Yukitoshi Ishikawa

Duchenne muscular dystrophy: survival by cardio-respiratory interventions.

We describe survival in Duchenne dystrophy by invasive and noninvasive ventilation vs. untreated. Patients were untreated prior to 1984 (Group 1), underwent tracheotomy from 1984 until 1991 (Group 2), and were managed by noninvasive mechanical ventilation and cardioprotective medications subsequently (Group 3). Symptoms, vital capacity, and blood gases were monitored for all and spirometry, cough peak flows, carbon dioxide tension, and oximetry for Group 3. Sleep nasal ventilation was initiated for symptomatic hypoventilation. An oximeter and mechanical cough assistance were prescribed for maximum assisted cough peak flow <300 L/m. Patients used continuous noninvasive ventilation and mechanically assisted coughing as needed to maintain pulse oxyhemoglobin saturation ≥95%. Survival was compared by Kaplan-Meier analysis. The 56 of Group 1 died at 18.6±2.9, the 21 Group 2 at 28.1±8.3 years of age with three still alive, and the 88 using noninvasive ventilation had 50% survival to 39.6 years, p<0.001, respectively. We conclude that noninvasive mechanical ventilation and assisted coughing provided by specifically trained physicians and therapists, and cardioprotective medication can result in more favorable outcomes and better survival by comparison with invasive treatment.

Oligonucleotides against a splicing enhancer sequence led to dystrophin production in muscle cells from a Duchenne muscular dystrophy patient

Yasuhiro Takeshima, Hiroko Wada, Mariko Yagi, Yukitoshi Ishikawa, Yuka Ishikawa, Ryoji Minami, Hajime Nakamura, Masafumi Matsuo* Department of Pediatrics, Kobe University Graduate School of Medicine, 7-5-1 Kusunokicho, Chuoku, Kobe 650 0017, Japan Division of Molecular Medicine, Kobe University Graduate School of Medicine, 7-5-1 Kusunokicho, Chuoku, Kobe 650 0017, Japan Department of Pediatrics, National Yakumo Hospital, 128 Miyazonocho, Yakumocho, Hokkaido 049 3198, Japan

Beneficial effects of beta-blockers and angiotensin-converting enzyme inhibitors in Duchenne muscular dystrophy.

BACKGROUND Patients with Duchenne muscular dystrophy (DMD) often have severe heart failure with a high mortality rate. Most DMD patients with cardiomyopathy became symptomatic in their early to middle teens and usually die of congestive heart failure within 2-3 years from the onset of symptoms. It has been reported that the combination of an angiotensin-converting enzyme (ACE) inhibitor and a beta-blocker has additive benefits in patients with heart failure. The aim of this study was to assess whether the combination of an ACE inhibitor and a beta-blocker is associated with long-term survival of DMD patients with left ventricular (LV) dysfunction. METHODS We retrospectively analyzed the outcomes of 52 DMD patients who had begun treatment for heart failure with an ACE inhibitor and a beta-blocker at National Yakumo Hospital during the period from 1992 to 2005. All patients used wheelchairs in their daily lives. Patients were classified as symptomatic or asymptomatic at the initiation of treatment with these two drugs. Twelve patients who had already had apparent symptoms due to heart failure were enrolled in a treatment group. Forty patients who had no symptoms with reduced LV ejection fraction (≤ 45% in echocardiography) were enrolled in a prevention group. RESULTS Five-year and 7-year survival rates of all patients were 93 and 84%, respectively. In the treatment group, 5-year and 7-year survival rate were 81 and 71%, respectively. Survival rate became zero at 10.9 years. In the prevention group, 5-year and 7-year survival rates were 97 and 84%, respectively, and 10-year survival rate was 72%. Nine patients in the prevention group remained event-free over 10 years. CONCLUSIONS In this study, the combination of an ACE inhibitor and a beta-blocker had a beneficial effect on long-term survival of DMD patients with heart failure. The treatment was particularly effective for asymptomatic patients with LV dysfunction.

