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10
result(s) for
"Kakizawa, Yasushi"
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Quantification of droplet and contact transmission risks among elementary school students based on network analyses using video-recorded data
by
Kato, Yasuki
,
Sugiyama, Junichi
,
Kikuchi, Shuta
in
Analysis
,
Biology and Life Sciences
,
Biosensors
2025
In elementary schools, immunologically immature students come into close contact with each other and are susceptible to the spread of infectious diseases. To analyze pathogen transmission among students, it is essential to obtain behavioral data. Questionnaires and wearable sensor devices were used for communication behavior and swab sampling was employed for contact behavior. However, these methods have been insufficient in capturing information about the processes and actions of each student that contribute to pathogen transmission. Therefore, in this study, actual behavioral data were collected using video recordings to evaluate droplet and contact transmission in elementary schools. The analysis of communication behavior revealed the diverse nature of interactions among students. By calculating the droplet transmission probabilities based on conversation duration, the risk of droplet transmission was quantified. In the contact behavior, we introduced a novel approach for constructing contact networks based on contact history. According to this method, well-known items, such as students’ desks, doors, and faucets, were predicted to be potential fomite. In addition, students’ shirts and shared items with high contact frequency and high centrality metrics in the network, which were not evaluated in swab sampling surveys, were identified as potential fomites. The reliability of the predictions was demonstrated through micro-simulations. The micro-simulations replicated virus transmission scenarios in which virus-carrying students were present in the actual contact history. The results showed that a significant amount of virus adhered to the items predicted to be fomites. Interestingly, the micro-simulations indicated that most viral copies were transmitted through single items. The analysis of contact history, contact networks, and micro-simulations relies on video-recorded behavioral data, highlighting the importance of this method. This study contributes significantly to the prevention of infectious diseases in elementary schools by providing evidence-based information about transmission pathways and behavior-related risks.
Journal Article
Comparison of oral metabolome profiles of stimulated saliva, unstimulated saliva, and mouth-rinsed water
by
Fukuda, Shinji
,
Tsutsumi, Kota
,
Umezawa, Kouta
in
631/61/320
,
639/638/11/296
,
692/698/3008/3014
2022
Saliva includes a substantial amount of biological information, which has enabled us to understand the relationship between oral metabolites and various oral and systemic disorders. However, collecting saliva using a controlled protocol is time-consuming, making saliva an unsuitable analyte in large cohort studies. Mouth-rinsed water (MW), the water used to rinse the mouth, can be collected easily in less time with less difference between subjects than saliva and could be used as an alternative in oral metabolome analyses. In this study, we investigated the potential of MW collection as an efficient alternative to saliva sample collection for oral metabolome profiling. MW, stimulated saliva, and unstimulated saliva were collected from 10 systemically healthy participants. The samples were subjected to metabolome analysis using capillary electrophoresis time-of-flight mass spectrometry, and the types and amounts of metabolites in the samples were compared. Qualitatively, MW contained the same metabolites as unstimulated and stimulated saliva. While the quantity of the metabolites did not drastically change between the sampling methods, all three reflected individual differences, and the features of MW were the same as those of the unstimulated saliva. Overall, these results suggest that MW may be an appropriate alternative to saliva in oral metabolome profile analysis.
Journal Article
Influence of cell culture-derived media and environmental contaminants on the effect of feline calicivirus inactivation agents
2025
Several studies on viral inactivation agents frequently overlook the influence of virus suspension conditions, which often leads to inconsistent conclusions. We investigated the impact of cell culture-derived media and environmental contaminants on the efficacy of viral inactivation agents against feline calicivirus (FCV). The FCV in Eagle’s minimum essential medium (EMEM) with cell-derived metabolites, was replaced with distilled water (DW) with using a column-based simple dispersant replacement method. Sodium dodecyl sulfate (SDS) or sodium hypochlorite (NaClO) were less effective against FCV in EMEM than DW, while didecyl dimethylammonium chloride (DDAC) was more effective. The inactivation effect of 50% v/v ethanol was stronger against FCV in EMEM than DW, whereas that of 70% v/v ethanol was more effective in DW. Analysis of the effect of EMEM components revealed that inorganic salts and basic amino acids (BAA) reduced SDS inactivation efficacy but enhanced DDAC’s. Similarly, inorganic salts reduced the effect of 70% v/v ethanol, while amino acids, especially BAA reduced that of NaClO’s. Since each inactivating agent affects FCV differently, the influence of each EMEM component is assumed to differ. Moreover, environmental contaminants, such as bovine serum and saliva, reduced the overall effectiveness of the agents owing to their inorganic substances and proteins.
