Complete chemical structures of human mitochondrial tRNAs

Mitochondria generate most cellular energy via oxidative phosphorylation. Twenty-two species of mitochondrial (mt-)tRNAs encoded in mtDNA translate essential subunits of the respiratory chain complexes. mt-tRNAs contain post-transcriptional modifications introduced by nuclear-encoded tRNA-modifying enzymes. They are required for deciphering genetic code accurately, as well as stabilizing tRNA. Loss of tRNA modifications frequently results in severe pathological consequences. Here, we perform a comprehensive analysis of post-transcriptional modifications of all human mt-tRNAs, including 14 previously-uncharacterized species. In total, we find 18 kinds of RNA modifications at 137 positions (8.7% in 1575 nucleobases) in 22 species of human mt-tRNAs. An up-to-date list of 34 genes responsible for mt-tRNA modifications are provided. We identify two genes required for queuosine (Q) formation in mt-tRNAs. Our results provide insight into the molecular mechanisms underlying the decoding system and could help to elucidate the molecular pathogenesis of human mitochondrial diseases caused by aberrant tRNA modifications

Neutrophil fixation protocols suitable for substrates to detect anti-neutrophil cytoplasmic antibodies by indirect immunofluorescence

Anti-neutrophil cytoplasmic antibodies (ANCAs) are autoantibodies that recognize neutrophil cytoplasmic antigens. The major ANCA antigens are myeloperoxidase and proteinase 3. Necrotizing small vessel vasculitis accompanied by ANCA production is called ANCA-associated vasculitis (AAV). In addition to AAV, ANCA is sometimes produced in patients with connective tissue diseases, such as systemic lupus erythematosus, and inflammatory bowel diseases. Indirect immunofluorescence (IIF) and enzyme immunoassay (EIA) have been used to detect ANCAs. Recently, the accuracy of EIA has improved and it has become the gold standard for ANCA detection. However, IIF does not lose its role in ANCA detection because EIA cannot detect ANCAs that recognize antigens other than those coated on the plate. For IIF, neutrophil substrates prepared with two different fixations, namely, ethanol fixation and formalin fixation, are used. There is a recommended protocol for ethanol fixation but not for formalin fixation. This study prepared neutrophil substrates according to the recommended protocol for ethanol fixation and protocols in the literature and original protocols for formalin fixation and then examined ANCA specificity and how storage period would influence the number of cells, antigen distribution, and antigenicity of the substrates. As a result, the number of cells and antigen distribution did not change after storage for up to 2 months regardless of fixation protocols, whereas a time-dependent decline in ANCA antigenicity and a fixation protocol-dependent difference in ANCA specificity were observed. How neutrophils are fixed on the glass slide needs to be checked upon evaluation of ANCAs by IIF

The ultrasound-guided nerve blocks of abdominal wall contributed to anesthetic management of cholecystectomy in a patient with Becker muscular dystrophy without using muscle relaxants

Abstract Becker muscular dystrophy (BMD) is a progressive neuromuscular disorder caused by mutations in the dystrophin gene. The sensitivity to non-depolarizing muscle relaxant in a patient with muscle dystrophy is reportedly higher than that in normal individuals, and the duration of the effect is known to be prolonged. In this report, we present the case of a 58-year-old man with BMD who underwent laparoscopic cholecystectomy for symptomatic cholelithiasis under total intravenous anesthesia without the use of muscle-relaxant drugs and supplemented with regional anesthesia. Anesthesia was induced and maintained with propofol, remifentanil, and fentanyl; ultrasound-guided bilateral rectus sheath block (RSB) and right-sided subcostal transversus abdominis plane block (TAP) were performed. The procedure required conversion to open surgery because of hard conglutination; intraoperative and postoperative periods were uneventful. Adequate analgesia was maintained after extubation because of the effect of RSB and TAP

Cerebrospinal fluid-contacting neuron tracing reveals structural and functional connectivity for locomotion in the mouse spinal cord

Cerebrospinal fluid-contacting neurons (CSF-cNs) are enigmatic mechano- or chemosensory cells lying along the central canal of the spinal cord. Recent studies in zebrafish larvae and lampreys have shown that CSF-cNs control postures and movements via spinal connections. However, the structures, connectivity, and functions in mammals remain largely unknown. Here we developed a method to genetically target mouse CSF-cNs that highlighted structural connections and functions. We first found that intracerebroventricular injection of adeno-associated virus with a neuron-specific promoter and Pkd2l1-Cre mice specifically labeled CSF-cNs. Single-cell labeling of 71 CSF-cNs revealed rostral axon extensions of over 1800 μm in unmyelinated bundles in the ventral funiculus and terminated on CSF-cNs to form a recurrent circuitry, which was further determined by serial electron microscopy and electrophysiology. CSF-cNs were also found to connect with axial motor neurons and premotor interneurons around the central canal and within the axon bundles. Chemogenetic CSF-cNs inactivation reduced speed and step frequency during treadmill locomotion. Our data revealed the basic structures and connections of mouse CSF-cNs to control spinal motor circuits for proper locomotion. The versatile methods developed in this study will contribute to further understanding of CSF-cN functions in mammals

Relation of Quantitative Eye Movements with Cognitive Dysfunction in Patients with Concussion

Inter-saccadic interval (ISI) prolongation during rapid number naming on King-Devick (K-D) testing has been shown to underlie longer test times in patients with a history of concussion. The ISI is a measure of time between saccades, representing saccadic latency and fixation duration. Prolongation may result from increased saccade latency either as a result of, or in concert with, impaired attention and/or cognition. We sought to determine the relation of ISI prolongation and neuropsychological testing in a range of cognitive domains in concussion