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result(s) for
"Kitahara, Takashi"
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Autophagy Has a Significant Role in Determining Skin Color by Regulating Melanosome Degradation in Keratinocytes
by
Hase, Tadashi
,
Kitahara, Takashi
,
Hachiya, Akira
in
Adult
,
African Americans
,
Autophagy - physiology
2013
Melanin in the epidermis determines the wide variation in skin color associated with ethnic skin diversity. Ethnic differences exist regarding melanosome loss in keratinocytes, but the mechanisms underlying these differences, and their contribution to the regulation of skin color, remain unclear. Here, we explored the involvement of autophagy in determining skin color by regulating melanosome degradation in keratinocytes. Keratinocytes derived from Caucasian skin exhibit higher autophagic activity than those derived from African American (AA) skin. Furthermore, along with the higher autophagy activity in Caucasian skin–derived keratinocytes compared with AA skin–derived keratinocytes, Caucasian skin–derived keratinocytes were more sensitive to melanosome treatment as shown by their enhanced autophagic activity, which may reflect the substantial mechanisms in the human epidermis owing to the limitations of the models. Melanosome accumulation in keratinocytes was accelerated by treatment with lysosomal inhibitors or with small interfering RNAs specific for autophagy-related proteins, which are essential for autophagy. Furthermore, consistent with the alterations in skin appearance, the melanin levels in human skin cultured ex vivo and in human skin substitutes in vitro were substantially diminished by activators of autophagy and enhanced by the inhibitors. Taken together, our data reveal that autophagy has a pivotal role in skin color determination by regulating melanosome degradation in keratinocytes, and thereby contributes to the ethnic diversity of skin color.
Journal Article
Analysis of vaporized caffeine in smoke from e-cigarettes using liquid chromatography–tandem mass spectrometry and clarification of minor components
2023
Purpose
Electronic cigarettes (e-cigarettes) are used widely, and e-cigarettes containing caffeine (Caf) have recently become commercially available. However, no risk evaluation of these Caf-containing products has been performed to date. Such an evaluation requires a sensitive analytical method for quantifying Caf in smoke from e-cigarettes. The aim of this study was to establish a liquid chromatography–tandem mass spectrometry (LC–MS/MS) method for quantifying vaporized Caf from commercially available e-cigarettes, and to determine minor components related to Caf in cigarette smoke extract (CSE).
Methods
A sampling system for Caf using a suction pump was designed and sampling conditions were optimized.
Results
The optimized LC–MS/MS conditions allowed the sensitive determination of Caf in smoke with a limit of detection of 0.03 ng/mL at a signal-to-noise ratio of 3. The method was applied to CSEs from five e-cigarette products and the concentration of Caf ranged from 0.894 ± 0.090 to 3.32 ± 0.14 μg/mL smoke (
n
= 3). Additionally, minor components related to Caf, such as theobromine, theophylline, and paraxanthine, were detected in CSE and in e-liquid at very low concentrations, indicating that they were impurities in e-liquid and vaporized along with Caf.
Conclusion
This is the first report to determine the concentration of vaporized Caf using an LC–MS/MS method and to clarify several minor components in smoke from e-cigarettes.
Journal Article
Population pharmacokinetic analysis identifies an absorption process model for mycophenolic acid in patients with renal transplant
2024
The pharmacokinetics (PKs) of mycophenolic acid (MPA) exhibit considerable complexity and large variability. We developed a population pharmacokinetic (popPK) model to predict the complex PK of MPA by examining an absorption model. Forty‐two patients who had undergone renal transplantation were included in this study. popPK analysis, incorporating several absorption models, was performed using the nonlinear mixed‐effects modeling program NONMEM. The MPA area under the concentration‐time curve at 0–12 h (AUC0–12) was simulated using the final model to calculate the recommended dose. The PK of MPA was adequately described using a two‐compartment model incorporating sequential zero‐ and first‐order absorption with lag time. Total body weight, renal function (RF), and posttransplantation day (PTD) were included as covariates affecting MPA PK. The final model estimates were 7.56, 11.6 L/h, 104.0 L, 17.3 L/h, 169.0 L, 0.0453, 0.283, and 1.95 h for apparent nonrenal clearance, apparent renal clearance, apparent central volume of distribution, apparent intercompartmental clearance, apparent peripheral volume of distribution, absorption half‐life, lag time, and duration of zero‐order absorption, respectively. Simulation results showed that a dose regimen of 500–1000 mg twice daily is recommended during the early posttransplantation period. However, dose reduction could be required with increased PTD and decreased RF. The complex PK of MPA was explained using an absorption model. The developed popPK model can provide useful information regarding individual dosing regimens based on PTD and RF.
