Dynamic interactions in the l-lactate oxidase active site facilitate substrate binding at pH4.5.

The crystal structure of l-lactate oxidase in complex with l-lactate was solved at a 1.33 Å resolution. The electron density of the bound l-lactate was clearly shown and comparisons of the free form and substrate bound complexes demonstrated that l-lactate was bound to the FMN and an additional active site within the enzyme complex. l-lactate interacted with the related side chains, which play an important role in enzymatic catalysis and especially the coupled movement of H265 and D174, which may be essential to activity. These observations not only reveal the enzymatic mechanism for l-lactate binding but also demonstrate the dynamic motion of these enzyme structures in response to substrate binding and enzymatic reaction progression.

Effectiveness of Electroconvulsive Therapy in Patients With Advanced Parkinson Disease.

OBJECTIVES: In addition to motor symptoms, patients with Parkinson disease (PD) experience various psychiatric comorbidities, including impulse control disorders (ICDs). Moreover, antiparkinsonian drugs sometimes cause psychiatric symptoms. Antiparkinsonian and antipsychotic drugs are competitive in pharmacodynamics, and psychotropic drugs, including antidepressants, may worsen motor symptoms or induce adverse reactions. Considering this conflicting situation, we examined the effectiveness of electroconvulsive therapy (ECT) on both motor and psychiatric symptoms in PD. METHODS: We retrospectively examined 12 PD patients with advanced motor symptoms and drug-resistant psychiatric symptoms, including ICDs, who had undergone ECT. Both before and after ECT, the severity of PD motor symptoms were evaluated using Hoehn and Yahr staging, while psychiatric symptoms were evaluated using the Neuropsychiatric Inventory. The patients' doses of antiparkinsonian and antipsychotic drugs were also assessed before and after ECT. RESULTS: Both the mean Hoehn and Yahr and Neuropsychiatric Inventory scores were significantly decreased after ECT. The symptoms of ICDs, which were observed in 5 patients, disappeared following ECT. Improvements in motor symptoms and psychiatric symptoms lasted for more than 1 year in 5 cases and 9 cases, respectively. Furthermore, the daily dose of antiparkinsonian drugs was significantly decreased in 6 cases. CONCLUSIONS: Our results demonstrated that ECT was effective for both severe motor symptoms and psychiatric symptoms in advanced PD patients. ECT might be a solution for the conflicting problem of treating both motor and psychiatric symptoms in PD.

Skin Sensitization to Fluorescein Isothiocyanate Is Enhanced by Butyl Paraben in a Mouse Model.

Contact hypersensitivity (CHS) to preservatives is receiving increased attention. Parabens are widely used in foods, pharmaceutics and cosmetics as preservatives. The skin sensitizing activity of parabens remains controversial but a few investigations have been made as to whether parabens could facilitate sensitization to other chemicals. We have shown that di-n-butyl phthalate (DBP), a phthalate ester, has an adjuvant effect in a fluorescein isothiocyanate (FITC)-induced CHS mouse model. We have also demonstrated that DBP activates transient receptor potential ankyrin 1 (TRPA1) cation channels expressed on sensory neurons. Comparative studies of phthalate esters revealed that TRPA1 agonistic activity and the adjuvant effect on FITC-CHS coincide. Here we focused on two commonly used parabens, butyl paraben (BP) and ethyl paraben (EP), as to their adjuvant effects. BALB/c mice were epicutneously sensitized with FITC in acetone in the presence or absence of a paraben. Sensitization to FITC was evaluated as the ear-swelling response after FITC challenge. BP but not EP enhanced skin sensitization to FITC, but the effect of BP was much weaker than that of DBP. Mechanistically, BP enhanced the trafficking of FITC-presenting CD11c+ dendritic cells (DCs) from the skin to draining lymph nodes as well as cytokine production by draining lymph nodes. When the TRPA1 agonistic activity was measured with a cell line expressing TRPA1, BP exhibited higher activity than EP. The present study provides direct in vivo evidence that BP causes sensitization to other chemicals by means of a mouse FITC-CHS model.

