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742 result(s) for "Nakamura, Shinya"
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Selection of the optimal tyrosine hydroxylation enzyme for (S)-reticuline production in Escherichia coli
We have constructed an Escherichia coli-based platform producing (S)-reticuline, an important intermediate of benzylisoquinoline alkaloids (BIAs), using up to 14 genes. (S)-reticuline was produced from a simple carbon source such as glucose and glycerol via l-DOPA, which is synthesized by hydroxylation of l-tyrosine, one of the rate-limiting steps of the reaction. There are three kinds of enzymes catalyzing tyrosine hydroxylation: tyrosinase (TYR), tyrosine hydroxylase (TH), and 4-hydroxyphenylacetate 3-monooxygenase (HpaBC). Here, to further improve (S)-reticuline production, we chose eight from these three kinds of tyrosine hydroxylation enzymes (two TYRs, four THs, and two HpaBCs) derived from various organisms, and examined which enzyme was optimal for (S)-reticuline production in E. coli. TH from Drosophila melanogaster was the most suitable for (S)-reticuline production under the experimental conditions tested. We improved the productivity by genome integration of a gene set for l-tyrosine overproduction, introducing the regeneration pathway of BH4, a cofactor of TH, and methionine addition to enhance the S-adenosylmethionine supply. As a result, the yield of (S)-reticuline reached up to 384 μM from glucose in laboratory-scale shake flask. Furthermore, we found three inconsistent phenomena: an inhibitory effect due to additional gene expression, conflicts among the experimental conditions, and interference of an upstream enzyme from an additional downstream enzyme. Based on these results, we discuss future perspectives and challenges of integrating multiple enzyme genes for material production using microbes.Key points• There are three types of enzymes catalyzing tyrosine hydroxylation reaction: tyrosinase, tyrosine hydroxylase, and 4-hydroxyphenylacetate 3-monooxygenase.• Tyrosine hydroxylase from Drosophila melanogaster exhibited the highest activity and was suitable for (S)-reticuline production in E. coli.• New insights were provided on constructing an alkaloid production system with multi-step reactions in E. coli.
Clinicopathological features of type 1 autoimmune pancreatitis without elevated serum IgG4 level
Elevated serum IgG4 is a key diagnostic marker for type 1 autoimmune pancreatitis (AIP), but some patients lack IgG4 elevation, complicating diagnosis. This study investigated the clinicopathological features of AIP without elevated serum IgG4 levels. A total of 323 patients diagnosed with AIP at Hiroshima University Hospital and affiliated institutions were analyzed. Patients were categorized into IgG4-positive (≥ 135 mg/dL), IgG4-negative (< 135 mg/dL with “definite” or “probable” diagnosis), and possible (with “possible” diagnosis) groups. Comparative analysis was performed between the IgG4-positive ( n  = 281) and IgG4-negative ( n  = 20) groups. Segmental or focal narrowing of the main pancreatic duct (MPD) and retroperitoneal fibrosis were significantly more common in the IgG4-negative group (90.0% vs. 58.7%, P  = 0.011; and 35.0% vs. 12.5%, P  = 0.012, respectively). Although the number of pathological findings was comparable, the rate of surgical intervention was significantly higher in the IgG4-negative group ( P  < 0.001). No significant differences were observed in relapse rates or relapse sites between the two groups. These findings suggest that MPD narrowing and retroperitoneal fibrosis may be characteristic of AIP without elevated IgG4. Vigilant monitoring for relapse is warranted, regardless of serum IgG4 levels.