Journal Article
Variations in the ceramide profile in different seasons and regions of the body contribute to stratum corneum functions
by
Hase, Tadashi
,
Ishikawa, Junko
,
Ito, Shotaro
in
Adult
,
Body Surface Area
,
Ceramides - chemistry
2013
The objective of this study was to clarify variations of the ceramide (CER) profile in human stratum corneum (SC) in different seasons and in different regions of the body and to estimate the contributions of CERs to the SC barrier and water-holding functions. Based on the information that there are great variations of SC functions among body sites, we compared the CER profiles obtained from ten different anatomical sites in healthy Japanese males in four seasons. Not only the physiological parameters of skin but also the CER profile showed body region and seasonal variations. The total CER level, the CER composition and the C34-CER[NS] species displayed strong correlations with the values of transepidermal water loss and capacitance throughout the body. Especially in the cheek, a strong correlation between the capacitance and the CER profile was observed. There were seasonal variations of the CER profile in the lip, upper arm and palm. Our results indicate that regional and seasonal variations of the CER profile may contribute to SC functions.
Journal Article
Development and practical validation of BUBBLESS tapping instrument for efficient bubble removal during antibody drug mixing
2026
Background
Antibody drugs play a central role in modern medical treatments, despite their tendency to aggregate under physical stimuli being a major challenge. Generically, these are prone to foaming, and bubble from syringes is typically manually removed by means of tapping. Hence, this study aimed to develop and evaluate the efficacy of a tapping instrument for bubble removal from syringes with minimal physical stress.
Methods
The instrument was designed with a columnar shape to minimize contact area with the syringe surface. This instrument was named BUBBLESS, a coined term combining “bubble” and “less.” To measure the force applied to syringes, a cutting-force measurement system was employed. Twelve participants each drew 50 mL of distilled water into syringes and removed naturally occurring bubbles. Bubble removal was performed three times each by hand and using BUBBLESS per participant. Infliximab was the model antibody drug to evaluate aggregation, and its solutions were immediately imaged, following bubble removal by manual or BUBBLESS tapping, under a laser microscope.
Results
A columnar shape, based on its contact area with the syringe, and polyacetal resin were used for developing BUBBLESS (weight: approximately 38.0 g). The median maximum force (interquartile range [IQR]) applied to the syringe was 129.1 (113.1–175.2) N by hand and 60.7 (47.9–80.9) N with BUBBLESS (
p
< 0.0001). The median total applied force (IQR) was 1,665,283 (1,176,238–2,445,051) N by hand and 575,061 (400,170.3–731,369.6) N with BUBBLESS (
p
< 0.0001). Laser microscopy revealed visible aggregation of infliximab following manual tapping but almost none after BUBBLESS tapping. No further changes were observed during a 10-min observation period in either case. The largest recorded horizontal and vertical diameters were approximately 12.5 and 13.4 μm, respectively, with no further changes observed in the aggregate during the 10-min observation period.
Conclusions
This study shows the potential of the BUBBLESS tapping method as a novel approach to suppress antibody drug aggregation.
Journal Article
Bibliometric analysis of pharmacist’s research on antimicrobial stewardship in Japan: an interrupted time series analysis on the implementation of the certification system for infection control pharmacists
by
Miyake, Takefumi
,
Ueda, Satoru
,
Matsugi, Ken-ichi
in
Analysis
,
Antibiotics
,
Antimicrobial agents
2021
Background
Pharmacist plays an integral role in promoting antimicrobial stewardship (AS) strategies by committing to the evidence-based activities in this field. The present study aims to document trends in actual achievements through bibliometric analysis and identify the future direction of pharmacists with expertise in AS by describing the characteristics of articles on AS written by Japanese pharmacists.
Methods
The study searched for articles written in Japanese and English on Ichushi-Web and MEDLINE, respectively, until December 2020 for published articles relevant to AS. The articles were classified into the seven groups according to content. Interrupted time series analysis (ITSA) was performed to identify the effect of the certification system for infection control pharmacy specialists (ICPSs) on the number of articles in Japanese.
Results
The study retrieved 476 and 145 titles from Ichushi-Web and MEDLINE, respectively, out of which 383 and 123 articles written in Japanese and English, respectively, were considered relevant to AS. A continued publication was found for Japanese articles written by pharmacists assigned to large-sized hospitals since 1998, whereas few articles in English were published until 2017. The most frequent content of articles in both languages was intervention (56.7 and 59.0%, respectively). ITSA indicated that the number of publication slightly increased before [
β
1 = 1.33, 95% confidence interval (CI): − 0.62–3.28;
P
= 0.169] the implementation of the system. Moreover, the level (
β
2 = 11.41, 95%CI: − 0.23–23.05;
P
= 0.054) increased after the implementation of the system, whereas the slope decreased (
β
3 = − 2.07, 95%CI: − 4.16–0.03;
P
= 0.053). However, the changes were not statistically significant.
Conclusion
The study identified the contribution of pharmacists by documenting trends in AS practice and by conducting bibliometric analysis. The implementation of the ICPS certification system positively influenced the trend of publications. Therefore, the study recommends that policymakers and stakeholders should promote and support the evidence-based activities for AS for pharmacists in small- to medium-sized hospitals.
