Roles of the cerebellum and basal ganglia in temporal integration: Insights from a synchronized tapping task.

OBJECTIVE: The aim of this study was to clarify the roles of the cerebellum and basal ganglia for temporal integration. METHODS: We studied 39 patients with spinocerebellar degeneration (SCD), comprising spinocerebellar atrophy 6 (SCA6), SCA31, Machado-Joseph disease (MJD, also called SCA3), and multiple system atrophy (MSA). Thirteen normal subjects participated as controls. Participants were instructed to tap on a button in synchrony with isochronous tones. We analyzed the inter-tap interval (ITI), synchronizing tapping error (STE), negative asynchrony, and proportion of delayed tapping as indicators of tapping performance. RESULTS: The ITI coefficient of variation was increased only in MSA patients. The standard variation of STE was larger in SCD patients than in normal subjects, especially for MSA. Negative asynchrony, which is a tendency to tap the button before the tones, was prominent in SCA6 and MSA patients, with possible basal ganglia involvement. SCA31 patients exhibited normal to supranormal performance in terms of the variability of STE, which was surprising. CONCLUSIONS: Cerebellar patients generally showed greater STE variability, except for SCA31. The pace of tapping was affected in patients with possible basal ganglia pathology. SIGNIFICANCE: Our results suggest that interaction between the cerebellum and the basal ganglia is essential for temporal processing. The cerebellum and basal ganglia and their interaction regulate synchronized tapping, resulting in distinct tapping pattern abnormalities among different SCD subtypes.

Nuclear Imaging Data-Driven Classification of Parkinson's Disease.

BACKGROUND: Parkinson's disease (PD) is a heterogeneous neurodegenerative disorder characterized by motor and nonmotor symptoms. Several features have prognostic importance and have been used as key indicators for identifying clinical subtypes. However, the symptom-based classification approach has limitations with respect to the stability of the obtained subtypes. OBJECTIVES: The purpose of this study was to identify subtypes of PD using nuclear imaging biomarkers targeting the cardiac sympathetic nervous and nigro-striatal systems and to compare patterns of cortical morphological change among obtained subtypes. METHODS: We performed unbiased hierarchical cluster analysis using 123 I-metaiodobenzylguanidine cardiac scintigraphy and 123 I-N-(3-fluoropropyl)-2ß-carbomethoxy-3ß-(4-iodophenyl) nortropane single photon emission computed tomography data for 56 patients with PD. We compared clinical characteristics and the patterns of cortical atrophy in the obtained clusters. RESULTS: Three clusters were identified and showed distinct characteristics in onset ages and dopamine-replacement therapy and deep brain stimulation requirements. According to the characteristics, clusters were classified into two subtypes, namely, "cardio-cortical impairment (CC)" and "dopaminergic-dominant dysfunction (DD)" subtype. The three clusters were named according to subtype and time since onset in which 14 patients were classified as "early DD," 25 as "advanced DD," and 17 as "early CC." Compared with the early DD subtype, the early CC subtype showed parietal-dominant diffuse cortical atrophy and the advanced DD subtype showed left-side predominant mild cortical atrophy. CONCLUSIONS: Nuclear imaging biomarker-based classification can be used to identify clinically and pathologically relevant PD subtypes with distinct disease trajectories. © 2023 International Parkinson and Movement Disorder Society.

Bedside evaluation of swallowing function to predict aspiration pneumonia in Duchenne muscular dystrophy.

