Two distinct degenerative types of nigrostriatal dopaminergic neuron in the early stage of parkinsonian disorders

Introduction

The present study characterized the degeneration of nigrostriatal dopaminergic neurons in the early stages of parkinsonian disorders using integrative neuroimaging analysis with neuromelanin-sensitive MRI and 123I-FP-CIT dopamine transporter (DAT) SPECT.

Methods

Thirty-one, 30, and 29 patients with progressive supranuclear palsy (PSP), corticobasal syndrome (CBS) with abnormal specific binding ratio (SBR) in either hemisphere (mean ± 2SD), and parkinsonism-predominant multiple system atrophy (MSA-P), respectively, were enrolled. Neuromelanin-related contrast (NRC) in the substantia nigra (NRCSN) and locus coeruleus (NRCLC) and the SBR of DAT SPECT were measured. All the patients underwent both examinations simultaneously within five years after symptom onset. After adjusting for interhemispheric asymmetry on neuromelanin-related MRI contrast using the Z-score, linear regression analysis of the NRCSN and SBR was performed for the most- and least-affected hemispheres, as defined by the interhemispheric differences per variable (SBR, NRCSN, standardized [SBR + NRCSN]) in each patient.

Results

Although the variables did not differ significantly between PSP and CBS, a significant correlation was found for CBS in the most-affected hemisphere for all the definitions, including the clinically defined, most-affected hemisphere. No significant correlation was found between the NRCSN and SBR for any of the definitions in either PSP or MSA-P.

Conclusion

Together with the findings of our previous study of dementia with Lewy bodies (DLB) and Parkinson's disease (PD), the present findings indicated that neural degeneration in the disorders examined may be categorized by the significance of the NRCSN-SBR correlation in PD and CBS and its non-significance in DLB, PSP, and MSA-P.

[MR neurography reveals fascicular constriction of the median nerve in a patient with neuralgic amyotrophy]

Diagnosing neuralgic amyotrophy can be challenging in clinical practice. Here, we report the case of a 37-years old Japanese woman who suddenly developed neuropathic pain in the right upper limb after influenza vaccination. The pain, especially at night, was severe and unrelenting, which disturbed her sleep. However, X-ray and MRI did not reveal any fractures or muscle injuries, and brain MRI did not reveal any abnormalities. During neurological consultation, she was in a posture of flexion at the elbow and adduction at the shoulder. Manual muscle testing suggested weakness of the flexor pollicis longus, pronator quadratus, flexor carpi radialis (FCR), and pronator teres (PT), while the flexor digitorum profundus was intact. Medical history and neurological examination suggested neuralgic amyotrophy, particularly anterior interosseous nerve syndrome (AINS) with PT/FCR involvement. Innervation patterns on muscle MRI were compatible with the clinical findings. Conservative treatment with pain medication and oral corticosteroids relieved the pain to minimum discomfort, whereas weakness remained for approximately 3 months. For surgical exploration, lesions above the elbow and fascicles of the median nerve before branching to the PT/FCR were indicated on neurological examinations; thus, we performed high-resolution imaging to detect possible pathognomonic fascicular constrictions. While fascicular constrictions were not evident on ultrasonography, MR neurography indicated fascicular constriction proximal to the elbow joint line, of which the medial topographical regions of the median nerve were abnormally enlarged and showed marked hyperintensity on short-tau inversion recovery. In patients with AINS, when spontaneous regeneration cannot be expected, timely surgical exploration should be considered for a good outcome. In our case, MR neurography was a useful modality for assessing fascicular constrictions when the imaging protocols were appropriately optimized based on clinical assessment.

Hashimoto Encephalopathy Presenting with Acute Psychosis and Inappropriate Secretion of Antidiuretic Hormone: A Rare Case Responding to Steroid Therapy

BACKGROUND Hashimoto's encephalopathy (HE) is an autoimmune encephalopathy that can involve various symptoms including psychosis. Syndrome of inappropriate secretion of antidiuretic hormone (SIADH) may be a complication in some neurological diseases. However, the simultaneous occurrence of subacute psychosis and SIADH as the manifestation of HE, observed in the present case, has rarely been reported. CASE REPORT A 72-year-old man was hospitalized with a 4-month history of abnormal behaviors, including talkativeness, stopping consumption of coffee and cigarettes, hoarding garbage, and sleep disorders. On physical examination, increased and incoherent speech with flight of idea and delusion were observed. The Mini-Mental State Examination score was 28/30. Laboratory findings included hyponatremia due to SIADH and a positive result for anti-thyroid and anti-NH2 terminal of alpha-enolase antibodies. Cerebrospinal fluid examination revealed only elevation of IL-6. Brain magnetic resonance imaging was unremarkable; however, (I-123)-iodoamphetamine single-photon emission computed tomography showed extensive hyperperfusion involving the brainstem and bilateral frontal and medial temporal lobes. Electroencephalography showed generalized slow waves, but there were no epileptiform discharges. After 2 courses of high-dose intravenous methylprednisolone followed by oral prednisolone, his symptoms improved. Based on the findings of clinical features and steroid responsiveness, he was diagnosed with HE. Oral prednisolone and antipsychotic drugs were decreased without a relapse and he was discharged to his home. CONCLUSIONS Although psychosis complicating SIADH is rare, HE should be considered in the differential diagnosis because of its treatment efficacy.

Clinical course of pathologically confirmed corticobasal degeneration and corticobasal syndrome