An Aliphatic Ester Diisopropyl Sebacate Exhibited an Adjuvant Effect on Fluorescein Isothiocyanate-Induced Contact Hypersensitivity Mouse Models.

Alternative plasticizers have become more popular due to health concerns about phthalate esters. We demonstrated that phthalate esters enhanced skin sensitization to fluorescein isothiocyanate (FITC) in mouse contact hypersensitivity models. Alternative plasticizers have not been well studied as to their effect on the immune system. We previously found that diisopropyl adipate (DIPA), an aliphatic dicarboxylic acid ester, enhanced skin sensitization to FITC. Sebacate esters are also widely used as alternative plasticizers. Here we tested diisopropyl sebacate (DIPS), which has the same alcohol with an aliphatic dicarboxylic acid of longer chain, using BALB/c mice. The results showed that DIPS facilitated skin sensitization to FITC and increased FITC-presenting dendritic cell trafficking from the skin to draining lymph nodes. Furthermore, DIPS activated transient receptor potential ankyrin 1 (TRPA1). The latter feature has been commonly observed for phthalate esters and DIPA, which have adjuvant effects. In summary, the adjuvant effect of a sebacate ester was demonstrated in a mouse model.

Dibutyl Maleate and Dibutyl Fumarate Enhance Contact Sensitization to Fluorescein Isothiocyanate in Mice.

Di-n-butyl phthalate (DBP), a phthalate ester, has been shown to have an adjuvant effect on fluorescein isothiocyanate (FITC)-induced contact hypersensitivity (CHS) mouse models. Di-n-butyl maleate (DBM), widely used as a plasticizer for industrial application, has been reported to cause dermatitis in humans. DBM is a butyl alcohol ester of di-carboxylic acid that represents a part of the DBP structure, while di-n-butyl fumarate (DBF) is a trans isomer of DBM. We examined whether DBM or DBF exhibits an adjuvant effect like DBP does. When BALB/c mice were epicutaneously sensitized with FITC in the presence of DBM or DBF, the FITC-specific CHS response was enhanced, as we have observed for DBP. As to underlying mechanisms, DBM and DBF facilitated the trafficking of FITC-presenting CD11c(+) dendritic cells (DCs) from skin to draining lymph nodes and increased the cytokine production by draining lymph nodes. In conclusion, DBM and DBF may have an effect that aggravates contact dermatitis through a skin sensitization process.

Systems approach to excitation-energy and electron transfer reaction networks in photosystem II complex: model studies for chlorophyll a fluorescence induction kinetics.

Photosystem II (PS II) is a protein complex which evolves oxygen and drives charge separation for photosynthesis employing electron and excitation-energy transfer processes over a wide timescale range from picoseconds to milliseconds. While the fluorescence emitted by the antenna pigments of this complex is known as an important indicator of the activity of photosynthesis, its interpretation was difficult because of the complexity of PS II. In this study, an extensive kinetic model which describes the complex and multi-timescale characteristics of PS II is analyzed through the use of the hierarchical coarse-graining method proposed in the authors׳ earlier work. In this coarse-grained analysis, the reaction center (RC) is described by two states, open and closed RCs, both of which consist of oxidized and neutral special pairs being in quasi-equilibrium states. Besides, the PS II model at millisecond scale with three-state RC, which was studied previously, could be derived by suitably adjusting the kinetic parameters of electron transfer between tyrosine and RC. Our novel coarse-grained model of PS II can appropriately explain the light-intensity dependent change of the characteristic patterns of fluorescence induction kinetics from O-J-I-P, which shows two inflection points, J and I, between initial point O and peak point P, to O-J-D-I-P, which shows a dip D between J and I inflection points.