OBJECTIVE: Aspiration pneumonia is one of the leading causes of death in patients with muscular dystrophy; therefore, it is important to predict its occurrence in the clincal setting. We aimed to examine the usefulness of repeated saliva swallowing test (RSST), modified water swallowing test (MWST), and flexible endoscopic evaluation of swallowing (FEES) for evaluating the Hyodo score at the bedside, to predict the risk of aspiration pneumonia in patients with Duchenne muscular dystrophy (DMD). METHODS: In this retrospective cohort study involving 43 patients, we evaluated the swallowing function using the RSST, MWST, and FEES, and predicted the likelihood of aspiration pneumonia within 2 years after the assessment. The Hyodo score, a scoring system for evaluating the swallowing function determined by the FEES, was used. RESULTS: Pneumonia was observed in 14 patients (32.6%). The RSST was not significantly useful for predicting the onset of pneumonia. The MWST was reported to have a cutoff value of < 4 points. Significantly more patients in the pneumonia group had an MWST score of < 4 points. The results revealed that the occurrence of pneumonia could be predicted based on a Hyodo cutoff score of ≥ 6. Significantly more patients in the pneumonia group had an MWST score of < 4 or a Hyodo score of ≥ 6. CONCLUSIONS: Combining MWST and FEES is useful for evaluating the bedside swallowing function and predicting the onset of pneumonia.

The characteristics of dysphagia and the incidence of pneumonia in Myotonic dystrophy type 1 patients especially concerning swallowing function evaluated by endoscopy.

OBJECTIVE: The objectives of the study were to clarify the characteristics of dysphagia and the incidence of pneumonia in Myotonic dystrophy type 1 (DM1) patients, and to investigate the relationship between the development of pneumonia and the DM1 patient's background, especially concerning swallowing function evaluated by endoscopy. METHODS: The subjects were 88 DM1 patients who underwent swallowing function evaluation. The severity of disease in DM1patients was assessed based on the muscular impairment rating scale (MIRS), and the number of CTG repeats. Patients were divided into two groups; those who developed aspiration pneumonia within two years after swallowing assessment and those who did not develop aspiration pneumonia. Swallowing function was assessed using the food intake level scale (FILS), repetitive saliva swallowing test (RSST), the modified water swallowing test (MWST), and the Hyodo score. RESULTS: Onset of pneumonia within two years of assessment was observed in 22 cases (25%). Age, FILS, and Hyodo score were significantly different between pneumonia and non-pneumonia groups. There was a significant difference in swallowing function tests such as FILS, RSST, and Hyodo score between males and females. The Hyodo score cutoff value for predicting pneumonia within two years was determined by ROC analysis. A cutoff value of 6 was found to have a sensitivity of 0.545 and a specificity of 0.833 (area under the curve=0.722). CONCLUSION: It is important to evaluate the swallowing function of DM1 patients by endoscopy to prevent aspiration pneumonia. In addition, male patients are more likely to deteriorate in swallowing function and should be carefully monitored.

The generation of pancreatic ß-cell spheroids in a simulated microgravity culture system.

Islet transplantation can induce a substantial improvement in the treatment of type 1 diabetes mellitus. However, the clinical application of islet transplantation is severely limited by the shortage of donor organs. It is thus essential to improve the engraftment rate to achieve the expected outcome in the treatment of diabetes mellitus using a limited amount of donor islets. In this manuscript, we describe the generation of ß-cell spheroids using mouse insulinoma cells (MIN6) as a model of ß-cells. We established a 3D culture system that simulates microgravity using a 3D clinostat. Using this method, we were able to produce 100 spheroids per mL of culture media. The optimization of the culture conditions in the clinostat produced spheroids with a size of approximately 250 µm, which is a size that is known to induce good graft survival after islet transplantation. The spheroids produced in the clinostat expressed several ß-cell signature genes at higher levels than the levels that were found in MIN6 cells that were cultured in a standard 2D culture dish (MIN6-2D). The transplantation of the spheroids into the portal vein of streptozotocin-induced diabetic mice ameliorates hyperglycemia, whereas the transplantation of the equivalent number of 2D-cultured cells failed to cure diabetes. These results indicate that the clinostat culture provides a new method for the reconstitution of a large number of functional ß-cell spheroids for diabetes treatment.

Clinical features and a mutation with late onset of limb girdle muscular dystrophy 2B.