The clinical presentation of corticobasal degeneration is diverse, while the background pathology of corticobasal syndrome is also heterogeneous. Therefore, predicting the pathological background of corticobasal syndrome is extremely difficult. Herein, we investigated the clinical findings and course in patients with pathologically, genetically and biochemically verified corticobasal degeneration and corticobasal syndrome with background pathology to determine findings suggestive of background disorder. Thirty-two patients were identified as having corticobasal degeneration. The median intervals from the initial symptoms to the onset of key milestones were as follows: gait disturbance, 0.0 year; behavioural changes, 1.0 year; falls, 2.0 years; cognitive impairment, 2.0 years; speech impairment, 2.5 years; supranuclear gaze palsy, 3.0 years; urinary incontinence, 3.0 years; and dysphagia, 5.0 years. The median survival time was 7.0 years; 50% of corticobasal degeneration was diagnosed as corticobasal degeneration/corticobasal syndrome at the final presentation. Background pathologies of corticobasal syndrome (n = 48) included corticobasal degeneration (33.3%), progressive supranuclear palsy (29.2%) and Alzheimer's disease (12.5%). The common course of corticobasal syndrome was initial gait disturbance and early fall. In addition, corticobasal degeneration-corticobasal syndrome manifested behavioural change (2.5 years) and cognitive impairment (3.0 years), as the patient with progressive supranuclear palsy-corticobasal syndrome developed speech impairment (1.0 years) and supranuclear gaze palsy (6.0 years). The Alzheimer's disease-corticobasal syndrome patients showed cognitive impairment (1.0 years). The frequency of frozen gait at onset was higher in the corticobasal degeneration-corticobasal syndrome group than in the progressive supranuclear palsy-corticobasal syndrome group [P = 0.005, odds ratio (95% confidence interval): 31.67 (1.46-685.34)]. Dysarthria at presentation was higher in progressive supranuclear palsy-corticobasal syndrome than in corticobasal degeneration-corticobasal syndrome [P = 0.047, 6.75 (1.16-39.20)]. Pyramidal sign at presentation and personality change during the entire course were higher in Alzheimer's disease-corticobasal syndrome than in progressive supranuclear palsy-corticobasal syndrome [P = 0.011, 27.44 (1.25-601.61), and P = 0.013, 40.00 (1.98-807.14), respectively]. In corticobasal syndrome, decision tree analysis revealed that 'freezing at onset' or 'no dysarthria at presentation and age at onset under 66 years in the case without freezing at onset' predicted corticobasal degeneration pathology with a sensitivity of 81.3% and specificity of 84.4%. 'Dysarthria at presentation and age at onset over 61 years' suggested progressive supranuclear palsy pathology, and 'pyramidal sign at presentation and personality change during the entire course' implied Alzheimer's disease pathology. In conclusion, frozen gait at onset, dysarthria, personality change and pyramidal signs may be useful clinical signs for predicting background pathologies in corticobasal syndrome.

Dopa-responsive dystonia in spinocerebellar ataxia 6: A case report

Spinocerebellar ataxia 6 (SCA6) often presents with pure cerebellar ataxia. It is rarely accompanied by extrapyramidal symptoms, such as dystonia and parkinsonism. Here, we describe a case of SCA6 with dopa-responsive dystonia for the first time. A 75-year-old woman was admitted to the hospital with slowly progressive cerebellar ataxia and dystonia in the left upper limb for the past six years. Genetic testing confirmed the diagnosis of SCA6. Her dystonia improved with oral levodopa, and she was able to raise her left hand. Oral levodopa administration may provide early-phase therapeutic benefits for SCA6-associated dystonia.

Degeneration of nigrostriatal dopaminergic neurons in the early to intermediate stage of dementia with Lewy bodies and Parkinson's disease

OBJECTIVE

To investigate differences in nigrostriatal dopaminergic neuron degeneration between dementia with Lewy bodies (DLB) and Parkinson's disease (PD) in the early to intermediate stage of these diseases.

METHODS

An integrative neuroimaging analysis was developed using 3-Tesla neuromelanin-sensitive MRI and ¹²³I-FP-CIT dopamine transporter SPECT, and the relationship and laterality of three variables, including neuromelanin-related contrast in the substantia nigra (NRC_SN) and locus coeruleus (NRC_LC) and the specific binding ratio (SBR) in the striatum, were examined in detail. Patients with DLB and PD and control subjects (n = 29, 52, and 18, respectively) were enrolled.

RESULTS

A significantly greater decrease in the SBR in the bilateral hemispheres was observed in DLB than in PD. After adjusting for the interhemispheric asymmetry in neuromelanin-related MRI contrast by using the Z-score, linear regression between the NRC_SN and SBR was performed for the most-affected/least-affected sides of the hemispheres as defined by the interhemispheric differences in each variable (SBR, NRC_SN, standardized [SBR + NRC_SN]). In DLB, the highest, albeit statistically non-significant, correlation was observed in the SBR-based, most-affected side. In PD, the highest correlation was observed in the (SBR + NRC_SN)-based, most-affected side, which approximated the value of the clinically-defined, most-affected side. A non-significant correlation was observed only in the (SBR + NRC_SN)-based or clinically-defined, least-affected side.

CONCLUSION

Loss of the soma and presynaptic terminals may occur independently in DLB with a large decrease in the presynaptic terminals. The close relationship observed between the degeneration of the soma and presynaptic terminals suggested that axon degeneration may dominate in PD.

Leucine-rich Glioma-inactivated 1 Encephalitis Followed by Isaacs Syndrome: Alternating Presence of Pathogenic Autoantibodies to Leucine-rich Glioma-inactivated 1 and Contactin-associated Protein-like 2

The coexistence of leucine-rich glioma-inactivated 1 (LGI1) and contactin-associated protein-like 2 (CASPR2) autoantibodies in the same individual is surprisingly often observed. We herein report the first case of LGI1 encephalitis followed by Isaacs syndrome in which LGI1 and CASPR2 antibodies in the serum and cerebrospinal fluid (CSF) were measured during the entire disease course. After the resolution of limbic encephalitis, LGI1 antibodies disappeared from the CSF simultaneously with the appearance of CASPR2 antibodies in the serum. The alternating presence of these pathogenic autoantibodies along with the clinical and phenotypic alternations suggested that LGI1 encephalitis was associated with CASPR2 autoantibody production in the peripheral tissue, leading to CASPR2-associated Isaacs syndrome.

Myoclonic Epilepsy with Ragged-red Fibers with Intranuclear Inclusions

We herein report a case of myoclonic epilepsy with ragged-red fibers (MERRF) harboring a novel variant in mitochondrial cysteine transfer RNA (MT-TC). A 68-year-old woman presented with progressive myoclonic epilepsy with optic atrophy and peripheral neuropathy. A skin biopsy revealed p62-positive intranuclear inclusions. No mutations were found in the causative genes for diseases known to be related to intranuclear inclusions; however, a novel variant in MT-TC was found. The association between intranuclear inclusions and this newly identified MERRF-associated variant is unclear; however, the rare complication of intranuclear inclusions in a patient with typical MERRF symptoms should be noted for future studies.

