Recently, the epidemic types of methicillin-resistant Staphylococcus aureus (MRSA) in hospital and community settings in Japan have changed significantly. Before 2010, approximately 80% of the MRSA strains isolated from hospitals were typical healthcare-associated MRSA (HA-MRSA) with staphylococcal cassette chromosome (SCC) mec type II. However, USA400-like community-associated MRSA (CA-MRSA) with SCCmec type IV (defined as USA400/J) has become dominant in hospitals since 2014. By contrast, skin infections caused by the highly virulent CA-MRSA USA300 clone have increased. The USA300 clone is associated with intractable skin infections and necrotizing pneumonia because it carries a cytolytic pore-forming toxin, Panton–Valentine leukocidin (PVL), and an arginine catabolic mobile element that promotes skin colonization. In the past decade, the USA300 clone has shown limited prevalence and has not been considered a serious problem in Japan. However, the USA300 clone has recently spread in community and hospital settings. This review discusses the evolution and current status of the molecular epidemiological features of HA-MRSA and CA-MRSA strains in Japan.
This review shows how the prevalence of methicillin-resistant
Staphylococcus aureus (MRSA) in Japan has changed significantly in just a
decade. In particular, the prevalence of the USA300 clone, a highly virulent
community-associated MRSA, has become a serious problem in the community, and
the number of patients with severe skin infections has increased. If such
highly virulent strains of MRSA spread to hospitals, where there are many
compromised patients, there is a risk of serious outbreaks. This review
highlights the importance of staying abreast of the latest MRSA prevalence and
implementing appropriate infection control.
Antimicrobial resistance (AMR) is a serious global concern. AMR pathogens are found in hospitals and communities. Haemophilus influenzae is a common pathogen associated with community-acquired infections. H. influenzae infections are usually treated with β-lactams, macrolides, and quinolones. However, the drug-resistant strains have emerged. The resistance mechanisms of H. influenzae are complex but are roughly characterized by the acquisition of a mutation in antimicrobial-targeting genes and exogenous resistant genes. Generally, the former cannot be transferred horizontally to a susceptible strain. However, several studies have demonstrated that, in the case of H. influenzae, both the former and the latter can be transferred horizontally. In this review, we provide an overview of the bacterial features and antimicrobial resistance of H. influenzae. We also summarize the unique and ingenious antimicrobial resistance mechanisms used by this pathogen based on the findings of recent studies. These are expected to facilitate the understanding of AMR pathogens in the community and develop strategies to combat infections.
Haemophilus influenzae is one of the most common
pathogens causing community infections. Historically, H. influenzae has been
known for its rapid emergence of antimicrobial-resistant isolates in response
to antimicrobial usage. In this paper, the authors summarised the mechanisms of
antimicrobial resistance to therapeutic agents based on recently published
studies. Furthermore, they highlighted the transformation ability of H.
influenzae, which allows it to adapt to its environment by acquiring extracellular
DNA. This unique and ingenious feature could serve as an efficient system for
the spread of antimicrobial resistance.
In this study, we investigated (1) the functional role of large-conductance Ca2+-activated K+ (BKCa) channels in the regulation of guinea pig vas deferens smooth muscle (VDSM) contractions and (2) the potential contractile effects of 33 physiologically active substances and related chemicals that have not been previously reported to contract VDSM. Iberiotoxin (an inhibitor of BKCa channels, 10–7 M) was the most potent enhancer of both noradrenaline (10–5 M)- and ATP (10–6 M)-induced contractions among the 6 types of K+ channel inhibitors. In addition, BKCa channel mRNA expression was the highest among the 32 types of K+ channel mRNAs. Iberiotoxin also enhanced the contractions induced by acetylcholine (10–6 M), histamine (5 × 10–5 M), bradykinin (10–6 M), neurokinin A (10–6 M), neurokinin B (10–6 M), and substance P (10–6 M). In the 33 tested physiologically active substances and related chemicals (15 peptides, 5 amino acids and their derivatives, 11 prostanoid- and isoprostane-related drugs, 1 endocannabinoid, and 1 phospholipid), we found that 3 bombesin-like peptides, neuromedin B (NMB) (10–6 M), gastrin-releasing peptide (GRP, 10–8 M), and NMC (10–6 M), contracted VDSM in the absence of iberiotoxin, and these contractions were strongly enhanced in the presence of iberiotoxin. Among the 3 bombesin receptor subtypes, the mRNA expression level of Grpr (BB2 receptor) was the highest. These findings suggest that (1) BKCa channels are the most powerful negative regulator of VDSM contractility and (2) NMB, GRP, and NMC are physiologically active substances that contract VDSM.
[Highlighted Paper selected by Editor-in-Chief]
This
study is the first to demonstrate that bombesin-like peptides—neuromedin B,
gastrin-releasing peptide, and neuromedin C—induce contraction in guinea pig
vas deferens smooth muscle (VDSM), likely through activation of bombesin BB2
receptors, highlighting a novel physiological role for these peptides. It
further reveals that large-conductance Ca2+-activated K+
channels act as key negative regulators of VDSM contractility by suppressing
voltage-dependent Ca2+ channels. These findings provide new insights
into the regulation of the reproductive system and suggest potential
therapeutic targets in urogenital physiology.