Shearing rate effect on residual strength of landslide soils in the slow rate range
In the present study, we investigate the influence of shearing rate on the residual strength parameters, ϕ r , in landslide soils using ring-shear tests at two shearing rates (0.01 and 0.5 mm/min) under selected effective normal stresses. The landslide soil samples used for this study cover a wide range of soil types and properties. Relationships between the ϕ r and soil properties, such as liquid limit, plasticity index, and the clay fraction show that the ϕ r decreases with increasing soil LL, I p and CF. The differences in the ϕ r at two shearing rates, ϕ r (0.5)  −  ϕ r (0.01) , under different effective normal stresses are either negative or positive values of which the maximum magnitude is generally about 1.0°. The relationships between the ϕ r (0.5)  −  ϕ r (0.01) and the soil properties (LL, I p , and CF) are not exhibited in a regular pattern. On the other hand, the ϕ r (0.5) and ϕ r (0.01) determined at each effective normal stress suggest that the tendency for increased negative effect of the ϕ r with decreasing effective normal stress is more noticeable in the slow shearing rate range. The absolute value of ϕ r (0.5)  −  ϕ r (0.01) at lower effective normal stress is found to be greater than 1.0°, with the maximum of about 4.0°. The negative shearing rate effect on ϕ r at low effective normal stress is affected by the undulating shear behavior due to poor or no slickenside development.
Association of computed tomography‐derived muscle mass and quality with delayed acquisition independent walking after cardiovascular surgery
Background In the context of cardiovascular surgery, the foremost concern lies in delayed functional recovery, as typified by the acquisition of independent walking after surgery, among older patients with decline in skeletal muscle mass and quality. Computed tomography (CT), which is typically employed for the preoperative assessment of pathological conditions in patients undergoing cardiovascular surgery, is also suitable for screening for potential decline in skeletal muscle mass and quality. The aim of this study was to examine the predictive capabilities of CT‐derived parameters such as muscle mass and muscle quality for the delayed acquisition of independent walking in the postoperative period. Methods This retrospective study enrolled consecutive Japanese patients who underwent elective cardiovascular surgery between May 2020 and January 2023. In total, 139 patients were included in the analyses. Based on the preoperative CT image, the psoas muscle volume index (PMVI) and psoas muscle attenuation (PMA) were calculated. Information on patient characteristics, including preoperative physical fitness such as handgrip strength/body mass index (GS/BMI), short physical performance battery (SPPB), and 6‐min walking distance (6MWD), were obtained from the medical records. We defined delayed acquisition of independent walking after surgery as the inability to walk 100 m within 4 days after surgery. Results The median age of the patients was 72 (interquartile: 64–78) years, and 74.8% (104/139) were men; 47.5% corresponded to the delayed group. The areas under the curves of SPPB, GS/BMI, 6MWD, PMVI, and PMA against delayed acquisition of independent walking after surgery were 0.68 [95% confidence interval (CI): 0.59 to 0.77], 0.72 (95% CI: 0.63 to 0.80), 0.73 (95% CI: 0.65 to 0.82), 0.69 (95% CI: 0.60 to 0.78), and 0.78 (95% CI: 0.70 to 0.85), respectively. In the multivariate logistic regression analysis, low PMA was significantly associated with delayed acquisition of independent walking even after adjustment for patient characteristics including physical fitness [model 1: SPPB (OR, 1.14; 95% CI: 1.03–1.25), model 2: GS/BMI (OR, 1.13; 95% CI: 1.03–1.25), and model 3: 6MWD (OR, 1.14; 95% CI: 1.03–1.25)], but PMVI was not. Conclusions Our study revealed a strong association between PMA, a marker of CT‐derived muscle quality, and the postoperative delay in achieving independent walking in patients who underwent cardiovascular surgery. The technique to obtain information on muscle quality during the time period before surgery may be an option for timely therapeutic intervention in patients who may have delayed acquisition of independent walking after surgery.