Mild form of Danon disease: two case reports

Danon disease is typically lethal by the mid-twenties in male patients due to cardiomyopathy. This report aims to describe two unrelated male patients showing mild manifestations of the disease. A 39-year-old man presented with a 10-year history of elevated serum creatine kinase levels with slowly progressive muscle weakness. Muscle pathology showed autophagic vacuoles with sarcolemmal features. Genetic testing revealed a hemizygous mutation in exon 9b, an alternatively spliced exon, of lysosome-associated membrane protein-2 (LAMP-2) (c.1097_1098delAA). Cardiac testing showed asymptomatic mild left ventricular hypertrophy. He had borderline intelligence. Early stage of retinopathy was detected. Another male patient, currently 53-year-old, had asymptomatic supraventricular extrasystole and muscle weakness but no intellectual disability, harboring the same mutation. He also had retinopathy. The present patients commonly carry a mutation in exon 9b of LAMP-2, suggesting that mutations in the exon are associated with a mild form of Danon disease.

Iliopsoas Hematomas in a Patient with Progressive Encephalomyelitis with Rigidity and Myoclonus

Progressive encephalomyelitis with rigidity and myoclonus (PERM) is a rare and severe syndrome characterized by rigidity of the limb and truncal muscles, brainstem signs, myoclonus, and hyperekplexia. Iliopsoas hematoma is a serious complication of bleeding disorders that occurs most commonly in patients with hemophilia and also in association with anti-coagulant drug treatment. We herein present a case of PERM complicated with bilateral iliopsoas hematomas. His neurological symptoms improved after immunotherapy, and thereafter the iliopsoas hematomas disappeared. Neurologists should consider iliopsoas hematomas as a serious potential complication of PERM.

[A case of chronic postural tachycardia syndrome with positive anti-ganglionic acetylcholine receptor (gAChR) antibody]

Postural orthostatic tachycardia syndrome (POTS) is a form of orthostatic intolerance characterized by symptoms such as lightheadedness, fainting, and brain fog that occur with a rapid elevation in heart rate when standing up from a reclining position. The etiology of POTS has yet to be established. However, a growing body of evidence suggests that POTS may be an autoimmune disorder such as autoimmune autonomic ganglionopathy, an acquired, immune-mediated form of diffuse autonomic failure. Many patients have serum antibodies that bind to the ganglionic acetylcholine receptors (gAChRs) in the autonomic ganglia. Herein, we describe a 39-year-old female patient with an eight-year history of orthostatic intolerance. POTS was diagnosed based on the findings of a head-up tilt test, in which a rapid increase in the patient's heart rate from 58 bpm in the lying position to 117 bpm in the upright position without orthostatic hypotension was observed. The POTS symptoms were refractory to various medications except for pyridostigmine bromide, which resulted in a partial resolution of her symptoms. Her serum was found to be strongly positive for anti-gAChR (β4 subunit) autoantibody (2.162 A.I., normal range: below 1.0). Based on these findings, a limited form of autoimmune POTS was diagnosed. After obtaining written informed consent, she was treated with intravenous immunoglobulin (IVIg) 400 mg/kg/day for five days, which led to clinical improvement by reducing her heart rate increase in the upright position. She was able to return to work with IVIg treatment at regular intervals. Our case provides further evidence of a potential autoimmune pathogenesis for POTS. Aggressive immunotherapy may be effective for POTS even in chronic cases.

Immunoglobulin G4-related Disease Accompanied by Peripheral Neuropathy: A Report of Two Cases

Due to its rarity and the limited literature, the clinicopathological characteristics of peripheral nerve involvement in immunoglobulin G4 (IgG4)-related disease are unknown. We present two cases of IgG4-related disease, accompanied by peripheral neuropathy, presenting as unilateral ptosis (case 1) and sclerosing cholangitis (case 2), respectively. In both cases, sural nerve biopsy indicated vasculitis as the underlying pathophysiology; the peripheral neuropathy was refractory to corticosteroid therapy. In contrast to the previously proposed pathomechanism of IgG4-related neuropathy (direct lymphoplasmacytic infiltration), the pathological findings in our cases suggest that vasculitis occurs secondary to systemic autoimmune conditions.

Midbrain atrophy related to parkinsonism in a non-coding repeat expansion disorder: five cases of spinocerebellar ataxia type 31 with nigrostriatal dopaminergic dysfunction

Background

Spinocerebellar ataxia type 31 (SCA31) is caused by non-coding pentanucleotide repeat expansions in the BEAN1 gene. Clinically, SCA31 is characterized by late adult-onset, pure cerebellar ataxia. To explore the association between parkinsonism and SCA31, five patients with SCA31 with concomitant nigrostriatal dopaminergic dysfunction (NSDD) development, including three cases of L-DOPA responsive parkinsonism, were analyzed.

Methods

To assess regional brain atrophy, cross-sectional and longitudinal imaging analyses were retrospectively performed using magnetic resonance imaging (MRI) planimetry. The midbrain-to-pons (M/P) area ratio and cerebellar area were measured on midsagittal T1-weighted MRI in five patients with SCA31 with concomitant NSDD (NSDD(+)), 14 patients with SCA31 without NSDD (NSDD(−)), 32 patients with Parkinson’s disease (PD), and 15 patients with progressive supranuclear palsy (PSP). Longitudinal changes in the M/P area ratio were assessed by serial MRI of NSDD(+) (n = 5) and NSDD(−) (n = 9).

Results

The clinical characteristics assessed in the five patients with NSDD were as follows: the mean age at NSDD onset (72.0 ± 10.8 years), prominence of bradykinesia/akinesia (5/5), rigidity (4/5), tremor (2/5), dysautonomia (0/5), vertical gaze limitation (1/5), and abnormalities on ¹²³I-ioflupane dopamine transporter scintigraphy (3/3) and 3-Tesla neuromelanin MRI (4/4). A clear reduction in the midbrain area and the M/P area ratio was observed in the NSDD(+) group (p < 0.05) while there was no significant difference in disease duration or in the pons area among the NSDD(+), NSDD(−), and PD groups. There was also a significant difference in the midbrain and pons area between NSDD(+) and PSP (p < 0.05). Thus, mild but significant midbrain atrophy was observed in NSDD(+). A faster rate of decline in the midbrain area and the M/P area ratio was evident in NSDD(+) (p < 0.05).

Conclusion

The clinical characteristics of the five patients with SCA31 with concomitant NSDD, together with the topographical pattern of atrophy, were inconsistent with PD, PSP, and multiple system atrophy, suggesting that SCA31 may manifest NSDD in association with the pathomechanisms underlying SCA31.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40673-021-00134-4.