Occurrence of ceramide-glycanase in the earthworm, Lumbricusterrestris

We have detected the presence of ceramide-glycanase in the earthworm, Lumbricus terrestris. We have also devised a simple method for the preparation of this enzyme from the earthworm. This enzyme cleaved the linkage between the ceramide and the glycan chain in LacCer, GbOse3Cer, GbOse4Cer, GbOse5Cer, GM3, GM2, GM1 and GD1a. By using tritium-labeled GM2 as substrate, the optimum pH of this enzyme was found to be between pH 4 and 4.5. In the earthworm, the ceramide-glycanase was mainly found in the muscle. The intestine was found to contain a very low level of this enzyme. Because of their easy availability, earthworms should become a convenient source for the preparation of ceramide-glycanase.

Rett syndrome: findings suggesting axonopathy and mitochondrial abnormalities

We report the histopathologic findings of 3 sural nerve biopsies and 1 muscle biopsy from 3 patients with Rett syndrome. The 3 sural nerve biopsies demonstrated a few ultrastructural abnormalities, including the presence of many Pi-granules and mitochondrial changes in the cytoplasm of Schwann cells, occasional bands of Büngner and onion-bulb formations, and mitochondrial alterations in myelinated axons. Morphometric analysis disclosed reduction in the number of large myelinated fibers with normal densities in comparison to those of an age-matched normal control. Light microscopic examination of the biopsied muscle from a 6-year-old patient with Rett syndrome revealed the existence of many small, dark, angulated fibers with NADH-TR staining. Ultrastructural investigation of the muscle confirmed the presence of the dumbbell-shaped mitochondria. Peripheral nerve involvement and the possibility of mitochondrial abnormalities in Rett syndrome were suggested by the results.

Biochemical Basis of Type AB GM2 Gangliosidosis in a Japanese Spaniel

Abstract: The biochemical basis of a case of GM2 gangliosidosis in a Japanese Spaniel was studied. This dog had a massive accumulation of GM2 ganglioside in the brain. The β‐hexosaminidase activity in this affected dog brain was ∼ 12 times higher than that of normal brain. However, the activity toward p‐nitrophenyl‐6‐sulfo‐2‐acetamido‐2‐de‐oxyglucopyranoside was only four times higher in the affected brain than in normal brain. The GM2 activator preparation obtained from the normal dog brain could stimulate the hydrolysis of GM2 ganglioside by β‐hexosaminidase isolated from the affected dog. However, the corresponding activator fraction from the affected dog could not stimulate such a reaction. It was concluded that the biochemical basis of the Gm2 gangliosidosis in this Japanese Spaniel was due to the attenuation in the stimulatory activity of GM2 activator. This case represents the first animal form similar to the activator deficiency (or defect) of Type AB GM2 gangliosidosis in humans.

Amino‐terminal deletion of 53% of dystrophin results in an intermediate Duchenne‐Becker muscular dystrophy phenotype

We report a Japanese boy with muscular dystrophy whose clinical symptoms were intermediate between those usually considered typical of Duchenne and Becker muscular dystrophies. The patient had a large inframe deletion extending from exons 3 to 41 of the dystrophin gene, which would be expected to cause the production of a dystrophin protein composing only 53% of the normal polypeptide chain. Such an inframe deletion would be expected to cause Becker muscular dystrophy. We did not obtain evidence for alternative splicing or for RNA editing. Immunocyto-chemical analysis of skeletal muscle showed that a dystrophin-related polypeptide was detectable with antibody directed against the carboxyl-terminal part of the polypeptide but not with antibodies directed against the amino-terminal part, although labeling by antibody against the carboxyl-terminal was faint and patchy. The severity of the disease in this case may be due to the lack of the amino-terminal, actin-binding domain of dystrophin.

