[Neurological symptoms associated with hypercortisolism].
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Biomedical subjects
Publications and source records attributed to G Hirose.
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Human neuronal Elav-like proteins contain three RNP-type RNA recognition motifs (RRMs). Previous reports demonstrated that a single RRM of the proteins is not sufficient to bind to the uridine-rich stretch in the 3' untranslated region of mRNAs and that the bi-RRM peptide consisting of the first two RRMs is necessary for the binding. The present study was designed to examine the potential contributions of the first two RRMs when binding to a cytokine mRNA. Deletions of the internal or terminal amino acid residues of the first RRM (RRM1) of the HuC/ple21 ELAV-like protein completely abolished RNA binding. However, removal of any region of the second RRM (RRM2) except for the eight amino acid residues, which correspond to the potent fourth beta-sheet structure of RRM2, did not affect RNA binding. Conjugation of the eight amino acid residues to RRM1 enhanced the RNA binding as well as the entire RRM2, indicating that the octapeptide of RRM2 can be compensated for by the binding function of RRM2. The present study also showed that the substitutions of glutamic acid at 42 for aspartic acid and leucine at 44 for phenylalanine in the first potent alpha-helix structure of RRM1, as were seen in another ELAV-like protein Hel-N1, markedly affected the RNA binding.
Tumor necrosis factor-alpha (TNF-alpha) is a proinflammatory cytokine that is involved in the pathogenesis of several human CNS disorders. The AU-rich element (ARE) in the 3'-untranslated region (UTR) of TNF-alpha mRNA is implicated in post-transcriptional control of TNF-alpha. In this study, we showed that a human neuronal ELAV-like protein binds to the ARE in the 3'-UTR of TNF-alpha mRNA. The protein binds to the uridine stretch in AUUUA pentanucleotides inside the ARE in the 3'-UTR of TNF-alpha mRNA. The TNF-alpha mRNA-binding region in the protein appears to be identical to the c-myc and IL-3 mRNA-binding regions. Moreover, this study showed that in vitro treatment of neuroblastoma cells with interleukin-4 (IL-4), which inhibits TNF-alpha production, reduced the expression of the neuronal ELAV-like proteins. These results suggest that the expression of neuronal ELAV-like proteins may be closely associated with the expression of TNF-alpha in neuronal cells.
The PLE21/HuC neural protein is an autoantigen for anti-neuronal nuclear autoantibodies (ANNA-1/anti-Hu/Type IIa antibodies) from a patient with paraneoplastic limbic encephalomyelitis and small cell lung carcinoma. This antigen belongs to the Hu/ELAV-like protein family, contains three RNA recognition motifs (RRMs) and has RNA binding capacity. In many autoimmune diseases mediated by autoantibodies, antibodies often interfere with the biological functions of their target antigens. To investigate the influences of the autoantibodies on the biological function of the antigen, we mapped the regions which were required for the antibody recognition and for the RNA binding. Deletion analysis of the antigen revealed that the epitopes for the antibodies were localized in the regions of 12 residues, amino acids 161-172, and eight residues, amino acids 29-38, of the first and second RRMs. It was also shown that the eight residues, amino acids 29-38, and the 10 residues, amino acids 187-194, were required for the RNA binding. Although amino acids 29-38 were necessary for both the antibody recognition and the RNA bindings, pre-incubation of the PLE21 antigen with the antibodies did not inhibit the formation of the complex of PLE21, the antibodies and RNA. Thus, the regions required for the antibody recognition are not identical with those for the RNA binding, and it seems unlikely that the autoantibodies interfere with RNA binding of the antigen.
Previously we have demonstrated that ibudilast, which is used clinically for treating patients with asthma and cerebrovascular diseases, prevents excitotoxicity of oligodendroglial lineage mediated by Ca2+ influx via non-N-methyl-D-aspartate (NMDA) glutamate receptor (GluR) channels. We here present a finding that ibudilast prevents oxygen-glucose deprivation (OGD)-induced oligodendroglial injury. The oligodendrocyte-like cells (OLC), differentiated from the CG-4 cell line established from rat oligodendrocyte-type-2 astrocyte (O-2A) progenitor cells, were exposed to hypoxia in the absence of glucose for 12 h and subsequent reoxygenation for 2 h. Cell damage was evaluated by measuring activity of lactate dehydrogenase (LDH) released into the culture medium. OGD for 12 h induced 30 to 50% LDH release into the medium. OLC damage induced by deprivation of oxygen and glucose was prevented by ibudilast at concentrations of > or = 50 microM. The protection given by ibudilast against OGD-induced injury was enhanced by prostacyclin (PGI2). OGD-induced OLC injury was prevented by 6-cyano-7-nitroquinoxaline-2, 3-dione (CNQX), an inhibitor of non-NMDA GluR or deprivation of Ca2+ from culture medium. While ibudilast increased intracellular cAMP at concentrations of > or = 10 microM, at least 100 microM concentrations were needed to increase intracellular cGMP. Therefore, we concluded that ibudilast prevented OGD-induced oligodendroglial injury possibly by increasing intracellular cAMP which modulates Ca2+ influx via non-NMDA GluR channels.