Journal Article
Branched-chain amino acids and specific phosphatidylinositols are plasma metabolite pairs associated with menstrual pain severity
2025
Menstrual pain affects women’s quality of life and productivity, yet objective molecular markers for its severity have not been established owing to the variability in blood levels and chemical properties of potential markers such as plasma steroid hormones, lipid mediators, and hydrophilic metabolites. To address this, we conducted a metabolomics study using five analytical methods to identify biomarkers that differentiate menstrual pain severity. This study included 20 women, divided into mild (
N
= 12) and severe (
N
= 8) pain groups based on their numerical pain rating scale. We developed pretreatment procedures that allowed all analyses from only 100 µL of finger-prick blood collected across the menstrual cycle. Among the 692 quantified metabolites, branched-chain amino acids and specific phosphatidylinositol (PI), especially PI(36:2), were identified as potential biomarkers. Furthermore, the ratio of PI(36:2) to each BCAA or total BCAA effectively discriminated between the severity levels of menstrual pain. These ratios correlated positively with NPRS, indicating high accuracy in pain assessment. This study highlights the potential of small molecular markers to objectively assess menstrual pain severity, aiding evidence-based support and intervention.
Journal Article
Comparison of oral microbiome profiles in stimulated and unstimulated saliva, tongue, and mouth-rinsed water
2019
Epidemiological studies using saliva have revealed relationships between the oral microbiome and many oral and systemic diseases. However, when collecting from a large number of participants such as a large-scale cohort study, the time it takes to collect saliva can be a problem. Mouth-rinsed water, which is water that has been used to rinse the oral cavity, can be used as an alternative method for collecting saliva for oral microbiome analysis because it can be collected in a shorter time than saliva. The purpose of this study was to verify whether mouth-rinsed water is a suitable saliva substitute for analyzing the oral microbiome. We collected samples of mouth-rinsed water, stimulated saliva, unstimulated saliva, and tongue coating from 10 systemic healthy participants, and compared the microbial diversity and composition of the samples using next-generation sequencing of 16S rRNA-encoding genes. The results showed that the microbial diversity of mouth-rinsed water was similar to that of unstimulated and stimulated saliva, and significantly higher than that of tongue-coating samples. The microbial composition at the species level of mouth-rinsed water also showed a very high correlation with the composition of unstimulated and stimulated saliva. These results suggest that the mouth-rinsed water is a suitable collection method instead of saliva for oral microbiome analysis.
Journal Article
Involvement of propionate, citrulline, homoserine, and succinate in oral microbiome metabolite-driven periodontal disease progression
2025
Dysbiosis of the oral microbiome has been implicated in the onset and progression of periodontal diseases. An altered oral microbiome can significantly affect the concentration and composition ratio of bacterial-derived metabolites, thereby contributing to disease development. However, there is limited research on the role of metabolites derived from the oral microbiota. This study aimed to identify specific bacteria-derived metabolites and their contributions to pathogenicity. Mouth-rinsed water was collected from 24 patients with periodontal disease and 22 healthy individuals. We conducted a correlation analysis between periodontal disease-associated bacteria and metabolites present in mouth-rinsed water. We evaluated the effects of these metabolites on human gingival epithelial cells analysis of oral bacteria culture supernatants confirmed the origin of these metabolites. We identified 20 metabolites associated with bacteria that are significantly more prevalent in periodontal disease. Notably, propionate, succinate, citrulline, and homoserine—metabolites derived from the oral microbiome—were identified as being associated with periodontal disease. These results suggested that metabolites derived from the oral microbiota are involved in periodontal disease.
