Anti-Kv1.4 Antibody-positive Nivolumab-induced Myasthenia Gravis and Myositis Presenting with Bilateral Ptosis and Demonstrating Different Pathophysiologies.

Nivolumab blocks inhibitors of T-cell activation and restores antitumor immunity but promotes T-cell activity in host tissues by blocking inhibition of the T-cell function, resulting in immune-related adverse effects. We herein report an 80-year-old man presenting with nivolumab-related myasthenia gravis with anti-muscular voltage-gated potassium channel-complex (Kv1.4) antibodies. On day 29 after nivolumab administration, he simultaneously developed rapidly progressing right ptosis and left facial paralysis. Nivolumab administration was discontinued. He subsequently presented with bulbar paralysis, dyspnea, and muscle weakness and received intravenous immunoglobulin, methylprednisolone, and plasma exchange. The severity of nivolumab-related myasthenia gravis with anti-Kv1.4 antibodies presented with diverse clinical findings.

Persistent Severe Cerebral Edema with Neutrophil Infiltration Following Listeria Meningitis.

A 51-year-old man was admitted to the hospital with a diagnosis of Listeria monocytogenes meningitis. Diffuse cerebral edema appeared after improvement of meningitis with appropriate treatment and worsened for two months. Due to brain herniation, brain tissue leaked through the incision made during the drain insertion in a hydrocephalus surgery. We found pathological evidence of significant neutrophil infiltration with a few lymphocytes without bacterial detection in the degraded brain tissue. The present case indicates that fatal cerebral edema with significant neutrophil infiltration may develop even after appropriate treatment for L. monocytogenes meningitis.

Autoimmune basal ganglia encephalitis associated with anti-recoverin antibodies: A case report.

Autoimmune basal ganglia encephalitis causes neurological symptoms such as parkinsonism associated with basal ganglia lesions. Here, we report a case of autoimmune basal ganglia encephalitis without retinal lesions or malignancy harboring anti-recoverin antibodies. The patient was a 67-year-old Japanese woman who developed anorexia, parkinsonism, and disturbance of consciousness 7 days before admission. Brain magnetic resonance imaging showed hyperintense bilateral basal ganglia lesions on fluid-attenuated inversion recovery images. 18F-fluorodeoxyglucose-positron emission tomography showed no malignancy in the trunk, and dopamine transporter single-photon emission computed tomography with dopamine transporters revealed reduced radiotracer uptake in the basal ganglia. Further, anti-recoverin IgG antibodies were detected in serum immunoblot. Based on the clinical and imaging findings, the patient was diagnosed with autoimmune basal ganglia encephalitis with anti-recoverin antibodies and administered high-dose immunoglobulins (HD-IVIG), which led to an improvement in clinical symptoms. Anti-recoverin antibodies are paraneoplastic antibodies that explicitly bind to Ca2+-binding proteins in the retina and cause retinopathy. This pathological sequence is defined as cancer-associated retinopathy (CAR). However, in our case, autoimmune basal ganglia encephalitis developed without CAR syndrome or malignancy. Clinicians should be aware of the possibility of autoimmune basal ganglia encephalitis showing anti-recoverin antibodies but no CAR syndrome or malignancy, which should be treated with HD-IVIG therapy.

Clioquinol Decreases Levels of Phosphorylated, Truncated, and Oligomerized Tau Protein.

The neuropathological hallmarks of Alzheimer's disease (AD) are senile plaques (SPs), which are composed of amyloid ß protein (Aß), and neurofibrillary tangles (NFTs), which consist of highly phosphorylated tau protein. As bio-metal imbalance may be involved in the formation of NFT and SPs, metal regulation may be a direction for AD treatment. Clioquinol (CQ) is a metal-protein attenuating compound with mild chelating effects for Zn2+ and Cu2+, and CQ can not only detach metals from SPs, but also decrease amyloid aggregation in the brain. Previous studies suggested that Cu2+ induces the hyperphosphorylation of tau. However, the effects of CQ on tau were not fully explored. To examine the effects of CQ on tau metabolism, we used a human neuroblastoma cell line, M1C cells, which express wild-type tau protein (4R0N) via tetracycline-off (TetOff) induction. In a morphological study and ATP assay, up to 10 µM CQ had no effect on cell viability; however, 100 µM CQ had cytotoxic effects. CQ decreased accumulation of Cu+ in the M1C cells (39.4% of the control), and both total and phosphorylated tau protein. It also decreased the activity of c-Jun N-terminal kinase (JNK) and p38 mitogen-activated protein kinase (p38 MAPK) (37.3% and 60.7% levels of the control, respectively), which are tau kinases. Of note, activation of protein phosphatase 2A (PP2A), which is a tau phosphatase, was also observed after CQ treatment. Fractionation experiments demonstrated a reduction of oligomeric tau in the tris insoluble, sarkosyl soluble fraction by CQ treatment. CQ also decreased caspase-cleaved tau, which accelerated the aggregation of tau protein. CQ activated autophagy and proteasome pathways, which are considered important for the degradation of tau protein. Although further studies are needed to elucidate the mechanisms responsible for the effects of CQ on tau, CQ may shed light on possible AD therapeutics.

