Beneficial effect of tacrolimus on myasthenia gravis with thymoma.

We examined the effect of tacrolimus on myasthenia gravis (MG). Five patients with thymoma and 5 patients without thymoma underwent prior thymectomy but showed persistent myasthenic symptoms. Oral administration with tacrolimus significantly improved MG scores 1, 3, and 6 months following the beginning of treatment in all patients (P < 0.05), and the improvement was significantly higher in the thymoma group compared with the nonthymoma group (P < 0.05). However, there was no significant change in antiacetylcholine receptor titers in either group. This indicates a particular application of immunosuppressive therapy for thymomatous MG following thymectomy.

Delayed motor and sensory neuropathy in a patient with brainstem encephalitis.

Bickerstaff's brainstem encephalitis (BBE), Miller Fisher syndrome (MFS) and Guillain-Barré syndrome (GBS) are thought to be closely related and to form a continuous spectrum. However, chronic polyneuropathy in BBE has not been reported. We report the temporal profile of anti-ganglioside antibody titer in a case of BBE-like brainstem encephalitis complicated with chronic polyneuropathy. A 71-year-old Japanese woman presented with drowsiness and cerebellar ataxia in addition to mild weakness in distal limb muscles. Anti-GalNAc-GD1a IgG and anti-GalNAc-GM1b IgG antibodies were positive in her serum. Brain magnetic resonance imaging revealed high-intensity signals in the midbrain, pons, and middle cerebellar peduncles on T2-weighted images. Central nervous system manifestations improved after immunomodulating therapy that included prednisolone, plasmapheresis and intravenous immunoglobulin. Nevertheless, the distal muscle weakness was exacerbated when the anti-GalNAc-GD1a IgG titer was elevated. Nerve conduction study indicated motor and sensory neuropathy which was developed motor dominant axonal damage. These findings suggest that anti-ganglioside antibodies, including anti-GalNAc-GD1a IgG, may be involved in a common autoimmune mechanism in BBE-like brainstem encephalitis and chronic motor dominant axonal neuropathy. However, the fact that the latter manifestation exacerbated after the improvement of former one possibly indicates different thresholds of neurologic symptoms mediated by anti-ganglioside antibodies in the present patient.

Central motor conduction in cervical dystonia with cervical spondylotic myelopathy.

OBJECTIVES: It has been known that cervical dystonia develops secondarily to spinal cord injuries as secondary dystonia. However, little is known about the pathophysiological mechanism. PATIENTS AND METHODS: We examined motor and sensory conduction in six patients with symptomatic cervical dystonia by transcranial magnetic stimulation (TMS). All of the patients exhibited unilateral head rotation. They had symptoms corresponding to cervical myelopathy and felt discomfort in the neck, shoulders or arms before involuntary movement occurred. RESULTS: Although the overall central motor conduction time (CMCT) was not different from that of normal controls, contralateral CMCT was significantly delayed compared to ipsilateral CMCT (p<0.05). The results of somatosensory evoked potential study demonstrated that contralateral central conduction time (CCT) was not significantly different from ipsilateral CCT. CONCLUSION: These findings indicate that there is a selective interference with the contralateral corticospinal tract in patients with symptomatic cervical dystonia.

Guillain-Barré syndrome and hemophagocytic lymphohistiocytosis in a patient with severe chronic active Epstein-Barr virus infection syndrome.

Epstein-Barr virus (EBV) infection causes a wide range of neurologic and hematologic manifestations. We report a 72-year-old Japanese male patient with severe chronic active EBV infection syndrome (SCAEBV) who presented with Guillain-Barré syndrome (GBS) and developed hemophagocytic lymphohistiocytosis (HLH) several months after the onset of GBS. He showed acute onset of distal muscle weakness, ophthalmoplegia and bulbar palsy. Results of nerve conduction study revealed acute motor-sensory axonal neuropathy (AMSAN). His serum was positive for anti-LM1 IgG and anti-GM1b IgM. Titers of antibodies to EBV-related antigens indicated chronic reactivated EBV infection. Treatment with IVIg resolved the acute ophthalmoplegia, but there was no notable improvement in the AMSAN and bulbar palsy despite repeated. Finally, he developed refractory HLH resulting in a fatal outcome. In the present patient, it seems that SCAEBV was associated with the development of GBS and fatal HLH via parainfectious autoimmunity and direct infectious immune mechanisms, respectively.

Spontaneous mutation in Big Blue mice from fetus to old age: tissue-specific time courses of mutation frequency but similar mutation types.

