Heterozygous deletion of ITPR1, but not SUMF1, in spinocerebellar ataxia type 16.

We have previously mapped autosomal dominant spinocerebellar ataxia (SCA) 16 to 3p26, overlapping with the locus of SCA15. Recently, partial deletions of ITPR1 and the neighbouring SUMF1 in the SCA15 and two additional families were reported. In the present study we determined the copy number of these genes by real time quantitative polymerase chain reaction (PCR) and found a heterozygous deletion of exons 1-48 of ITPR1, but not SUMF1 in SCA16. Breakpoint analysis revealed that the size of the deletion is 313,318 bp and the telomeric breakpoint is located in the middle of their intergenic region. Our data provide evidence that haploinsufficiency of ITPR1 alone causes SCA16 and SCA15.

A novel mutation of the GTP-cyclohydrolase I gene in a patient with hereditary progressive dystonia/dopa-responsive dystonia.

We report a 37-year-old Japanese woman with hereditary progressive dystonia with marked diurnal fluctuation and dopa-responsive dystonia. She developed dystonia in the lower limbs at the age of 11 years, followed by spasmodic torticollis and resting tremor of the feet, which responded remarkably to low doses of levodopa (100 mg/day). Concentrations of biopterin and neopterin in CSF were decreased. Polymerase chain reaction analysis of the guanosine 5'-triphosphate cyclohydrolase I gene revealed a novel mutation (Thr186-->Lys).

Adrenoleukodystrophy protein enhances association of very long-chain acyl-coenzyme A synthetase with the peroxisome.

OBJECTIVE: To clarify the function of adrenoleukodystrophy protein (ALDP) using our ALDP-deficient mice established by gene targeting. BACKGROUND: X-linked adrenoleukodystrophy (ALD) is characterized biochemically by the accumulation of very long-chain fatty acids (VLCFA) in tissues and body fluids, and is caused by impairment of peroxisomal beta-oxidation. In ALD, very long-chain acyl-coenzyme A synthetase (VLACS), which is necessary for peroxisomal beta-oxidation, does not function. METHODS: The ALDP-deficient mice and C57BL/6J mice were used. VLACS or ALDP were transiently expressed by lipofection in murine fibroblasts, and VLCFA beta-oxidation was assayed. Liver peroxisomes were purified by sequential centrifugations and a Nycodenz gradient centrifugation. The peroxisomal localization of VLACS was compared between the mutant and control mice using a Western blot analysis. RESULTS: Impairment of VLCFA beta-oxidation in ALDP-deficient fibroblasts was not corrected by the additional expression of VLACS alone but was by the coexpression of VLACS and ALDP. Although the tissue-specific expression of VLACS was similar in ALDP-deficient and normal mice, peroxisomal VLACS was clearly lower in ALDP-deficient than in normal mice. CONCLUSIONS: ALDP plays a role in the peroxisomal localization of VLACS, and VLACS does not function unless localized in the peroxisome.

Autosomal dominant familial spinal and bulbar muscular atrophy with gynecomastia.

The proband, a 53-year-old man, developed progressive spinal and bulbar muscular atrophy and gynecomastia at the age of 50. His father had weakness of lower limbs, and his son had a nasal voice, ocular movement abnormalities, and gynecomastia, whereas two of the proband's brothers showed either gynecomastia or tongue fasciculations. None of the patients showed any expansion of CAG repeat in the androgen receptor gene or any hormonal abnormality. Thus, this family is affected by a form of autosomal dominant spinal and bulbar muscular atrophy with gynecomastia.

A novel autosomal dominant spinocerebellar ataxia (SCA16) linked to chromosome 8q22.1-24.1.

OBJECTIVE: To characterize a distinct form of autosomal dominant cerebellar ataxia (ADCA) clinically and genetically. BACKGROUND: ADCAs are a clinically, pathologically, and genetically heterogeneous group of neurodegenerative disorders. Nine responsible genes have been identified for SCA-1, -2, -3, -6, -7, -8, -10, and -12 and dentatorubral-pallidoluysian atrophy (DRPLA). Loci for SCA-4, -5, -11, -13, and -14 have been mapped. METHODS: The authors studied a four-generation Japanese family with ADCA. The 19 members were enrolled in this study. The authors performed the mutation analysis by PCR and a genome-wide linkage analysis. RESULTS: Nine members (five men and four women) were affected. The ages at onset ranged from 20 to 66 years. All affected members showed pure cerebellar ataxia, and three patients also had head tremor. Head MRI demonstrated cerebellar atrophy without brain stem involvement. The mutation analysis by PCR excluded diagnoses of SCA-1, -2, -3, -6, -7, -8, and -12 and DRPLA. The linkage analysis suggested linkage to a locus on chromosome 8q22.1-24.1, with the highest two-point lod score at D8S1804 (Z = 3.06 at theta = 0.0). The flanking markers D8S270 and D8S1720 defined a candidate region of an approximately 37.6-cM interval. This candidate region was different from the loci for SCA-4, -5, -10, -11, -13, and -14. CONCLUSION: The family studied had a genetically novel type of SCA (SCA-16).