Laminar Organization of the Entorhinal Cortex in Macaque Monkeys Based on Cell-Type-Specific Markers and Connectivity
The entorhinal cortex (EC) is a major gateway between the hippocampus and telencephalic structures, and plays a critical role in memory and navigation. Through the use of various molecular markers and genetic tools, neuron types constituting EC are well studied in rodents, and their layer-dependent distributions, connections, and functions have also been characterized. In primates, however, such cell-type-specific understandings are lagging. To bridge the gap between rodents and primates, here we provide the first cell-type-based global map of EC in macaque monkeys. The laminar organization of the monkey EC was systematically examined and compared with that of the rodent EC by using immunohistochemistry for molecular markers which have been well characterized in the rodent EC: reelin, calbindin, and Purkinje cell protein 4 (PCP4). We further employed retrograde neuron labeling from the nucleus accumbens and amygdala to identify the EC output layer. This cell-type-based approach enabled us to apply the latest laminar definition of rodent EC to monkeys. Based on the similarity of the laminar organization, the monkey EC can be divided into two subdivisions: rostral and caudal EC. These subdivisions likely correspond to the lateral and medial EC in rodents, respectively. In addition, we found an overall absence of a clear laminar arrangement of layer V neurons in the rostral EC, unlike rodents. The cell-type-based architectural map provided in this study will accelerate the application of genetic tools in monkeys for better understanding of the role of EC in memory and navigation.
NYK's Approach for Autonomous Navigation - Structure of Action Planning System and Demonstration Experiments
NYK Line and its group companies have been conducting research projects towards autonomous ship operation. This paper shows the structure of our Action Planning System (APS), which integrates several support functions with man-machine interface, targeted at supporting decision making for seafarers. By conducting risk assessment with reference to class guidelines for autonomous ships, the safety of APS is verified. This paper also introduces our demonstration experiment of this system, which will be conducted in FY2019.
Clinical and safety outcomes of simultaneous bilateral total knee arthroplasty for Japanese octogenarian patients: a retrospective analysis
Purpose The demand for simultaneous bilateral total knee arthroplasty (SiBTKA) in older adults is expected to increase with an aging population, thus necessitating evaluating its efficacy and safety. However, there is limited information regarding the clinical outcomes of SiBTKA in older adults, particularly in octogenarians. We aimed to assess the clinical outcomes and safety of SiBTKA in Japanese patients aged ≥ 80 years. Methods Of the 176 consecutive knees that underwent SiBTKA between July 2016 and January 2022 at our hospital, 172 were selected. They were divided into two groups according to the patient age as follows: the octogenarian group (≥ 80 years, 74 knees) and the younger control group (< 80 years, 98 knees). In addition, we assessed their preoperative clinical information, clinical outcomes using the Knee Society Score for knee (KSS-K) and function (KSS-F), and the incidence of early (≤ 90 days) and late (> 90 days) postoperative complications. Results The mean follow-up period was 3.5 years. The KSS-K scores of both groups improved postoperatively than that preoperatively. Both preoperative and postoperative KSS-F scores were lower in the octogenarians; however, their improvement rates were similar to those of the younger controls. We observed no significant intergroup differences in early or late postoperative complications, including infection, systemic complications, periprosthetic fractures, aseptic loosening, and mortality. Conclusion SiBTKA for octogenarians had clinical outcomes and postoperative complication incidence similar to that for younger controls. Therefore, SiBTKA may be a safe and effective treatment option for octogenarians with painful bilateral knee deformities.
Effect of Calcium Ion Concentrations on Osteogenic Differentiation and Hematopoietic Stem Cell Niche-Related Protein Expression in Osteoblasts
Apatite biomaterials have potential not only as cell vehicles for engineering bone tissue but also as regulators of calcium (Ca) concentration in situ for controlling osteoblast functions, for example, osteogenic differentiation and fate management of hematopoietic stem cells (HSCs). To design apatite materials having optimal chemical properties for the latter purpose, more detailed investigations into what effect Ca concentrations have on osteoblast functions is crucial. In this study, osteoblasts were cultured at different Ca concentrations, and the temporal alterations in osteogenic differentiation and HSC niche-related protein (angiopoietin-1, 2 [Ang1, 2]) expression were investigated. The different Ca concentrations (1.8–50 mmol/L) in the cell culture medium had no effect on the proliferation of osteoblasts, but did on the cell morphology. The higher Ca concentrations (<6 mmol/L) enhanced the mineralization as well as Ang1 expression. In addition, Ang1 expression in osteoblasts showed higher correlation with expression of connexin43, the major marker of cell–cell interactions, whereas Ang2 related to integrin β1, the major marker of cell–matrix interactions. Thus, the local Ca concentration regulates cell morphology through the cell–cell or cell–matrix interactions, leading to the alteration of Ang1 expression in osteoblasts. Since these changes triggered by Ca are concerned with the osteogenic differentiation or reproduction of HSCs niche microenvironment, the results obtained in this study might be useful for designing apatite materials with optimal chemical properties.