A case of eosinophilic fasciitis without skin manifestations: a case report in a patient with lupus and literature review.

Eosinophilic fasciitis (EF) is a rare connective tissue disease that causes inflammation and fibrosis of the fascia, inducing pain and motor dysfunction. Characteristic skin manifestations, such as edema, erythema, induration, peau d'orange appearance, and the groove sign, are of diagnostic significance and observed in the majority of patients with EF. We herein report a case of EF without these characteristic skin manifestations. A 66-year-old Japanese woman developed progressive limb pain and motor dysfunction. No skin changes were observed. We diagnosed the patient with EF based on the clinical course, magnetic resonance imaging, and en bloc biopsy containing fascia and muscle. Oral prednisolone therapy markedly attenuated limb pain and motor dysfunctions. Through a systemic search of the medical literature, we retrieved 4 juvenile cases and 8 adult cases of EF without characteristic skin manifestations during the clinical course. We herein present a systemic review on EF without skin manifestations and discuss differences between the two proposed sets of diagnostic criteria of EF.

[A case of post-surgical inflammatory neuropathy with lower-extremity weakness after surgery for anorectal malignant melanoma that showed the effectiveness of immunotherapy].

A 59-year-old man with past histories of bronchial asthma and chronic sinusitis underwent transanal resection of anorectal malignant melanoma with general anesthesia. On the third day after surgery, he presented with subacute weakness with right dominant hypoesthesia in the bilateral lower limbs. Tendon reflexes were diminished without pathological reflexes. Blood examination showed increased eosinophils (2,058/µl) and elevated serum immunoglobulin E (675.0 IU/ml). Cerebrospinal fluid examination showed elevated protein (200 mg/dl) without pleocytosis (<5/µl). A nerve conduction study suggested multiple mononeuropathy with motor and axonal dominance in the right tibial, peroneal, and sural nerves. Because of eosinophilia and his past medical history (i.e., bronchial asthma and chronic sinusitis), we initially suspected eosinophilic polyangiitis granulomatosis (EGPA) as the cause of postoperative polyneuropathy. However, his neurological symptoms did not improve despite the decreased eosinophil count after tumor resection, which was inconsistent with EGPA. We biopsied the left sural nerve to exclude EGPA and make a diagnosis. Pathological findings revealed no demyelination, axonal degeneration, or eosinophil infiltration with granuloma formation; however, lymphocyte-dominated inflammation was observed around the epineurial small vessels. Thus, the patient was diagnosed with early onset post-surgical inflammatory neuropathy (PIN) based on his clinical course and the pathological findings. On post-surgery day 48, oral administration of prednisolone (40 mg/day) was started. His neurological symptoms improved quickly and remarkably. Our case suggests that, when multiple mononeuropathy develops early after surgery, PIN should be considered as a differential diagnosis to initiate appropriate treatment based on the pathological condition of neuropathy.

An autopsy case of tuberculous meningitis undiagnosed by nested-PCR of CSF samples and brain biopsy.