Increased preproenkephalin mRNA and preprotachykinin mRNA in the striatum of Rolling mouse Nagoya.

Although Rolling mouse Nagoya (RMN) has been considered to demonstrate cerebellar dysfunction, our previous metabolic and electrophysiological studies also revealed a dysfunction of the basal ganglia, with the presumable primary site of dysfunction being the striatum. In the present study, we investigated the neurochemical functions of the striatum. In RMN, both preproenkephalin mRNA and preprotachykinin mRNA increased significantly in the striatum, with unaltered GAD mRNA, [(3)H]spiperone binding, [(3)H]QNB binding and preprosomatostatin mRNA, thus indicating the dysfunction of striatal projection neurons. These findings support the hypothesis that the site of primary dysfunction in the basal ganglia is in the striatum of RMN.

Somatostatin enhances neurofilament expression and neurite outgrowth in cultured rat cerebellar granule cells.

Somatostatin and its receptors are transiently expressed at a high level in the cerebellum around birth, before declining to adult levels by 2-3 weeks postnatally. We therefore investigated the neurotrophic effects of somatostatin (SS) on rat cerebellar granule cells in culture by measuring the percentage of cells with processes, the content of mRNA and protein for neurofilament (NF) and mRNA for glutaminase, and the number of viable cells (MTS assay). SS increased the percentage of cells with processes at 8 h after plating. After 1 day in vitro (DIV), SS caused a 2-fold increase in NF mRNA, and a 23% increase in NF protein. The mRNA increase was maximal at DIV1 whereas by DIV7 the NF protein content of control cells reached that of SS-treated cells. SS had no effect on glutaminase mRNA or on the number of viable neurons from either postnatal day 5 or 8 animals. These results demonstrated that SS has a neurotrophic effect on neurite production, including initiation of neurite outgrowth, but no effect on neuronal survival, cell proliferation, or phenotype differentiation (glutaminase expression), and support the possibility that SS plays a role in the differentiation of immature cerebellar granule cells during central nervous system development.

The soleus late response elicited by transcranial magnetic stimulation reflects agonist-antagonist postural adjustment in the lower limbs.

OBJECTIVES: We studied the origin and underlying mechanism of the soleus late response (SLR) at a mean latency of 90 ms following transcranial magnetic stimulation. METHODS: The soleus primary response (SPR) and SLR were recorded from the soleus (SOL) muscle in 27 normal subjects under various conditions using a double-cone coil. We also tested 28 patients demonstrating neurological disorders with postural disturbance. RESULTS: The amplitude of the SPR gradually increased and its latency gradually decreased against the voluntary contraction (0-80%) of the tibialis anterior (TA) muscle. In contrast, the SLR amplitude was the greatest at a 20% TA contraction while the SLR latency was the shortest at a 40% TA contraction. The preactivation of SOL enhanced the SPR response but did not evoke the SLR. The SPR amplitude was significantly augmented while standing, however, the SLR amplitude tended to decrease. The SLR was never obtained following the stimulation of the brainstem, lumbar roots and peroneal nerve. The SLR was abnormal in patients with cerebellar ataxia and Parkinson's disease while the SPR was normal. CONCLUSIONS: A lack of any correlation between the SPR and SLR suggests that the SLR does not originate in the corticospinal tract. The SLR may thus be a polysynaptic response related to the postural control of the agonist and antagonist organization between the TA and SOL.

Glutamate enhances phosphorylation of neurofilaments in cerebellar granule cell culture.

