Shikoku Region Research Articles

Heat impacts on an aging society: a spatio-temporal analysis of heatstroke deaths in Japan

Abstract Climate change, especially through heatwaves, significantly affects human health and is a growing global concern. Concurrently, population aging is occurring worldwide, with many countries experiencing an increase in their elderly populations. As the elderly are particularly susceptible to extreme temperatures and unevenly distributed due to internal migration of younger populations, a spatio-temporal analysis integrating temperature changes and demographic data is essential. This study focuses on Japan, a super-aged society where over 25% of the total population is 65 years or older. We examined the effects of climate and the proportion of the elderly population on heatstroke deaths through spatio-temporal analysis within a Bayesian framework. We estimated the annual relative risk of heatstroke-related deaths at the prefecture level from 2008 to 2019. The results indicate a strong spatial autocorrelation in heatstroke deaths across Japan. The spatio-temporal interaction model was the best-performing, showing that regional and temporal variations significantly impact heatstroke mortality. In this model, a one-degree increase in temperature anomaly was linked to a 0.35 (95% CI 0.25 to 0.46) times higher odds of heatstroke deaths, while a 1% increase in the population aged 65 years or older was associated with 4.85 (95% CI 0.92 to 8.65) times higher odds. We found that not only metropolitan areas but also rural areas, such as the Tohoku and Shikoku regions, face a high risk of heatstroke, emphasizing the need to address the challenges in rural communities. Our study highlights the necessity of integrating temperature changes and demographic data in a spatio-temporal context for heatstroke risk assessment. It demonstrates the profound effects of temperature anomalies and the proportion of the elderly population on heatstroke mortality. This research framework could be applicable to other countries experiencing aging and heatwave issues, aiding in the development of targeted public health interventions.

Report of the 8th Annual Meeting of the Chugoku & Shikoku Region of the JSCPT

Report of the 8th Annual Meeting of the Chugoku & Shikoku Region of the JSCPT

Optimization of a Tsunami Gauge Configuration for Pseudo‐Super‐Resolution of Wave Height Distribution

AbstractIn this study, we present an optimization method for determining a cost‐effective sparse configuration for tsunami gauges to realize the reconstruction of high‐resolution wave height distribution throughout the target region based on the concept of super‐resolution. This optimization method consists of three procedures. First, we generate time series data of tsunami wave heights at synthetic gauges by conducting numerical simulations of various earthquake and tsunami scenarios at the target site. Next, we apply proper orthogonal decomposition to the synthetic tsunami data to extract the spatial features of the wave height distribution. Finally, according to these spatial features, an optimization process is performed to determine a sparse configuration of synthetic gauges. In the optimization, the optimal gauges are sequentially selected from the set of synthetic gauges to reconstruct the wave height distribution with the highest accuracy. Targeting hypothetical Nankai Trough earthquakes and tsunamis, we determine the optimal configuration near Shikoku and demonstrate the wave height reconstruction capability of the approach by comparing the performance of networks with optimally and randomly placed gauges. The results indicate that coastal gauges contribute more to improving the reconstruction accuracy and that a configuration with 21 optimal gauges has satisfactory performance. In addition, we assess the performance of the existing NOWPHAS network installed in the Shikoku region and find that the reconstruction performance of the existing network is equivalent to that of the optimal gauge network.

Prevalence of Encephalitozoon hellem among companion and exhibition birds in Japan.

Microsporidia can cause infection in various animals and humans. To determine the recent prevalence of Encephalitozoon in companion birds in Japan, 364 bird feces and 16 conjunctival exudates, as well as 28 exhibition bird feces, were examined using polymerase chain reaction (PCR). Thirty-five (9.6%) feces and 2 (12.5%) conjunctival exudates from companion birds were PCR positive, and sequence analysis revealed that all detected organisms were Encephalitozoon hellem genotype 1A. The prevalence by region varied from 4.5% in the Shikoku region to 14.3% in the Chugoku region. By age, the prevalence in birds younger than 6 months of age was 13.3%. We also discuss the threat of human infection as a zoonotic disease.

