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Biomedical subjects

Kenji Sugai

Publications and source records attributed to Kenji Sugai.

At least 19 recordsLinked to original sources

[A case of Möbius syndrome presenting with symptoms of severe infantile form of congenital muscular disorder].

Möbius syndrome is a rare disorder characterized by congenital bilateral facial nerve palsy. Abducent palsy or other cranial nerve palsy, facial malformations, limb malformations, and skeletal malformations are common features associated with this syndrome. We report a 9-month-old infant in whom congenital muscular disorder was previously suspected because of facial muscle involvement (mask-like face), respiratory and swallowing disturbances, and hypotonia since birth. After an improvement in the respiratory infection, she showed slightly exaggerated deep tendon reflexes and an improvement in muscle tone. The occurrence of combined facial nerve palsy, glossopharyngeal nerve palsy, vagus nerve palsy, and hypoglossal nerve palsy strongly suggested that she had Möbius syndrome. Finally, the absence of the roots of bilateral facial nerves on an MRI confirmed that the disorder was Möbius syndrome. We propose that a thin slice MRI should be obtained to observe the cranial nerves around the brain stem if patients show symptoms of congenital myopathy or congenital myotonic dystrophy as well as facial nerve and other cranial nerve paralyses.

Brain Stem↗

Periaxin mutation in Japanese patients with Charcot-Marie-Tooth disease.

Periaxin (PRX) plays an important role in the myelination of the peripheral nerve and consequently in the pathogenesis of Charcot-Marie-Tooth disease (CMT). To date, nine nonsense or frameshift PRX mutations have been reported in eight families with CMT. The patients with PRX mutations appeared to show characteristic clinical features with early onset but slow or no progression, a common result of mutations that lead to missing a C-terminal acidic domain. Here, we report a Japanese CMT patient with these characteristic clinical features, who was a compound heterozygote for PRX R1070X and L132FsX153 mutations. We previously reported that three Japanese isolated families also had the homozygous R1070X mutation. To examine the potential founder effect of the R1070X mutation in the Japanese population, we performed haplotype analysis and found that each R1070X allele lay on a different haplotype background in these four families. Therefore, the high frequency of the R1070X mutation among the Japanese population is not likely the consequence of a founder effect, but probably a result of a mutation hot spot.

Adult↗

Basal ganglia lesions in a patient with 3-hydroxyisobutyric aciduria.

3-hydroxyisobutyric aciduria (3HiB-uria) is a very rare organic aciduria that involves valine metabolism. We report the case of a 7-year-old boy with 3HiB-uria who has suffered more than 20 ketoacidotic episodes since the age of 15 months. In the most recent ketoacidotic episode, which was particularly severe, he developed mild dystonia and choreoathetosis. Magnetic resonance imaging (MRI) revealed bilateral swelling and signal abnormalities of the putamina and heads of the caudate nuclei. The abnormal movements showed a gradual improvement over several months, in correlation with neuroradiological findings. 3HiB-uria should be recognized as one of the group of branched chain organic acidemias that can produce lesions in the basal ganglia.

Basal Ganglia↗

[Pleural effusion associated with long-term dantrolene administration in three patients with severe motor and intellectual disabilities].

Chronic unilateral pleural effusion developed in three patients with severe motor and intellectual disabilities. All patients received 5-15 years of dantrolene administration for their spasticity. The cause of pleural effusion was indistinct, despite close investigations for etiologies such as infection or tumor. The pleural fluid consisted of sterile exudate in all patients. One patient had eosinophilia in his pleural fluid, while peripheral blood eosinophilia was seen in the other two. The pleural biopsy and autopsy specimens revealed only non-specific inflammatory findings. After dantrolene therapy was discontinued, pleural effusion almost disappeared in two patients in the following several months, but the other died of multi-organ failure from another underlying disease. It is important to take chemical pleurisy into consideration when dealing with pleural effusion of unknown etiology. Moreover, respiratory side effect should be examined in patients treated with chronic dantrolene administration.

