Biomedical subjects
Publications and source records attributed to S Akaboshi.
Prenatal diagnosis was performed by both DNA and enzymatic analysis on non-identical twins conceived by in vitro fertilization and at risk of succinate semialdehyde dehydrogenase deficiency. One fetus was predicted to be affected and one unaffected and selective fetal reduction was performed.
Inherited succinic semialdehyde dehydrogenase (SSADH; EC1.2.1.24; McKusick 271980) deficiency is a defect of GABA degradation which leads to accumulation of 4-hydroxybutyric acid (gamma-hydroxybutyric acid; GHB) in physiologic fluids of patients. Prenatal diagnosis (PND) was performed in three at-risk pregnancies employing combinations of: (1) reverse-transcription-polymerase chain reaction (RT-PCR) and genomic DNA amplification followed by sequencing using isolated leukocytes or cultured human lymphoblasts; (2) GHB quantitation in amniotic fluid; or (3) SSADH enzyme assay in chorionic villus (CV) and/or amniocytes. In two pregnancies, all analyses were concordant for prediction of disease status in the fetus. In the third case, enzyme activity in CV (deficient) and metabolite analysis in amniotic fluid (normal) were discordant. For clarification, mutation analysis was undertaken in CV, confirming heterozygosity for the mutation previously identified in the proband. We hypothesize that delayed transit time for shipment of CV between Greece and the United States (8 days) led to enhanced degradation of heterozygous SSADH enzyme activity. Our data demonstrate the importance of combined metabolite, enzyme, and DNA analysis for increased accuracy in the PND of SSADH deficiency.
Forced normalization (FN) is a well known phenomenon of acute psychosis accompanying seizure control. An 11-year-old boy with intractable myoclonic epilepsy and severe psychomotor delay experienced FN during medication of ethosuximide. Although his myoclonic seizures were completely controlled, behavioral changes, more of the manic type, became evident. EEG during this phenomenon showed almost normal findings. Generally, withdrawal of anti-epileptic drugs in patients with FN is still controversial and much debated. We could conclude that the physician should judge comprehensively the treatment considering the more favorable situation for the patient and the family.
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We present the developmental changes of peroxisomal enzymes, catalase, L-bifunctional protein (L-BF) and D-bifunctional protein (D-BF), in the normal brains, and patients with D-BF deficiency, a new peroxisomal disease. D-BF immunoreactivity was observed in controls as early as 13 gestational weeks (GW) and increased with maturation. The adult pattern with fine granule staining of somata and dendrites became apparent in adolescence. L-BF appeared at 20 GW in the cerebral cortex and Purkinje cells and positive glia appeared early in the white matter at 17 GW, and then increased with age. Catalase-positive neurons were identified in the same manner as L-BF, D-BF deficiency in both fetus and infant showed markedly diminished enzyme immunoreactivity. Patients demonstrate reduced D-BF expression. Zellweger syndrome shows decreased expression for the three proteins. This study shows that the peroxisomal enzymes may be closely related to neuronal maturation and gliogenesis in human brain and to disturbance of neuronal migration as seen in Zellweger syndrome significant. D-BF deficiency may exhibit a range of symptoms during the neonatal and early infantile periods some of which may be similar to Zellweger syndrome.
We report a case of a 13-year-old female with atypical absence seizures induced by prolonged administration of long-acting leuprolide acetate (LA). This patient had brain involvement resulting from chemotherapy and radiotherapy for a medulloblastoma. At 13 years of age, administration of long-acting LA was started. After the third dose of long-acting LA, atypical absence seizures appeared. After discontinuing long-acting LA, the seizures stopped without administration of any antiepileptic drugs. However, 2 years, 6 months later, the same seizures again appeared. On the basis of the findings of endocrinologic investigations and the reported data of pharmacokinetics of LA, we speculate that her seizures were induced by LA and that the seizures were associated with the presence of brain damage in the patient. Care should therefore be taken when using long-acting LA or other gonadotropin-releasing hormone analogues for pediatric patients with diffuse brain damage.
A case of a 5-year-old boy with non-24 hour sleep-wake syndrome and mental retardation is reported. His free-running sleep-wake rhythm was remarkably improved by the oral administration of melatonin. The circadian variation in melatonin secretion was extremely low, and circadian rhythm of cortisol secretion was noted. It was speculated that his non-24 hour sleep-wake syndrome was due to a congenital deficiency of melatonin secretion, and supplemental melatonin therapy proved effective for treating his condition.
