Kenji Nihei

A point mutation in the mitochondrial tRNALeu(UUR) gene in melas (mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes)

Mitochondrial myopathy, encephalopathy, lactic acidosis and strokelike episode (MELAS) is a major group of heterogeneous mitochondrial disorders. To identify the defective gene, mitochondrial DNA from a patient with MELAS was sequenced by using amplified DNA fragments as sequencing templates. In 14.1 kbp determined out of 16.6 kbp of the whole mitochondrial gene, at least 21 nucleotides were different from those of a control human mitochondrial DNA. One of the substitutions was a transition of A to G in the tRNA(Leu) (UUR) gene at Cambridge nucleotide number 3,243. This nucleotide is conserved not only in many mitochondrial tRNAs but in most cytosolic tRNA molecules. An Apa I restriction site was gained by the substitution of this nucleotide. The Apa I digestion of the amplified DNA fragment revealed that all independent 6 patients had G at nucleotide number 3,243 in their mitochondrial DNAs, but none of 11 control individuals had G at this position. This result strongly suggests that the mutation in the mitochondrial tRNALeu gene causes MELAS.

Mutation and polymorphism analysis of the TRKA (NTRK1) gene encoding a high-affinity receptor for nerve growth factor in congenital insensitivity to pain with anhidrosis (CIPA) families

The human TRKA gene encodes a high-affinity tyrosine kinase receptor for nerve growth factor. Congenital insensitivity to pain with anhidrosis (CIPA) is an autosomal recessive genetic disorder reported from various countries and characterized by anhidrosis (inability to sweat), the absence of reaction to noxious stimuli, and mental retardation. We have found that TRKA is the gene responsible for CIPA. We have studied TRKA in 46 CIPA chromosomes derived from 23 unrelated Japanese CIPA families. including three that have been previously reported, and identified 11 novel mutations. Four (L93P, G516R, R648 C, and D668Y) are missense mutations that result in amino acid substitutions at positions conserved in the TRK family, including TRKA, TRKB, and TRKC. Three (S131 fs, L579 fs, and D770 fs) are frameshift mutations. Three (E164X, Y359X, and R596X) are nonsense mutations. The other is an intronic branch-site (IVS7-33T-->A) mutation, causing aberrant splicing in vitro. We also report the characterization of eight intragenic polymorphic sites, including a variable dinucleotide repeat and seven single nucleotide polymorphisms, and describe the haplotypic associations of alleles at these sites in 106 normal chromosomes and 46 CIPA chromosomes. More than 50% of CIPA chromosomes share the frameshift mutation (R548 fs) that we described earlier. This mutation apparently shows linkage disequilibrium with a rare haplotype in normal chromosomes, strongly suggesting that it is a common founder mutation. These findings represent the first extensive analysis of CIPA mutations and associated intragenic polymorphisms; they should facilitate the detection of CIPA mutations and aid in the diagnosis and genetic counseling of this painless but severe genetic disorder with devastating complications.

Measles virus-specific T helper 1/T helper 2-cytokine production in subacute sclerosing panencephalitis.

Live measles virus-specific T helper 1/T helper 2-cytokine productions by peripheral blood mononuclear cells in response to live measles, mumps or varicella virus were measured in 15 patients with subacute sclerosing panencephalitis and 15 controls by enzyme-linked immunosorbent assays. Most patients with subacute sclerosing panencephalitis had a defect in measles virus-specific production of interferon-gamma, one of the T helper 1 type cytokines, despite persistent presence of measles virus, with preserved interleukin-10 (T helper 2 type cytokine) synthesis. Patients with subacute sclerosing panencephalitis were divided into two groups: responders (group A) with significant interferon-gamma production (>20 pg/mL) in response to live measles virus and non-responders (group B) with a little or no interferon-gamma production. Comparison of the clinical courses between groups A and B revealed that all the patients of group A retained receptive function for a long time, while most patients of group B lost the function rapidly (P<0.01). An inverse correlation between interferon-gamma production by peripheral blood mononuclear cells and disease progression suggested that interferon-gamma plays an antiviral role in subacute sclerosing panencephalitis.

Clinical effects of MND-19 (Inosiplex) on subacute sclerosing panencephalitis: — A multi-institutional collaborative study—

A total of 151 cases of subacute sclerosing panencephalitis (SSPE), comprising 89 cases treated with MND-19 (Inosiplex) and 62 untreated cases, were retrospectively investigated as to background characteristics, survival rate and clinical course in order to compare the findings in the 2 groups of cases. The survival rate for the cases treated with MND-19 (MND-19-treated group) was significantly higher than that for the untreated cases (control group), which was also true on stratified analysis or on smoothing of the background factors by means of Coxs multiple regression model. Investigation of the clinical course revealed that progression through the disease stages was significantly slow in the MND-19-treated group, compared with in the control group. Global rating of the clinical course showed that a prolonged remission was obtained in more MND-19-treated cases than control cases. The measles virus antibody titer was in no way affected in the former group. Side effects of MND-19 were observed in 17 of the 89 treated cases (19.1%).