Transgenic mouse mutation detection systems permit rapid determination of the frequency and type of mutations allowing direct examination of mutational markers for aging, neurodegeneration, and cancer. The Big Blue transgenic mouse mutation detection system was used to determine the frequency and nature of spontaneous mutations versus age in multiple tissue types. Nuclear DNA was extracted from whole fetus at 13.5 days postcoitus (dpc) and from six tissues postbirth (cerebellum, forebrain, thymus, liver, adipose tissue, and male germline) of Big Blue transgenic mice at four ages: 10 days and at 3, 10, and 25 months postbirth. Forty million total plaque-forming units (pfu) were screened. The time course of mutation frequency with age had a significantly different shape in different tissues (P < 10(-6)). By 13.5 dpc, the whole fetus mutation frequency had already started increasing from the theoretical zero at conception to a value that was about one-half the mid-adulthood (3-10 months) average. From 10 days to 3 months, mutation frequency increased significantly in liver (P = 0.007) and showed an increasing trend in cerebellum, forebrain, and thymus. From 3 to 10 months, there was no significant change in mutation frequency in any tissue examined. From 10 to 25 months, the mutation frequency increased significantly in liver (P < 10(-6)) and adipose tissue (P = 0.002), but not in the other tissues examined (cerebellum, forebrain, and male germline). It is of interest that the mutation frequency in the male germline is consistently the lowest, remaining essentially unchanged in old age. The spectrum of mutation types was unaltered with age, tissue type and gender, although, as previously reported, tandem GG-->TT mutations are tissue specific and show significant increases with age and certain hotspots (Buettner VL et al. [1999]: Environ Mol Mutagen 33:320-324; Hill KA et al. [2003]: Mutat Res 534:173-186). The spectrum of mutation types was generally the same for all tissue types, despite the tissue-specific increases in mutation frequency with age. These data provide a useful reference for future studies of endogenous and exogenous mutagenesis.

Isolated cranial neuropathy associated with anti-glycolipid antibodies.

We describe seven patients with isolated cranial neuropathy in whom serum anti-glycolipid antibodies were detected. Trigeminal sensory neuropathy was found in four patients, who had exhibited symptoms for 2 months to 4 years. The other three patients showed facial nerve palsy with or without ophthalmoparesis. Temporal profile analysis of anti-glycolipid antibodies revealed that titers of anti-glycolipid IgM antibodies against GM2 and LM1 gradually decreased in patients having chronic trigeminal sensory neuropathy. In patients with acute trigeminal sensory neuropathy, elevation of anti-LM1 antibody titers continued over 12 months although anti-GalNAc-GD1a antibody disappeared. On the other hand, titers of anti-glycolipid antibodies rapidly decreased in patients with acute facial nerve palsy with or without ophthalmoparesis. We conclude that anti-glycolipid antibodies may play an important role in the development of isolated cranial neuropathy in some patients.

Dissociation between titer of anti-ganglioside antibody and severity of symptoms in a case of Guillain-Barré syndrome with treatment-related fluctuation.

Since plasma exchange (PE) and intravenous immunoglobulin (i.v.Ig) have been widely used in treatment for Guillain-Barré syndrome (GBS), early relapse and treatment-related fluctuation have been a potential problem, but little is known about the mechanism of relapse and fluctuation. We describe a patient who had GBS with treatment-related fluctuation. A 37-year-old Japanese man exhibited acute distal-dominant weakness in upper limbs after upper respiratory infection. His cranial nerve system was normal and muscle weakness was limited to upper limbs. Anti-GT1a IgG was strongly positive and anti-GQ1b IgG was also detected in his serum. Muscle weakness responded well to double-filtration plasmapheresis (DFPP) followed by i.v.Ig, but relapsed 45 days after the initial treatment. Although repeated treatments were effective, the patient showed additional minor deterioration twice. Motor nerve conduction velocities (MCVs) corresponded to the muscle weakness, but elevated level of cerebrospinal fluid (CSF) protein remained and anti-ganglioside antibody titers steadily decreased throughout the clinical course. These findings indicate that the clinical fluctuation was not due to changes in the production of anti-ganglioside antibodies but presumably to the transient beneficial effects of DFPP/i.v.Ig and the outlasting inflammatory response in peripheral nerves.

Complicated paraneoplastic neurological syndromes: a report of two patients with small cell or non-small cell lung cancer.

Paraneoplastic neurological syndromes are frequently associated in patients with small cell lung cancer (SCLC) and antineuronal antibodies are involved in the autoimmune mechanism. Multiple syndromes are sometimes complicated in a single patient with SCLC. However, little is known about non-SCLC-associated neurological manifestations. We report two patients with complicated paraneoplastic neurological syndromes. Patient 1 showed paraneoplastic limbic encephalitis (PLE), paraneoplastic sensory neuropathy (PSN) and Lambert-Eaton myasthenic syndrome (LEMS) associated with SCLC. Patient 2 developed opsoclonus-ataxia and probable PLE associated with non-SCLC. Analysis of various antineuronal antibodies revealed that anti-Hu and P/Q-type voltage-gated calcium channel (VGCC) antibodies were positive in Patient 1 but any antibodies were not in Patient 2. Brain MRI demonstrated high intensity signals in temporal lobes particularly on fluid-attenuated inversion recovery (FLAIR) or diffusion-weighted images. These findings suggest that complicated paraneoplastic neurological syndromes occur in non-SCLC as well as SCLC and that unidentified antineuronal autoantibodies may underlie the pathophysiology.

