Conversion map from quantitative parameter mapping to myelin water fraction: comparison with R1·R2* and myelin water fraction in white matter.

OBJECTIVE: To clarify the relationship between myelin water fraction (MWF) and R1⋅R2* and to develop a method to calculate MWF directly from parameters derived from QPM, i.e., MWF converted from QPM (MWFQPM). MATERIALS AND METHODS: Subjects were 12 healthy volunteers. On a 3 T MR scanner, dataset was acquired using spoiled gradient-echo sequence for QPM. MWF and R1⋅R2* maps were derived from the multi-gradient-echo (mGRE) dataset. Volume-of-interest (VOI) analysis using the JHU-white matter (WM) atlas was performed. All the data in the 48 WM regions measured VOI were plotted, and quadratic polynomial approximations of each region were derived from the relationship between R1·R2* and the two-pool model-MWF. The R1·R2* map was converted to MWFQPM map. MWF atlas template was generated using converted to MWF from R1·R2* per WM region. RESULTS: The mean MWF and R1·R2* values for the 48 WM regions were 11.96 ± 6.63%, and 19.94 ± 4.59 s-2, respectively. A non-linear relationship in 48 regions of the WM between MWF and R1·R2* values was observed by quadratic polynomial approximation (R2 ≥ 0.963, P < 0.0001). DISCUSSION: MWFQPM map improved image quality compared to the mGRE-MWF map. Myelin water atlas template derived from MWFQPM may be generated with combined multiple WM regions.

Read-through transcription of tRNA underlies the cell cycle-dependent dissociation of IHF from the DnaA-inactivating sequence datA.

Timely initiation of chromosomal DNA replication in Escherichia coli is achieved by cell cycle-coordinated regulation of the replication origin, oriC, and the replication initiator, ATP-DnaA. Cellular levels of ATP-DnaA increase and peak at the time for initiation at oriC, after which hydrolysis of DnaA-bound ATP causes those to fall, yielding initiation-inactive ADP-DnaA. This hydrolysis is facilitated by the chromosomal locus datA located downstream of the tRNA-Gly (glyV-X-Y) operon, which possesses a cluster of DnaA-binding sequences and a single binding site (IBS) for the DNA bending protein IHF (integration host factor). While IHF binding activates the datA function and is regulated to occur specifically at post-initiation time, the underlying regulatory mechanisms remain obscure. Here, we demonstrate that datA-IHF binding at pre-initiation time is down-regulated depending on the read-through transcription of datA IBS initiated at the glyV-X-Y promoter. During the cell cycle, the level of read-through transcription, but not promoter activity, fluctuated in a manner inversely related to datA-IHF binding. Transcription from the glyV-X-Y promoter was predominantly interrupted at datA IBS by IHF binding. The terminator/attenuator sequence of the glyV-X-Y operon, as well as DnaA binding within datA overall, contributed to attenuation of transcription upstream of datA IBS, preserving the timely fluctuation of read-through transcription. These findings provide a mechanistic insight of tRNA transcription-dependent datA-IHF regulation, in which an unidentified factor is additionally required for the timely datA-IHF dissociation, and support the significance of datA for controlling the cell cycle progression as a connecting hub of tRNA production and replication initiation.

In vitro study of the embolic characteristics of imipenem/cilastatin particles.

BACKGROUND: Imipenem/cilastatin (IPM/CS) has long been administered intravenously as a carbapenem antibiotic. However, since this agent is poorly soluble in liquid, occasional reports have described its use as a short-acting, temporary embolic agent. The purpose of this study was to elucidate the characteristics of IPM/CS particles, which are thought to have pain-relieving effects against osteoarthritis-related pain, as an embolic agent. METHODS: Three aspects of IPM/CS as an embolic agent were evaluated in vitro: particle size; particle shape; and change in particle size over time. For particle size, the long diameter was measured. RESULTS: Mean particle size (n=244) was 29.2±12.0 µm (range, 1-60 µm). Shape (n=109) was round in 18.35%, elliptical in 11.93%, and polygonal in 69.72%, showing that most particles were polygonal. In observations of changes in particle size over time (n=9), particles had decreased to 75% of their original size at 82±10.7 min, 50% at 89.3±9.14 min, 25% at 91.3±8.74 min, complete dissolved at 91.8±9.02 min. A rapid shrinkage in diameter was seen in the final period. CONCLUSIONS: IPM/CS particles are ultrafine and the majority display a polygonal shape. This substance shows ultra-short embolic activity. This study revealed the characteristics of a substance that demonstrates an embolic effect not found in existing embolic materials.

