseous muscles was 131 in the control group, whereas it was 48, 34, 15, and 8 for Medical Research Council scales of 5, 4, 3, and 2, respectively, in the ALS patients. The optimal cutoff point gave a sensitivity of 0.89 and a specificity of 1.0. Among 9 intact first dorsal interosseous muscles of the ALS patients, 8 showed MUNIX values below the cutoff point, whereas only 2 first dorsal interosseous muscles showed denervation on needle electromyography. Conclusions: MUNIX could serve as a sensitive technique to detect denervation of clinically intact muscles of ALS patients.

Characterizing Postural Sway during Quiet Stance Based on the Intermittent Control Hypothesis

This article illustrates a signal processing methodology for the time series of postural sway and accompanied electromyographs from the lower limb muscles during quiet stance. It was shown that the proposed methodology was capable of identifying the underlying postural control mechanisms. A preliminary application of the methodology provided evidence that supports the intermittent control hypothesis alternative to the conventional stiffness control hypothesis during human quiet upright stance.

A case of chronic inflammatory demyelinating polyradiculoneuropathy presenting recurrent attacks associated with pregnancies

At 37 years of age, the patient initially presented with symptoms of chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) during her 1st pregnancy. She was treated with intravenous immunoglobulin (IVIg), and showed favorable recovery, becoming almost asymptomatic by the age of 38. At 39 years of age, during her puerperal period of her second pregnancy, she developed symmetrical muscle weakness and sensory disturbance of the upper and lower limbs. Nerve conduction studies revealed diffuse demyelination of peripheral nerves, and she was diagnosed with recurrence of CIDP. Once again, she showed remarkable improvement after IVIg therapy, and she has remained asymptomatic without the induction of preventative therapies. Recurrence of CIDP triggered in accordance with multiple pregnancies is extremely rare, and its clinical and electrophysiological features are presented in this report.