Vitiligo vulgaris is an acquired disorder that is thought to arise from the suppression of melanin synthesis by melanocytes in the basal epidermal layer. To develop therapeutic agents for vitiligo vulgaris, it is critical to identify compounds that promote melanization. In this study, we established a digital image-based method to quantify melanization that does not require biochemical procedures. B16F10 cells were seeded in a white-bottom 96-well microplate. After treatment with or without α-melanocyte-stimulating hormone, followed by fixation of the cells, digital images of the microplates were captured, and the total signal intensity of each well on the image was measured. The extent of melanization in the cells in each well was defined after the subtraction of the signal from the corresponding blank well. This method was found to quantify melanization more sensitively than the conventional technique that measures the absorbance of cell lysates at UV-A wavelengths. We obtained statistical parameters showing that this method was applicable to a high-throughput screening assay; thus, this method appears to be useful for screening and identifying molecules that suppress or promote melanization, the latter of which may be developed as therapeutic agents for vitiligo vulgaris.
The authors established a simple method to quantify
melanization by analyzing the digital images of the entire microplates.
Compared to the conventional method measuring the absorbance of cell lysates at
UV-A wavelengths, their digital image-based method was found to have higher
sensitivity and be applicable to high-throughput screening assays to identify
molecules that affect melanization.
Gestational diabetes mellitus (GDM) is a glucose metabolism abnormality that first emerges during pregnancy and may negatively affect the behavioral and neurodevelopmental outcomes of offspring. Quetiapine (QUE) has been shown to promote differentiation of oligodendrocyte precursor cells (OPCs) and protect oligodendrocytes and myelination. To explore the effects of QUE on improving the expression of conditioned place preference (CPP) and myelination in the infralimbic cortex (IL) of the medial prefrontal cortex in alcohol-exposed GDM offspring mice, we evaluated CPP expression in 5-week-old alcohol-exposed GDM offspring and treated them with QUE and the extracellular-regulated protein kinase (ERK) inhibitor U0126. Immunohistochemical staining compared the numbers of mature oligodendrocytes, OPCs, and myelin expression levels. Immunofluorescence staining was employed to examine OPC differentiation and the activation of the ERK1/2 signaling pathway. In GDM offspring, CPP expression increased considerably following alcohol exposure, whereas early treatment with QUE or U0126 significantly decreased CPP expression. Meanwhile, alcohol exposure resulted in substantial activation of the ERK1/2 signaling pathway within OPCs in the IL region, as well as a substantial reduction in OPC differentiation, mature oligodendrocyte count, and myelin expression. QUE or U0126 inhibited the activation of the ERK1/2 signaling pathway within OPCs in the IL region of alcohol-exposed GDM offspring and markedly restored OPC differentiation, mature oligodendrocyte numbers, and myelin expression. Collectively, QUE enhanced the differentiation of OPCs in the IL region of GDM offspring after alcohol exposure by regulating the overactivation of the ERK1/2 signaling pathway, thus partially reversing myelination loss and ultimately improving CPP expression.
Total Purine and Purine Base Content of Common Foodstuffs for Facilitating Nutritional Therapy for Gout and Hyperuricemia
Released on J-STAGE: May 01, 2014 | Volume 37 Issue 5 Pages 709-721
Kiyoko Kaneko, Yasuo Aoyagi, Tomoko Fukuuchi, Katsunori Inazawa, Noriko Yamaoka
Views: 6,486
Effect of Psilocin on Extracellular Dopamine and Serotonin Levels in the Mesoaccumbens and Mesocortical Pathway in Awake Rats
Released on J-STAGE: January 01, 2015 | Volume 38 Issue 1 Pages 134-138
Yuichi Sakashita, Kenji Abe, Nobuyuki Katagiri, Toshie Kambe, Toshiaki Saitoh, Iku Utsunomiya, Yoshie Horiguchi, Kyoji Taguchi
Views: 782
Ginsenosides in Panax ginseng Extract Promote Anagen Transition by Suppressing BMP4 Expression and Promote Human Hair Growth by Stimulating Follicle-Cell Proliferation
Released on J-STAGE: January 20, 2024 | Volume 47 Issue 1 Pages 240-244
Tokuro Iwabuchi, Kazuki Ogura, Kenta Hagiwara, Shogo Ueno, Hiroaki Kitamura, Haruyo Yamanishi, Yuki Tsunekawa, Akinori Kiso
Views: 619
Selective Androgen Receptor Modulator, YK11, Up-Regulates Osteoblastic Proliferation and Differentiation in MC3T3-E1 Cells
Released on J-STAGE: March 01, 2018 | Volume 41 Issue 3 Pages 394-398
Tomofumi Yatsu, Taichi Kusakabe, Keisuke Kato, Yoshio Inouye, Kiyomitsu Nemoto, Yuichiro Kanno
Views: 619
Effects of Human Placenta Extract (Laennec) on Ligament Healing in a Rodent Model
Released on J-STAGE: December 01, 2019 | Volume 42 Issue 12 Pages 1988-1995
Eun Ho Shin, Moonhang Kim, Binika Hada, Chang Taek Oh, Min Jung Jang, Jeom Yong Kim, Hae Jung Han, Dong Hwan Kim, Byung Hyune Choi, Bom Soo Kim
Views: 518