Forelimb force direction and magnitude independently controlled by spinal modules in the macaque

腕の自由自在な動きをつくりだす多機能な神経細胞群の発見 --運動の方向と大きさを同時にコントロールする神経メカニズムの解明--. 京都大学プレスリリース. 2020-10-14.Primates aren't quite frogs. 京都大学プレスリリース. 2020-10-19.Modular organization of the spinal motor system is thought to reduce the cognitive complexity of simultaneously controlling the large number of muscles and joints in the human body. Although modular organization has been confirmed in the hindlimb control system of several animal species, it has yet to be established in the forelimb motor system or in primates. Expanding upon experiments originally performed in the frog lumbar spinal cord, we examined whether costimulation of two sites in the macaque monkey cervical spinal cord results in motor activity that is a simple linear sum of the responses evoked by stimulating each site individually. Similar to previous observations in the frog and rodent hindlimb, our analysis revealed that in most cases (77% of all pairs) the directions of the force fields elicited by costimulation were highly similar to those predicted by the simple linear sum of those elicited by stimulating each site individually. A comparable simple summation of electromyography (EMG) output, especially in the proximal muscles, suggested that this linear summation of force field direction was produced by a spinal neural mechanism whereby the forelimb motor output recruited by costimulation was also summed linearly. We further found that the force field magnitudes exhibited supralinear (amplified) summation, which was also observed in the EMG output of distal forelimb muscles, implying a novel feature of primate forelimb control. Overall, our observations support the idea that complex movements in the primate forelimb control system are made possible by flexibly combined spinal motor modules

Reproducibility and validity of food group intake in a short food frequency questionnaire for the middle-aged Japanese population

Purpose: The purpose of this study was to evaluate the reproducibility and validity of a short food frequency questionnaire (FFQ) for food group intake in Japan, the reproducibility and partial validity of which were previously confirmed for nutrients. Methods: A total of 288 middle-aged healthy volunteers from 11 different areas of Japan provided nonconsecutive 3-day weighed dietary records (DRs) at 3-month intervals over four seasons. We evaluated reproducibility based on the first (FFQ1) and second (FFQ2) questionnaires and their validity against the DRs by comparing the intake of 20 food groups. Spearman’s rank correlation coefficients (SRs) were calculated between energy-adjusted intake from the FFQs and that from the DRs. Results: The intake of 20 food groups estimated from the two FFQs was mostly equivalent. The median energy-adjusted SRs between the FFQ1 and FFQ2 were 0.61 (range 0.38–0.86) for men and 0.66 (0.45–0.84) for women. For validity, the median de-attenuated SRs between DRs and the FFQ1 were 0.51 (0.17–0.76) for men and 0.47 (0.23–0.77) for women. Compared with the DRs, the proportion of cross-classification into exact plus adjacent quintiles with the FFQ1 ranged from 58 to 86% in men and from 57 to 86% in women. According to the robust Z scores and the Bland–Altman plot graphs, the underestimation errors in the FFQ1 tended to be greater in individuals with high mean levels of consumption for meat for men and for other vegetables for both men and women. Conclusion: The FFQ demonstrated high reproducibility and reasonable validity for food group intake. This questionnaire is short and remains appropriate for identifying associations between diet and health/disease among adults in Japan

Aseptic Meningitis with Relapsing Polychondritis Mimicking Bacterial Meningitis

Relapsing polychondritis (RP) is a rare multisystem autoimmune disease. Though meningitis in RP is not common, some cases with cerebrospinal fluid (CSF) pleocytosis of lymphocyte cells have been reported. Of the 18 previously reported cases, two cases demonstrated pleocytosis of polymorphonuclear leukocytes (PMN) in the CSF. In addition, the cases whose glucose level in the CSF was decreased also were seen. Our case also demonstrated pleocytosis of PMN in CSF mimicking bacterial meningitis. In the clinical field, we cannot get the culture of CNF on the day. We regard the gulucose level and cellular fraction as impotant. Therefore, we must look upon meningitis in RP as a differential diagnosis of bacterial meningitis