Adult-onset Mitochondrial Myopathy, Encephalopathy, Lactic Acidosis, and Stroke (MELAS)-like Encephalopathy Diagnosed Based on the Complete Sequencing of Mitochondrial DNA Extracted from Biopsied Muscle without any Myopathic Changes

The clinical features of mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) are not uniform. We herein report a male patient with unusual MELAS-like encephalopathy who had been experiencing isolated recurrent stroke-like episodes since he was 33 years old without any particular family history. Despite an extensive investigation, he had no other signs suggestive of MELAS. Although the muscle pathology showed a normal appearance, a mitochondrial genome sequence analysis of the biopsied muscle revealed a heteroplasmic m.10158T>C mutation in the mitochondrial complex I subunit gene, MT-ND3. To prevented further deterioration of the higher brain function, the early diagnosis and treatment of mitochondrial stroke-like episodes is important.

Effects of Melatonin and Rilmazafone on Nocturia in the Elderly

We compared the effects of melatonin, an antioxidant and sleep inducer in humans, and rilmazafone hydrochloride, a hypnotic, in elderly patients with nocturia. Patients received either melatonin (2 mg/day; n = 20) or rilmazafone (2 mg/day; n = 22) for 4 weeks. There were no significant differences in the mean age, the quality of life (QoL) score and the serum melatonin levels between the two groups at baseline. After 4 weeks' treatment, the number of nocturnal urinations was significantly decreased and the QoL score was significantly improved in both groups. There was no significant difference between the patient-reported effectiveness ratings between the two groups. The serum melatonin level was significantly increased in the melatonin-treated group, but it remained unchanged in the rilmazafone-treated group. Melatonin and rilmazafone were equally effective for nocturia in the elderly. We recommend that the problems of sleep disturbance should be considered when choosing a therapy for nocturia.

[Familial progressive external opthalmoplegia, parkinsonism and polyneuropathy associated with POLG1 mutation]

Multiple mitochondrial DNA (mtDNA) deletions usually occur secondarily to a mutation in one of the enzymes involved in mtDNA maintenance, such as polymerase γ, which is encoded by the nuclear polymerase γ1 gene (POLG1) and POLG2. Patients with multiple mtDNA deletion disorders show clinical heterogeneity of symptoms, in addition to usually seen progressive external ophthalmoplegia (PEO). We conducted clinical, histological and genetic analyses of two affected sisters in a family with the autosomal dominant inheritance pattern of PEO. A 73-year-old woman (patient 1) with congenital hypogonadism and PEO developed L-dopa responsive parkinsonism about the age of 60. Neurological examination revealed mild proximal muscle weakness and polyneuropathy too. Her 69-year-old sister (patient 2) also showed PEO, parkinsonism and polyneuropathy. Histopathological studies of biopsied muscle specimens from patient 1 revealed numerous ragged red fibers as well as fibers with increased succinate dehydrogenase activity and decreased cytochrome c oxidase activity. Multiple mtDNA deletions were detected, both by Southern blot and long-range PCR assays of total DNA from the biopsied muscle specimens. A systemic mutational analysis in both sisters revealed a heterozygous p.Y955C (c.2864A>G) mutation in POLG1. This is the first Japanese family identified with this mutation. We reviewed cases with this mutation highlighting a wide phenotypic spectrum of this disorder.

Prognostic role of "prion-like propagation" in SOD1-linked familial ALS: an alternative view

“Prion-like propagation” has recently been proposed for disease spread in Cu/Zn superoxide dismutase 1 (SOD1)-linked familial amyotrophic lateral sclerosis (ALS). Pathological SOD1 conformers are presumed to propagate via cell-to-cell transmission. In this model, the risk-based kinetics of neuronal cell loss over time appears to be represented by a sigmoidal function that reflects the kinetics of intercellular transmission. Here, we describe an alternative view of prion-like propagation in SOD1-linked ALS – its relation to disease prognosis under the protective-aggregation hypothesis. Nucleation-dependent polymerization has been widely accepted as the molecular mechanism of prion propagation. If toxic species of misfolded SOD1, as soluble oligomers, are formed as on-pathway intermediates of nucleation-dependent polymerization, further fibril extension via sequential addition of monomeric mutant SOD1 would be protective against neurodegeneration. This is because the concentration of unfolded mutant SOD1 monomers, which serve as precursor of nucleation and toxic species of mutant SOD1, would decline in proportion to the extent of aggregation. The nucleation process requires that native conformers exist in an unfolded state that may result from escaping the cellular protein quality control machinery. However, prion-like propagation-SOD1 aggregated form self-propagates by imposing its altered conformation on normal SOD1-appears to antagonize the protective role of aggregate growth. The cross-seeding reaction with normal SOD1 would lead to a failure to reduce the concentration of unfolded mutant SOD1 monomers, resulting in continuous nucleation and subsequent generation of toxic species, and influence disease prognosis. In this alternative view, the kinetics of neuronal loss appears to be represented by an exponential function, with decreasing risk reflecting the protective role of aggregate and the potential for cross-seeding reactions between mutant SOD1 and normal SOD1.

[Rapid progressive focal myositis of the head and neck region: a case report]

A 46-year-old woman noticed a painful lump in the neck following fluctuating multiple arthralgia in the previous 3 months. The neck nodule grew rapidly, and was associated with an elevation of the serum creatine kinase activity. Under a diagnosis of focal myositis, corticosteroids were introduced, soon resulting in an amelioration of the symptoms. A biopsy from the neck nodule revealed a muscle tissue with scattered foci of densely packed inflammatory cells. Some of the cells had features similar to the granuloma, which were compact collection of cells and partial tendency of the cell fusion. These findings suggest a close relation between some cases focal myositis and granulomatous myopathy.

Minocycline-associated rimmed vacuolar myopathy in a patient with rheumatoid arthritis

BACKGROUND

The autophagic vacuolar myopathies (AVM) are a group of inherited myopathies defined by the presence of autophagic vacuoles in pathological muscle specimens. AVM can be categorized into three groups: acid maltase deficiency, myopathies characterized by autophagic vacuoles with unique sarcolemmal features, and rimmed vacuolar myopathies (RVM). While the pathogeneses of these conditions are still being elucidated, some drugs (e.g., chloroquine, its analog, hydroxychloroquine, and colchicine) can also cause AVM. Minocycline is a disease-modifying anti-rheumatic drug that may be used in the treatment of rheumatoid arthritis (RA). Here, we describe the first case of minocycline-associated AVM with rimmed vacuole formation.