Adult↗

[Case of 12-year-old boy with idiopathic recurrent neuralgic amyotrophy].

Here we report a 12-year-old boy with idiopathic neuralgic amyotrophy who had two episodes of shoulder pain followed by shoulder muscle atrophy and weakness at the age of 7 and 11 years, respectively. These symptoms were self-limited and disappeared within 9 months. During the second episode, electromyograph (EMG) revealed neurogenic changes in the deltoid muscle. Muscle imaging showed the right deltoid muscle atrophy with slightly high intensity areas on T1 and T2 weighted images in MRI. Muscle biopsy from the right deltoid muscle revealed neurogenic changes with denervating and reinnervating processes. Neuralgic amyotrophy is characterized by neuralgic pain followed by weakness and atrophy at a unilateral extremity and is usually self-limited. EMG and imaging studies showed focal neurogenic abnormalities, which were confirmed by muscle biopsy. Neuralgic amyotrophy usually occurs in young adults and it is very rare in children.

Brachial Plexus Neuritis↗

[Two boys with non-progressive unilateral atrophy of the calf muscles].

We report here two boys who presented with atrophy of the right calf muscle. The onset was insidious and the symptom was found in infancy in case 2. They were followed for more than 5 years and no progression was seen. No sensory disturbances or autonomic nervous system symptoms were observed. Although needle electric myograph and muscle biopsy findings showed a neurogenic pattern, no cause was confirmed. Recently, a new disease concept of "benign monomelic amyotrophy of lower limb" was established and this could be applied to these patients. This disorder is rare and it is seen in young adults. It is characterized by non-progressive unilateral calf muscle atrophy. There is almost no possibility that this disorder is a variant of spinal muscular atrophy. When a patient presents with unilateral calf muscle atrophy, the treatable causes of the atrophy, including spinal cord disorders or peripheral nerve disorders, should be excluded first. If a confirmed cause cannot be found, then there should be a careful follow-up of the patient, even if the symptoms are stable.

Adolescent↗

Complex behavioral automatism arising from insular cortex.

We describe two cases of complex partial seizures with ictal violent movements arising from the insular cortex. The first patient, a 14-year-old girl, presented with hyperkinetic behavior such as rolling, thrashing, and pedaling, and the second case, a 38-year-old woman, had been suffering from frequent daytime hyperkinetic seizures characterized by bizarre vocalization, jumping, and violent bimanual movements. Both patients showed a slight high signal change in the right posterior ventral insular cortex in fluid-attenuated inversion recovery (FLAIR) studies involving magnetic resonance imaging, and extensive subdural electroencephalographic monitoring revealed EEG seizure onset from the temporal lobe. The posterior ventral insular and lateral temporal cortices were resected, resulting in complete seizure freedom in both cases. The histological diagnoses were focal cortical dysplasia in the first case and gliosis in the second case. There may exist a group of patients with complex partial seizures with ictal violent automatism that can be ameliorated by the resection of epileptogenic lesions in the insular cortex. Careful inspection of the insular cortex is necessary to diagnose this type of epileptic seizure.

Adolescent↗

Fluctuating hearing loss, episodic headache, and stroke with platelet hyperaggregability: coexistence of auditory neuropathy and cochlear hearing loss.

We encountered a 10-year-old girl with fluctuating sensorineural hearing loss, episodic headache, and white matter stroke. Strenuous exercise, febrile illness, and general anesthesia all temporarily worsened hearing. Audiologic findings were asymmetric: left-sided retrocochlear dysfunction consistent with auditory neuropathy contrasted with cochlear hearing loss in the right ear. Platelets obtained during a headache-free period showed excessive responsiveness to collagen in vitro, while episodic elevations of thromboxane B(2) and thrombin-antithrombin III complex were noted in blood sampled during headache. Treatment of hyperaggregability of platelets with aspirin and antioxidant vitamins relieved headache, while adenosine triphosphate administration improved hearing thresholds. In this patient, hearing impairment and white matter strokes appeared to respectively related to impaired blood flow to the cochlea and white matter caused by platelet dysfunction triggered by physiologic stresses.