In amyotrophic lateral sclerosis (ALS), an abnormal increase of glutamate in the central nervous system indicates that it may play a key role in motor neuron death. The neuronal accumulation of phosphorylated neurofilaments (NFs) suggests an alteration of phosphorylation of NFs is also involved. Rat cerebellar granule cells (CGCs) are sensitive to glutamate neurotoxicity and provide a suitable model system for clarifying its mechanisms. Using cultured CGCs, we investigated the relationship between glutamate neurotoxicity and the phosphorylation of NFs. Because glutamate showed a dose-dependent neurotoxicity for CGCs, we adopted a 10 microM glutamate treatment, which produced no acute neurotoxicity during the experiments. The number of phosphorylated heavy subunits of neurofilaments (NF-Hs) increased to approximately twice that of the control after 72 h, although the total number of NF-Hs remained constant throughout the experiment. The phosphorylation of NF-Hs was significantly suppressed by the AMPA-receptor antagonist CNQX, but not by the NMDA-receptor antagonist MK-801. Our findings therefore suggest that exposure to a low concentration of glutamate enhances the phosphorylation of NF-Hs, mainly via the AMPA receptor.

Positron emission tomography (PET) in Machado-Joseph disease.

Positron emission tomography studies on the regional cerebral glucose metabolism (rCMRglc) and 18F-fluorodopa (18F-Dopa) uptake were performed in 3 patients with Machado-Joseph disease (MJD), a dominantly inherited degenerative disease in the cerebellum, brainstem and basal ganglia. The rCMRglc in MJD was found to be significantly decreased in the cerebellum, brainstem, striatum and whole cerebral cortex in comparison to that in normal subjects. These results of rCMRglc were different from those for dominantly inherited olivopontocerebellar atrophy (dOPCA) or cerebellar cortical degeneration (CCD), however they were similar to those for sporadic olivopontocerebellar atrophy (sOPCA) and multiple system atrophy (MSA). The 18F-Dopa uptake in MJD was found to be significantly decreased in the putamen and relatively spared in the caudate, which was different from that of MSA. In addition, these results indicate that MJD showed a dysfunction, not only in the regions with apparent pathological involvement such as cerebellum, brainstem and nigro-striatal dopaminergic system, but also in the cerebral cortex and the striatum where no pathology could be observed using conventional morphological techniques.

Positron emission tomographic (PET) studies in dementia.

Positron emission tomographic (PET) studies of regional cerebral glucose metabolism were performed in patients with various types of dementia, patients with Parkinson's disease but without dementia, and healthy normal controls. Patients with Alzheimer-type dementia showed significant decreases in glucose metabolism in frontal, temporal, parietal, sensory-motor and striatal regions. Patients with Pick's disease revealed decreased glucose metabolism in frontal and temporal regions. Parkinsonian patients with dementia had significant reductions of glucose metabolism in frontal, temporal, parietal, occipital, sensory-motor and striatal regions. Patients with Huntington's disease revealed decreased glucose metabolism in frontal, parietal and striatal regions. Patients with Creutzfeldt-Jakob's disease showed marked decreases in glucose metabolism throughout all brain regions. On the other hand, patients with Parkinson's disease but without dementia exhibited no reductions of cerebral glucose metabolism. Cerebral glucose hypometabolism in these various types of dementia might reflect neuronal dysfunction and cell death.

Changes in the clinical phenotypes of multiple sclerosis during the past 50 years in Japan.

In order to clarify whether or not marked changes in the social environment during the past 50 years in Japan may have altered the clinical phenotypes of multiple sclerosis (MS), we retrospectively analyzed 143 consecutive patients with clinically definite MS who developed the disease between 1950 and 1997. Fifty-two patients were classified as Asian type MS showing a selective involvement of the optic nerves and the spinal cord, while 91 patients were considered to have Western type MS which demonstrated the involvement of multiple sites in the central nervous system including the cerebrum, cerebellum and brainstem. The ratio of Asian type versus Western type MS was 1:0.5 in the patients born in the 1920s and 1:1.27, 1:1.64 and 1:1.7 in those born in the 1930s, 1940s and 1950s, respectively, and thereafter it increased to 1:4.67 in those born in the 1960s and 1:4 in those born after the 1970s. As a result, the proportion of Asian type MS significantly decreased in the patients born after 1960 as compared with those born from 1930 to 1959 (P=0.0121). In the Asian type MS, the age of onset was significantly higher in the patients who developed the disease from 1985 to 1997 (42.4+/-13.5 years) than in those who developed the disease from 1950 to 1984 (32.3+/-12.4 years) (P=0.0149), while in the Western type MS no such change in the age of onset was observed. These findings suggest that the frequency of Asian type MS has apparently decreased in younger Japanese born after 1960 when Japan's rapid economic growth had just started, and environmental factors are therefore considered to contribute to determine the clinical phenotypes of MS in Asians.

Th1 dominance in HAM/TSP and the optico-spinal form of multiple sclerosis versus Th2 dominance in mite antigen-specific IgE myelitis.