CASE PRESENTATION

A 75-year-old woman suffering from RA has been continuously treated with minocycline (200 mg/day) for the past 7 years. During this time, she developed a myopathy that predominantly affected her lower limbs. Histological studies of biopsied muscle revealed scattered atrophic myofibers with rimmed vacuoles that contained pigment granules. Histochemical staining revealed that the pigment comprised both iron and melanin, which is consistent with type II minocycline-induced cutaneous pigmentation. Under electron microscopy, autophagic vacuoles were consistently observed in association with numerous collections of pigment granules.

CONCLUSIONS

This is the first report of minocycline-induced pigmentation in skeletal muscle. The strong association between autophagic vacuoles and the accumulation of minocycline-induced pigments suggest that long-term minocycline treatment induced pigment accumulation, leading to elevation of autophagic activity and RVM. It might also be possible that minocycline directly activated autophagy, as the observed pigments are known to form complexes containing minocycline and/or its metabolites. As long-term minocycline treatment is expected to be used more widely in the future, we must draw attention to this adverse effect.

Quantitative connection between polyglutamine aggregation kinetics and neurodegenerative process in patients with Huntington's disease

BACKGROUND

Despite enormous progress in elucidating the biophysics of aggregation, no cause-and-effect relationship between protein aggregation and neurodegenerative disease has been unequivocally established. Here, we derived several risk-based stochastic kinetic models that assess genotype/phenotype correlations in patients with Huntington's disease (HD) caused by the expansion of a CAG repeat. Fascinating disease-specific aspects of HD include the polyglutamine (polyQ)-length dependence of both age at symptoms onset and the propensity of the expanded polyQ protein to aggregate. In vitro, aggregation of polyQ peptides follows a simple nucleated growth polymerization pathway. Our models that reflect polyQ aggregation kinetics in a nucleated growth polymerization divided aggregate process into the length-dependent nucleation and the nucleation-dependent elongation. In contrast to the repeat-length dependent variability of age at onset, recent studies have shown that the extent of expansion has only a subtle effect on the rate of disease progression, suggesting possible differences in the mechanisms underlying the neurodegenerative process.

RESULTS

Using polyQ-length as an index, these procedures enabled us for the first time to establish a quantitative connection between aggregation kinetics and disease process, including onset and the rate of progression. Although the complexity of disease process in HD, the time course of striatal neurodegeneration can be precisely predicted by the mathematical model in which neurodegeneration occurs by different mechanisms for the initiation and progression of disease processes. Nucleation is sufficient to initiate neuronal loss as a series of random events in time. The stochastic appearance of nucleation in a cell population acts as the constant risk of neuronal cell damage over time, while elongation reduces the risk by nucleation in proportion to the increased extent of the aggregates during disease progression.

CONCLUSIONS

Our findings suggest that nucleation is a critical step in gaining toxic effects to the cell, and provide a new insight into the relationship between polyQ aggregation and neurodegenerative process in HD.

Variable phenotypes in a family with mitochondrial encephalomyopathy harboring a 3291T > C mutation in mitochondrial DNA

We present a Japanese family suffering from mitochondrial encephalomyopathy associated with a T-to-C transition at mitochondrial DNA (mtDNA) nucleotide position 3291. Clinical manifestations of the patients include cerebellar ataxia with myopathy, recurrent headache, and myoclonus and epilepsy. The phenotypic variation among the affected members of a single family and the mutational analysis showing maternal inheritance in a heteroplasmic fashion are consistent with well-recognized phenomena associated with many pathogenic point mutations of mtDNA tRNA genes. The 3291 mutation is a rare mtDNA mutation whose clinical presentation had only been reported in three sporadic cases. This is the first report of a family segregating the 3291 mutation with multigenerational matrilinear recurrence of mitochondrial encephalopathy. Our findings provide conclusive evidence for the pathogenicity of the 3291T > C mutation in mtDNA and its characteristic clinical heterogeneity.

Stem cell biology in the study of pathological conditions

The current focus of researchers is to create certain types of cells in vitroas transplantation materials. The problem of this approach is that terminally differentiated cells may not integrate into the host. To overcome this problem, we may want to transplant premature cells, which can migrate and differentiate due to environmental cues received from the host, allowing for intrinsic proper functioning of the cells. Thus, we have to consider the effects that the pathological environment might have on the transplanted cells. Here, we show the effects of amyloid precursor protein and reelin on neural stem cell (NSC) differentiation, and demonstrate how we have regulated this effect to produce desirable cells under pathological conditions. We found that amyloid precursor protein increases glial differentiation via the notch and cytokine-signaling pathway, while reelin induces radial glial differentiation followed by neuronal differentiation via increasing phosphorylation of adapter protein disabled-1. Since amyloid and reelin are found in plaques within Alzheimer's disease, these findings may closely associate with NSC biology in the context of its pathology. By regulating these factors in Alzheimer's disease, we may be able to not only guide differentiation of transplanted NSCs, but also to modify progression of disease by guiding differentiation of endogenous NSCs.

Nucleation of protein aggregation kinetics as a basis for genotype-phenotype correlations in polyglutamine diseases

Recent studies of inherited neurodegenerative disorders have suggested a linkage between the propensity toward aggregation of mutant protein and disease onset. This is particularly apparent for polyglutamine (polyQ) diseases caused by expansion of CAG-trinucleotide repeats. However, a quantitative framework for relating aggregation kinetics with molecular mechanisms of neurodegeneration initiation is lacking. Here, using the repeat-length-dependent age-of-onset in polyQ diseases, we derived a mathematical model based on nucleation of aggregation kinetics to describe genotype-phenotype correlations, and validated the model using both in vitro data and clinical data. Instead of describing polyQ aggregation kinetics with a derivative equation, our model divided age-of-onset (equivalent to the time required for aggregation) into two processes: nucleation lag time (a first-order exponential function of CAG-repeat length) and elongation time. With the exception of spinocerebellar ataxia (SCA) 3, the relation between CAG-repeat length and age-of-onset in all examined polyQ diseases, including Huntington's disease, dentatorubral-pallidoluysian atrophy and SCA1, -2, -6 and -7, could be well explained by three parameters derived from linear regression analysis based on the nucleated growth polymerization model. These parameters composed of probability of nucleation at an individual repeat, a protein concentration associated factor, and elongation time predict the overall features of neurodegeneration initiation, including constant risk for cell death, toxic polyQ species, main pathological subcellular site and the contribution of cellular factors. Our model also presents an alternative therapeutic strategy according to the distinct subcellular loci by the finding that nuclear localization of soluble mutant protein monomers itself has great impact on disease onset.

