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result(s) for
"Keita Kato"
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Tobacco Nicotine Uptake Permease Regulates the Expression of a Key Transcription Factor Gene in the Nicotine Biosynthesis Pathway
by
Kato, Keita
,
Shoji, Tsubasa
,
Hashimoto, Takashi
in
Alkaloids
,
Amino Acids - metabolism
,
Biological Transport
2014
The down-regulation of a tobacco (Nicotiana tabacum) plasma membrane-localized nicotine uptake permease, NUP1, was previously reported to reduce total alkaloid levels in tobacco plants. However, it was unclear how this nicotine transporter affected the biosynthesis of the alkaloid nicotine. When NUP1 expression was suppressed in cultured tobacco cells treated with jasmonate, which induces nicotine biosynthesis, the MCOTJNE2-locus transcription factor gene ETHYLENE RESPONSE FACTOR189 (ERF189) and its target structural genes, which function in nicotine biosynthesis and transport, were strongly suppressed, resulting in decreased total alkaloid levels. Conversely, NUP1 overexpression had the opposite effect. In these experiments, the expression levels of the MYC2 transcription factor gene and its jasmonate-inducible target gene were not altered. Inhibiting tobacco alkaloid biosynthesis by suppressing the expression of genes encoding enzymes in the nicotine pathway did not affect the expression of ERF189 and other nicotine pathway genes, indicating that ERF189 is not regulated by cellular alkaloid levels. Suppressing the expression of jasmonate signaling components in cultured tobacco cells showed that NUP1 acts downstream of the CORONATINE INSENSITIVE1 receptor and MYC2, but upstream of ERF189. These results suggest that although jasmonate-activated expression of MYC2 induces the expression of both NUP1 and ERF189, expression of ERF189 may actually be mediated by NUP1. Furthermore, NUP1 overexpression in tobacco plants inhibited the long-range transport of nicotine from the roots to the aerial parts. Thus, NUP1 not only mediates the uptake of tobacco alkaloids into root cells, but also positively controls the expression of ERF189, a key gene in the biosynthesis of these alkaloids.
Journal Article
Ice slurry ingestion improves physical performance during high-intensity intermittent exercise in a hot environment
by
Akihisa Morito
,
Shigeyuki Tahara
,
Naohiko Kohtake
in
Biology and Life Sciences
,
Body temperature
,
Body Temperature Regulation
2022
Ice slurry ingestion enhances exercise performance by lowering the core body temperature. However, an operational issue related to this ingestion is the requirement for a high intake of 7.5 g·kg -1 to produce the desired effects. We investigated the effects of the intake of low amounts of ice slurry at −2°C on the tympanic temperature and exercise performance during repeated high-intensity intermittent exercises in a hot environment. This study was a randomized, crossover study, with a 6-day washout period. Twelve university rugby union players performed two 30-min sessions of high-intensity intermittent exercises separated by a 15-min half-time break on a cycle ergometer in a hot environment (28.8°C ± 0.1°C, 49.5% ± 0.6% relative humidity). The participants ingested 450 g of −2°C-ice slurry (ICE), or a 30°C-beverage (CON) having the same composition as ICE, or 30°C-water (WAT) during the half-time break. The tympanic temperature and skin temperature were measured as the physiological data, and the peak power and mean power as the exercise performance data. The tympanic temperature at the half-time break and beginning of the 2 nd session was significantly lower in the ICE group as compared with the CON and WAT groups. The skin temperature at the half-time break was significantly lower in the ICE group as compared with the WAT group. While the peak power and mean power during the 2 nd session were significantly greater in the ICE group as compared with the CON and WAT groups. Our findings suggest that even the intake of lower amounts, as compared with those used in previous studies, of low-temperature ice slurry can reduce the body temperature and improve the peak power. These results suggest that intake of low-temperature ice slurry as a strategy for internal body cooling is useful for improving endurance exercise performance in hot environments.