Significant increase in the prevalence of Panton–Valentine leukocidin-positive methicillin-resistant Staphylococcus aureus , particularly the USA300 variant ΨUSA300, in the Japanese community

ABSTRACT USA300, a major Panton–Valentine leukocidin (PVL)-producing methicillin-resistant Staphylococcus aureus (MRSA) clone associated with skin and soft tissue infections (SSTIs), carries a type IV staphylococcal cassette chromosome mec (SCC mec ) element. Recently, a USA300 variant, ΨUSA300, with a 12-bp deletion of ccrB2 in the SCC mec element, was identified in Japan by Takadama et al. (15). To understand the current status of PVL-positive MRSA in the community, a nationwide surveillance of MRSA isolated from outpatients at dermatology departments was conducted. This study included 1,619 outpatients who visited dermatology departments at 22 healthcare facilities in 11 prefectures in Japan between 2018 and 2021; S. aureus were isolated from these outpatients. Molecular epidemiological analysis was performed using PCR, SCC mec and spa typing, pulsed-field gel electrophoresis, multilocus sequence typing, and antimicrobial susceptibility testing. A total of 980 S . aureus were isolated, 293 of which were identified as MRSA. Among MRSA isolates, PVL genes were detected in 18 of 63 (28.6%) in 2018, 34 of 85 (40.0%) in 2019, 29 of 65 (44.6%) in 2020, and 40 in 80 (50.0%) in 2021. Among the PVL-positive MRSA, 16 of 121 (13.2%) and 94 of 121 (77.7%) isolates were identified as USA300 and ΨUSA300, respectively. ΨUSA300 strains were collected from six prefectures in Japan: Kagawa, Osaka, Tokyo, Kanagawa, Fukushima, and Saitama. ΨUSA300 was isolated more frequently than USA300 from patients with deep-seated SSTIs ( P < 0.05). Our findings showed that PVL-positive MRSA isolates were significantly increased in the Japanese community. Furthermore, the USA300 variant ΨUSA300 has emerged as the predominant PVL-positive MRSA clone across the Kanto, Kinki, and Shikoku regions of Japan, and this variant may possess a greater propensity to cause deep-seated SSTIs than in USA300. IMPORTANCE USA300 is an MRSA clone producing PVL, a toxin associated with SSTIs. ΨUSA300 is a USA300 variant recently identified in Japan by Takadama et al. (15). Here, we found that the prevalence rate of PVL-positive MRSA in S. aureus was elevated in the Japanese community, and ΨUSA300 accounted for most of them. ΨUSA300 strains have been isolated from several areas in Japan and were associated with deep-seated SSTIs. This study highlighted the emerging threat posed by ΨUSA300 in Japan.

Clinical characteristics of human pulmonary dirofilariasis in Japan: An uncommon differential diagnosis of a solitary pulmonary nodule.

Human pulmonary dirofilariasis (HPD) is a zoonosis caused by Dirofilaria immitis. Most HPD cases are asymptomatic and are either found on annual health checkups or incidentally identified during investigation of another disease, particularly primary or metastatic pulmonary lung cancer. However, the frequency of Japanese HPD and clinical features remain not well-known. We analyzed data from the Japanese Medical Abstract Society database and identified 69 cases from 1978 to 2022. The incidence of HPD had increased until the 2000s but declined markedly in the 2010s. The incidence was higher in the southwestern and lower in the northeastern region of Japan. Health checkups were the primary diagnostic opportunity. High incidence rates per population were observed in the Chugoku and Shikoku regions. The diagnosis of HPD using a noninvasive procedure is typically difficult due to absence of specific clinical symptoms, and approximately 70% of the cases were detected using video-assisted thoracoscopic surgery. Global warming may increase the incidence of HPD in the northeastern region of Japan, and travel to countries with poor vector control may be a risk factor for HPD transmission. Physicians should consider this parasitic infectious disease when examining patients who present with a solitary nodule in the lungs.

Relationship between the Physiological Activity of Japanese Post-Fermented Teas and Lactic Acid Bacteria

Post-fermented tea is a beverage or food made by fermenting tea leaves with microorganisms. Four types of post-fermented tea are traditionally produced in Japan. Three of these post-fermented teas are produced by lactic acid fermentation in the Shikoku region. Post-fermented tea has physiological activities such as antioxidant, antiallergic, and fat accumulation inhibitory effects. The composition of catechins in post-fermented tea differs from that in green tea. Compared to green tea, epigallocatechin, epigallocatechin gallate, epicatechin, and epicatechin gallate are reduced, and catechin polymers are formed in the post-fermented tea. In addition, post-fermented teas contain pyrogallol, γ-aminobutyric acid (GABA), and D-amino acids. The lactate fermentation of post-fermented teas on Shikoku Island involves Lactiplantibacillus plantarum and Lactiplantibacillus pentosus as the dominant species in the fermentation process. L. planratum and L. brevis isolated from Ishizuchi-kurocha, one of the post-fermented teas of Shikoku, contain amino acid racemases that produce D-amino acids. In addition, L. brevis has a high capacity for GABA production. Furthermore, L. plantarum is likely to produce bacteriocin. Lactic acid bacteria, represented by the L. plantarum group, play an essential role in the physiological activity of post-fermented tea, including lactic acid fermentation. An attempt has been made to create new post-fermented tea (brewed tea) based on traditional post-fermented tea production methods.