Practical issues in stem cell therapy for Alzheimer's disease

We have demonstrated that aged animals show significant improvements in cognitive function and neurogenesis after brain transplantation of human neural stem cells or of human adult mesenchymal stem cells that have been dedifferentiated by transfection of the embryonic stem cell gene. We have also demonstrated that peripheral administration of a pyrimidine derivative increased cognition, endogenous brain stem cell proliferation and neurogenesis. These results indicate a bright future for stem cell therapies in Alzheimer's disease (AD). Before this is realized, however, we need to consider the affect of AD pathology on stem cell biology to establish an effective stem cell therapy for this disease. Although amyloid-beta (Abeta) deposition is a hallmark of AD, an absence of a phenotype in the beta-amyloid precursor protein (APP) knockout mouse, might lead one to underestimate the potential physiological functions of APP and suggest that it is unessential or can be compensated for. We have found, however, that APP is needed for differentiation of neural stem cells (NSCs) in vitro, and that NSCs transplanted into a APP-knockout mouse did not migrate or differentiate -- indicating that APP plays an important role in differentiation or migration process of NSCs in the brain. Then again, treatment with high a concentration of APP or its over-expression increased glial differentiation of NSCs. Human NSCs transplanted into APP-transgenic mouse brain exhibited less neurogenesis and active gliosis around the plaque like formations. Treatment of such animals with the compound, (+)-phenserine, that is known to reduce APP protein levels, increased neurogenesis and suppressed gliosis. These results suggest APP levels can regulate NSC biology in the adult brain, that altered APP metabolism in Down syndrome or AD may have implications for the pathophysiology of these diseases, and that a combination of stem cell therapy and regulation of APP levels could provide a treatment strategy for these disorders.

Polyglutamine expansion mutation yields a pathological epitope linked to nucleation of protein aggregate: determinant of Huntington's disease onset

Polyglutamine (polyQ) expansion mutation causes conformational, neurodegenerative diseases, such as Alzheimer's and Parkinson's diseases. These diseases are characterized by the aggregation of misfolded proteins, such as amyloid fibrils, which are toxic to cells. Amyloid fibrils are formed by a nucleated growth polymerization reaction. Unexpectedly, the critical nucleus of polyQ aggregation was found to be a monomer, suggesting that the rate-limiting nucleation process of polyQ aggregation involves the folding of mutated protein monomers. The monoclonal antibody 1C2 selectively recognizes expanded pathogenic and aggregate-prone glutamine repeats in polyQ diseases, including Huntington's disease (HD), as well as binding to polyleucine. We have therefore assayed the in vitro and in vivo aggregation kinetics of these monomeric proteins. We found that the repeat-length-dependent differences in aggregation lag times of variable lengths of polyQ and polyleucine tracts were consistently related to the integration of the length-dependent intensity of anti-1C2 signal on soluble monomers of these proteins. Surprisingly, the correlation between the aggregation lag times of polyQ tracts and the intensity of anti-1C2 signal on soluble monomers of huntingtin precisely reflected the repeat-length dependent age-of-onset of HD patients. These data suggest that the alterations in protein surface structure due to polyQ expansion mutation in soluble monomers of the mutated proteins act as an amyloid-precursor epitope. This, in turn, leads to nucleation, a key process in protein aggregation, thereby determining HD onset. These findings provide new insight into the gain-of-function mechanisms of polyQ diseases, in which polyQ expansion leads to nucleation rather than having toxic effects on the cells.

Vitamin B6 deficiency augments endogenous oxalogenesis after intravenous l-hydroxyproline loading in rats

The effects of an intravenous hydroxyproline load on endogenous oxalogenesis were compared in rats fed a standard diet or a vitamin B6-deficient diet. Twelve male Wistar rats were randomized to two groups and were fed either a standard diet (control group) or a vitamin B6-deficient diet for 3 weeks. Then the animals were intravenously administered 100 mg (762.6 micromol)/ml hydroxyproline. In the control group, infusion of hydroxyproline increased the 5-h urinary oxalate and glycolate excretion above baseline to 0.27% (2.02 +/- 1.11 micromol) and 0.32% (2.43 +/- 1.60 micromol) of the administered dose (mol/mol), while it was respectively 2.01% (15.24 +/- 2.13 micromol) and 0.00% (-0.02 +/- 0.19 micromol) of the dose in the vitamin B6-deficient group. Therefore, vitamin B6 deficiency augmented endogenous synthesis of oxalate from hydroxyproline by 7.56-fold (15.24/2.02) compared with that in the control group. Urinary citrate excretion was significantly lower at baseline and all other times in the vitamin B6-deficient group compared with the control group. In conclusions, L-hydroxyproline loading augmented endogenous oxalogenesis in the vitamin B6-deficient group without causing hyperglycolic aciduria, and also led to significant hypocitraturia. These findings suggest that hydroxyproline is not metabolized to oxalate via glycolate, but rather via the 4-hydroxyglutamate to glyoxylate pathway (usually requiring vitamin B6-dependent enzymes) even in the presence of vitamin B6 deficiency.

Amyloid precursor protein regulates differentiation of human neural stem cells

Although amyloid beta (Abeta) deposition has been a hallmark of Alzheimer's disease (AD), the absence of a phenotype in the beta amyloid precursor protein (APP) knockout mouse, tends to detract our attention away from the physiological functions of APP. Although much attention has been focused on the neurotoxicity of Abeta, many studies suggest the involvement of APP in neuroplasticity. We found that secreted amyloid precursor protein (sAPP) increased the differentiation of human neural stem cells (hNSCs) in vitro, while an antibody-recognizing APP dose-dependently inhibited these activities. With a high dose of sAPP treatment or wild-type APP gene transfection, hNSCs were differentiated into astrocytes rather than neurons. In vivo, hNSCs transplanted into APP-transgenic mouse brain exhibited glial differentiation rather than neural differentiation. Our results suggest that APP regulates neural stem cell biology in the adult brain, and that altered APP metabolism in Down syndrome or AD may have implications for the pathophysiology of these diseases.