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We describe 3-year clinical course of a 54-year-old Japanese man who presented with action myoclonus, parkinsonism and epilepsy. There was no family history or consanguinity. The patient was well until the age of 51 years (in 1986), when he noted slow movements, memory disturbance and left hand tremor. He was treated with anti-Parkinson drugs without any improvements. Soon thereafter, he developed a gait disturbance and generalized tonic clonic seizures. He was admitted to our service at the age of 53 years. General physical examination revealed no hepatosplenomegaly. Neurological examination showed mild dementia. Neither retinal pigmentation nor cherry red spot was noted. He was unable to walk due to marked frozen gait. His upward gaze was limited and saccadic eye movement was slow. He had action myoclonus in both upper extremities and resting tremor on the left side. He showed mild left hemiparesis. Deep tendon reflex was hyperactive in both side with extensor plantar responses. MRI demonstrated cortical atrophy, especially marked at the bilateral temporal lobes with a right side predominance. Leukocyte lysosomal enzyme activities of beta-hexosaminidase, beta-galactosidase and sialidase were within normal limits. The patient died of pneumonia on April 25, 1989. At the time of a neurological CPC, neurologists reached the clinical diagnosis of adult-type neuronal ceroid-lipofuscinosis. Postmortem examination revealed bilateral bronchopneumonia. The brain weighed 1,219 g and showed atrophy of the temporal lobes. Histological examination showed neuronal cells with swollen cytoplasm and lipofuscin-like granules throughout the CNS, including the cerebral cortex, thalamus, substantia nigra, motor nuclei of the brain stem, dentate nuclei, inferior olivary nuclei. Clarke's nuclei and anterior horn cells. Marked neuronal loss was noted in the right temporal lobe and substantia nigra. Electron micrographs of the frontal cortex revealed "fingerprint profiles" in the cytoplasm of neuronal and glial cells. Pathological findings were consistent with the diagnosis of adult-type neuronal ceroid-lipofuscinosis (Kufs' disease).
We reported a 68-year-old man with progressive supranuclear palsy who present with apraxia of eyelid closure. He showed horizontal and vertical supranuclear ophthalmoplegia, neck dystonic posture, pseudobulbar palsy and subcortical dementia. He opened his eyes almost all day long except for sleeping. His spontaneous blinking was noted at less than 1 per a minute. Although he closed his eyes reflexively, he could not close his eyes by verbal command. He occasionally closed his eyelids by using both hands. The surface electromyographic (EMG) findings revealed that the frequency of frontal muscle contraction did not decrease, and rather increased during verbal command to close his eyes. The contraction frequency of orbicularis oculi muscle did not increase by the command of voluntary eyelid closure. It is suggested that abnormal contractions of frontalis and orbicularis oculi muscles which are correlated in eyelid closing and opening might contribute to the apraxia of eyelid closure.
We report on a patient who developed primary position upbeat nystagmus (ppUBN) due to a unilateral medial medullary infarction. On oculography, the slow phases of the nystagmus sometimes had an exponentially decreasing velocity waveform, indicating that the nystagmus was due to impairment of the vertical position-to-velocity neural integrator. On magnetic resonance imaging, the lesion was caudal to the vestibular nuclei and to the most rostral of the perihypoglossal nuclei, the nucleus intercalatus, a structure that was also involved in a previously reported case of ppUBN due to a unilateral medullary lesion. On the basis of these imaging and oculographic observations, we propose that a unilateral lesion of the nucleus intercalatus is sufficient to cause ppUBN and that the nucleus intercalatus is a part of the vertical position-to-velocity neural integrator in the human ocular-motor system.