Neuro-Behçet's disease with chorea after remission of intestinal Behçet's disease.

Neuro-Behçet's disease shows various neuropsychiatric symptoms, but chorea has rarely been reported. We report a case of neuro-Behçet's disease in a 67-year-old woman with depression and chorea that occurred 22 years after the onset of intestinal Behçet's disease. Brain magnetic resonance imaging (MRI) using a fluid-attenuated inversion-recovery (FLAIR) sequence demonstrated lesions more clearly than did T2-weighted MRI. Some of the lesions appeared as small ring-like foci, i.e. low-intensity spots rimmed with remarkable hyperintense signals, in the periventricular white matter and basal ganglia. A review of the literature revealed that the onset of chorea in cases of Behçet's disease varied from the time of onset of Behçet's disease to 31 years after onset of the disease. Psychiatric manifestations have often been associated with neuro-Behçet's disease. In the present patient, treatment with prednisolone resolved the chorea, suggesting that the chorea was caused by an autoimmune mechanism. It seems likely that the long-term development of vasculitis in patients with Behçet's disease results in the formation of these particular brain lesions on FLAIR MR images. Chorea should be taken into consideration as one of the manifestations of Behçet's disease, even many years after remission of the disease.

Dermatomyositis with peripheral nervous system involvement: activation of vascular endothelial growth factor (VEGF) and VEGF receptor (VEGFR) in vasculitic lesions.

We describe two cases of dermatomyositis (DM) with nervous system involvement. Polyneuropathy was observed in both patients, and cerebral vasculitis was suspected in one patient. Histological examination of biopsied specimens of skeletal muscles, skin and sural nerves revealed vasculitis. Furthermore, vascular endothelial growth factor (VEGF) and VEGF receptors (VEGFRs) were overexpressed in vasculitic lesions. Although, VEGF and VEGFRs were not detected in biopsied specimens of skeletal muscle from normal subjects, they were observed in one of two patients with DM who did not exhibit neuropathy. These findings suggest the possibility that VEGF overproduction is associated with development of vasculitis in some cases of DM complicated with peripheral neuropathy.

Anti-neuronal antibodies in acute pandysautonomia.

We encountered two patients with acute pandysautonomia who subacutely exhibited extensive autonomic dysfunction after antecedent infections. Although these patients had been suffering from autonomic disturbance for several months, they both had a good clinical course after plasma exchange and intravenous immunoglobulin therapy. Thin-layer chromatography (TLC)-immunostaining did not demonstrate any antibodies against gangliosides, but immunoblot analysis showed antibodies against a neuroblastoma cell line, SH-SY5Y, in serum samples. Furthermore, ganglionic acetylcholine receptor autoantibodies were detected in one patient. These findings suggest that neuronal antibodies against the autonomic nervous system play an important role in the pathogenesis of acute pandysautonomia.

Parkin affects mitochondrial function and apoptosis in neuronal and myogenic cells.

We investigated the effect of parkin on mitochondrial function and apoptosis in SH-SY5Y, L6, RD, and COS-1 cells. Wild-type parkin attenuated reactive oxygen species (ROS) production in SH-SY5Y cells and mutant parkin enhanced ROS production in SH-SY5Y and L6 cells. Reactive oxygen intermediates, that were detected in mitochondria, were decreased in cells with overexpression of parkin. Parkin prevented apoptosis and enhanced mitochondrial membrane potentials in SH-SY5Y and L6 cells not in COS-1 cells. Expressions and enzymatic activities of mitochondrial respiratory chain complexes were not uniformly enhanced but those of complex 1 were selectively enhanced. The present results suggest the cell-selective function of parkin, i.e., parkin possesses anti-apoptotic and anti-oxidant function in neuronal or myogenic cells but not in kidney cells.

Parkin enhances mitochondrial biogenesis in proliferating cells.

We describe a novel function of parkin, a RING protein, which is elaborately involved in mitochondrial biogenesis. Parkin was located within the mitochondrial organelle of proliferating cells. Anti-proliferative treatments released parkin from mitochondria to cytosol. Results of pharmacological treatments indicate that parkin was released from mitochondria when permeability transition pore was opened. The extra-mitochondrial localization was also observed in differentiated cells. In proliferating cells, transcription and replication of mitochondrial DNA was enhanced by parkin overexpression and attenuated by parkin suppression with siRNA. Parkin was associated with mitochondrial transcription factor A (TFAM) and enhanced TFAM-mediated mitochondrial transcription. These results indicate that parkin is involved in the regulation of mitochondrial transcription/replication other than the ubiquitin-mediated protein degradation system in proliferating cells.