Scapular Winging as a Symptom of Cervical Flexion Myelopathy

A 23-year-old man complained of weakness of the right arm that he first noted six years prior to his visit. Neurological examination revealed atrophy and weakness of the triceps and serratus anterior muscle on the right side, which resulted in scapular winging on that side. MRI with neck flexion revealed compression of the cervical cord enabling a diagnosis of flexion myelopathy. Proximal muscle weakness and atrophy in flexion myelopathies including Hirayama disease are extremely rare. Here, we report a case of unilateral, proximal upper limb atrophy with scapular winging, attributed to middle cervical flexion myelopathy

MERRF/MELAS overlap syndrome: A double pathogenic mutation in mitochondrial tRNA genes

Background : Myoclonic epilepsy with ragged-red fibres (MERRF) and mitochondrial encephalopathy, lactic acidosis and stroke-like episodes (MELAS) are established phenotypes of mitochondrial encephalomyopathy. The m.8356T>C transition in the mitochondrial tRNALys gene is a pathogenic mutations of MERRF. The m.3243A>G transition in the mitochondrial tRNALeu gene is detected in most MELAS patients. Although previous analyses of double mutations in mitochondrial DNA (mtDNA) were useful for discussing their nature, many unsolved questions remain. Objective : To describe the clinical and genetic features of a family with the above mtDNA double-point mutations and discuss the role of double mtDNA mutations in diverse clinical features in the family. Patients and methods : The proband was a 23-year-old woman with MERRF harbouring m.8356T>C and m.3243A>G transitions in mitochondrial tRNA genes. We assessed clinical aspects of her and those of her three relatives and performed mutation analyses on their mtDNA. Results : Phenotypes of the four patients were MERRF, MERRF/MELAS overlap syndrome and asymptomatic carrier. We hypothesise that the course of the phenotype of this family begins with MERRF and is followed by MELAS. This double mutation was heteroplasmic in blood of all four patients but with different rates in each patient, while m.8356T>C appeared homoplasmic and m.3243A>G was heteroplasmic in muscle of the two examined cases. No other mutations were detected in the total mtDNA sequence in this family. Conclusions : This is the first reported case of a double-point mutation in mtDNA, both of which were heteroplasmic and pathogenic for the established phenotypes

Genetic analysis of two Japanese families with progressive external ophthalmoplegia and parkinsonism.

Mutations in the progressive external ophthalmoplegia 1 (PEO1), adenine nucleotide translocator 1 (ANT1) and DNA polymerase gamma (POLG) genes were reported in patients with progressive external ophthalmoplegia and parkinsonism. However, the genotype-phenotype correlation and pathophysiology of these syndromes are still unknown. In order to define the molecular basis of progressive external ophthalmoplegia and parkinsonism, we screened for mutations in PEO1, ANT1, POLG genes and the whole mitochondrial genome in two families. In results, we identified a compound heterozygous POLG substitutions, c.830A>T (p.H277L) and c.2827C>T (p.R943C) in one of the families. These two mutations in the coding region of POLG alter conserved amino acids in the exonuclease and polymerase domains, respectively, of the POLG protein. Neither of these substitutions was found in the 100 chromosomes of ethnically matched control subjects. In the other family, no mutations were detected in any of the three genes and the whole mitochondrial genome in the blood sample, although mitochondrial DNA deletions were observed in the muscle biopsy sample. Progressive external ophthalmoplegia and parkinsonism are genetically heterogenous disorders, and part of this syndrome may be caused by mutations in other, unknown genes

Two Cases of Human T-Lymphotropic Virus Type I-Associated Myelopathy/Tropical Spastic Paraparesis Caused by Living-Donor Renal Transplantation

In rare instances, recipients of organ transplants from human T-lymphotropic virus type I- (HTLV-I-) positive donors reportedly developed neurologic symptoms due to HTLV-I-associated myelopathy (HAM). We present herein two cases of HAM associated with renal transplantation from HTLV-I seropositive living-donors. The first patient was a 42-year-old woman with chronic renal failure for twelve years and seronegative for HTLV-I. She underwent renal transplantation with her HTLV-I seropositive mother as the donor, and she developed HAM three years after the transplantation. The second patient was a 65-year-old man who had been suffering from diabetic nephropathy. He was seronegative for HTLV-I and underwent renal transplantation one year previously, with his HTLV-I seropositive wife as the donor. He developed HAM eight months after renal transplantation. Both cases showed neurological improvements after the immunomodulating therapies. We tried to shed some light on the understanding of immunological mechanisms of transplantation-associated HAM, focusing on therapeutic strategies based on the immunopathogenesis of the condition