4D Flow MRI Reflects Physiological Hemodynamics for the Diagnosis and Management of Portosystemic Shunts.

A woman in her sixties with portosystemic shunt and hepatic encephalopathy underwent open mesenteric vein ligation, resulting in improved portal flow and blood ammonia. In this case, 4D flow MRI was a valuable diagnostic and follow-up tool, visualizing and quantifying physiological portal hemodynamics with features distinct from those of contrast-enhanced CT and digital subtraction angiography. Our case study highlights the value of 4D flow MRI for managing portosystemic shunts.

Differences of white matter structure for diffusion kurtosis imaging using voxel-based morphometry and connectivity analysis.

Objectives: In a clinical study, diffusion kurtosis imaging (DKI) has been used to visualize and distinguish white matter (WM) structures' details. The purpose of our study is to evaluate and compare the diffusion tensor imaging (DTI) and DKI parameter values to obtain WM structure differences of healthy subjects. Methods: Thirteen healthy volunteers (mean age, 25.2 years) were examined in this study. On a 3-T MRI system, diffusion dataset for DKI was acquired using an echo-planner imaging sequence, and T1-weghted (T1w) images were acquired. Imaging analysis was performed using Functional MRI of the brain Software Library (FSL). First, registration analysis was performed using the T1w of each subject to MNI152. Second, DTI (eg, fractional anisotropy [FA] and each diffusivity) and DKI (eg, mean kurtosis [MK], radial kurtosis [RK], and axial kurtosis [AK]) datasets were applied to above computed spline coefficients and affine matrices. Each DTI and DKI parameter value for WM areas was compared. Finally, tract-based spatial statistics (TBSS) analysis was performed using each parameter. Results: The relationship between FA and kurtosis parameters (MK, RK, and AK) for WM areas had a strong positive correlation (FA-MK, R2 = 0.93; FA-RK, R2 = 0.89) and a strong negative correlation (FA-AK, R2 = 0.92). When comparing a TBSS connection, we found that this could be observed more clearly in MK than in RK and FA. Conclusions: WM analysis with DKI enable us to obtain more detailed information for connectivity between nerve structures. Advances in knowledge: Quantitative indices of neurological diseases were determined using segmenting WM regions using voxel-based morphometry processing of DKI images.

Dynamic action of an intrinsically disordered protein in DNA compaction that induces mycobacterial dormancy.

Mycobacteria are the major human pathogens with the capacity to become dormant persisters. Mycobacterial DNA-binding protein 1 (MDP1), an abundant histone-like protein in dormant mycobacteria, induces dormancy phenotypes, e.g. chromosome compaction and growth suppression. For these functions, the polycationic intrinsically disordered region (IDR) is essential. However, the disordered property of IDR stands in the way of clarifying the molecular mechanism. Here we clarified the molecular and structural mechanism of DNA compaction by MDP1. Using high-speed atomic force microscopy, we observed that monomeric MDP1 bundles two adjacent DNA duplexes side-by-side via IDR. Combined with coarse-grained molecular dynamics simulation, we revealed the novel dynamic DNA cross-linking model of MDP1 in which a stretched IDR cross-links two DNA duplexes like double-sided tape. IDR is able to hijack HU function, resulting in the induction of strong mycobacterial growth arrest. This IDR-mediated reversible DNA cross-linking is a reasonable model for MDP1 suppression of the genomic function in the resuscitable non-replicating dormant mycobacteria.

A case of development of autoimmune pulmonary alveolar proteinosis during the treatment of hypersensitivity pneumonitis.

Herein, we report the case of a 73-year-old woman with an occupational history of plaster grinding who developed autoimmune pulmonary alveolar proteinosis (PAP) during the treatment of fibrotic hypersensitivity pneumonitis with steroids and immunosuppressive drugs. Based on the changes in computed tomography imaging findings, poor response to steroid therapy, and markedly elevated KL-6 levels, PAP was suspected and diagnosed by bronchoscopy. Repeated segmental bronchoalveolar lavage under high-flow nasal cannula oxygen therapy resulted in slight improvement. Steroids and immunosuppressive treatments for other interstitial lung diseases may cause PAP or exacerbate latent PAP.

Acute exacerbation of pleuroparenchymal fibroelastosis with lower lobe usual interstitial pneumonia: An autopsy case.