Nested polymerase chain reaction (PCR) testing of cerebrospinal fluid (CSF) has higher diagnostic sensitivity with regard to tuberculous meningitis (TBM) than conventional methods. Herein we describe the autopsy case of a 70-year-old woman with TBM that could not be diagnosed via nested PCR in CSF, even though it was performed three times. The clinical course, magnetic resonance imaging results, and elevated adenosine deaminase levels in CSF were consistent with TBM. We also performed a brain biopsy from the thickened leptomeninges of the patient, which showed granulomatous leptomeningitis consistent with TBM. However, we were not able to identify tuberculous bacilli by the acid-fast bacterial staining, single PCR test, and culture of the biopsy preparations. We finally diagnosed TBM in this case by the positive results of both the fourth PCR test and culture of her CSF, which were taken 7 days before her death. This case suggests that even the combination of repetitive nested PCR in CSF and brain biopsy lacks adequate sensitivity to exclude TBM in some patients.

[A case of neuromyelitis optica spectrum disorder with persistent nausea and repeated syncope].

A 22-year-old woman was admitted to our hospital with persistent nausea and no apparent cause. There was no preceding infection. The patient lost consciousness for several seconds. Based on an electrocardiographic diagnosis of paroxysmal sinus arrest (PSA), a temporary pacemaker was implanted. She did not develop syncope, but vertigo, nystagmus, diplopia, and limb paresthesia were observed. Brain MRI revealed a high-intensity lesion in the dorsal medulla on FLAIR images. As the serum anti-aquaporin 4 (AQP4) antibody was positive, the patient was diagnosed with neuromyelitis optica spectrum disorder (NMOSD). After she received steroid pulse therapy (methylprednisolone at 1,000 mg/day for three days) twice, her symptoms markedly improved. In this patient, PSA was considered to be a symptom of area postrema syndrome of NMOSD. Therefore, NMOSD should be considered as a possible cause of PSA.

Rho-kinase ROCK inhibitors reduce oligomeric tau protein.

Neurofibrillary tangles, one of the pathological hallmarks of Alzheimer's disease, consist of highly phosphorylated tau proteins. Tau protein binds to microtubules and is best known for its role in regulating microtubule dynamics. However, if tau protein is phosphorylated by activated major tau kinases, including glycogen synthase kinase 3ß or cyclin-dependent kinase 5, or inactivated tau phosphatase, including protein phosphatase 2A, its affinity for microtubules is reduced, and the free tau is believed to aggregate, thereby forming neurofibrillary tangles. We previously reported that pitavastatin decreases the total and phosphorylated tau protein using a cellular model of tauopathy. The reduction of tau was considered to be due to Rho-associated coiled-coil protein kinase (ROCK) inhibition by pitavastatin. ROCK plays important roles to organize the actin cytoskeleton, an expected therapeutic target of human disorders. Several ROCK inhibitors are clinically applied to prevent vasospasm postsubarachnoid hemorrhage (fasudil) and for the treatment of glaucoma (ripasudil). We have examined the effects of ROCK inhibitors (H1152, Y-27632, and fasudil [HA-1077]) on tau protein phosphorylation in detail. A human neuroblastoma cell line (M1C cells) that expresses wild-type tau protein (4R0N) by tetracycline-off (TetOff) induction, primary cultured mouse neurons, and a mouse model of tauopathy (rTG4510 line) were used. The levels of phosphorylated tau and caspase-cleaved tau were reduced by the ROCK inhibitors. Oligomeric tau levels were also reduced by ROCK inhibitors. After ROCK inhibitor treatment, glycogen synthase kinase 3ß, cyclin-dependent kinase 5, and caspase were inactivated, protein phosphatase 2A was activated, and the levels of IFN-γ were reduced. ROCK inhibitors activated autophagy and proteasome pathways, which are considered important for the degradation of tau protein. Collectively, these results suggest that ROCK inhibitors represent a viable therapeutic route to reduce the pathogenic forms of tau protein in tauopathies, including Alzheimer's disease.

Subventricular glial nodules in neurofibromatosis 1 with craniofacial dysmorphism and occipital meningoencephalocele.

BACKGROUND: Neurofibromatosis 1 (NF1) is autosomally inherited disorder, characterized by café au lait spots and multiple neurofibromas. Subventricular glial nodules (SVGN) are multiple gliosis bulging into the ventricular lumen, and histologically consist of astrocytes and their processes. Damage to ependymal cells induces SVGN formation. CASE REPORT: This case report describes a 50-year-old man with NF1, craniofacial dysmorphism, including sphenoid dysplasia, bone defects at the middle posterior fossa, with disconnection of the parieto-occipital sutures, and the left orbital bone, and occipital meningoencephalocele. He died of status epileptics. Pathologically, many SVGN were found around the ventricular wall. Many ependymal cells were stripped during ventricular dilatation. Therefore, to prevent brain tissue insult from direct exposure to CSF, the proliferation of astrocytes and their processes was speculated to have substitute for ependymal cells and induced SVGN formation.