Journal Article
Ice slurry ingestion improves physical performance during high-intensity intermittent exercise in a hot environment
2022
Ice slurry ingestion enhances exercise performance by lowering the core body temperature. However, an operational issue related to this ingestion is the requirement for a high intake of 7.5 g·kg-1 to produce the desired effects. We investigated the effects of the intake of low amounts of ice slurry at -2°C on the tympanic temperature and exercise performance during repeated high-intensity intermittent exercises in a hot environment. This study was a randomized, crossover study, with a 6-day washout period. Twelve university rugby union players performed two 30-min sessions of high-intensity intermittent exercises separated by a 15-min half-time break on a cycle ergometer in a hot environment (28.8°C ± 0.1°C, 49.5% ± 0.6% relative humidity). The participants ingested 450 g of -2°C-ice slurry (ICE), or a 30°C-beverage (CON) having the same composition as ICE, or 30°C-water (WAT) during the half-time break. The tympanic temperature and skin temperature were measured as the physiological data, and the peak power and mean power as the exercise performance data. The tympanic temperature at the half-time break and beginning of the 2nd session was significantly lower in the ICE group as compared with the CON and WAT groups. The skin temperature at the half-time break was significantly lower in the ICE group as compared with the WAT group. While the peak power and mean power during the 2nd session were significantly greater in the ICE group as compared with the CON and WAT groups. Our findings suggest that even the intake of lower amounts, as compared with those used in previous studies, of low-temperature ice slurry can reduce the body temperature and improve the peak power. These results suggest that intake of low-temperature ice slurry as a strategy for internal body cooling is useful for improving endurance exercise performance in hot environments.
Journal Article
Assessing large language models for Lugano classification of malignant lymphoma in Japanese FDG-PET reports
2025
Purpose
This study evaluates the performance of four large language models (LLMs) in classifying malignant lymphoma stages using the Lugano classification from free-text FDG-PET reports in Japanese Specifically, we assess GPT-4o, Claude 3.5 Sonnet, Llama 3 70B, and Gemma 2 27B in their ability interpret unstructured radiology texts.
Materials and methods
In a retrospective single-center study, 80 patients who underwent staging FDG-PET/CT for malignant lymphoma were included. The “Findings” sections of their reports were analyzed without pre-processing. Each LLM assigned Lugano stages based on these reports. Performance was compared to reference standard stages determined by expert radiologists. Statistical analyses involved overall accuracy, weighted kappa for agreement.
Results
GPT-4o achieved the highest accuracy at 75% (60/80 cases) with substantial agreement (weighted kappa κ = 0.801). Claude 3.5 Sonnet had 61.3% accuracy (49/80, κ = 0.763). Gemma 2 27B and Llama 3 70B showed accuracies of 58.8% and 57.5%, respectively, all indicating substantial agreement.
Conclusion
GPT-4o outperformed other LLMs in assigning Lugano classification from Japanese FDG-PET free-text reports. This demonstrated the potential of advanced LLMs to interpret clinical texts. While the immediate clinical utility of automatically predicting a Lugano stage from an existing report may be limited, these results highlight the value of LLMs for understanding and standardizing free-text radiology data.
Journal Article
Scalable Parallel Manipulation of Single Cells Using Micronozzle Array Integrated with Bidirectional Electrokinetic Pumps
by
Shibata, Takayuki
,
Kato, Keita
,
Nagai, Moeto
in
Arrays
,
Bias
,
bidirectional electrokinetic pump
2020
High throughput reconstruction of in vivo cellular environments allows for efficient investigation of cellular functions. If one-side-open multi-channel microdevices are integrated with micropumps, the devices will achieve higher throughput in the manipulation of single cells while maintaining flexibility and open accessibility. This paper reports on the integration of a polydimethylsiloxane (PDMS) micronozzle array and bidirectional electrokinetic pumps driven by DC-biased AC voltages. Pt/Ti and indium tin oxide (ITO) electrodes were used to study the effect of DC bias and peak-to-peak voltage and electrodes in a low conductivity isotonic solution. The flow was bidirectionally controlled by changing the DC bias. A pump integrated with a micronozzle array was used to transport single HeLa cells into nozzle holes. The application of DC-biased AC voltage (100 kHz, 10 Vpp, and VDC: −4 V) provided a sufficient electroosmotic flow outside the nozzle array. This integration method of nozzle and pumps is anticipated to be a standard integration method. The operating conditions of DC-biased AC electrokinetic pumps in a biological buffer was clarified and found useful for cell manipulation.