Previously, we have demonstrated that cells of the oligodendroglial lineage express non-NMDA glutamate receptor genes and are damaged by kainate-induced Ca2+ influx via non-NMDA glutamate receptor channels, representing oligodendroglial excitotoxicity. We find in the present study that agents that elevate intracellular cyclic AMP prevent oligodendroglial excitotoxicity. After oligodendrocyte-like cells, differentiated from the CG-4 cell line established from rat oligodendrocyte type-2 astrocyte progenitor cells, were exposed to 2 mM kainate for 24 h, cell death was evaluated by measuring activity of lactate dehydrogenase released into the culture medium. Released lactate dehydrogenase increased about threefold when exposed to 2 mM kainate. Kainate-induced cell death was prevented by one of the following agents: adenylate cyclase activator (forskolin), cyclic AMP analogues (dibutyryl cyclic AMP and 8-bromo-cyclic AMP), and cyclic AMP phosphodiesterase inhibitors (3-isobutyl-1-methylxanthine, pentoxifylline, propentofylline, and ibudilast). Simultaneous addition of both forskolin and phosphodiesterase inhibitors prevented the kainate-induced cell death in an additive manner. A remarkable increase in Ca2+ influx (approximately 5.5-fold) also was induced by kainate. The cyclic AMP-elevating agents caused a partial suppression of the kainate-induced increase in Ca2+ influx, leading to a less prominent response of intracellular Ca2+ concentration to kainate. The suppressing effect of forskolin on the kainate-induced Ca2+ influx was partially reversed by H-89, an inhibitor of cyclic AMP-dependent protein kinase. In contrast to this, okadaic acid, an inhibitor of protein phosphatases 1 and 2A, brought about a decrease in the kainate-induced Ca2+ influx. We therefore concluded that cyclic AMP-elevating agents prevented oligodendroglial excitotoxicity by cyclic AMP-dependent protein kinase-dependent protein phosphorylation, resulting in decreased kainate-induced Ca2+ influx.
BACKGROUND AND PURPOSE: There have been few reports of pontine syndromes secondary to paramedian pontine infarctions. To clarify the clinicotopographical correlation and prognosis of paramedian pontine infarct syndromes, we analyzed the clinical signs and their association with MRI findings. METHODS: We studied 49 patients with acute paramedian pontine infarcts and classified them into three subtypes on the basis of lesion location on MRI. Patient clinical status was assessed by Rankin Disability Scale (RDS) scores on admission and at 60 days after onset of stroke. RESULTS: Twenty-seven patients had basal infarcts. Clinical findings included dysarthria (n = 27), hemiparesis with upper extremity predominance (n = 15), brachial monoparesis (n = 4), and pathological laughing (n = 3). Fifteen patients had basal-tegmental infarcts. Clinical findings presented with hemiparesis and horizontal gaze abnormalities, including abducens nerve palsy (n = 1), internuclear ophthalmoplegia (INO) (n = 5), horizontal gaze palsy (n = 1), one-and-a-half syndrome (n = 1), and superficial or proprioceptive sensory dysfunction (n = 8). Seven patients had tegmental infarcts. Clinical findings included INO (n = 1), horizontal gaze palsy (n = 2), one-and-a-half syndrome (n = 3), and sensory changes (n = 2). On both admission and 60 days later, the RDS scores of the patients with upper pontine lesions were significantly better than those with lower pontine lesions (P < .01). The RDS scores of the patients with basal-tegmental infarct in the upper pons were significantly better than those with infarct in the lower pons (P < .02). CONCLUSIONS: Paramedian pontine infarcts, which are usually due to thrombosis of perforating arteries, presented with a faciobrachial dominant hemiparesis with dysarthria, somatosensory disturbance, and horizontal gaze abnormalities. The favorable outcome may be related to the level of the pontine lesion, which influences the effect on the corticospinal tract.
Previously we have demonstrated that cells of oligodendroglial lineage express non-N-methyl-D-aspartate (NMDA) glutamate receptor (GluR) genes and are damaged by kainate induced Ca2+ influx via non NMDA GluR channels of the alpha-amino-3-hydroxy-5-methyl 4 isoxazole propionate (AMPA) type, representing oligodendroglial excitotoxicity. We here present the finding that ibudilast, which is used clinically for treat patients with asthma and cerebrovascular diseases, prevents oligodendroglia excitotoxicity. The oligodendrocyte like cells (OLC), differentiated from the CG-4 cell line established from rat oligodendrocyte-type 2 astrocyte (O-2A) progenitor cells, were exposed to 2 mM kainate for 24 h and cell death was evaluated by measuring activity of lactate dehydrogenase (LDH) released into the culture medium. Kainate induced cell death was prevented by 10 to 100 microM ibudilast, which increased intracellular cAMP. A 45Ca2+ influx study revealed that ibudilast attenuated kainate-induced Ca2+ influx. Inhibition of kainate-induced Ca2+ influx by ibudilast was decreased by H-89, a protein kinase A (PKA) inhibitor, but increased by okadaic acid, an inhibitor of phosphatase 1 and 2A. Therefore, we concluded that ibudilast prevented oligodendroglial excitotoxicity by a PKA-dependent phosphorylation process resulting in decreased kainate-induced Ca2+ influx.