Cladophialophora bantiana infection mimicking neuromyelitis optica.

Cladophialophora bantiana (C. bantiana) is a life-threatening melanized mycelial fungus causing brain abscess. C. bantiana is usually observed in tropical countries, including India. We report a Japanese case of C. bantiana presenting with myelitis mimicking neuromyelitis optica (NMO) and brain abscess. A 73-year-old man was administered prednisolone (30 mg/day) for antineutrophil cytoplasmic antibody (ANCA)-related vasculitis 100 days before admission. He had right side-dominant paraplegia and sensory loss in the right leg. T2-weighted spinal cord MRI revealed longitudinal high-intensity signals at the T7 to T12 levels. A ring-enhancing lesion at the T10 level was detected on gadolinium (Gd)-enhanced MRI. He was tentatively diagnosed with NMO, and steroid pulse therapy was performed. One month later, an abscess at the right cerebropontine angle was noted on Gd-enhanced brain MRI. Two months later, several subcutaneous intramuscular tumors were detected. Based on the morphological study of the cultured organelle obtained by tumor enucleation and the internal transcribed spacer sequence of ribosomal RNA, the pathogen was identified as C. bantiana. Although he received liposomal amphotericin B treatment, the patient died of respiratory insufficiency. C. bantiana infection should be considered in patients with myelitis presenting with longitudinal lesions and CNS abscess in an immunocompromised state.

Homocysteine Increases Tau Phosphorylation, Truncation and Oligomerization.

Increased plasma homocysteinemia is considered a risk factor of dementia, including Alzheimer's disease (AD) and vascular dementia. However, the reason elevated plasma homocysteinemia increases the risk of dementia remains unknown. A pathological hallmark of AD is neurofibrillary tangles (NFTs) that consist of pathologically phosphorylated tau proteins. The effect of homocysteine (Hcy) on tau aggregation was explored using human neuroblastoma M1C cells that constitutively express human wild-type tau (4R0N) under the control of a tetracycline off system, primary mouse cultured neurons, and by inducing hyperhomocysteinemia in a mouse model of tauopathy (HHCy mice). A wide range of Hcy concentrations (10-1000 µM) increased total tau and phosphorylated tau protein levels. Hcy activated glycogen synthase kinase 3, and cyclin dependent kinase 5, major tau phosphokinases, and inactivated protein phosphatase 2A, a main tau phosphatase. Hcy exhibited cytotoxic effects associated with enhanced activation of caspase. Truncation of tau in the C-terminus, the cleavage site of caspase 3 (i.e., D421, detected by the TauC3 antibody) was also increased. Total tau, phosphorylated tau, as well as C-terminal cleaved tau were increased in the sarkosyl insoluble tau fraction. Hcy also increased the level of tau oligomers, as indicated by the tau oligomer complex 1 (TOC1) antibody that specifically identifies oligomeric tau species, in the tris insoluble, sarkosyl soluble fraction. The levels of TOC1-positive oligomeric tau were increased in brain lysates from HHCy mice, and treating HHCy mice with S-adenosylmethionine, an intermediate of Hcy, reduced the levels of oligomeric tau to control levels. These observations suggest that Hcy increases the levels of phosphorylated tau as well as truncated tau species via caspase 3 activation, and enhanced tau oligomerization and aggregation.

Limbic encephalitis associated with anti-NH2-terminal of α-enolase antibodies: A clinical subtype of Hashimoto encephalopathy.