Journal Article
Influence of filtering on the effective concentration and sterility of a 2% cyclosporine ophthalmic solution: a quality improvement perspective
by
Takahiro Yamasaki
,
Masakazu Ozaki
,
Satoshi Okano
in
Automation
,
Biomedical and Life Sciences
,
Biomedicine
2023
Background
Pharmaceutical companies do not sell formulations for all diseases; thus, healthcare workers have to treat some diseases by concocting in-hospital preparations. An example is the high-concentration 2% cyclosporine A (CyA) ophthalmic solution. Utilizing a filter in sterility operations is a general practice for concocting in-hospital preparations, as is the case for preparing a 2% CyA ophthalmic solution. However, whether filtering is appropriate concerning the active ingredient content and bacterial contamination according to the post-preparing quality control of a 2% CyA ophthalmic solution is yet to be verified.
Methods
We conducted particle size, preparation concentration, and bacterial contamination studies to clarify aforementioned questions. First, we measured the particle size of CyA through a laser diffraction particle size distribution. Next, we measured the concentration after preparation with or without a 0.45-µm filter operation using an electrochemiluminescence immunoassay. Finally, bacterial contamination tests were conducted using an automated blood culture system to prepare a 2% CyA ophthalmic solution without a 0.45 μm filtering. Regarding the pore size of the filter in this study, it was set to 0.45 μm with reference to the book (the 6th edition) with recipes for the preparation of in-hospital preparations edited by the Japanese Society of Hospital Pharmacists.
Results
CyA had various particle sizes; approximately 30% of the total particles exceeded 0.45 μm. The mean ± standard deviation of filtered and non-filtered CyA concentrations in ophthalmic solutions were 346.51 ± 170.76 and 499.74 ± 76.95ng/mL, respectively (
p
= 0.011). Regarding bacterial contamination tests, aerobes and anaerobes microorganisms were not detected in 14 days of culture.
Conclusions
Due to the results of this study, the concentration of CyA may be reduced by using a 0.45-µm filter during the preparation of CyA ophthalmic solutions, and furthermore that the use of a 0.45-µm filter may not contribute to sterility when preparing CyA ophthalmic solutions.
Journal Article
Development of a DNA Vaccine for Melanoma Metastasis by Inhalation Based on an Analysis of Transgene Expression Characteristics of Naked pDNA and a Ternary Complex in Mouse Lung Tissues
by
Harasawa, Hitomi
,
Kodama, Yukinobu
,
Nakamura, Tadahiro
in
DNA vaccine
,
gene delivery
,
inhalation
2020
The present study investigated a pulmonary delivery system of plasmid DNA (pDNA) and its application to melanoma DNA vaccines. pCMV-Luc, pEGFP-C1, and pZsGreen were used as a model pDNA to evaluate transfection efficacy after inhalation in mice. Naked pDNA and a ternary complex, consisting of pDNA, dendrigraft poly-l-lysine (DGL), and γ-polyglutamic acid (γ-PGA), both showed strong gene expression in the lungs after inhalation. The transgene expression was detected in alveolar macrophage-rich sites by observation using multi-color deep imaging. On the basis of these results, we used pUb-M, which expresses melanoma-related antigens (ubiquitinated murine melanoma gp100 and tyrosinase-related protein 2 (TRP2) peptide epitopes), as DNA vaccine for melanoma. The inhalation of naked pUb-M and its ternary complex significantly inhibited the metastasis of B16-F10 cells, a melanoma cell line, in mice. The levels of the inflammatory cytokines, such as TNF-α, IFN-γ, and IL-6, which enhance Th1 responses, were higher with the pUb-M ternary complex than with naked pUb-M and pEGFP-C1 ternary complex as control. In conclusion, we clarified that the inhalation of naked pDNA as well as its ternary complex are a useful technique for cancer vaccination.
Journal Article
The Endogenous Protease Inhibitor TIMP-1 Mediates Protection and Recovery from Cutaneous Photodamage
by
Tsuboi, Ryoji
,
Yokose, Urara
,
Kitahara, Takashi
in
Adult
,
Animals
,
Antibodies, Neutralizing - pharmacology
2012
UVB exposure is well known to induce skin photodamage and photoaging that correlates with qualitative and quantitative deterioration of the dermal extracellular matrix (ECM) because of the upregulation of matrix metalloproteinases (MMPs). Although inhibitory effects of tissue inhibitor of metalloproteinases (TIMPs) on most MMPs have been reported, the protective role of TIMP-1 against photodamage is poorly understood. To address this, TIMP-1 function was augmented or abolished in a human skin xenograft photodamage model after the confirmation of significantly diminished TIMP-1 expression both in photoaged and intrinsically aged skins. During a chronic UVB exposure regimen, pre-treatment with a lentiviral vector overexpressing TIMP-1 or concomitant administration of an anti-TIMP-1-neutralizing antibody (NAB) led to photoprotection or more severe photodamage, respectively. Overexpression of TIMP-1 resulted in significant inhibition of UVB-induced ECM degradation, as well as suppression of decreased skin elasticity and roughness, whereas the NAB-mediated inhibition of TIMP-1 had opposite effects. Furthermore, UVB-induced production of the pro-inflammatory cytokine, tumor necrosis factor α, was inhibited by TIMP-1 treatment of human keratinocytes. Taken together, these data shed light on the important role of TIMP-1 in protection and recovery from cutaneous photodamage because of its suppression of ECM degradation and inflammation.
Journal Article