Adjuvant Effect of an Alternative Plasticizer, Diisopropyl Adipate, on a Contact Hypersensitivity Mouse Model: Link with Sensory Ion Channel TRPA1 Activation.

Due to health concerns about phthalate esters, the use of alternative plasticizers is being considered. Phthalate esters enhance skin sensitization to fluorescein isothiocyanate (FITC) in mouse models. We have demonstrated that phthalate esters stimulate transient receptor potential ankyrin 1 (TRPA1) cation channels expressed on sensory neurons. We also found a correlation between TRPA1 activation and the enhancing effect on FITC-induced contact hypersensitivity (CHS) when testing various types of phthalate esters. Here we investigated the effects of an alternative plasticizer, diisopropyl adipate (DIA). Activation of TRPA1 by DIA was demonstrated by calcium mobilization using Chinese hamster ovary cells expressing TRPA1 in vitro. The effect of DIA was inhibited by a TRPA1-specific antagonist, HC-030031. The presence of DIA or dibutyl phthalate (DBP; positive control) during skin sensitization of BALB/c mice to FITC augmented the CHS response, as revealed by the level of ear-swelling. The enhancing effect of DIA was inhibited by in vivo pretreatment with HC-030031. FITC-presenting CD11c(+) dendritic cell (DC)-trafficking to draining lymph nodes was facilitated both by DIA and by DBP. DBP and DIA were similarly active in the enhancement of interferon-γ production by draining lymph nodes, but the effect on interleukin-4 production was weaker with DIA. Overall, DIA activated TRPA1 and enhanced FITC-induced CHS, as DBP did. The adjuvant effects of adipate esters may need to be considered because they are used as ingredients in cosmetics and drug formulations topically applied to the skin.

Reliability of the unified multiple system atrophy rating scale using the telephone.

OBJECTIVE: The unified multiple system atrophy rating scale (UMSARS) was used to evaluate various symptoms of multiple system atrophy (MSA). And UMSARS part 1 was originally developed for use in interviews, but the need for telemedicine is increasing in COVID-19 pandemic. The purpose of this study is to evaluate the reliability of the UMSARS part 1 telephone survey. METHODS: Thirty-two MSA patients took the UMSARS part 1 face-to-face, followed by two more telephone evaluations. Intraclass correlation coefficients (ICC) and Cronbach's alpha (α) coefficients were calculated, and the inter-rater reliability was determined. At the same time, we asked about the problems in COVID-19 pandemic. RESULTS: The study participants included 15 men and 17 women with mean age of 67.1 years (SD, 8.3). For the total UMSARS part 1 score, the inter-rater ICC and Cronbach's α coefficient were 0.89 to 0.92, and 0.84 to 0.87, respectively. More than half of the items had a relatively high ICC. Cronbach's α coefficients were more than 0.7 for all items. Changes that occurred in COVID-19 pandemic included reduced outings and lack of rehabilitation in about half of the cases. CONCLUSION: The UMSARS part 1 has high inter-rater reliability and internal consistency. Evaluation of subjective symptoms showed that some variability could occur. In addition, there was concern about the influence of lack of rehabilitation due to COVID-19 pandemic.

The Movement Disorder Society Criteria: Its Clinical Usefulness in Multiple System Atrophy.