Several types of autoantibodies have been reported in autoimmune limbic encephalitis (LE), such as antibodies against the voltage-gated potassium channel (VGKC) complex including leucine-rich glioma inactivated 1 (LGI1). We recently reported a patient with autoimmune LE and serum anti-NH2-terminal of α-enolase (NAE) antibodies, a specific diagnostic marker for Hashimoto encephalopathy (HE), who was diagnosed with HE based on the presence of antithyroid antibodies and responsiveness to immunotherapy. This case suggests that LE patients with antibodies to both the thyroid and NAE could be diagnosed with HE and respond to immunotherapy. The aim of this study was to clarify the clinicoimmunological features and efficacy of immunotherapy in LE associated with anti-NAE antibodies to determine whether the LE is a clinical subtype of HE.We examined serum anti-NAE antibodies in 78 LE patients with limbic abnormality on magnetic resonance imaging and suspected HE based on positivity for antithyroid antibodies. Nineteen of the 78 patients had anti-NAE antibodies; however, 5 were excluded because they were double positive for antibodies to the VGKC complex including LGI1. No antibodies against the N-methyl-D-aspartate receptor (NMDAR), contactin-associated protein 2 (Caspr2), γ-aminobutyric acid-B receptor (GABABR), or α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid receptor (AMPAR) were detected in the 19 patients. Among the remaining 14 who were positive only for anti-NAE antibodies, the median age was 62.5 (20-83) years, 9 (64%) were women, and 8 (57%) showed acute onset, with less than 2 weeks between onset and admission. Consciousness disturbance (71%) and memory disturbance (64%) were frequently observed, followed by psychiatric symptoms (50%) and seizures (43%). The frequency of these symptoms significantly differed between the acute- and subacute-onset groups. Abnormalities in cerebrospinal fluid and electroencephalogram were commonly observed (92% for both). Tumors were not identified in any cases. All patients responded to immunotherapy or spontaneously remitted, thereby fulfilling the criteria of HE.This study demonstrated that LE associated with anti-NAE antibodies is a nonparaneoplastic LE and various limbic symptoms that depend on the onset type. Favorable therapeutic efficacy suggests that this LE can be considered a clinical subtype of HE and that anti-NAE antibodies may be a promising indicator of the need for immunotherapy.

A case of anti-3-hydroxy-3-methylglutaryl-coenzyme A reductase antibody-positive paraneoplastic necrotizing myopathy associated with advanced gastric cancer that responded to intravenous immunoglobulin therapy.

A 49-year-old woman presented with progressive muscle weakness of the limbs and dysphagia. Her past and family medical history were unremarkable and she did not take statins or any other medications. Laboratory tests showed that serum levels of creatine kinase were elevated (13,565 IU/l) and anti-3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCR) antibodies were detected in the serum. Other autoantibodies to the nuclear (ANA), RNP, aminoacyl-tRNA synthetases (ARS), and signal recognition particle (SRP) were negative. Pathological analysis of the left biceps muscle revealed minimal lymphocytic infiltration into the muscle fibers together with many necrotic and regenerated fibers, which corresponded to necrotizing myopathy. Abdominal CT and upper gastrointestinal endoscopy showed an advanced gastric cancer with lymph node metastasis. The patient was subsequently diagnosed with anti-HMGCR antibody-positive paraneoplastic necrotizing myopathy associated with advanced gastric cancer. The patient underwent radical surgery to remove the cancer and was initially treated with oral prednisolone and intravenous methylprednisolone pulse therapy; however, her symptoms worsened and she became bedridden. After an additional treatment with intravenous immunoglobulin (IVIg), she showed noticeable improvements in muscle strength and dysphagia and became ambulatory. This case and recent case-series studies suggest that anti-HMGCR antibody-positive necrotizing myopathy may be included in paraneoplastic syndrome and that physicians should screen for malignant tumors in patients with anti-HMGCR antibody-positive necrotizing myopathy. Moreover, IVIg can be a useful therapy in patients with anti-HMGCR antibody-positive paraneoplastic necrotizing myopathy who show refractoriness to tumor resection and corticosteroid therapies.

Pioglitazone prevents tau oligomerization.

Tau aggregation and amyloid ß protein (Aß) deposition are the main causes of Alzheimer's disease (AD). Peroxisome proliferator-activated receptor γ (PPARγ) activation modulates Aß production. To test whether the PPARγ agonist pioglitazone (PIO) is also effective in preventing tau aggregation in AD, we used a cellular model in which wild-type tau protein (4R0N) is overexpressed (M1C cells) (Hamano et al., 2012) as well as primary neuronal cultures. PIO reduced both phosphorylated and total tau levels, and inactivated glycogen synthase kinase 3ß, a major tau kinase, associated with activation of Akt. In addition, PIO decreased cleaved caspase3 and C-terminal truncated tau species by caspase, which is expected to decrease tau aggregation. A fractionation study showed that PIO reduced high molecular-weight (120 kDa), oligomeric tau species in Tris Insoluble, sarkosyl-soluble fractions. Tau decrease was reversed by adding GW9662, a PPARγ antagonist. Together, our current results support the idea that PPARγ agonists may be useful therapeutic agents for AD.