Journal Article
Pick-and-Place Operation of Single Cell Using Optical and Electrical Measurements for Robust Manipulation
2017
A robust pick and placement operation of a single cell is necessary for efficient sample collection. Detection and manipulation of single cells requires minimum invasiveness. We report a less-invasive method for picking up and placing single cells using optical and electrical observations for robust cell manipulation. We measured the ionic current through a glass pipette during a cell capture and release operation to detect its capture. Trapping a cell on the pipette tip by suction decreased the current and allowed the detection of cell capture within 1 s. A time-series ionic current was sensitive to the location of a cell and effective at detecting a single cell. A time-series ionic current had a higher signal-to-noise ratio than time-series microscope images. Cell membrane integrity was analyzed at the different capturing and voltage conditions. Serum protein coating shows improvement of a cell release from a pipette tip. Measurement of trajectory and distance of a cell reveals that the movement depends on an ejection flow and the flow in a dish. We achieved a pick-up and placement operation for single cells that was compatible with an open-top microwell while performing observations using optical microscopy and measurements using an electrical current.
Journal Article
Development and characterization of hollow microprobe array as a potential tool for versatile and massively parallel manipulation of single cells
by
Shibata, Takayuki
,
Kato, Keita
,
Nagai, Moeto
in
Adhesion
,
Arrays
,
Biological and Medical Physics
2015
Parallel manipulation of single cells is important for reconstructing
in vivo
cellular microenvironments and studying cell functions. To manipulate single cells and reconstruct their environments, development of a versatile manipulation tool is necessary. In this study, we developed an array of hollow probes using microelectromechanical systems fabrication technology and demonstrated the manipulation of single cells. We conducted a cell aspiration experiment with a glass pipette and modeled a cell using a standard linear solid model, which provided information for designing hollow stepped probes for minimally invasive single-cell manipulation. We etched a silicon wafer on both sides and formed through holes with stepped structures. The inner diameters of the holes were reduced by SiO
2
deposition of plasma-enhanced chemical vapor deposition to trap cells on the tips. This fabrication process makes it possible to control the wall thickness, inner diameter, and outer diameter of the probes. With the fabricated probes, single cells were manipulated and placed in microwells at a single-cell level in a parallel manner. We studied the capture, release, and survival rates of cells at different suction and release pressures and found that the cell trapping rate was directly proportional to the suction pressure, whereas the release rate and viability decreased with increasing the suction pressure. The proposed manipulation system makes it possible to place cells in a well array and observe the adherence, spreading, culture, and death of the cells. This system has potential as a tool for massively parallel manipulation and for three-dimensional hetero cellular assays.