Objective In 2022, Wenning et al. proposed the Movement Disorder Society Criteria (MDS Criteria) for the Diagnosis of Multiple System Atrophy (MSA). These criteria were expected to provide useful alternatives to the second consensus statement. We examined trends in these diagnostic criteria. Methods We used patient data registered with the Hokkaido Rare Disease Consortium for Multiple System Atrophy, which has been recruiting patients with MSA through medical facilities in Hokkaido since November 2014. Patients were evaluated according to the MDS criteria based on neurological examinations and imaging findings at three separate times: the first evaluation, the time of enrollment (diagnosis), and the most recent evaluation (final evaluation). Results The MDS criteria were examined in 68 of 244 patients enrolled between November 2014 and July 2022. At the initial evaluation, the classifications were as follows: clinically established (n=27; 39.7%); clinically probable (n=13; 19.1%); possible prodromal (n=12; 17.6%); and negative (did not meet criteria (n=16; 23.5%). At the time of diagnosis, the classifications were as follows: clinically established (n=45; 66.2%); clinically probable (n=12; 17.6%); possible prodromal (n=4; 5.9%); and negative (n=7; 10.3%). At the final evaluation, the classifications were as follows: clinically established (n=52; 76.5%); clinically probable (n=9; 13.2%); possible prodromal (n=2; 2.9%); and negative (n=5; 7.4%). Conclusions We were able to clarify the changes in the criteria values and transition of patients due to the clarification of imaging and supportive findings in the MDS criteria.

Severe Acute Pancreatitis Rapidly Developed Into Pulmonary Edema and Diffuse Alveolar Hemorrhage Leading to Respiratory Failure: An Autopsy Case.

Acute pancreatitis often results in life-threatening situations, making a prompt and accurate diagnosis cardinally important. To achieve these, it is crucial to correctly identify characteristic symptoms and test findings. However, when patients do not exhibit distinctive symptoms during a physician's examination, in addition to limited resources, these can become challenging. In this manuscript, we present an instructive case. A male in his twenties, who complained of generalized malaise, was admitted to our hospital. Unfortunately, however, he passed away within two days prior to undergoing detailed examinations or receiving therapeutic interventions. We performed an autopsy in order to ascertain the reasons for this outcome. The findings revealed that pulmonary edema and diffuse alveolar hemorrhage were the causative factors of his demise, with acute pancreatitis observed in the background. The occurrence of acute pancreatitis leading to death in youths is infrequent. Where could we have intervened to halt such an unfortunate course in a young individual? This patient probably had diabetic ketoacidosis and hyperlipidemia, both of which are known to be closely associated with acute pancreatitis. In retrospect, we should have noticed this point. In this case, the condition progressed too rapidly for appropriate therapeutic interventions. We believe that this case would provide educational instruction for similar situations that could arise in the future.

X-ray free electron laser observation of ultrafast lattice behaviour under femtosecond laser-driven shock compression in iron.

Over the past century, understanding the nature of shock compression of condensed matter has been a major topic. About 20 years ago, a femtosecond laser emerged as a new shock-driver. Unlike conventional shock waves, a femtosecond laser-driven shock wave creates unique microstructures in materials. Therefore, the properties of this shock wave may be different from those of conventional shock waves. However, the lattice behaviour under femtosecond laser-driven shock compression has never been elucidated. Here we report the ultrafast lattice behaviour in iron shocked by direct irradiation of a femtosecond laser pulse, diagnosed using X-ray free electron laser diffraction. We found that the initial compression state caused by the femtosecond laser-driven shock wave is the same as that caused by conventional shock waves. We also found, for the first time experimentally, the temporal deviation of peaks of stress and strain waves predicted theoretically. Furthermore, the existence of a plastic wave peak between the stress and strain wave peaks is a new finding that has not been predicted even theoretically. Our findings will open up new avenues for designing novel materials that combine strength and toughness in a trade-off relationship.

An ultrasensitive enzymatic method for measuring mevalonic acid in serum.