Statins and myotoxic effects associated with anti-3-hydroxy-3-methylglutaryl-coenzyme A reductase autoantibodies: an observational study in Japan.

Statins have a variety of myotoxic effects and can trigger the development of inflammatory myopathies or myasthenia gravis (MG) mediated by immunomodulatory properties. Autoantibodies to 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCR) have been identified in patients with statin-associated myopathy. The purpose of the present study is to develop an enzyme-linked immunosorbent assay (ELISA) of anti-HMGCR antibodies and to elucidate the clinical significance of anti-HMGCR antibodies in Japanese patients with inflammatory myopathies or MG. We enrolled 75 patients with inflammatory myopathies, who were all negative for anti-signal recognition particle and anti-aminoacyl transfer RNA synthetase antibodies. They were referred to Keio University and National Center of Neurology and Psychiatry between October 2010 and September 2012. We also studied 251 patients with MG who were followed at the MG Clinic at Keio University Hospital. Anti-HMGCR antibodies were detected by ELISA. We investigated demographic, clinical, radiological, and histological findings associated with anti-HMGCR antibodies. We established the anti-HMGCR ELISA with the recombinant protein. Protein immunoprecipitation detected autoantigens corresponding to HMGCR. Immunohistochemistry using muscle biopsy specimens revealed regenerating muscle fibers clearly stained by polyclonal anti-HMGCR antibodies and patients' serum. Anti-HMGCR autoantibodies were specifically detected in 8 patients with necrotizing myopathy. The seropositivity rate in the necrotizing myopathy patients was significantly higher than those in the patients with other histological diagnoses of inflammatory myopathies (31% vs 2%, P = 0.001). Statins were administered in only 3 of the 8 anti-HMGCR-positive patients. Myopathy associated with anti-HMGCR antibodies showed mild limb weakness and favorable response to immunotherapy. All 8 patients exhibited increased signal intensities on short T1 inversion recovery of muscle MRI. Of the 251 patients with MG, 23 were administered statins at the onset of MG. One late-onset MG patient experienced MG worsening after 4-wk treatment with atorvastatin. However, anti-HMGCR antibodies were not detected in the 251 MG patients except for one early-onset MG patient with no history of statin therapy. Anti-HMGCR antibodies are a relevant clinical marker of necrotizing myopathy with or without statin exposure, but they are not associated with the onset or deterioration of MG.

[A case of systemic lupus erythematosus predominantly presenting with myositis at onset].

A 42-year-old woman presented with rapid myalgia of the thigh and muscle weakness in the proximal limbs with markedly elevated serum CK. Despite positive for antibodies to anti-nuclear, anti-ds-DNA, anti-ss-DNA, anti-Sm, anti-SS-A/Ro, C-ANCA, anti-U1-RNP and anti-ribosome and slight lymphocytopenia and hypocomplementemia, there was no symptom associated with systemic lupus erythematosus (SLE). Proteinuria and hematuria were initially considered to be associated with renal damage due to myoglobinuria. Muscle MRI demonstrated high signal intensities in the rectus femoris. Muscle biopsy of the rectus femoris demonstrated a mild variation in fiber size, a few necrotic and several regenerating fibers and minimal lymphocytic infiltration in the endomysium, which suggested myopathic changes with mild necrotic and regenerating processes. Thus she was diagnosed as idiopathic myositis at first, and was treated by corticosteroid therapy. Her myalgia and CK level improved, but the proteinuria and hematuria were persistent. A renal biopsy demonstrated lupus nephritis, and SLE with myositis was confirmed. She was treated with additional tacrolimus administration, and her proteinuria and hematuria also improved. The present case suggests that patients who predominantly present with myositis accompanied by nephritis and autoantibodies should be considered as SLE with myositis.

Lymphomatosis cerebri: clinical characteristics, neuroimaging, and pathological findings.