An 87-year-old man presented with dyspnea. Computed tomography revealed progressive subpleural consolidation in the apex, reticular shadows in the lower lobes, and bilateral ground glass opacifications. He died of respiratory failure on day 3. The post-mortem examination showed exudative stage diffuse alveolar damage and pulmonary edema. Intraalveolar collagenous fibrosis and subpleural elastosis were observed in the upper lobes, accompanied by interlobular septal and pleural thickening and lung architecture remodeling in the lower lobes. He was diagnosed with acute exacerbation of pleuroparenchymal fibroelastosis with lower lobe usual interstitial pneumonia, which can be fatal.

Detection of impaired gas exchange using the 1-minute sit-to-stand test in patients with interstitial lung disease.

BACKGROUND: Although pulmonary function tests (PFTs) are important in patients with interstitial lung disease (ILD), they cannot be easily performed in a primary healthcare setting. This study aimed to examine the usefulness of the difference between pulse oxygen saturation (SpO2) at rest and the lowest SpO2 during the 1-min sit-to-stand test (delta SpO2-1STST) for predicting pulmonary function impairment. METHODS: We retrospectively reviewed 116 patients with ILD who underwent 1STST and PFTs. RESULTS: The delta SpO2-1STST and diffusing capacity for carbon monoxide (DLco) strongly correlated (ρ = 0.70). The delta SpO2-1STST was effective in predicting impaired gas exchange (cut-off value, -4%; AUC, 0.86; sensitivity, 74%; specificity, 87%). CONCLUSIONS: The Delta SpO2-1STST may be a reasonable tool for predicting abnormalities in PFTs.

Peculiar properties of tuber starch in a potato mutant lacking the α-glucan water dikinase 1 gene GWD1 created by targeted mutagenesis using the CRISPR/dMac3-Cas9 system.

Glucose chains in starch are phosphorylated and contribute to structural stabilization. Phosphate groups contained in starch also play a role in retaining moisture. α-Glucan water dikinase 1 (GWD1) is involved in the phosphorylation of glucose chains in starch. In this study, we generated potato mutants of the GWD1 gene using the CRISPR/dMac3-Cas9 system. Observation of the phenotypes of the GWD1-deficient mutants revealed their physiological roles in tuber starch formation. The 4-allele mutants showed growth retardation and a delay in tuber formation. A significant decrease in phosphorus content was detected in the tuber starch of the gwd1 mutant. This mutant starch showed a higher amylose content than the wild-type starch, whereas its gelatinization temperature was slightly lower than that of the WT starch. The peak viscosity of the mutant starch was lower than that of the WT starch. These observations revealed that the starch of the gwd1 mutants had peculiar and unique properties compared to those of WT, sbe3 and gbss1 mutant starches. The amount of tissue-released water due to freeze-thawing treatment was determined on tubers of the gwd1 mutant and compared with those of WT and the other mutants. Significantly less water loss was found in the gwd1, sbe3 and gbss1 mutant tubers than in the WT tubers. Our results indicate that the GWD1 gene is not only important for potato growth, but also largely effective for the traits of tuber starch.

Myelin-weighted imaging derived from quantitative parameter mapping.

PURPOSE: We developed a novel method which is applicable to visualize contrast according to myelin components in the human brain using relaxation time derived from quantitative parameter mapping magnetic resonance imaging (QPM-MRI). MATERIALS AND METHODS: Using healthy volunteer data (n = 10), we verified that our method demonstrated that the myelin-weighted contrast increased proportionally by products R1 and R2*, i.e., QPM-myelin-weighted image, in which modified T1-weighted/T2-weighted (T1w/T2w) ratio mapping method was applied. We compared measurement values in white matter (WM) and gray matter (GM) regions of the T1w/T2w ratio and R1·R2* product maps of healthy volunteers. Linear regression analysis between each value. Mann Whitney U test between WM and GM signals in each myelin map. In addition, Additionally, QPM-myelin-weighted image was applied to a 32-year-old female MS patient. RESULTS: Linear regression analysis showed a highly significant correlation between conventional T1w/T2w ratios and R1·R2* products derived from QPM (R = 0.73, P < 0.0001). Moreover, there is a significant difference between WM and GM structures in each myelin images (both, P < 0.0001). Additionally, in a clinical case, MS lesions enabled observation of not only MS plaques but also heterogeneous myelin signal loss associated with demyelination more clearly than T2w image and conventional T1w/T2w ratio image. CONCLUSION: Our myelin-weighted imaging technique using QPM may be useful for myelin visualization and is expected to become independent of measurement conditions due to having quantitative characteristics of QPM itself.