OBJECTIVE AND METHODS: Dysferlin encoded by DYSF deficiency leads to two main phenotypes, limb girdle muscular dystrophy (LGMD) 2B and Miyoshi myopathy. To reveal in detail the mutational and clinical features of LGMD2B in Japan, we observed 40 Japanese patients in 36 families with LGMD2B in whom dysferlin mutations were confirmed. RESULTS AND CONCLUSIONS: Three mutations (c.1566C>G, c.2997G>T and c.4497delT) were relatively more prevalent. The c.2997G>T mutation was associated with late onset, proximal dominant forms of dysferlinopathy, a high probability that muscle weakness started in an upper limb and lower serum creatine kinase (CK) levels. The clinical features of LGMD2B are as follows: (1) onset in the late teens or early adulthood, except patients homozygous for the c.2997G>T mutation; (2) lower limb weakness at onset; (3) distal change of lower limbs on muscle CT at an early stage; (4) impairment of lumbar erector spinal muscles on muscle CT at an early stage; (5) predominant involvement of proximal upper limbs; (6) preservation of function of the hands at late stage; (7) preservation of strength in neck muscles at late stage; (8) lack of facial weakness or dysphagia; (9) avoidance of scoliosis; (10) hyper-Ckaemia; (11) preservation of cardiac function; and (12) a tendency for respiratory function to decline with disease duration. It is important that the late onset phenotype is found with prevalent mutations.

Enantioselective direct aldol-type reaction of azlactone via protonation of vinyl ethers by a chiral Brønsted acid catalyst.

Highly enantio- and diastereoselective direct aldol-type reaction of azlactones with oxocarbenium ions generated by protonation of vinyl ethers using a chiral phosphoric acid catalyst is presented. The method provides efficient access to biologically and pharmaceutically intriguing beta-hydroxy-alpha-amino acid derivatives having a quaternary stereogenic center at the alpha-carbon atom.

Aromatic structure of tyrosine-92 in the extrinsic PsbU protein of red algal photosystem II is important for its functioning.

PsbU is one of the extrinsic proteins in red algal Photosystem II (PSII) and functions to optimize the availability of Ca(2+) and Cl(-) cofactors for water oxidation. To determine the functional residue of PsbU, we constructed various PsbU mutants from a red alga Cyanidium caldarium and reconstituted these mutants with the red algal PSII. The results revealed that Tyr-92 of PsbU, especially its aromatic ring, was essential for maintaining its function. From the crystal structure of PSII, Tyr-92 is located close to Pro-340 of D1, suggesting that the aromatic ring of Tyr-92 interacts with the CH group of Pro-340 of D1, and this CH/pi interaction is important for the optimal function of the Mn(4)Ca-cluster.

Tricyclic quinoxalinediones, aza-kynurenic acids, and indole-2-carboxylic acids as in vivo active NMDA-glycine antagonists.

This review article describes the development of in vivo active antagonists for the glycine binding site of the N-Methyl-D-Aspartate (NMDA) receptor. There were several difficulties in identifying a class of antagonists with in vivo efficacy and only a few compounds succeeded in emerging with activity in vivo. A series of tricyclic quinoxalinediones was highly potent glycine antagonists in vitro and the derivatives having a zwitterionic moiety including SM-18400 indeed showed in vivo activity. Similarly, tricyclic indole-2-carboxylic acids having a zwitterionic moiety such as SM-31900 were also active in vivo. In fact, SM-18400 and SM-31900 exhibited efficacy in several animal stroke models using intravenous infusion protocols. The practical syntheses of SM-18400 and SM-31900 as well as the novel synthesis of moderately active glycine antagonists, tricyclic azakynurenic acids, were also developed.

p21(Cip-1/SDI-1/WAF-1) expression via the mitogen-activated protein kinase signaling pathway in insulin-induced chondrogenic differentiation of ATDC5 cells.