Two boys developed rhythmic involuntary movements in the extremities on one side of the body after febrile illness. They also showed behavioral disturbances. In both patients, serum antistreptolysin-O and antistreptokinase titers were elevated in acute illness and decreased a few months later. One patient showed tremorous movement, and the other choreiform movement. In the former, a surface EMG showed short-duration (30 to 60 ms), highly frequent (6 to 8 Hz) and synchronous discharges of multiple muscles, including the antagonists, suggesting myoclonic jerk. In the latter, a surface EMG showed long-duration (0.5 to 1 s), repetitive (about 0.5 Hz) and synchronous or asynchronous discharges of the antagonists, suggesting choreoathetosis. In both patients, giant somatosensory evoked potentials and high-voltage slow EEG activities were observed predominantly in the hemisphere contralateral to the involuntary movement. In the myoclonic patient, long-latency EMG responses were enhanced and cortical potentials preceding the myoclonus were present by jerk-locked back averaging technique. The present data suggest that unilateral rhythmic involuntary movements occur secondary to streptococcal infection. The pathophysiology of the involuntary movements may be associated with sensorimotor cortex hyperexcitability.
We report the case of a 7-year old girl with Høyeraal-Hreidarsson syndrome (HHS) and review other cases of HHS. In addition to the previously described important signs of HHS, i.e., prenatal growth retardation, microcephaly, psychomotor retardation, progressive pancytopenia, immunological abnormalities, and cerebellar hypoplasia and ataxia, we consider that delayed myelination of cerebral white matter and hypoplastic corpus callosum should be added to the list of important signs. However, it is not clear whether delayed myelination of white matter in HHS indicates dysmyelination or demyelination. Furthermore, we suggest that immunological abnormalities of both T and B cells are one of the important signs of HHS. We consider these new important signs to be valuable for the diagnosis of HHS.
We investigated the molecular basis of holoprosencephaly in a sporadic patient and identified a novel missense mutation in the signal sequence of the sonic hedgehog (Shh) gene. Magnetic resonance imaging of the head showed a lobar type of holoprosencephaly and partial agenesis of the anterior corpus callosum. He was treated for craniosynostosis at 7 months of age. All three exons of the Shh gene were amplified by polymerase chain reaction from genomic DNA of the patient and controls. Sequencing analysis of the polymerase chain reaction fragments, screened by single-strand conformation polymorphism analysis, revealed a heterozygous mutation of a T-to-C substitution at nucleotide position 50. This mutation predicted an amino acid replacement of leucine to proline at codon 17 located in the signal peptide of SHH protein. It probably disturbs the translocation of the protein into the endoplasmic reticulum and may lead to holoprosencephaly because of haploinsufficiency of Shh.
A Japanese patient with tuberous sclerosis (TSC), who manifested with multiple lung cysts and pneumothorax, is described. All exons of two TSC genes, TSC1 and TSC2, in peripheral blood leukocytes from the patient were analyzed by polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP). A novel T-to-G transition was found in exon 19 of TSC2 at nucleotide position 2168. This mutation caused an amino acid change, L717R. There was no such mutation in any other family members or in 100 normal Japanese. An automated sequencer-assisted quantitative analysis of normal and mutated SSCP-bands revealed no loss of heterozygosity (LOH) in the lung cyst tissue of the patient.
The brains of two patients with Lesch-Nyhan syndrome (LNS) were studied. The concentration of dopamine was decreased in the caudate nucleus of LNS patients. Immunohistochemical methods revealed that the dopamine (DA) D1 and D2 receptor and methionine-enkephalin immunoreactivities (IRs) were increased in the putamen, and less significantly in the caudate nucleus. The D1 and D2 receptor IRs of the cingulate cortex, the tryptophan-hydroxylase IR in the dorsal nucleus of the midbrain, as well as the substance P and methionine-enkephalin IRs of the nociception-conducting structures, including the periaqueductal gray and spinal trigeminal nucleus, were not changed. Tyrosine-hydroxylase IR was not decreased in the substantia nigra of the LNS patients. Therefore, the cause of the decreased dopaminergic activity in LNS may not be involved in the production of tyrosine hydroxylase in the substantia nigra. Developmental abnormalities due to the DA defect at an early age might exist in the postsynaptic structure in the striatum.