Community attachment as a factor in the subjective well-being of older adults in urban and rural areas: a case study in Tokyo, Osaka, and Shikoku region in Japan

This study explored the relationship between community participation/community attachment and subjective well-being (SWB) among Japanese older adults. The study was conducted in Japanese urban (Tokyo and Osaka) and rural (Shikoku region) areas. Structural equation modelling was performed to assess the potential relationship between community participation, community attachment and SWB. Results showed that community participation and community attachment were positively associated in both areas. However, community attachment had a significant impact on SWB only in rural areas with little impact on increasing SWB in urban areas. We conclude that the role of community attachment varies according to regions with different socioeconomic properties. These findings contribute to the design of detailed region-specific initiatives to improve SWB of older adults.

Geochemical characteristics and risk assessment of minor elements in subsurface soils of abandoned mine-rich Shikoku region, Japan

Geochemical characteristics and risk assessment of minor elements in subsurface soils of abandoned mine-rich Shikoku region, Japan

The efficacy of mass screening for chronic obstructive pulmonary disease using screening questionnaires in a medical health check-up population

Chronic obstructive pulmonary disease (COPD) is a preventable and treatable disease, highlighting the need for efficient screening strategies to identify patients with COPD. However, there is little evidence regarding the efficacy of mass screening for COPD, and no epidemiological studies on COPD have been conducted in the Shikoku region of Japan. In this cross-sectional study, we originally investigated the efficacy of mass screening for COPD among community residents in the aforementioned region using two COPD screening questionnaires. From July 2018 through January 2019, 688 participants were enrolled. COPD was diagnosed using the Global Initiative for the Chronic Obstructive Lung Disease criteria. Twenty-one patients were newly diagnosed with COPD and 19 (90.5%) had early stages COPD. The prevalence of COPD in this study was 3.1%. The COPD Population Screener (COPD-PS) questionnaire and the International Primary Care Airways Guidelines (IPAG) questionnaire had extremely high negative predictive values in discriminating participants with COPD from those without. The scores of both questionnaires were correlated with spirometric tests and with each other. The COPD-PS questionnaire had significantly better specificity and area under the receiver operating characteristic curve value than the IPAG questionnaire. Moreover, only the COPD-PS questionnaire was identified as an independent factor for predicting COPD diagnosis in the multivariate analysis. Mass screening for COPD using screening questionnaires, particularly the COPD-PS questionnaire, might be useful to identify the early stages of COPD in a medical health check-up population.

The chemical and microbiological characteristics of Awa‐bancha, Japanese post‐fermented tea

Awa-bancha is a traditional Japanese post-fermented tea made by residents in Tokushima Prefecture in the Shikoku region. Tea was picked, boiled, rubbed, anaerobic fermented, and dried in the process of making Awa-bancha. Nevertheless, the details of making Awa-bancha differs depending on the producer, such as how the tea leaves are boiled, the weight of the stones, and the length of anaerobic fermentation. Therefore, the objective of this study was to examine the chemical and microbiological characteristics of Awa-bancha among different producers. The result explicated that the total phenolic compounds of Awa-bancha extracted by water at 95°C for 10 min ranged from 20.41 ± 0.66 to 35.49 ± 3.90 mg GAE/g DW, the average DPPH activity was 877.4 ± 307.81 mmol Trolox/g DW, and the average α-glucosidase inhibition activity (IC50) was 2.27 ± 0.63 mg/ml. The result revealed that Awa-bancha differed due to differences in statistical analysis labels (p ≤ 0.05), resulting in various chemical functionality among the producers. Suggesting that processing or fermentation of Awa-bancha may influence the bioactive compound in tea leaves changing from epicatechin (EC) to other compounds as well as HPLC analysis results show Epigallocatechin gallate (EGCg) is the main bioactive compound in Awa-bancha. The higher the acidity produced from the fermentation process, the higher concentration of the reducing sugar and total phenolic compounds, which affect antioxidant activity and α-glucosidase inhibition activity. Furthermore, the results show that Lactiplantibacillus plantarum is the dominating bacteria in Awa-bancha which is well known as a probiotic and beneficial to the human gastrointestinal tract by producing antimicrobial substances. According to this study, based on its health benefits, Awa-bancha could be possibly considered one of the functional drinks in the food industry. Novelty Impact Statement This study focused on the diversity of Awa-bancha, a traditional post-fermented tea from various producers in Kamikatsu Town, Tokushima, Japan and discovered a statistically significant difference in reducing sugar content and total phenolic content. Additionally, it was discovered that the chemical functionality of the Awa-bancha product was related to its higher acidity, higher polyphenolic content, antioxidant activity, and glucosidase inhibitory activity.