The embryonal carcinoma-derived cell line, ATDC5, differentiates into chondrocytes in response to insulin or insulin-like growth factor-I stimulation. In this study, we investigated the roles of mitogen-activated protein (MAP) kinases in insulin-induced chondrogenic differentiation of ATDC5 cells. Insulin-induced accumulation of glycosaminoglycan and expression of chondrogenic differentiation markers, type II collagen, type X collagen, and aggrecan mRNA were inhibited by the MEK1/2 inhibitor (U0126) and the p38 MAP kinase inhibitor (SB203580). Conversely, the JNK inhibitor (SP600125) enhanced the synthesis of glycosaminoglycan and expression of chondrogenic differentiation markers. Insulin-induced phosphorylation of ERK1/2 and JNK but not that of p38 MAP kinase. We have previously clarified that the induction of the cyclin-dependent kinase inhibitor, p21(Cip-1/SDI-1/WAF-1), is essential for chondrogenic differentiation of ATDC5 cells. To assess the relationship between the induction of p21 and MAP kinase activity, we investigated the effect of these inhibitors on insulin-induced p21 expression in ATDC5 cells. Insulin-induced accumulation of p21 mRNA and protein was inhibited by the addition of U0126 and SB203580. In contrast, SP600125 enhanced it. Inhibitory effects of U0126 or stimulatory effects of SP600125 on insulin-induced chondrogenic differentiation were observed when these inhibitors exist in the early phase of differentiation, suggesting that MEK/ERK and JNK act on early phase differentiation. SB202580, however, is necessary not only for early phase but also for late phase differentiation, indicating that p38 MAP kinase stimulates differentiation by acting during the entire period of cultivation. These results for the first time demonstrate that up-regulation of p21 expression by ERK1/2 and p38 MAP kinase is required for chondrogenesis, and that JNK acts as a suppressor of chondrogenesis by down-regulating p21 expression.

Upregulation of striatal adenosine A2A receptor mRNA in 6-hydroxydopamine-lesioned rats intermittently treated with L-DOPA.

To determine whether the adenosine A2A receptor might play a role in L-DOPA-induced dyskinesia in Parkinson's disease, we analyzed changes in the expression of A2A receptor mRNA in response to intermittent treatment with L-DOPA in rats with dopaminergic denervation by 6-hydroxydopamine (OHDA) infusion into the medial forebrain bundle. Intermittent treatment with L-DOPA increased A2A receptor mRNA levels in the dopamine-depleted striatum of 6-OHDA-lesioned rats exhibiting behavioral sensitization to L-DOPA. These results suggest that A2A receptor activation is associated with the development of motor complications induced by L-DOPA treatment.

Tricyclic indole-2-carboxylic acids: highly in vivo active and selective antagonists for the glycine binding site of the NMDA receptor.

A series of tricyclic indole-2-carboxylic acid derivatives were synthesized and evaluated by the radioligand binding assay and the anticonvulsant effects in the mouse NMDA-induced seizure model. Among them, derivatives of 3S-(-)-4 such as 3a, 3f, and 3g which had certain zwitterionic anilides showed high affinity to the NMDA-glycine binding site. The absolute configuration of 3S-(-)-4 was confirmed by X-ray crystallographic analysis. In particular, 3g (SM-31900) was found to be a highly active glycine antagonist for both in vitro and in vivo assays (K(i) = 1.0 +/- 0.1 nM, ED(50) = 2.3 mg/kg, iv) and also showed high selectivity for the glycine site. In addition, 3g was soluble enough in aqueous media (>10 mg/mL at pH 7.4) to use for medications by intravenous injection.

SCA8 repeat expansion: large CTA/CTG repeat alleles are more common in ataxic patients, including those with SCA6.

We analyzed the SCA8 CTA/CTG repeat in a large group of Japanese subjects. The frequency of large alleles (85-399 CTA/CTG repeats) was 1.9% in spinocerebellar ataxia (SCA), 0.4% in Parkinson disease, 0.3% in Alzheimer disease, and 0% in a healthy control group; the frequency was significantly higher in the group with SCA than in the control group. Homozygotes for large alleles were observed only in the group with SCA. In five patients with SCA from two families, a large SCA8 CTA/CTG repeat and a large SCA6 CAG repeat coexisted. Age at onset was correlated with SCA8 repeats rather than SCA6 repeats in these five patients. In one of these families, at least one patient showed only a large SCA8 CTA/CTG repeat allele, with no large SCA6 CAG repeat allele. We speculate that the presence of a large SCA8 CTA/CTG repeat allele influences the function of channels such as alpha(1A)-voltage-dependent calcium channel through changing or aberrant splicing, resulting in the development of cerebellar ataxia, especially in homozygous patients.