To clarify the Th1/Th2 balance in spinal cord inflammation, we used ELISA to measure the total and allergen-specific IgE in 69 patients with clinically definite multiple sclerosis (MS), including 24 patients with the optico-spinal form of MS, 45 with HAM/TSP, 30 HTLV-I carriers without HAM/TSP, 40 patients with acute myelitis, 43 with neurodegenerative disorders, and 42 healthy subjects, and flow cytometry to study the intracellular IFNgamma-positive versus IL-4-positive cell ratio (intracellular IFNgamma/IL-4 ratio) in peripheral blood CD4(+) T cells in 40 patients with MS, including 17 patients with the optico-spinal form of MS, 23 with HAM/TSP, 22 with acute myelitis, 23 with neurodegenerative disorders, and 36 healthy subjects. Patients with HAM/TSP showed a significantly higher intracellular IFNgamma/IL-4 ratio, lower IL-4(+)/IFN-gamma(-) cell percentages, lower total IgE level, and lower frequency of cedar pollen-specific IgE than did the controls. The patients with optico-spinal MS showed a significantly higher intracellular IFNgamma/IL-4 ratio and higher IL-4(-)/IFN-gamma(+) cell percentages than the controls even at remission or in the convalescence phase. In contrast, in the patients with acute myelitis, the total serum IgE level and the frequency of mite antigen-specific IgE were significantly elevated in comparison to the controls, while those having mite antigen-specific IgE myelitis showed a significantly lower IFNgamma/IL-4 ratio in the CD4(+) T cells in comparison to the controls. These findings suggest that the Th1 cell response is predominant in HAM/TSP and optico-spinal MS, whereas the Th2 cell response is predominant in mite antigen-specific IgE myelitis.

Heterogeneity of glucose metabolism in corticobasal degeneration.

A positron emission tomography (PET) study on the regional cerebral glucose metabolism (rCMRglc) was performed in six patients with corticobasal degeneration (CBD). The clinical features included asymmetrical parkinsonism with apraxia, were related to the cerebral cortical and basal ganglionic dysfunction. An MRI study showed all cases to have asymmetrical atrophy in the front-parietal cortex contralateral to the dominantly affected limb; however, no case was pathologically verified. A PET study revealed three cases to have asymmetrical glucose hypometabolism in the parietal lobe and thalamus, which was compatible with the results of previous reports. However, two patients demonstrated symmetrical glucose hypometabolism in the frontal lobe, striatum and parietal lobe while one case had a diffuse hypometabolism, in spite of a marked asymmetry of the neurological findings. These results therefore suggest the heterogeneity of the glucose hypometabolism in CBD based on the PET findings.

Positron emission tomography (PET) in "pure akinesia".

Positron emission tomography (PET) studies on regional cerebral glucose metabolism and [18F]fluorodopa uptake were performed on 3 patients with "pure akinesia without rigidity and tremors", 3 progressive supranuclear palsy (PSP) patients, and 5 patients with Parkinson's disease. The "pure akinesia" and PSP patients showed a marked decrease in glucose metabolism in the frontal cortex and striatum, and a decreased uptake of [18F]fluorodopa in the striatum. While the Parkinson's disease patients had a decreased uptake of [18F]fluorodopa in the striatum but no abnormality in the glucose metabolism. Magnetic resonance imaging (MRI) showed atrophy of the pretectum and dorsal pons in "pure akinesia" and PSP patients, but there was no such abnormality in the Parkinson's disease patients. As described above, patients with "pure akinesia" and PSP patients revealed similar findings on PET and MRI studies, while Parkinson's disease patients showed substantially different results.

Expression and processing of recombinant human galactosylceramidase.

Stable transformants of CHO cells that overexpress human galactosylceramidase (GALC) were established. The GALC within the cell consisted of 50- and 30-kDa proteins. The active GALC secreted into the culture medium in large amounts consisted of the 80-kDa precursor enzyme. We confirmed that the precursor enzyme was taken up by fibroblasts via the mannose-6-phosphate receptor and processed into the 50- and 30-kDa fragments. Fragmentation was inhibited by the lysosomotropic agents chloroquine and NH4Cl, suggesting that it occurs within the lysosome. GALC mutations identified in globoid cell leukodystrophy suppressed fragmentation. Neither the 50- or 30-kDa fragment expressed had GALC activity, indicative that the entire structure is necessary for enzyme activity and that fragments expressed separately cannot associate to form the active enzyme.

Auditory agnosia restricted to environmental sounds following cortical deafness and generalized auditory agnosia.