Anesthesia for Patients with Congenital Insensitivity to Pain and Anhidrosis: A Questionnaire Study in Japan

UNLABELLED We investigated the anesthetic management of patients with congenital insensitivity to pain and anhidrosis (CIPA) in Japan. CIPA is a rare inherited disease characterized by a lack of pain sensation and thermoregulation. Although lacking pain sensation, some patients do have tactile hyperesthesia. Thus, anesthetics are a necessity during operations. We also determined that because patients with CIPA have problems with thermoregulation, temperature management is a concern during the perioperative period and sufficient sedation is necessary to avoid accidental fractures. Additionally, it was found that the use of muscle relaxants does not present a problem, malignant hyperthermia is not associated with CIPA, and that the possibility of abnormalities in the autonomic nervous system must be taken into consideration. Therefore, patients with CIPA can be safely managed with anesthesia. IMPLICATIONS We investigated the anesthetic management of patients with congenital insensitivity to pain and anhidrosis. We clarified the following three important points: anesthesia is necessary, temperature management must be maintained, and there must be sufficient perioperative sedation in the anesthetic management of patients with congenital insensitivity to pain and anhidrosis.

Trial of intraventricular ribavirin therapy for subacute sclerosing panencephalitis in Japan

Ten patients with SSPE were surveyed during the last 4 years from the viewpoint of clinical safety for use of ribavirin therapy. Although effectiveness varied among cases, they were all treated safely with intraventricular ribavirin. This study suggests that treatment is safe and well-tolerated.

Neurological prognosis correlated with variations over time in the number of subependymal nodules in tuberous sclerosis

In tuberous sclerosis (TS), brain CT reveals subependymal nodules, cortical tubers and white matter lesions. This study is a retrospective analysis of the relationship between the variations over time in the number of subependymal nodules and the clinical course in cases of tuberous sclerosis. Twenty-four children with tuberous sclerosis, who attended the National Childrens Hospital as outpatients, were followed by means of brain CT examinations for 7 years and 1 month on average. Cranial MRI was also performed in 22 cases. Brain CT disclosed subependymal nodules already in early infancy. In almost all cases, the number of subependymal nodules gradually increased with age, especially around the frontal horn of the lateral ventricle. The increase stopped at around age 10. The cases with five or more subependymal nodules at the initial or subsequent CT examination ( 17 patients; Group A) exhibited a significantly greater number of cortical tubers than those with less than five (five patients; Group B) and had white matter lesions unlike Group B. In addition, the number of cases with either infantile spasms or mental retardation was significantly higher in Group A than Group B (P < 0.005). In conclusion, the number of ventricular subependymal nodules may allow prediction of the severity of the cerebral dysfunction in TS. Our results suggest that its variation may reflect the degree of the embryologic disorder when neuronal cells grow in the early gestational period.

Virtual sand box: Development of an application of virtual environments for clinical medicine

The sand play technique (Sandspiel) has often been used in psychological treatments. The primary purpose of this study was to construct a practical virtual environment to support the application of this technique with computers. The prototype application called Virtual Sand Box was developed to test the Sand Play Technique in the diagnosis and treatment of autistic patients. The display system and input device are discussed. A detailed description is also provided for how a virtual environment was constructed to cater input systems into output systems in order to facilitate manipulation tasks for the user. Experimental results gave insight into the feasibility and advantages of applying virtual reality technology to clinical medicine, particularly with respect to the diagnosis of the people with psychological and psychiatric sicknesses such as autism and neurosis.

Determination of free N-acetylneuraminic acid in human body fluids by high-performance liquid chromatography with fluorimetric detection

Determinations of both the free and bound form of N-acetyl-neuraminic acid (NANA) in several human body fluids, such as serum, cerebrospinal fluid (CSF), saliva, urine, amniotic fluid, and milk were carried out by HPLC with fluorimetric detection. The method utilized 1,2-diamino-4,5-methylenedioxybenzene dihydrochloride (DMB) as a fluorimetric derivatizing reagent. Free-form NANA was obtained from the body fluids after ultrafiltration with Microcon 10 (YM-10 cellulose membrane, filtration limit M(r) = 10,000, Amicon). The DMB derivative of NANA was separated isocratically by a Nucleosil 5C18 column with a mixture of 0.1 M sodium phosphate buffer (pH 2.0)-methanol (75:25, v/v). A gradient elution system was used for urine analysis. Analysis times were 10-30 min. Recoveries of free NANA by ultrafiltration were satisfactory: 95.66 +/- 1.80% for serum and 97.27 +/- 1.55% for CSF, respectively. The high sensitivity and specificity render this method applicable to all the body fluids tested. Although a physiological role for free NANA has not yet been elucidated, the method presented promises to contribute to the basic understanding of the NANA metabolism.

Studies on pediatric patients with absent auditory brainstem response (ABR) later components

Eleven pediatric patients with only wave I or waves I and II of their ABR were clinically analyzed. The clinical diagnoses of these patients were as follows: 1) anoxic encephalopathy in two cases; 2) neonatal asphyxia in one; 3) infantile Gauchers disease in one; 4) mitochondrial encephalomyopathy in one; 5) suspected Pelizaeus-Merzbacher disease in three; 6) degenerative disease of unknown etiology in two (presumptive diagnosis were progressive supranuclear palsy and dentate-rubro-pallido-Luysian atrophy); and 7) infantile spasms with congenital malformation of the brain and bones in one. The incidence of the patients with this type of ABR abnormality was 0.67% among 1,650 of our pediatric patients whose ABRs were examined because of audiological or neurological problems. All eleven patients showed severe mental retardation. Nine of the eleven had convulsions and likewise, eight of eleven showed deterioration in mental and/or motor activities. Furthermore seven of eleven had disturbed consciousness and four of these seven were in deep coma. Other brainstem and bulbar signs and symptoms were frequently found in these patients. In our series, patients without the later components of ABR manifested marked neurological abnormalities inside and outside the brainstem.