Report of the 6th Annual Meeting of the Chugoku & Shikoku Region of the JSCPT

Report of the 6th Annual Meeting of the Chugoku & Shikoku Region of the JSCPT

Spatial and temporal influence of sea level on inland stress based on seismic velocity monitoring

Earth’s crust responds to perturbations from various environmental factors. To evaluate this response, seismic velocity changes offer an indirect diagnostic, especially where velocity can be monitored on an ongoing basis from ambient seismic noise. Investigating the connection between the seismic velocity changes and external perturbations could be useful for characterizing dynamic activities in the crust. The seismic velocity is known to be sensitive to variations in meteorological signals such as temperature, snow, and precipitation as well as changes in sea level. Among these perturbations, the impact of variations in sea level on velocity changes inferred from seismic interferometry of ambient noise is not well known. This study investigates the influence of the ocean in a 3-year record of ambient noise seismic velocity monitoring in the Chugoku and Shikoku regions of southwest Japan. First, we applied a bandpass filter to determine the optimal period band for discriminating among different influences on seismic velocity. Then, we applied a regression analysis between the proximity of seismic station pairs to the coast and the ocean influence, as indicated by the correlation of sea level to seismic velocity changes between pairs of stations. Our study suggests that for periods between 0.0036 to 0.0155 cycle/day (64–274 days), the ocean’s influence on seismic velocity decreases with increasing distance of station pairs from the coast. The increasing sea level deforms the ocean floor, affecting the stress in the adjacent coast. The stress change induced by the ocean loading may extend at least dozens of kilometers from the coast. The correlation between sea level and inland seismic velocity changes is negative or positive. Although it is difficult to clearly interpret the correlation based on a simple model, they could depend on the in situ local stress, orientation of dominant crack, and hydraulic conductivity. Our study shows that seismic monitoring may be useful for evaluating the perturbation in the crust associated with an external load.Graphical abstract

Effects of an Advance Care Planning Training Program for Certified Palliative Care Nurses in Japan

Education programs for certified palliative care nurses who promote advance care planning (ACP) for cancer patients are important, but not currently available in Japan. This study aimed to develop an educational program of ACP for certified palliative care nurses in Japan and evaluate its effectiveness. A program consisting of four modules was implemented for 60 certified palliative care nurses in the Kyushu, Chugoku, and Shikoku regions. Participants attended one training session, and 39 responded to a survey on changes in ACP practice and difficulties with cancer nursing 3 months after the intervention. The Wilcoxon signed-rank test was performed to compare data before and after the intervention. The results obtained showed an increase in dialogue on ACP among patients/families and healthcare professionals (mean before the intervention = 24.49, mean after the intervention = 27.59, p = 0.045), and a significant decrease in the sense of difficulty with knowledge of and skills for ACP (mean before the intervention = 4.85, mean after the intervention = 4.30, p = 0.001). More than 90% of the participants gave positive comments on the evaluation items such as understanding and satisfaction with the educational program and appropriateness of the contents. After attending the training program, participants’ sense of difficulty with their knowledge of and skills for ACP decreased, and their practice of ACP increased. This program may promote the practice of ACP for cancer patients in the future.

An abnormal birth in bovine suspected of being caused by Peaton virus first occurred in Shikoku region, Japan.

Peaton virus (PEAV) is a type of arthropod-borne virus (arbovirus) belonging to the genus Orthobunyavirus, much like Akabane virus and Aino virus. These arboviruses cause stillbirth and congenital malformations of fetuses in ruminants. In Japan, abnormal birth in bovine caused by PEAV were reported in Okinawa, Kyushu, and Chugoku regions, but it has never been reported in Shikoku region. The abnormal birth occurred in 2020 in Ehime Prefecture (Shikoku region) and suspected of being caused by PEAV from results of clinical signs, pathological findings, and virus neutralization test using PEAV. However, PEAV was not detected and isolated. This report describes the case of abnormal birth in bovine suspected of being caused by PEAV first occurred in Shikoku region, Japan.