Paraneoplastic neurologic syndromes are degenerative diseases of the central or peripheral nervous system that develop in association with a systemic neoplasm without a direct invasion by tumor. The pathogenesis of this disorder has been hypothesized in the past, and now there is increasing evidence that autoimmune processes triggered by the underlying neoplasm play a major role in the pathophysiology, as documented by many reports of identification of autoantibodies that react with both the target neural tissue and the underlying neoplasm, as evidenced by the extensive application of molecular biology techniques. The presence of antibodies in serum or CSF of some patients with this disorder now accurately identifies the subgroup of the disorders related to specific neoplasms. The trend of recent studies on the pathogenesis of this disease may in the future lead to a new era to clarify the pathogenesis.
The PCD17 protein is a paraneoplastic cerebellar degeneration (PCD)-associated neural autoantigen which is recognized by autoantibodies in sera of PCD patients. The localization of the PCD17 mRNA was examined by in situ hybridization histochemistry using a PCD17 cRNA probe. In the cerebellum, the localization of the transcript was in agreement with the distribution of PCD17-immunoreactivity. On the other hand, intense hybridization signals were detected in most of cells in the hippocampus in which notable PCD17-immunoreactivity was undetected. These observations suggest that some negative translational or post-transcriptional mechanisms of the PCD17 mRNA may be involved in neurons of the hippocampus.
We immunized five different strains of mice with the recombinant human PCD17 protein, which is recognized by anti-Purkinje cell antibodies in the sera of patients with paraneoplastic cerebellar degeneration, and explored whether or not antibodies against cerebellar Purkinje cells could be induced in vivo. Autoantibodies against the cytoplasmic protein of Purkinje cells and other neurons were raised in all the strains of mice. These antisera stained the cytoplasm of cytoplasm of the Purkinje cell in a coarse, granular pattern, but spared the nucleus. The antisera did not stain cerebellar granular cells. This pattern of immunostaining seen with the mouse antisera is similar to that seen with the human PCD sera, but more widespread cells in the central nervous system were stained with these antisera. The titers of the induced antibodies were comparable to or even higher than those of humans. The deposition of IgG was also demonstrated in the cytoplasm of Purkinje cells in the immunized mice. In spite of the generation of anti-Purkinje cell antibodies in vivo, neither clinical nor pathological changes consistent with cerebellar degeneration were detected 1 year following the first immunization.
We presented a case of critical illness polyneuropathy after bacterial peritonitis. A 62-year-old male was received an emergency colectomy because of perforation of the sigmoid colon five days after the endoscopic polypectomy. He developed sepsis from peritonitis after operation in spite of the antibiotics therapy. On 15-th hospital days he developed muscle weakness and numbness of all limbs. He needed an artificial ventilator due to respiratory failure. Hematological and blood chemical findings showed a leukocytosis and metabolic acidosis with renal dysfunction because of sepsis. Serum anti-Campylobacter antibody was negative. Serial CSF examinations failed to show any abnormalities including albuminocytologic dissociation. Electrophysiological studies revealed a primary axonal degeneration, mainly in the motor, but also in the sensory nerve. Compound muscle and sensory action potentials were not elicited or markedly reduced without conduction velocity prolongation. Microscopic findings of the left sural nerve biopsy showed a primary axonal degeneration without evidence of inflammation. His prognosis was poor and three months later, he still required ventilatory assistance. Because of these clinical findings this patient was thought to have a critical illness polyneuropathy after excluding various etiologies of polyneuropathies. This case suggests that sepsis may be one of a cause of primary axonal polyneuropathy. The certain mechanism of this disease is still unknown. However cytokine, tumor necrotic factor(TNF) and/or Platelet activating factor(PAF) that secreted during sepsis may have an important role for the primary axonal degeneration.