Indicators for ventilator use in Duchenne muscular dystrophy

BACKGROUND Noninvasive mechanical ventilation is being used up to continuously by patients with Duchenne muscular dystrophy (DMD). Invasive and noninvasive tests are used to assess ventilatory function but there are few reports relating them to extent of ventilator dependence for which simple and cost effective parameters are needed. OBJECTIVE To investigate the relative efficacy of noninvasive lung function parameters for determining extent of need for ventilator use. MATERIALS AND METHODS 83 DMD patients were divided into three groups: no ventilator use (asymptomatic) (n = 26) [Group 1], nocturnal ventilator use (symptomatic) (n = 20) [Group 2], and full-time ventilator dependence (n = 37) [Group 3]. Tidal volume (TV), vital capacity (VC), respiratory rate (RR), inspiratory time (Ti), respiratory cycle time (Ttot), rapid shallow breathing index (RSBI [RR/TV]), breathing intolerance index (BITI), ventilator requirement index (VRI) and a new parameter RR/VC were monitored and compared. Data were analyzed with receiver-operating-characteristic curves (ROC) and the area under the curve (AUC) was calculated. RESULTS In group 2 and 3, patients used NIV for 3.3 ± 2.1 and 11.2 ± 4.7 years, respectively. By ROC comparison, RR/VC (RR/VC ≥ 0.024 [AUC, 0.921] and ≥0.071 [AUC, 0.935]), RR/TV (RR/TV ≥ 0.024 [AUC, 0.905] and ≥0.153 [AUC, 0.905]), and VC (VC ≤ 770 ml [AUC, 0.896] and ≤370 ml [AUC, 0.898]) represented to introduce nocturnal and continuous ventilator use, respectively. TV/VC, BITI, and VRI were either less sensitive or less specific. CONCLUSIONS Lung function parameters including RR/VC, RR/TV, and VC are useful and inexpensive in predicting the extent of need for ventilator use. Overall, RR/VC is the most appropriate predictor for determining extent of need for ventilator use.

Proximal and distal motor nerve conduction velocities in Werdnig-Hoffmann disease

Using the latencies of M and F responses, we assessed motor nerve conduction velocity along the entire course of the median and ulnar nerves from the spinal cord to the muscle in 14 patients with the less severe forms of Werdnig-Hoffmann disease. In these forms, the motor nerve conduction velocities were decreased significantly over both proximal (cord-to-elbow) and distal (elbow-to-wrist) segments in both the nerves as compared with normal values; however, the mean motor nerve conduction velocities in the proximal segments were faster than those in the distal segments by about the same amount as the normal controls. These findings indicate that motor conduction abnormalities in Werdnig-Hoffmann disease are diffuse over the entire course of the nerve and appear to eliminate a dying-back process in which the affected axons are severely damaged, beginning with the more distal sites.

Decreased expression of full‐length mRNA for cBCD541 does not correlate with spinal muscular atrophy phenotype severity

Spinal muscular atrophy (SMA) is characterized by degeneration of spinal cord anterior horn cells and muscular atrophy and has three phenotypes based on clinical severity and age of onset. One of the responsible genes for SMA is the survival motor neuron (SMN) gene, which is homozygously absent or interrupted in more than 90% of SMA patients. The cBCD541 (BCD) gene is a highly homologous copy of the SMN gene, which has a single synonymous transition in the coding region and may compensate for the loss of the SMN gene. To evaluate the effects of the BCD gene expression on the phenotypes of SMA, we examined lymphocyte mRNA from 9 SMA patients lacking the SMN gene, 10 asymptomatic parents, and 15 control subjects. We amplified mRNA fragments containing exon 7 of the SMN or BCD genes using reverse transcription-polymerase chain reaction since the transcript lacking exon 7 encodes a putative protein with a different C-terminal end. We used glyceraldehyde-3-phosphate dehydrogenase (GAPDH) transcript as an internal control, and the relative expression level of the SMN or BCD gene was shown as the ratio of SMN or BCD transcript to GAPDH transcript (S/G ratio). The mean S/G ratios of the patients were significantly lower than that of the parents and controls. However, among the patients examined in this study, there was no relationship between the S/G ratios and phenotypes of SMA. The results showed that the BCD gene expression was not related to the phenotypes of SMA. Furthermore, there was an overlap between the S/G ratios in patients and controls. As our discrimination study showed that the S/G ratio reflected the expression of the BCD transcripts in patients and the SMN transcripts in controls, this finding suggested that the BCD gene expression per se does not compensate for the loss of the SMN gene.