We have developed a simple, precise, and ultrasensitive enzymatic method for measuring serum mevalonic acid (MVA) concentration, which is thought to be a good indicator of the in vivo cholesterol biosynthesis rate. This assay is based on an enzyme cycling reaction and makes use of HMG-CoA reductase (HMGR), thio-NAD, NADH, and CoA. MVA participates in the HMGR cycling reaction, and its level is measured based on the production of thio-NADH, which is determined from the change in absorbance at 405 nm. To achieve high specificity, we used mevalonate kinase (MVK) in addition to HMGR. Only substrates able to participate in both the HMGR cycling reaction and the MVK reaction are measured as MVA. The detection limit for MVA is 0.4 ng/ml (2.7 nmol/l), and the calibration curve for MVA is linear up to 44 ng/ml (300 nmol/l). Regression analysis with 40 serum samples showed the accuracy of quantifying MVA with this enzymatic assay to be comparable to that using LC-MS/MS (correlation: y = 0.83x + 0.24; r = 0.97). This procedure is simple, precise, and robust. It is also rapid and has a high throughput, making it potentially useful for clinical applications.

Extensive loss of connexins in Baló's disease: evidence for an auto-antibody-independent astrocytopathy via impaired astrocyte-oligodendrocyte/myelin interaction.

Extensive aquaporin-4 (AQP4) loss without perivascular deposition of either activated complement or immunoglobulins is a characteristic of Baló's disease. Our aim in this study was to investigate the relationship between astrocytopathy and demyelination in Baló's disease, focusing on connexins (Cx), which form gap junctions among glial cells and myelin. Autopsied specimens from four cases that provided seven actively demyelinating concentric lesions infiltrated with numerous CD68(+) macrophages were immunohistochemically examined for the astrocyte markers glial fibrillary acidic protein (GFAP), AQP4, Cx43, Cx30 and megalencephalic leukoencephalopathy with subcortical cyst 1 (MLC1). Specimens were also stained for oligodendrocyte/myelin markers, namely Cx32, Cx47, myelin-associated glycoprotein (MAG), myelin oligodendrocyte glycoprotein (MOG), oligodendrocyte-specific protein (OSP) and Nogo-A. Serum samples from six patients that had undergone magnetic resonance imaging, confirming a diagnosis of Baló's disease, were assayed for the presence of anti-Cx43, -Cx32 and -AQP4 antibodies. Despite the presence of numerous GFAP- and MLC1-positive astrocytes, there was a marked decrease in the levels of Cx43, Cx32 and Cx47. At the leading edges, Cx43 and AQP4 were mostly absent despite positive GFAP, MLC1, Cx32, Cx47, MOG, MAG, and OSP immunoreactivity. Of the six Baló's disease patients, none were positive for anti-Cxs or -AQP4 antibodies. Baló's disease is characterized by extensive loss of Cxs and AQP4, and a lack of auto-antibodies to Cxs and AQP4. Loss of Cx43 and AQP4 in the presence of other oligodendrocyte/myelin proteins at the leading edges suggests the possibility that auto-antibody-independent astrocytopathy may contribute to disease pathology via the disruption of astrocyte-oligodendrocyte/myelin interactions.

Crystallinity in periodic nanostructure surface on Si substrates induced by near- and mid-infrared femtosecond laser irradiation.

Laser-induced periodic surface structure (LIPSS), which has a period smaller than the laser wavelength, is expected to become a potential technique for fine surface processing. We report the microscopic and macroscopic observations of the crystallinity of LIPSSs, where the characteristics such as defects generation and residual strain were analyzed, respectively. The LIPSSs were formed on a Si substrate using two different femtosecond pulses from Ti:Sapphire laser with near-infrared wavelength (0.8 µm) and free-electron laser (FEL) with mid-infrared wavelength (11.4 µm). The photon energies of the former and latter lasers used here are higher and lower than the Si bandgap energies, respectively. These LIPSSs exhibit different crystalline states, where LIPSS induced by Ti:Sapphire laser show residual strain while having a stable crystallinity; in contrast, FEL-LIPSS generates defects without residual strain. This multiple analysis (microscopic and macroscopic observations) provides such previously-unknown structural characteristics with high spatial resolution. To obtain LIPSS with suitable properties and characteristics based on each application it is paramount to identify the laser sources that can achieve such properties. Therefore, identifying the structural information of the LIPSS generated by each specific laser is of great importance.