Involvement of mitochondria in myasthenia gravis complicated with dermatomyositis and rheumatoid arthritis: a case report.

We report a 57-year-old male with myasthenia gravis complicated with dermatomyositis and rheumatoid arthritis without evidence of thymoma. He showed prominent muscle wasting and weakness in the four extremities and trunk in addition to swallowing disturbance. He showed intolerance to exercise on a bicycle ergometer, and muscle biopsy specimens demonstrated ragged-red fibers. An anti-acetylcholine receptor (AChR) antibody was detected in his serum but no anti-mitochondrial M2 component antibody was found. In contrast, results of immunohistochemical study indicated that his serum sample reacted to muscle mitochondria as well as AChR. These results indicate the presence of an unidentified anti-mitochondrial antibody that may be involved in the development of mitochondrial dysfunction in skeletal muscle of the present patient.

Beneficial effect of steroid pulse therapy on acute viral encephalitis.

Corticosteroids are often used in the treatment of acute viral encephalitis, although the efficacy of corticosteroid therapy has not been proven. We examined the effects of high-dose corticosteroid therapy on acute viral encephalitis in 5 patients with progressive disturbances of consciousness. In 3 patients who were treated within 5 days after the onset of illness, pulse therapy dramatically reduced the degree of consciousness disturbance. They became alert within 24 h, and then neurological symptoms gradually improved. Corticosteroid therapy in the other 2 patients, in whom treatment was started more than 3 weeks after the onset of illness, was not as effective, but repeated therapy at 2-week intervals resulted in complete recovery. These findings suggest that high-dose corticosteroid therapy is effective, particularly for disturbances of consciousness, an important prognostic factor in acute viral encephalitis.

Overexpressions of myoglobin and antioxidant enzymes in ragged-red fibers of skeletal muscle from patients with mitochondrial encephalomyopathy.

To determine the relationship between myoglobin (Mb) and the defense system against reactive oxygen species in various myopathies, we performed immunohistochemical analyses of Mb and various antioxidant enzymes, including manganese superoxide dismutase (Mn-SOD), copper zinc SOD (CuZn-SOD), catalase (CAT), and glutathione peroxidase (GSH-Px). Biopsied muscle specimens were obtained from patients with chronic progressive external ophthalmoplegia (CPEO), Kearns-Sayre syndrome (KSS), Duchenne muscular dystrophy (DMD), and polymyositis (PM). In patients with CPEO/KSS, stainings of Mb, SOD, CAT, and GSH-Px in nonatrophic ragged-red fibers (RRFs) were more intense than those in non-RRFs. These pronounced stainings corresponded to ragged-red lesions. The staining intensities of these antioxidant enzymes were significantly correlated with that of Mb (P < 0.001). Atrophic RRFs in specimens from patients with CPEO/KSS showed intense stainings of these antioxidant enzymes but not intense staining of Mb. In specimens from patients with DMD/PM, the antioxidant enzymes but not Mb were overexpressed in degenerative fibers. These results suggest that oxidative stress is associated with Mb expression specifically in mitochondrial diseases. The antioxidant enzymes seem to be upregulated to protect against muscle damage in nonatrophic RRFs. However, the Mb-mediated oxidative damage may become more extensive and result in further mitochondrial dysfunction and progressive atrophy of RRF with impaired upregulation of Mb.

Oxidative stress-associated mitochondrial dysfunction in corticosteroid-treated muscle cells.

We analyzed the effects of corticosteroid on mitochondrial membrane potentials (DeltaPsi(m)), generation of reactive oxygen species (ROS), and apoptosis in a human rhabdomyosarcoma cell line, RD, and a dopaminergic neuroblastoma cell line, SH-SY5Y. The cell lines were cultured in the presence or absence of dexamethasone and superoxide dismutase (SOD) for up to 1 week. Dexamethasone treatment increased DeltaPsi(m), ROS generation, and apoptosis in proliferating RD cells. Treatment with SOD attenuated ROS generation and apoptosis, but not DeltaPsi(m). The increase in DeltaPsi(m) seemed to be the primary effect of dexamethasone on proliferating RD cells, which is probably mediated by mitochondrial transcription. In differentiated RD cells, but not differentiated SH-SY5Y cells, dexamethasone treatment showed a delayed effect of interfering with the DeltaPsi(m) and increasing ROS generation and apoptosis. Since these changes disappeared in the presence of SOD, dexamethasone primarily induced ROS generation, resulting in apoptosis. We speculate that this mechanism provides the basis of a pathophysiological model of corticosteroid myopathy.