Adenosine Triphosphate↗

Functional characterization of five novel CYP2C8 variants, G171S, R186X, R186G, K247R, and K383N, found in a Japanese population.

Cytochrome P450 2C8 is one of the primary enzymes responsible for the metabolism of a wide range of drugs such as paclitaxel, cerivastatin, and amiodarone. We have sequenced the CYP2C8 gene from 201 Japanese subjects and found five novel nonsynonymous single nucleotide polymorphisms (SNPs): 511G>A (G171S), 556C>T (R186X; X represents the translational stop codon), 556C>G (R186G), 740A>G (K247R), and 1149G>T (K383N), with the allele frequency of 0.0025. The CYP2C8 variants were heterologously expressed in COS-1 cells and functionally characterized in terms of expression level, paclitaxel 6alpha-hydroxylase activity, and intracellular localization. The prematurely terminated R186X variant was undetectable by Western blotting and inactive toward paclitaxel 6alpha-hydroxylation. The G171S, K247R, and K383N variants exhibited properties similar to those of the wild-type CYP2C8. Paclitaxel 6alpha-hydroxylase activity of the R186G transfectant was only 10 to 20% that of wild-type CYP2C8. Furthermore, the R186G variant displayed a lower level of protein expression in comparison to the wild type, which was restored by the addition of a proteasome inhibitor (MG-132; Z-Leu-Leu-Leu-aldehyde). The reduced CO-difference spectral analysis using recombinant proteins from an insect cell/baculovirus system revealed that the R186G variant has a minor peak at 420 nm in addition to the characteristic Soret peak at 450 nm, suggesting the existence of improperly folded protein. These results indicate that the novel CYP2C8 SNPs, 556C>T (R186X) and 556C>G (R186G), could influence the metabolism of CYP2C8 substrates such as paclitaxel and cerivastatin.

Animals↗

Haplotype structures of EPHX1 and their effects on the metabolism of carbamazepine-10,11-epoxide in Japanese epileptic patients.

OBJECTIVE: Microsomal epoxide hydrolase (mEH) is an enzyme that detoxifies reactive epoxides and catalyzes the biotransformation of carbamazepine-10,11-epoxide (CBZ-epoxide) to carbamazepine-10,11-diol (CBZ-diol). Utilizing single nucleotide polymorphisms (SNPs) of the EPHX1 gene encoding mEH, we identified the haplotypes of EPHX1 blocks and investigated the association between the block haplotypes and CBZ-epoxide metabolism. METHODS: SNPs of EPHX1 were analyzed by means of polymerase chain reaction amplification and DNA sequencing using DNA extracted from the blood leukocytes of 96 Japanese epileptic patients, including 58 carbamazepine-administered patients. The plasma concentrations of CBZ and its four metabolites were determined using high-performance liquid chromatography. RESULTS: From sequencing all 9 exons and their surrounding introns, 29 SNPs were found in EPHX1. The SNPs were separated into three blocks on the basis of linkage disequilibrium, and the block haplotype combinations (diplotypes) were assigned. Using plasma CBZ-diol/CBZ-epoxide ratios (diol/epoxide ratios) indicative of the mEH activity, the effects of the diplotypes in each EPHX1 block were analyzed on CBZ-epoxide metabolism. In block 2, the diol/epoxide ratios increased significantly depending on the number of haplotype *2 bearing Y113H (P=0.0241). In block 3, the ratios decreased depending on the number of haplotype *2 bearing H139R (P=0.0351). Also, an increasing effect of a *1 subtype, *1c, was observed on the ratio. CONCLUSION: These results show that some EPHX1 haplotypes are associated with altered CBZ-epoxide metabolism. This is the first report on the haplotype structures of EPHX1 and their potential in vivo effects.

Adolescent↗

Clinical aspects of hemimegalencephaly by means of a nationwide survey.