SM-31900, a novel NMDA receptor glycine-binding site antagonist, reduces infarct volume induced by permanent middle cerebral artery occlusion in spontaneously hypertensive rats.

The purpose of this study was to investigate the effect of (3S)-7-chloro-3-[2-((1R)-1-carboxyethoxy)-4-aminomethylphenyl]aminocarbonylmethyl-1,3,4,5-tetrahydrobenz[c,d]indole-2-carboxylic acid hydrochloride (SM-31900), an antagonist with high selectivity and affinity for the NMDA receptor glycine-binding site, on the cerebral infarct volume in a permanent middle cerebral artery occlusion (MCAo) model, which was constructed by electrocoagulation of a unilateral middle cerebral artery distal to the olfactory tract using spontaneously hypertensive rats (SHRs). To investigate the dose-response characteristics and the therapeutic time window of SM-31900 in this MCAo model, we conducted three experiments, in which the administration of SM-31900 was started 5min (experiment I), 30min (experiment II), or 60min (experiment III) after MCAo, respectively. In all the studies, SM-31900 was administered by intravenous bolus injection followed by continuous intravenous infusion to obtain a steady-state level of this compound in blood immediately after its administration. The treatment with SM-31900 was continued until 24h after MCAo, at which time the cerebral infarct volume was measured. In experiment I, SM-31900 significantly reduced the infarct volume by 37% at a dosage of 0.38mg/kg bolus followed by 1.5mg/kg/h continuous infusion (0.38mg/kg+1.5mg/kg/h). In experiment II, the neuroprotective effect of SM-31900 was also significant, with a 25% reduction in infarct volume at a dosage of 0.38mg/kg+1.5mg/kg/h, and a 40% reduction at 1.5mg/kg+6.0mg/kg/h. Furthermore, even in experiment III, SM-31900 exerted a significant neuroprotective effect, with a 20% reduction at 1.5mg/kg+6.0mg/kg/h. These studies revealed that SM-31900 can exert a neuroprotective effect when it is administered up to at least 60min after the onset of ischemia in the MCAo model, an animal model of stroke, indicating that SM-31900 is a good candidate for treating acute brain ischemia.

In vitro and in vivo antagonistic activities of SM-31900 for the NMDA receptor glycine-binding site.

The purpose of this study was to clarify the in vitro pharmacological profile and the in vivo activity of (3S)-7-chloro-3-[2-((1R)-1-carboxyethoxy)-4-aminomethylphenyl]aminocarbonylmethyl-1,3,4,5-tetrahydrobenz[c,d]indole-2-carboxylic acid hydrochloride (SM-31900). SM-31900 inhibited the binding of [3H]glycine and [3H]5,7-dichlorokynurenic acid, radioligands for the N-methyl-D-aspartate (NMDA) receptor glycine-binding site, to rat brain membranes in a competitive manner, with K(i) values of 11+/-2 and 1.0+/-0.1 nM, respectively, and completely prevented the binding of [3H]dizocilpine (MK-801), a radioligand for the NMDA receptor channel site. In cultures of rat cortical neurons, SM-31900 markedly prevented the neuronal cell death induced by transient exposure to glutamate, in a concentration-dependent manner. Its neuroprotective potency was much stronger than those of other glycine-binding site antagonists (4-trans-2-carboxy-5,7-dichloro-4-phenylaminocarbonylamino-1,2,3,4-tetrahydroquinoline (L-689,560), 5,7-dichlorokynurenic acid, and 7-chlorokynurenic acid). Furthermore, SM-31900 showed anticonvulsant activity when administered systemically, unlike other antagonists. These data indicate that SM-31900 is a systemically active antagonist with high affinity for the NMDA receptor glycine-binding site.