We encountered a case of auditory agnosia restricted to environmental sounds, which was associated with the development of bilateral subcortical lesions after suffering a bilateral putaminal hemorrhage. The patient had a history of a putaminal hemorrhage on her left side without any major disability. Three years later, she suffered a putaminal hemorrhage on the other side. The clinical picture started with cortical deafness, then changed to generalized auditory agnosia for verbal and environmental sounds, and finally developed into auditory agnosia confined to the perception of environmental sounds. Her errors in a test of sound recognition were discriminative rather than associative in nature. Neuro-radiological examinations revealed bilateral subcortical lesions involving the fibers from the medial geniculate body to the temporal lobes after bilateral putaminal hemorrhage. This case suggested that the subcortical lesion involving bilateral acoustic radiation could cause either cortical deafness, auditory agnosia of all sounds, or auditory agnosia restricted to environmental sounds.

[Functional imaging for disorders of basal ganglia].

The nigrostriatal dopaminergic function and regional glucose metabolism were evaluated in patients suffering from various disorders of basal ganglia by using positron emission tomography with 18F-dopa and 18F-FDG, respectively. The 18F-dopa uptake in the striatum (the caudate head and the putamen) decreased in patients with Parkinson's disease but was relatively unaffected in the caudate. The cerebral glucose metabolism was normal in patients with Parkinson's disease. The 18F-dopa uptake in the striatum also decreased in cases of multiple system atrophy and progressive supranuclear palsy, but there was no difference in the uptake between the caudate and the putamen. The glucose metabolism decreased in the cerebral cortices and the striatum: this finding was also different from those of Parkinson's disease. A normal 18F-dopa uptake with a markedly decreased striatal glucose metabolism was observed in cases of Huntington's disease. The 18F-dopa uptake increased and the glucose metabolism was normal in cases of idiopathic dystonia. Various patterns of 18F-dopa uptake and glucose metabolism were thus observed in the various disorders of basal ganglia. These results suggest that the measurements of the 18F-dopa uptake and glucose metabolism would be useful for evaluating the function of the basal ganglia in various disorders of basal ganglia.

[The advantages and limitations of brain function analyses by PET].

PET has been proved to be a powerful tool for exploring the brain function. We discussed the advantages and limitations of PET for analyzing the brain function on the basis of our clinical and experimental experiences of functional imaging. A multimodality PET study measuring cerebral energy metabolism (CMRO2 and CMRglc), cerebral blood flow (CBF), oxygen extraction fraction (OEF) and neurotransmitter function (presynaptic and postsynaptic) opens up a closer insight into a precise pathophysiology of the brain dysfunction: In cerebral infarction, it reveals a state of "misery perfusion" in the acute stage, "luxury perfusion" in the intermediate stage, and proportionately decreased CBF and CMRO2 in the chronic stage. Neurotransmitter function may identify specifically a neuronal subgroup of dysfunction. Owing to the low temporal resolution of PET, a neuronal activity may propagate transsynaptically to remote areas during the period of scanning, resulting in an obscured primary site of the neuronal activity. Uncoupling between neuronal activities and cerebral energy metabolism/CBF may occur under a certain state of brain pathology, particularly after an acute destructive lesion, according to our experimental studies. Neurotransmitter function may reveal the effect of drugs on the brain function, and may be useful for developing a new method of drug therapy for brain diseases in the future.

[A case of familial type IIa hypercholesterolemia with the clinical features similar to cerebrotendinous xanthomatosis].

A 63-years-old woman noticed unsteady gait at the age of 56 years and then developed dysarthria two years later. A general physical examination at age 56 revealed mild hypertrophy of both Achilles tendons. On neurological examination, she had scanning speech, moderate limb and truncal ataxia, and moderate hyperreflexia of all limbs. A soft tissue X-ray examination disclosed hypertrophy of both Achilles tendons with multiple punctate calcification. Brain MRI showed diffuse cerebellar atrophy. Motor evoked potentials in the right limb disclosed a prolonged central conduction time. Blood chemistry showed familial type IIa hypercholesterolemia (cholesterol 320 mg/dl, and LDL-cholesterol 245 mg/dl), yet cholestanol level was normal. A examination of CTX gene mutation at hot spots revealed no mutation. Her mother and two siblings also had hypertrophy of Achilles tendons as well as type IIa hypercholesterolemia. In addition, the one sibling showed mild ataxia of lower limbs, respectively. This report suggests a possible link between familial type IIa hypercholesterolemia and cerebellar degeneration syndrome clinically mimicking CTX.