We surveyed Japanese patients with hemimegalencephaly by means of a questionnaire. Clinical findings, including intellectual and motor function levels and epileptic symptoms, were investigated. All 44 patients (28 males and 16 females) with hemimegalencephaly were sporadic. Sixteen patients had underlying neurocutaneous syndromes. The number of patients with right-sided hemimegalencephaly (n = 29) was almost twice that of patients with left-sided hemimegalencephaly (n = 15). Forty-one patients had mental retardation and hemiparesis and 14 patients were bedridden. All patients had epileptic seizures, which first appeared within a month in 18 cases and within 6 months in 11 cases. In 42 patients, magnetic resonance imaging revealed both cortical and white-matter abnormalities in the affected hemisphere. Antiepileptic drugs were not very effective. Fifteen patients were surgically treated. Eleven patients underwent functional hemispherectomy, which resulted in fairly good seizure control and improved development. There is a correlation between the onset of epilepsy and the degree of clinical severity of motor deficit and intellectual level. Neither underlying disorders nor laterality of the affected side was related to the degree of clinical severity.

Adolescent↗

Single nucleotide polymorphisms and haplotypes of CYP1A2 in a Japanese population.

In order to identify genetic polymorphisms and haplotype frequencies of CYP1A2 in a Japanese population, the enhancer and promoter regions, all the exons with their surrounding introns, and intron 1 were sequenced from genomic DNA from 250 Japanese subjects. Thirty-three polymorphisms were found, including 13 novel ones: 2 in the enhancer region, 5 in the exons, and 6 in the introns. The most common single nucleotide polymorphism (SNP) was -163C>A (CYP1A2*1F allele) with a 0.628 frequency. In addition to six previously reported non-synonymous SNPs, three novel ones, 125C>G (P42R, CYP1A2*15 allele, MPJ6_1A2032), 1130G>A (R377Q, *16 allele, MPJ6_1A2033), and 1367G>A (R456H, *8 allele, MPJ6_1A2019), were found with frequencies of 0.002, 0.002, and 0.004, respectively. No polymorphism was found in the known nuclear transcriptional factor-binding sites in the enhancer region. Based on linkage disequilibrium analysis, the CYP1A2 gene was analyzed as one haplotype block. Using the 33 detected polymorphisms, 14 haplotypes were unambiguously identified, and 17 haplotypes were inferred by aid of an expectation-maximization-based program. Among them, the second major haplotype CYP1A2*1L is composed of -3860G>A (*1C allele), -2467delT (*1D allele), and -163C>A (*1F allele). Network analysis suggested that relatively rare haplotypes were derived from three major haplotypes, *1A, *1M, and *1N in most cases. Our findings provide fundamental and useful information for genotyping CYP1A2 in the Japanese, and probably Asian populations.

Adrenergic beta-Antagonists↗

[Continuous midazolam infusion for refractory nonconvulsive status epilepticus in children].

We examined efficacy of continuous midazolam (MDL) infusion in seven episodes of refractory nonconvulsive status epilepticus (NCSE) in five children. Diagnosis included Lennox-Gastaut syndrome (two cases), and symptomatic generalized epilepsy, ring chromosome 20 syndrome, and epilepsy with continuous spike-waves during slow-wave sleep (one case each). One patient with Lennox-Gastaut syndrome and another with ring chromosome 20 syndrome had two episodes of NCSE. MDL was given as an initial bolus of 0.15 to 0.3 mg/kg, followed by continuous intravenous infusion at 0.1 to 0.2 mg/kg/hr. The infusion rate was increased slowly by 0.1 mg/kg/hr every 0.5 to 1.0 hr, up to 0.4 mg/kg/hr or until NCSE was controlled. The electroencephalogram, vital signs, blood pressure, and oxygen saturation were monitored during therapy. Electrical status epilepticus was abolished within a few hours in five of the seven episodes, and two patients could maintain wakefulness, oral intake, and bowel and bladder control throughout the continuous infusion. In one patient in whom NCSE recurred, it then remained uncontrolled even at a maximum dose. Serious complications such as respiratory depression or hypotension were not observed. Continuous intravenous infusion of MDL was effective and safe for NCSE in children, and can be used as firstline therapy for this condition.