The flexible N-terminal motif of uL11 unique to eukaryotic ribosomes interacts with P-complex and facilitates protein translation.

Eukaryotic uL11 contains a conserved MPPKFDP motif at the N-terminus that is not found in archaeal and bacterial homologs. Here, we determined the solution structure of human uL11 by NMR spectroscopy and characterized its backbone dynamics by 15N-1H relaxation experiments. We showed that these N-terminal residues are unstructured and flexible. Structural comparison with ribosome-bound uL11 suggests that the linker region between the N-terminal domain and C-terminal domain of human uL11 is intrinsically disordered and only becomes structured when bound to the ribosomes. Mutagenesis studies show that the N-terminal conserved MPPKFDP motif is involved in interacting with the P-complex and its extended protuberant domain of uL10 in vitro. Truncation of the MPPKFDP motif also reduced the poly-phenylalanine synthesis in both hybrid ribosome and yeast mutagenesis studies. In addition, G→A/P substitutions to the conserved GPLG motif of helix-1 reduced poly-phenylalanine synthesis to 9-32% in yeast ribosomes. We propose that the flexible N-terminal residues of uL11, which could extend up to ∼25 Šfrom the N-terminal domain of uL11, can form transient interactions with the uL10 that help to fetch and fix it into a position ready for recruiting the incoming translation factors and facilitate protein synthesis.

Well-Controlled Living Polymerization of N-Propargylamides and Their Derivatives by Rhodium Catalysis.

A substantially improved method for living polymerization of N-propargylamides and their derivatives has been developed. Rhodium(I) complexes bearing an aryl-substituted 1,3,5-hexatriene chain can work as excellent initiators of the polymerization of such non-conjugated terminal alkynes to give the corresponding cis-stereoregular polymers having a narrow molecular weight distribution. The typical living nature has been confirmed by investigating the effects of initial feed ratios of the monomer to the initiator on the molecular weight of the resulting polymers as well as multistage polymerization. Moreover, we demonstrated that the present method enables functionalization of both polymer chain ends and synthesis of novel block copolymers consisting of poly(N-propargylamide) and poly(phenylacetylene) blocks with a narrow molecular weight distribution.

The 1-minute sit-to-stand test to detect desaturation during 6-minute walk test in interstitial lung disease.

Although the 6 min walk test (6MWT) is well-established for assessing desaturation in patients with interstitial lung disease (ILD), it cannot be easily performed in primary healthcare settings. This retrospective observational study aimed to evaluate the usefulness of the 1 min sit-to-stand test (1STST) for assessing desaturation during 6MWT in ILD patients with normal resting blood oxygen levels. We included 116 patients, and the pulse oxygen saturation (SpO2) for both methods was analyzed. The SpO2 nadir during the 1STST and 6MWT correlated strongly (ρ = 0.82). The frequency of patients with nadir SpO2 < 90% was consistent for both tests (κ = 0.82). 1STST was superior to diffusing capacity for carbon monoxide in detecting desaturation during the 6MWT. These findings were similarly stratified according to performance status or dyspnea scale. The 1STST can easily measure exertional desaturation in ILD patients with normal resting blood oxygen levels and is an alternative to the 6MWT.

A novel ribosome-dimerization protein found in the hyperthermophilic archaeon Pyrococcus furiosus using ribosome-associated proteomics.

Ribosome dimerization is one of the bacterial events that suppresses protein synthesis in the stationary phase. Protein factors responsible for ribosome dimerization in bacteria are well characterized, whereas no information is available for the corresponding factors in archaeal and eukaryotic cells. Here we describe a protein found among the ribosome-associated proteins which dimerizes the 30S ribosomal subunit of the archaeon Pyrococcus furiosus. The ribosome-associated proteins were prepared by high-salt wash of crude ribosomes, and analyzed by nanoflow liquid chromatography-tandem mass spectrometry (nano LC-MS/MS). Of the detected proteins we focused on a protein (PF0560) whose Protein Score was the highest of all of the function-unknown proteins. PF0560 protein had a pronounced effect on the sedimentation pattern of the 30S ribosomal subunit; addition of this protein to isolated 30S subunit reduced the 30S fraction and increased the amount of the 50S fraction. This increase presumably corresponds to the dimer of the 30S subunit. The PF0560-dependent 30S-dimerization, was also observed by gel electrophoretic analysis. This effect was not observed in EDTA-treated 30S subunit, with protein-free 16S rRNA or with bacterial/eukaryotic ribosomal small subunits. Furthermore, PF0560 protein suppressed the formation of functional 70S ribosomes. These results suggest that PF0560 is a novel 30S dimerization factor, which might participate in regulation of archaeal translation.