Journal Article
Dysbiosis of oral microbiome persists after dental treatment-induced remission of periodontal disease and dental caries
2023
Oral diseases, such as periodontal disease and dental caries, have a high risk of recurrence and are considered to be related to dysbiosis of the oral microbiome and metabolome. It is, therefore, important to understand the state of the oral microbiome and metabolome after disease treatment to prevent recurrence. The current study sought to clarify whether oral dysbiosis improves the following remission of symptoms by dental treatment. To this end, the salivary microbiome and metabolome of healthy participants were compared to those with periodontal disease, dental caries, or both (concurrent). Saliva was collected as mouth-rinsed water and the microbiome was measured using 16S rRNA gene targeted sequencing and metabolome using capillary electrophoresis–time-of-flight mass spectrometry. Comparisons with healthy participants were performed before and after treatment, and several months after transition to self-care. Dental treatment significantly improved the oral health condition of each group; several months after treatment, oral health did not deteriorate. However, even after remission, the salivary microbiome of the two groups (oral disease and healthy) differed significantly. Additionally, after remission, significant differences, compared with healthy participants, remained in the relative abundances of disease-related bacteria and nitrate-reducing bacteria. After remission, significant differences were observed in the salivary metabolome in the healthy group in terms of threonate and pyrimidine metabolism-related component concentrations, which are assumed to reflect the high relative abundance of periodontal disease-related bacteria in the microbiome. Oral microbiome dysbiosis persisted even after dental treatment-induced disease remission with a sustained increased risk of disease when compared with healthy participants. We characterized the oral conditions, salivary microbiome, and metabolome after dental treatment by investigating the state after treatment completion and transition to self-care. Dental treatment improved oral health conditions, resulting in oral disease remission; however, the imbalanced state of the salivary microbiome continued even after remission. Although the results of this study are preliminary, owing to the small number of participants in each group when compared to larger cohort studies, they indicate that the risk of disease may remain higher than that of healthy participants, thereby demonstrating the importance of removing dental plaque containing disease-related bacteria using appropriate care even after treatment completion. We also identified bacterial species with relative abundances that differed from those of healthy participants even after remission of symptoms, which may indicate that the maturation of certain bacterial species must be controlled to improve the oral microbiome and reduce the risk of disease recurrence.
Journal Article
Functional maintenance of calcium store by ShcB adaptor protein in cerebellar Purkinje cells
2020
Intracellular Ca
2+
levels are changed by influx from extracellular medium and release from intracellular stores. In the central nervous systems, Ca
2+
release is involved in various physiological events, such as neuronal excitability and transmitter release. Although stable Ca
2+
release in response to stimulus is critical for proper functions of the nervous systems, regulatory mechanisms relating to Ca
2+
release are not fully understood in central neurons. Here, we demonstrate that ShcB, an adaptor protein expressed in central neurons, has an essential role in functional maintenance of Ca
2+
store in cerebellar Purkinje cells (PCs). ShcB-knockout (KO) mice showed defects in cerebellar-dependent motor function and long-term depression (LTD) at cerebellar synapse. The reduced LTD was accompanied with an impairment of intracellular Ca
2+
release. Although the expression of Ca
2+
release channels and morphology of Ca
2+
store looked intact, content of intracellular Ca
2+
store and activity of sarco/endoplasmic reticular Ca
2+
-ATPase (SERCA) were largely decreased in the ShcB-deficient cerebellum. Furthermore, when ShcB was ectopically expressed in the ShcB-KO PCs, the Ca
2+
release and its SERCA-dependent component were restored. These data indicate that ShcB plays a key role in the functional maintenance of ER Ca
2+
store in central neurons through regulation of SERCA activity.
Journal Article
Junctophilin-mediated channel crosstalk essential for cerebellar synaptic plasticity
by
Takeshima, Hiroshi
,
Miyazaki, Taisuke
,
Sakagami, Hiroyuki
in
Action Potentials
,
afterhyperpolarization
,
Animals
2007
Functional crosstalk between cell‐surface and intracellular ion channels plays important roles in excitable cells and is structurally supported by junctophilins (JPs) in muscle cells. Here, we report a novel form of channel crosstalk in cerebellar Purkinje cells (PCs). The generation of slow afterhyperpolarization (sAHP) following complex spikes in PCs required ryanodine receptor (RyR)‐mediated Ca
2+
‐induced Ca
2+
release and the subsequent opening of small‐conductance Ca
2+
‐activated K
+
(SK) channels in somatodendritic regions. Despite the normal expression levels of these channels, sAHP was abolished in PCs from mutant mice lacking neural JP subtypes (JP‐DKO), and this defect was restored by exogenously expressing JPs or enhancing SK channel activation. The stimulation paradigm for inducing long‐term depression (LTD) at parallel fiber–PC synapses adversely established long‐term potentiation in the JP‐DKO cerebellum, primarily due to the sAHP deficiency. Furthermore, JP‐DKO mice exhibited impairments of motor coordination and learning, although normal cerebellar histology was retained. Therefore, JPs support the Ca
2+
‐mediated communication between voltage‐gated Ca
2+
channels, RyRs and SK channels, which modulates the excitability of PCs and is fundamental to cerebellar LTD and motor functions.
Journal Article