Ataxia-telangiectasia (AT) is an autosomal recessive disorder characterized by progressive ataxia, telangiectasia, sinopulmonary infections, hypersensitivity to ionizing radiation, and combined immunodeficiency. Recently, the AT gene (ATM) was cloned and shown to be mutated in AT patients. In this report, mutation analysis of ATM was performed in a 24-year-old AT patient without immunodeficiency. ATM amplified with reverse transcriptase-polymerase chain reaction (RT-PCR) was screened with a ribonuclease (RNase) cleavage assay and auto-sequenced. This patient, a compound heterozygote, showed two mutations in ATM: one missense mutation leading to a Leu2656Pro substitution and the other to the truncation at codon 3047 (Arg-->ter). The latter mutation is within the phosphatidylinositol 3-kinase (PI 3-kinase)-like domain and the former is outside but close to the domain. The particular phenotype in our patient, no immunodeficiency, suggests incomplete functional loss of ATM protein. The clinical spectrum of AT caused by ATM mutations may be broader than previously thought. Further analysis of patients with similar phenotypes will make the relation between ATM genotype and phenotype clear.
Cultured fibroblasts from patients with Niemann-Pick disease type C (NP-C) are characterized by lysosomal accumulation of unesterified cholesterol and a defect in intracellular trafficking of cholesterol. We have found the accumulation of GM2 ganglioside in NP-C fibroblasts [Yano T, Taniguchi M, Akaboshi S, Vanier MT, Tai T, Sakuraba H, et al. Proc Japan Acad 1996;72B:214-219]. In this communication we show that several inhibitors known to inhibit intracellular cholesterol transport, progesterone, imipramine and KN-62, elicit accumulation of not only unesterified cholesterol but also GM2 ganglioside. This finding suggests that intracellular transport of cholesterol may be coupled with that of GM2 ganglioside. The accumulation of free cholesterol and GM2 ganglioside may be a clue for understanding the basic defect of NP-C. Recently NPC1 gene is found by the positional cloning. The mechanism of accumulating of GM2 ganglioside should be further investigated by studying of the functions of NPC1 gene.
A 15-year-old boy was suffering from splenomegaly and a 10-year history of a neurologic disorder that included mental retardation, vertical supranuclear gaze palsy, dysarthria, ataxia, and dystonia. Bone marrow aspirates revealed foamy cells with storage materials which were positive with filipin staining. Cultured skin fibroblasts derived from the patient showed moderate loss of sphingomyelinase activity and the impairment of cholesterol esterification. The characteristic clinical presentations and typical histochemical findings of this patient met the diagnostic criteria of Niemann-Pick disease type C (NPC). In the fibroblasts from the patient, there was an accumulation of GM2 ganglioside around their cytoplasms. Increased levels of glycolipids. including GM2 ganglioside are reported in the cerebral cortex of NPC, but not in the fibroblasts. The fibroblasts derived from NPC may reflect the abnormal metabolism of glycolipids in the central nervous system of NPC.
We describe a 4-year-old boy with delirium including somnolence, irritability, agitation and visual hallucination, associated with Mycoplasma pneumoniae (MP) encephalitis. The MP encephalitis was diagnosed from increased MP-antibody (> 1:1280). Electroencephalography during sleep revealed continuous 9 Hz fast wave activity over the bilateral frontocentral regions, which was thought to represent extreme spindles. These extreme spindles were in parallel with the degree of delirium. Transient extreme spindles have not previously been reported in MP or other encephalitis.
We investigated the hypothesis that cell membrane function is abnormal in brains of subjects with Duchenne muscular dystrophy (DMD) using proton-nuclear magnetic resonance (NMR) spectroscopy of human brain extracts. The total amount of choline-containing compounds was significantly higher (about three times) than in normal controls and patients with other myopathies, while N-acetyl-L-aspartic acid and creatine were within the normal range. These findings indicate that abnormal cell membrane function may be correlated with the abnormal dystrophin or lack of dystrophin in the brain of patients with DMD.
A cell line (SPM-3T3) derived from a C57BL/KsJ mouse model of Niemann-Pick disease type C (NP-C) shows biochemical abnormalities similar to those in fibroblasts derived from NP-C. Somatic cell hybridization analysis of the SPM-3T3 cells and five fibroblast strains derived from NP-C patients (four childhood cases and one adult case) was carried out. The criterion for complementation was the restoration of a normal intracellular fluorescent pattern in multinucleated cells stained with filipin to demonstrate cholesterol accumulation. These cells can be assigned to two complementation groups. The SPM-3T3 cells did not complement cell strains derived from childhood-type NP-C, while they complemented a cell strain derived from an adult patient. Our results suggest that SPM-3T3 represents a genetically authentic model of a major complementation group of NP-C, and that NP-C consists of genetically heterogeneous groups.