Relapse rate and predictors of relapse after cessation of glucocorticoid maintenance therapy in type 1 autoimmune pancreatitis: a multicenter retrospective study
Background Type 1 autoimmune pancreatitis responds well to glucocorticoid therapy with a high remission rate. Moreover, glucocorticoid maintenance therapy can help prevent relapse. However, the relapse rate following cessation of long-term glucocorticoid therapy is unknown. The aim of this study was to clarify the relapse rate and predictors of relapse following long-term glucocorticoid therapy cessation. Methods We analyzed 94 patients who achieved remission after undergoing glucocorticoid therapy, discontinued treatment after at least 6 months of maintenance therapy, and were subsequently followed up for at least 6 months. The patients were divided into three groups based on treatment duration (< 18, 18–36, and ≥ 36 months), and their relapse rates were compared. Univariate and multivariate analyses of clinical factors were conducted to identify relapse predictors. Results After discontinuing glucocorticoid therapy, relapse was observed in 43 (45.7%) patients, with cumulative relapse rates of 28.2% at 1 year, 42.1% at 3 years, 47.0% at 5 years, and a plateau of 77.6% at 9 years. Of the 43 patients who relapsed, 25 (58.1%) relapsed within 1 year after after cessation of glucocorticoid therapy. Relapse and cumulative relapse rates did not differ significantly according to treatment duration. In the multivariate analysis, an elevated serum IgG4 level at the time of glucocorticoid cessation was found to be an independent predictor of relapse (hazard ratio, 4.511; p  < 0.001). Conclusions A high relapse rate occurred after cessation of glucocorticoid maintenance therapy, regardless of the duration of maintenance therapy, especially within the first year after cessation. However, the normalization of long-term serum IgG4 levels may be a factor in considering cessation.
Objective evaluation criteria for the safety certification of autonomous navigation system
In Japan, the commercialization of the autonomous ship is aiming at the full-scale commercial operation around 2030 with the cooperation of industry, academia and government. The autonomous navigation system that the ships will be equipped with is one of the main functions of the autonomous ship. Commercialized autonomous ships coming soon are scheduled to operate on domestic routes. In areas covered by the Collision avoidance Regulations (COLREGs), autonomous ships will basically navigate without human intervention, including in congested waters. The Japan Captains’ Association believes that ships equipped with such autonomous navigation systems must have the same safety level as conventional ships and comply with the COLREGs. In other words, the autonomous ship should not cause anxiety to encountering ships. Based on the above basic policy, the Japan Captains’ Association and ClassNK conducted a large-scale verification experiment aimed at formulating standards for classification companies to objectively evaluate the safety of autonomous navigation systems and developed evaluation area diagrams for certification. This paper introduces the evaluation area diagrams that objectively evaluates autonomous navigation systems to have the same or higher safety level as conventional ships and to objectively evaluate compliance with COLREGs. In the evaluation area diagram, “Safety area”, “Caution area”, and “Danger area” are calculated based on the relative distance and bearing (compass bearing) change rate etc, between the autonomous ship and the encountered ships. When a ship using an autonomous navigation system navigates in a way that avoids entering “Caution area” and “Danger area”, it can be said that the ship is reducing risk before there is a risk of collision. ClassNK will use the evaluation area diagram introduced here to carry out certification work for the autonomous navigation system which will undergo demonstration experiments in 2025. This paper also discusses how to objectively explain compliance with the COLREGs, which contains many ambiguous expressions.