Stem cell strategies for Alzheimer's disease therapy

We have found much evidence that the brain is capable of regenerating neurons after maturation. In our previous study, human neural stem cells (HNSCs) transplanted into aged rat brains differentiated into neural cells and significantly improved the cognitive functions of the animals, indicating that HNSCs may be a promising candidate for cell-replacement therapies for neurodegenerative diseases including Alzheimer's disease (AD). However, ethical and practical issues associated with HNSCs compel us to explore alternative strategies. Here, we report novel technologies to differentiate adult human mesenchymal stem cells, a subset of stromal cells in the bone marrow, into neural cells by modifying DNA methylation or over expression of nanog, a homeobox gene expressed in embryonic stem cells. We also report peripheral administrations of a pyrimidine derivative that increases endogenous stem cell proliferation improves cognitive function of the aged animal. Although these results may promise a bright future for clinical applications used towards stem cell strategies in AD therapy, we must acknowledge the complexity of AD. We found that glial differentiation takes place in stem cells transplanted into amyloid-( precursor protein (APP) transgenic mice. We also found that over expression of APP gene or recombinant APP treatment causes glial differentiation of stem cells. Although further detailed mechanistic studies may be required, RNA interference of APP or reduction of APP levels in the brain can significantly reduced glial differentiation of stem cells and may be useful in promoting neurogenesis after stem cell transplantation.

An aggregate-prone conformational epitope in trinucleotide repeat diseases

A broad range of neurodegenerative disorders is associated with accumulation of misfolded protein that is toxic to the cells. Knowledge of the conformational structure of the protein implicated is essential for understanding how an aggregate-prone protein causes disease. Here we show that a conformational epitope associated with aggregation property and cell toxicity is preserved in homopolymeric amino acid stretches implicated in oculopharyngeal muscular dystrophy (OPMD) and polyglutamine diseases. These disorders are characterized by the nuclear inclusions and a genetic gain of function. This is the first report of a candidate pathogenic structure, which may trigger aggregation of the proteins in trinucleotide repeat diseases including OPMD and polyglutamine diseases. It provides a possible therapeutic target useful for these disorders.

Neuroreplacement therapy and stem cell biology under disease conditions

Recent advances in stem cell technology are expanding our ability to replace a variety of cells throughout the body. In the past, neurological diseases caused by the degeneration of neuronal cells were considered incurable because of a long-held 'truism'; neurons do not regenerate during adulthood. However, this statement has been challenged, and we have now found much evidence that the brain is indeed capable of regenerating neurons after maturing. Based on this new concept, researchers have shown neural differentiation of stem cells and recovery of function following transplantation of these cells into the brain. These results may promise a bright future for clinical applications of stem cell strategies in neurological diseases; however, we must consider the pathophysiological environments of individual diseases that may affect stem cell biology. Before we begin to develop clinical applications, we must consider environmental factors that have not been discussed in the current preclinical studies. Here, we study cases of Alzheimer's disease and schizophrenia and discuss the effects of environmental factors under disease conditions.

Differentiation of human neural stem cells into retinal cells

We have previously reported that transplanted human neural stem cells (HNSCs) display extensive migration and positional incorporation into the aged rat brain, which is associated with an improvement in cognitive function. In the current study, to investigate whether HNSCs are capable of differentiating into retinal cells, we treated HNSCs with human transforming growth factor-beta3 (TGF-beta3) under a serum-free differentiation condition. After 5 days of differentiation in vitro we detected opsin-immunopositive cells in the culture treated with TGF-beta3. We also transplanted TGF-beta3-treated HNSCs into the rat vitreous cavity. The donor cells migrated and differentiated into opsin-positive cells in the host retinal cell layer. Here we show for the first time that TGF-beta3-treated HNSCs differentiate into retinal cells.

Reelin function in neural stem cell biology

In the adult brain, neural stem cells (NSC) must migrate to express their neuroplastic potential. The addition of recombinant reelin to human NSC (HNSC) cultures facilitates neuronal retraction in the neurospheroid. Because we detected reelin, alpha3-integrin receptor subunits, and disabled-1 immunoreactivity in HNSC cultures, it is possible that integrin-mediated reelin signal transduction is operative in these cultures. To investigate whether reelin is important in the regulation of NSC migration, we injected HNSCs into the lateral ventricle of null reeler and wild-type mice. Four weeks after transplantation, we detected symmetrical migration and extensive neuronal and glial differentiation of transplanted HNSCs in wild-type, but not in reeler mice. In reeler mice, most of the injected HNSCs failed to migrate or to display the typical differentiation pattern. However, a subpopulation of transplanted HNSCs expressing reelin did show a pattern of chain migration in the reeler mouse cortex. We also analyzed the endogenous NSC population in the reeler mouse using bromodeoxyuridine injections. In reeler mice, the endogenous NSC population in the hippocampus and olfactory bulb was significantly reduced compared with wild-type mice; in contrast, endogenous NSCs expressed in the subventricular zonewere preserved. Hence, it seems likely that the lack of endogenous reelin may have disrupted the migration of the NSCs that had proliferated in the SVZ. We suggest that a possible inhibition of NSC migration in psychiatric patients with a reelin deficit may be a potential problem in successful NSC transplantation in these patients.

Signatures of hippocampal oxidative stress in aged spatial learning-impaired rodents

Neurons and glia within the hippocampus of aged, spatial learning-impaired Long-Evans rats exhibit uniquely altered gene expression profiles, and we have postulated oxidative stress as the basis for this. To test this hypothesis we quantitated the extent of protein and nucleic acid oxidative damage, evaluated the status of mitochondrial DNA integrity, and examined several signaling entities and molecular indicators frequently associated with oxidative stress and gliosis. Immunoblotting demonstrated elevated heme oxygenase-1 in the aged-impaired hippocampus and immunocytochemistry suggested that heme oxygenase-1 is largely cytosolic and at least partly neuronal in nature. In the aged-impaired group, immunoreactivity to 8-hydroxy-2'-deoxyguanosine, an oxidative nucleic acid adduct, was found to be elevated in the dentate gyrus and in area CA1 of the hippocampal formation. Isolated mitochondrial DNA was found to be significantly damaged in the aged-impaired group. In the aged learning-impaired rats only, proteins in a 65-kDa band were found to contain excessive levels of carbonyl residues. Glial activation was examined by in situ hybridization histochemistry to tumor necrosis factor alpha and by immunocytochemistry with OX-6, which detects activated microglia. White matter in aged brains exhibited a modest up-regulation of tumor necrosis factor alpha mRNA and OX-6 immunoreactivity, but the hippocampal formation expressed tumor necrosis factor alpha mRNA equivalent to young animals and few OX-6-positive microglia. The mRNA for manganese-dependent superoxide dismutase, which is elevated in the aged hippocampus, was found preferentially expressed in neurons. We conclude that aged hippocampal neurons appear to be under oxidative stress and this is more severe in the learning-impaired subjects, suggesting a possible basis for age-induced cognitive decline.