An autopsied case of sporadic adult-onset amyotrophic lateral sclerosis with FUS-positive basophilic inclusions.

Basophilic inclusions (BIs), which are characterized by their staining properties of being weakly argyrophilic, reactive with Nissl staining, and immunohistochemically negative for tau and transactive response (TAR) DNA-binding protein 43 (TDP-43), have been identified in patients with juvenile-onset amyotrophic lateral sclerosis (ALS) and adult-onset atypical ALS with ophthalmoplegia, autonomic dysfunction, cerebellar ataxia, or a frontal lobe syndrome. Mutations in the fused in sarcoma gene (FUS) have been reported in cases of familial and sporadic ALS, and FUS immunoreactivity has been demonstrated in basophilic inclusion body disease (BIBD), neuronal intermediate filament inclusion disease (NIFID), and atypical frontotemporal lobar degeneration with ubiquitin-positive and tau-negative inclusions (aFTLD-U). In the present study, we immunohistochemically and ultrastructurally studied an autopsy case of sporadic adult-onset ALS with numerous BIs. The patient presented with the classical clinical course of ALS since 75 years of age and died at age 79. Postmortem examination revealed that both Betz cells in the motor cortex and motor neurons in the spinal cord were affected. The substantia nigra was spared. Notably, BIs were frequently observed in the motor neurons of the anterior horns, the inferior olivary nuclei, and the basal nuclei of Meynert. BIs were immunopositive for p62, LC3, and FUS, but immunonegative for tau, TDP-43, and neurofilament. Ultrastructurally, BIs consisted of filamentous or granular structures associated with degenerated organelles with no limiting membrane. There were no Bunina bodies, skein-like inclusions, or Lewy-like inclusions. All exons and exon/intron boundaries of the FUS gene were sequenced but no mutations were identified.

Current Status of Antimicrobial Drug Use in Japanese Companion Animal Clinics and the Factors Associated With Their Use.

The Japanese National Action Plan on Antimicrobial Resistance (AMR) was adopted to strengthen AMR surveillance and monitoring in companion animals. The Japanese Veterinary Antimicrobial Resistance Monitoring (JVARM) system monitors the sale of veterinary antimicrobial drugs by pharmaceutical companies, and the sale of human drugs by principal wholesale companies to companion animal (dogs and cats) clinics. However, the data do not include sales by local drug suppliers and personal importation to companion animal clinics in Japan. The purposes of this study were to estimate total antimicrobial drug use by companion animal clinics in Japan and to identify the factors associated with their use. In 2018, questionnaires gathering data on attributes of the clinic and volumes of antimicrobial drugs used were sent to 212 clinics across Japan by the Japan Veterinary Medical Association. Out of the clinics, 170 valid questionnaires were returned (80.2% response rate). Antimicrobial drugs were categorized first as human, veterinary, or imported drugs and then further categorized as important drugs (critically important drugs for humans and second-choice veterinary drugs) or others. Total antimicrobial drug use was estimated based on the number of clinics reported in 2016. The relationships between antimicrobial drug use and various questionnaire items were analyzed using non-parametric regression analysis. Total antimicrobial drug use was estimated at 29.9t, which was 2.1 times higher than reported by the JVARM survey on the sales of antimicrobial drugs. In terms of total use, important drugs and human drugs accounted for 12.6 and 61.8%, respectively. Clinic income per veterinarian was associated with total antimicrobial use per veterinarian. The proportion of important drugs among all antimicrobial drugs used in a clinic was high in recently established clinics with middle-aged and older directors.

Multiple system atrophy in Hokkaido, Japan: a prospective registry study of natural history and symptom assessment scales followed for 5 years.