Leptin Is an Important Endocrine Player That Directly Activates Gonadotropic Cells in Teleost Fish, Chub Mackerel.

Leptin, secreted by adipocytes, directly influences the onset of puberty in mammals. Our previous study showed that leptin stimulation could promote the secretion of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) from pituitary cells in primary culture and ovarian development in chub mackerel. This study aimed to elucidate the detailed mechanism of leptin-induced effects on gonadotropin hormone-producing cells. We produced recombinant leptin using silkworm pupae and investigated the effects of leptin on FSH and LH secretion and gene expression in the primary culture of pituitary cells from chub mackerel. The presence or absence of co-expression of lepr mRNA, FSH and LH b-subunit mRNA in gonadotropic cells was examined by double-labeled in situ hybridization. The addition of leptin significantly increased the secretion and gene expression of FSH and LH from male and female pituitary cells in primary culture. In contrast, gonadotropin-releasing hormone 1 affected neither FSH secretion in cells from females nor fshb and lhb expression in cells from males and females. The expression of lepr was observed in FSH- and LH-producing cells of both males and females. The results indicate that leptin directly regulates gonadotropin synthesis and secretion and plays an important role in the induction of puberty in teleost fish.

Drug discovery and development scheme for liver-targeting bridged nucleic acid antisense oligonucleotides.

Antisense oligonucleotides (ASOs) containing bridged nucleic acids (BNAs) have been proven to be very powerful. However, ensuring a reliable discovery and translational development scheme for this class of ASOs with wider therapeutic windows remains a fundamental challenge. We here demonstrate the robustness of our scheme in the context of the selection of ASOs having two different BNA chemistries (2,'4'-BNA/locked nucleic acid [LNA] and amido-bridged nucleic acid [AmNA]) targeting human proprotein convertase subtilisin/kexin type 9 (PCSK9). The scheme features a two-step process, including (1) a unique and sensitive in vitro screening approach, called Ca2+ enrichment of medium (CEM) transfection, and (2) a ligand-targeted drug delivery approach to better reach target tissues, averting unintended accumulation of ASOs. Using CEM screening, we identified a candidate ASO that shows >70% cholesterol-lowering action in monkeys. An N-acetylgalactosamine (GalNAc) ligand then was appended to the candidate ASO to further broaden the therapeutic margin by altering the molecule's pharmacokinetics. The GalNAc conjugate, HsPCSK9-1811-LNA, was found to be at least ten times more potent in non-human primates (compared with the unconjugated counterpart), with reduced nephrotoxicity in rats. Overall, we successfully showed that our drug development scheme is better suited for selecting clinically relevant BNA-based ASOs, especially for the treatment of liver-associated diseases.

Fibrin glue-induced eosinophilic pleural effusion after pulmonary resection: A case report.

INTRODUCTION AND IMPORTANCE: Prolonged air leakage after pulmonary resection is a common complication, and fibrin glue is used as a sealant to reduce this. Fibrin glue-induced adverse events are generally rare. Herein, we describe a rare case of fibrin glue-induced eosinophilic pleural effusion (EPE). CASE PRESENTATION: A 77-year-old man underwent partial pulmonary resection for right lower lobe lung cancer, and the pulmonary staple stump was subsequently covered with fibrin glue. Antibacterial drugs were administered for the treatment of postoperative pneumonia. However, re-elevation of the inflammatory cell number was observed, and computed tomography revealed an increase in right pleural effusion. Although thoracoscopy was performed based on a possibility of empyema, no empyema was observed. The eosinophil count in the pleural effusion was 11%; thus, the patient was diagnosed with EPE, which was resolved after thoracic drainage, without corticosteroid administration. Fibrin glue was identified as the causative agent, using a drug-induced lymphocyte stimulation test. CLINICAL DISCUSSION: EPE is defined as an eosinophil count of ≥10% in the pleural effusion. If pleural effusion on the surgical side, with fever or an elevated inflammatory cell number, is observed in the early postoperative period after pulmonary resection, empyema should be considered foremost. In this case, the administration of antibacterial drugs was ineffective, and the patient was eventually diagnosed with EPE. CONCLUSION: EPE should be considered as a rare fibrin glue-induced adverse event after pulmonary resection. It is recommended that the leukocyte fraction be examined, if pleural effusion is collected for postoperative pleural effusion.