Adolescent↗

[Establishment of a brain perfusion single photon emission computed tomography database in children by statistical imaging analysis].

We made a 3-dimensional, 99mTc-ECD brain perfusion single photon emission computed tomography (SPECT) database in children by a statistical analysis. We selected 52 individuals between 1 and 15 years of age whose brain SPECT and brain MRI findings were normal, and divided them into three age groups: 1-5, 6-10 and 11-15 years. By comparing databases obtained for each group, an age-dependent change of regional cerebral blood flow was investigated. The results showed that the relative blood flow increases in the frontal lobe and cerebeller hemisphere and decrease in the occipital lobe with increasing age, findings consistent with those of previous reports. This database enabled us to easily find 3-dimensional brain perfusion abnormality in individual patient by SPECT, and may help elucidate the pathophysiology of many brain disorders.

Adolescent↗

Renal disease in Arima syndrome is nephronophthisis as in other Joubert-related Cerebello-oculo-renal syndromes.

Clinicopathological features of the renal disease in Arima syndrome were studied in five autopsy cases. All cases showed insidious development of end-stage renal disease during childhood, preceded by polyuria/polydipsia, anemia, and growth failure. Decreased urinary concentrating ability and excessive sodium loss were the characteristic laboratory findings. Gross examination showed that both kidneys were small and showed multiple cysts of various sizes. The histological examinations revealed chronic sclerosing tubulo-interstitial nephropathy with cystic tubuli predominantly located at cortico-medullary areas. These observations suggest that the renal disease in Arima syndrome is in accordance with nephronophthisis both clinically and pathologically. Contrary to the previous literature which described that Arima syndrome can be distinguished from other Joubert-related cerebello-oculo-renal syndromes by its unique renal disease, i.e., cystic dysplastic kidney (CDK), our study indicates that the phenotype of the renal disease is common among these syndromes as well as abnormalities in other organs, suggesting the underlying similar molecular mechanisms.

Adolescent↗

Haplotypes of CYP3A4 and their close linkage with CYP3A5 haplotypes in a Japanese population.

In order to identify single nucleotide polymorphisms (SNPs) and haplotype frequencies of CYP3A4 in a Japanese population, the distal enhancer and proximal promoter regions, all exons, and the surrounding introns were sequenced from genomic DNA of 416 Japanese subjects. We found 24 SNPs, including 17 novel ones: two in the distal enhancer, four in the proximal promoter, one in the 5'-untranslated region (UTR), seven in the introns, and three in the 3'-UTR. The most common SNP was c.1026+12G>A (IVS10+12G>A), with a 0.249 frequency. Four non-synonymous SNPs, c.554C>G (p.T185S, CYP3A4(*)16), c.830_831insA (p.E277fsX8, (*)6), c.878T>C (p.L293P, (*)18), and c.1088 C>T (p.T363M, (*)11) were found with frequencies of 0.014, 0.001, 0.028, and 0.002, respectively. No SNP was found in the known nuclear transcriptional factor-binding sites in the enhancer and promoter regions. Using these 24 SNPs, 16 haplotypes were unambiguously identified, and nine haplotypes were inferred by aid of an expectation-maximization-based program. In addition, using data from 186 subjects enabled a close linkage to be found between CYP3A4 and CYP3A5 SNPs, especially among the SNPs at c.1026+12 in CYP3A4 and c.219-237 (IVS3-237, a key SNP site for CYP3A5(*)3), c.865+77 (IVS9+77) and c.1523 in CYP3A5. This result suggested that CYP3A4 and CYP3A5 are within the same gene block. Haplotype analysis between CYP3A4 and CYP3A5 revealed several major haplotype combinations in the CYP3A4-CYP3A5 block. Our findings provide fundamental and useful information for genotyping CYP3A4 (and CYP3A5) in the Japanese, and probably Asian populations.

Cytochrome P-450 CYP3A↗