Journal Article
Novel Loci for Kernel Hardness Appeared as a Response to Heat and Combined Heat-Drought Conditions in Wheat Harboring Aegilops tauschii Diversity
by
Gorafi, Yasir Serag Alnor
,
Yamasaki, Yuji
,
Kato, Keita
in
Aegilops tauschii
,
agronomy
,
Baking
2021
Kernel hardness influences the milling and baking quality of wheat. Stress environments such as heat and combined heat-drought can produce harder kernels, thereby affecting the overall wheat quality. Beside puroindoline genes that are known to determine hardness, other QTLs contribute to the hardness. These QTLs, especially under stress conditions, need extensive research. Moreover, understanding the modification or stabilization of hardness under stress condition and the relationship with stress tolerance will facilitate the selection of superior lines that maintain both high yield and quality even under the stress environment. Therefore, in the current work, we aimed to identify the genetic loci and marker trait associations (MTAs) that contributes for hardness under optimum conditions in Japan, and heat and combined heat-drought (HD) conditions in Sudan. We used a panel of multiple synthetic derivatives (MSD) having diverse Aegilops tauschii genome segments and investigated the association between hardness stabilization and stress tolerance. Under stress conditions, we observed that less reduction of kernel weight is associated with either low change or stable kernel hardness. We identified 47 markers associated with hardness under all conditions; the D genome was the main contributor. For the first time, we found a significant association with hardness under stress conditions on chromosome 4D. We dissected several candidate genes associated with the change of hardness under stress conditions. Our results will improve the understanding of the genetic factors that affect wheat hardness stability.
Journal Article
Clinical risk factors for portal hypertension-related complications in systemic therapy for hepatocellular carcinoma
2024
BackgroundDuring systemic therapy, the management of portal hypertension (PH)-related complications is vital. This study aimed to clarify factors associated with the incidence and exacerbation of PH-related complications, including the usefulness of contrast-enhanced computed tomography (CECT) in the management of PH-related complications during systemic therapy.MethodsA total of 669 patients who received systemic therapy as first-line treatment (443 patients for sorafenib, 131 for lenvatinib, and 90 for atezolizumab/bevacizumab [ATZ/BEV]) were enrolled in this retrospective study. Additionally, the lower esophageal intramural vessel diameters (EIV) on CECT and endoscopic findings in 358 patients were compared.ResultsThe cutoff values of the EIV diameter on CECT were 3.1 mm for small, 5.1 mm for medium, and 7.6 mm for large varices, demonstrating high concordance with the endoscopic findings. esophageal varices (EV) bleeding predictors include EIV ≥ 3.1 mm and portal vein tumor thrombosis (PVTT). In patients without EV before systemic therapy, factors associated with EV exacerbation after 3 months were EIV ≥ 1.9 mm and ATZ/BEV use. Predictors of hepatic encephalopathy (HE) include the ammonia level or portosystemic shunt diameter ≥ 6.8 mm. The incidence of HE within 2 weeks was significantly higher (18%) in patients with an ammonia level ≥ 73 μmol/L and a portosystemic shunt ≥ 6.8 mm. The exacerbating factors for ascites after 3 months were PVTT and low albumin levels.ConclusionsCareful management is warranted for patients with risk factors for exacerbation of PH-related complications; moreover, the effective use of CECT is clinically important.
Journal Article
Coculture with hiPS-derived intestinal cells enhanced human hepatocyte functions in a pneumatic-pressure-driven two-organ microphysiological system
2021
Examining intestine–liver interactions is important for achieving the desired physiological drug absorption and metabolism response in in vitro drug tests. Multi-organ microphysiological systems (MPSs) constitute promising tools for evaluating inter-organ interactions in vitro. For coculture on MPSs, normal cells are challenging to use because they require complex maintenance and careful handling. Herein, we demonstrated the potential of coculturing normal cells on MPSs in the evaluation of intestine–liver interactions. To this end, we cocultured human-induced pluripotent stem cell-derived intestinal cells and fresh human hepatocytes which were isolated from PXB mice with medium circulation in a pneumatic-pressure-driven MPS with pipette-friendly liquid-handling options. The cytochrome activity, albumin production, and liver-specific gene expressions in human hepatocytes freshly isolated from a PXB mouse were significantly upregulated via coculture with hiPS-intestinal cells. Our normal cell coculture shows the effects of the interactions between the intestine and liver that may occur in vivo. This study is the first to demonstrate the coculturing of hiPS-intestinal cells and fresh human hepatocytes on an MPS for examining pure inter-organ interactions. Normal-cell coculture using the multi-organ MPS could be pursued to explore unknown physiological mechanisms of inter-organ interactions in vitro and investigate the physiological response of new drugs.
Journal Article