Lymphomatosis cerebri is a rare variant of primary central nervous system lymphoma. We present a case involving a 56-year-old immunocompetent woman who complained of rapid deterioration of her higher brain function over a 4-month period. Magnetic resonance imaging showed extensive white-matter lesions. During brain biopsy, a diffusely infiltrating lymphoma with distinctive immunohistochemical features was detected. Awareness of this unique presentation and early tissue diagnosis provide the best hope for instituting appropriate treatments.

Radiolabeled Cu-ATSM as a novel indicator of overreduced intracellular state due to mitochondrial dysfunction: studies with mitochondrial DNA-less ρ0 cells and cybrids carrying MELAS mitochondrial DNA mutation.

OBJECTIVES: Radiolabeled Cu-diacetyl-bis (N(4)-methylthiosemicarbazone) (*Cu-ATSM), including (60/62/64)Cu-ATSM, is a potential imaging agent of hypoxic tumors for positron emission tomography (PET). We have reported that *Cu-ATSM is trapped in tumor cells under intracellular overreduced states, e.g., hypoxia. Here we evaluated *Cu-ATSM as an indicator of intracellular overreduced states in mitochondrial disorders using cell lines with mitochondrial dysfunction. METHODS: Mitochondrial DNA-less ρ(0)206 cells; the parental 143B human osteosarcoma cells; the cybrids carrying mutated mitochondria from a patient of mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes (MELAS) (2SD); and that carrying wild-type one (2SA) were used. Cells were treated under normoxia or hypoxia, and (64)Cu-ATSM uptake was examined to compare it with levels of biological reductant NADH and NADPH. RESULTS: ρ(0)206 cells showed higher (64)Cu-ATSM uptake than control 143B cells under normoxia, whereas (64)Cu-ATSM uptake was not significantly increased under hypoxia in ρ(0)206 cells. Additionally, (64)Cu-ATSM uptake showed correlate change to the NADH and NADPH levels, but not oxygenic conditions. 2SD cells showed increased (64)Cu-ATSM uptake under normoxia as compared with the control 2SA, and (64)Cu-ATSM uptake followed NADH and NADPH levels, but not oxygenic conditions. CONCLUSIONS: (64)Cu-ATSM accumulated in cells with overreduced states due to mitochondrial dysfunction, even under normoxia. We recently reported that (62)Cu-ATSM-PET can visualize stroke-like episodes maintaining oxygen supply in MELAS patients. Taken together, our data indicate that *Cu-ATSM uptake reflects overreduced intracellular states, despite oxygenic conditions; thus, *Cu-ATSM would be a promising marker of intracellular overreduced states for disorders with mitochondrial dysfunction, such as MELAS, Parkinson's disease and Alzheimer's disease.

[Paraneoplastic retinopathy and optic neuropathy].

Paraneoplastic retinopathy including cancer-associated retinopathy (CAR) and melanoma-associated retinopathy (MAR), and paraneoplastic optic neuropathy (PON) are visual disorders associated with systemic cancer. Patients with CAR typically present with progressive loss of vision and photopsia, which are related to dysfunction of both cones and rods in photoreceptors. The triad of photosensitivity, ring scotoma, and a reduced caliber of the retinal arteriole along with undetectable signals in electroretinogram (ERG) are specific manifestations of CAR. CAR is associated most commonly with small-cell lung cancer (SCLC) and occasionally with gynecologic tumors, and it is usually caused by autoantibodies against recovering, which is a calcium-binding photoreceptor protein that participates in the transduction of light. MAR is characterized by shimmering, flickering, or pulsating photopsias, and usually occurs in the patients with a cutaneous melanoma. MAR differs from CAR in terms of visual acuity and color vision and is associated with a characteristic pattern detected in ERG. Autoantibodies against the bipolar cells of the retina have been identified in patients with MAR. Patients with PON frequently present with progressive visual loss and optic disc edema, or with other paneoplastic neurologic syndromes related to SCLC, such as paraneoplastic encephalomyelitis or retinitis, ophthalmoplegia, and subacute cerebellar syndrome. Autoantibodies against collapsin-responsive mediator protein-5 (CRMP-5, also called anti-CV2) are considered to be as the causative factor. Treatments with corticosteroids, plasma exchange, and intravenous immune globulin as well as treatment of the tumor itself, occasionally improves these paraneoplastic visual syndromes. However, the prognosis depends on their underlying malignancy.