OBJECTIVES: Multiple system atrophy (MSA) is a refractory neurodegenerative disease, but novel treatments are anticipated. An accurate natural history of MSA is important for clinical trials, but is insufficient. This regional registry was launched to complement clinical information on MSA. SETTING: Patient recruitment started in November 2014 and is ongoing at the time of submission. The number of participating facilities was 66. Postal surveys were sent to medical facilities and patients with MSA in Hokkaido, Japan. PARTICIPANTS: After obtaining written consent from 196 participants, 184 overview surveys and 115 detailed surveys were conducted. PRIMARY AND SECONDARY OUTCOME MEASURES: An overview survey evaluated conformity to diagnostic criteria and a detailed survey implemented an annual assessment based on the Unified Multiple System Atrophy Rating Scale (UMSARS). RESULTS: At the time of registration, 58.2% of patients were diagnosed with cerebellar symptoms predominant type MSA (MSA-C) and 29.9% were diagnosed with parkinsonism predominant type MSA (MSA-P). UMSARS Part Ⅳ score of 4 or 5 accounted for 53.8% of participants. The higher the UMSARS Part Ⅳ score, the higher the proportion of MSA-P. At baseline, levodopa was used by 69 patients (37.5%) and the average levodopa dose was 406.7 mg/day. The frequency of levodopa use increased over time. Eleven cases changed from MSA-C to MSA-P during the study, but the opposite was not observed. Information about survival and causes of death was collected on 54 cases. Half of deaths were respiratory-related. Sudden death was recorded even in the group with UMSARS Part Ⅳ score of 1. CONCLUSIONS: This study is the first large-scale prospective MSA cohort study in Asia. MSA-C was dominant, but the use of antiparkinsonian drugs increased over the study period. Changes from MSA-C to MSA-P occurred, but not vice versa.

Ultrafast olivine-ringwoodite transformation during shock compression.

Meteorites from interplanetary space often include high-pressure polymorphs of their constituent minerals, which provide records of past hypervelocity collisions. These collisions were expected to occur between kilometre-sized asteroids, generating transient high-pressure states lasting for several seconds to facilitate mineral transformations across the relevant phase boundaries. However, their mechanisms in such a short timescale were never experimentally evaluated and remained speculative. Here, we show a nanosecond transformation mechanism yielding ringwoodite, which is the most typical high-pressure mineral in meteorites. An olivine crystal was shock-compressed by a focused high-power laser pulse, and the transformation was time-resolved by femtosecond diffractometry using an X-ray free electron laser. Our results show the formation of ringwoodite through a faster, diffusionless process, suggesting that ringwoodite can form from collisions between much smaller bodies, such as metre to submetre-sized asteroids, at common relative velocities. Even nominally unshocked meteorites could therefore contain signatures of high-pressure states from past collisions.

Aquaporin-4 astrocytopathy in Baló's disease.

Baló's concentric sclerosis (BCS) is considered to be a rare variant of multiple sclerosis and characterized by alternating rings of demyelinated and preserved myelin layers. The mechanism underlying BCS remains to be elucidated. Recently, occurrence of concentric rings of Baló was described in the brainstem of a patient with neuromyelitis optica (NMO). Because selective loss of aquaporin-4 (AQP4) and vasculocentric deposition of complement and immunoglobulins are characteristic in NMO, we aimed to assess AQP4 expression in the concentric demyelinating lesions of BCS patients. We evaluated AQP4 expression relative to expression of another astrocytic marker (glial fibrillary acidic protein), the extent of demyelination, lesion staging and perivascular deposition of complement and immunoglobulin in four cases with BCS, and 30 individuals with other neurological diseases. All cases with BCS demonstrated extensive AQP4 loss in both demyelinated and myelinated layers of all actively demyelinating lesions, with perivascular lymphocytic cuffing of T cells, but no deposition of immunoglobulins or complement around vessels. These findings suggest that AQP4 loss occurs in heterogeneous demyelinating conditions, namely NMO and BCS. Furthermore, acute BCS lesions are characterized by extensive AQP4 loss without vasculocentric deposition of complement or immunoglobulin.