Micturition in thoracic spinal cord injured cats with autografting of the adrenal medulla to the sacral spinal cord

PURPOSE

The role of noradrenergic projection from the pontine micturition center to the sacral spinal cord during micturition was examined in thoracic spinal cord injured cats after autografting the adrenal medulla to the sacral spinal cord.

MATERIALS AND METHODS

In 13 female cats the lower thoracic cord was transected and the right adrenal gland was removed under halothane anesthesia. The resected adrenal medulla was divided into several small pieces, which were subsequently autografted to the sacral spinal cord in 7 cats. Another 6 cats underwent sham operation and served as controls. Continuous cystometry and electromyography of the external urethral sphincter were performed every 2 weeks postoperatively without anesthesia. At week 8 the sacral spinal cord was removed and immunohistochemical testing was done to assess tyrosine hydroxylase immunoreactivity.

RESULTS

At week 6 the relative mean duration of detrusor-external sphincter coordination plus or minus standard error during bladder contraction was 62.4% +/- 4.9% in adrenal grafted cats, which was significantly (p = 0.0485) longer than in controls (34.2% +/- 12.6%). However, maximum bladder contraction pressure, bladder contraction duration and post-void residual urine volume were not significantly different in the 2 groups. Tyrosine hydroxylase immunoreactive cells were observed in and on the sacral spinal cord in adrenal grafted animals but not in controls.

CONCLUSIONS

Autografting the adrenal medulla to the sacral spinal cord prolonged detrusor-external sphincter coordination during bladder contraction in thoracic spinal cord injured cats, although other urodynamic parameters did not change. Therefore, noradrenergic projections to the sacral spinal cord may relax the external urethral sphincter during bladder contraction.

Stem cell strategies for neuroreplacement therapy in Alzheimer's disease

The existence of neural stem cells (NSCs) in the adult human brain provides impetus for investigating possible neuroreplacement therapies for neurodegenerative disease. Due to recent advances in techniques affording isolation and maintenance of NSCs using non-serum culture media, these cells have become exciting candidates for therapeutic strategies. We are able to expand NSCs by mitogenic growth factors in vitro and in defined conditions, NSCs differentiate into each of the diverse brain cell types: neurons, astrocytes and oligodendrocytes. This article addresses the involvement of amyloid-beta precursor protein and the presenilins in NSCs' biology and possible application of NSCs for therapeutic approaches in Alzheimer's disease. Ongoing studies in our laboratory, and recent findings by others using human neural progenitors, serve as the conceptual frame for this article.

[Glial activation and brain aging]

While basal forebrain cholinergic neurons degenerate in aging and Alzheimer's disease, the cholinergic groups of the upper brainstem are preserved. Since the brainstem reticular-like cholinergic neurons differ from the rostral cholinergic phenotype by their high expression of nitric oxide synthase (NOS) mRNA, we hypothesized that they contain biochemical mechanisms to protect themselves against self-induced damage by nitric oxide (NO). Our initial question was a source of the NO during the aging process. We found a significant correlation between cognitive function and markers for glial activation and oxidative stress using aged rats. This result indicates that oxidative stress accompanied by glial activation may be occurred in the cognitively impaired animals. We also found mitochondrial DNA (mDNA) was significantly damaged in these animals, while accumulation of oxidative damage was not evident in other molecules. Therefore, oxidative damage to the mDNA by glial activation may occur in the cells having poor protection against oxidative stress during aging. Then the dysfunction of mitochondria, induced by the mDNA damage, may induce cell death as well as produce another oxidative stress to cause neuronal damage. The damaged neurons induce further glial activation and such self-accelerated immune-like response results in progressive neurodegeneration.

Transitional cell carcinoma of the renal pelvis forming tumor thrombus in the vena cava

A 47-year-old man presented with a left renal incidentaloma without hematuria. The tumor was complicated by inferior vena cava (IVC) thrombus extending from Th11 to L4. A temporary IVC filter was introduced prior to surgery. A midline incision was used to perform a left radical nephrectomy and en bloc lymphadenectomy with excision of the inferior vena cava from above the level of the left renal vein to 2.5 cm above the confluence of the common iliac veins. The pathological diagnosis was invasive transitional cell carcinoma. The tumor thrombus consisted of transitional cell carcinoma that histologically invaded the walls of the IVC. He died of cancer 17 months after the operation for the liver metastases. This is the 18th case report of such a presentation in the literature.

A mutation in the largest (catalytic) subunit of RNA polymerase II and its relation to the arrest of the cell cycle in G(1) phase

Transcriptional activity of RNA polymerase II is modulated during the cell cycle. We previously identified a temperature-sensitive mutation in the largest (catalytic) subunit of RNA polymerase II (RPB1) that causes cell cycle arrest and genome instability. We now characterize a different cell line that has a temperature-sensitive defect in cell cycle progression, and find that it also has a mutation in RPB1. The temperature-sensitive mutant, tsAF8, of the Syrian hamster cell line, BHK21, arrests at the non-permissive temperature in the mid-G(1) phase. We show that RPB1 in tsAF8--which is found exclusively in the nucleus at the permissive temperature--is also found in the cytoplasm at the non-permissive temperature. Comparison of the DNA sequences of the RPB1 gene in the wild-type and mutant shows the mutant phenotype results from a (hemizygous) C-to-A variation at nucleotide 944 in one RPB1 allele; this gives rise to an ala-to-asp substitution at residue 315 in the protein. Aligning the amino acid sequences from various species reveals that ala(315) is highly conserved in eukaryotes.