Report of the 5th Annual Meeting of the Chugoku & Shikoku Regions of the JSCPT

Report of the 5th Annual Meeting of the Chugoku & Shikoku Regions of the JSCPT

Le Paléolithique supérieur dans l’ouest de l’île principale du Japon

The Kinki, Chugoku and Shikoku regions are located in the western part of the Japanese mainland. This area lacks the Pleistocene volcanic soil except a part of Chugoku Mountains. For this reason, the chronology of the late Paleolithic stone industries has been mainly studied by technology and typology of the fields excavated. However, after the late 1980s, the analysis of volcanic ash that contained the Paleolithic sediments had remarkable development. As a result, the cultural layer between the distant Paleolithic sites is compared by several widespread volcanic ashes such as Aira-Tanzawa (in short AT) as key bed. In this paper, we offered chronological order of the late Paleolithic culture in these regions by comparing cultural layers on the basis of the widespread volcanic ashes, referring to typological analysis of industries. The Sétoüchi technique and Ku industry characterize the late Paleolithic culture in these regions. The Sétoüchi technique is the unique one to produce the Ku type backed knife blunting on only one side, using the particular side-blow flaking technology based on physical characteristics of sanukite stone which is a kind of andesite. However, a hypothesis named the “Sétoüchi concept” was proposed in 2001, and it has been used as a substitute of the “Sétoüchi technique” by a few Japanese researchers. So we point out the mistake of the Sétoüchi concept relying on the fact which yielded stratigraphically two different industries in the Suncheon site.

Acceleration of hidden Markov model fitting using graphical processing units, with application to low-frequency tremor classification

Hidden Markov models (HMMs) are general purpose models for time-series data widely used across the sciences because of their flexibility and elegance. Fitting HMMs can often be computationally demanding and time consuming, particularly when the number of hidden states is large or the Markov chain itself is long. Here we introduce a new Graphical Processing Unit (GPU)-based algorithm designed to fit long-chain HMMs, applying our approach to a model for low-frequency tremor events. Even on a modest GPU, our implementation resulted in an increase in speed of several orders of magnitude compared to the standard single processor algorithm. This permitted a full Bayesian inference of uncertainty related to model parameters and forecasts based on posterior predictive distributions. Similar improvements would be expected for HMM models given large number of observations and moderate state spaces (<80 states with current hardware). We discuss the model, general GPU architecture and algorithms and report performance of the method on a tremor dataset from the Shikoku region, Japan. The new approach led to improvements in both computational performance and forecast accuracy, compared to existing frequentist methodology.

Clinical Course of 60 Cesarean Scar Pregnancies.

Early diagnosis and therapy are important in a cesarean scar pregnancy (CSP), which can cause uterine rupture with resultant massive bleeding. However, there are some reports of CSPs continued to term. The optimal management of CSPs remains unclear; therefore, we investigated the clinical courses of CSPs diagnosed and treated at perinatal institutions in the Chugoku and Shikoku regions of Japan. We enrolled 60 women diag-nosed with CSP at 21 institutions from January 2006 to December 2015. Of the 60 women diagnosed with CSP, 57 were treated. Pregnancy was terminated in 48 women and continued in 9. Thirteen women underwent transabdominal hysterectomy; they experienced no postoperative complications or allogeneic blood transfu-sion. Nine women received therapies such as dilation and curettage, and 26 received non-surgical therapies such as methotrexate and topical administration of potassium chloride. Among 9 women who chose to con-tinue with their CSP, 7 successfully delivered newborns, 2 had uterine ruptures in the second trimester, and all women required transabdominal hysterectomy. Diagnosis and therapy in the first trimester of pregnancy are important in the management strategy of a CSP. When continuing a CSP, the risk of uterine rupture and trans-abdominal hysterectomy must be considered.

A survey of fertility preservation in patients with hematologic malignancies in the Chugoku and Shikoku regions

We interviewed the adult and pediatric hematologists in the Chugoku and Shikoku regions in order to determine their opinions and attitudes about fertility preservation in 2020. A questionnaire on fertility preservation practices was sent to 59 doctors in 46 adult and pediatric hematology-oncology hospitals, out of which 52 doctors (88.1%) responded. Forty doctors (76.9%) had no rules about the explanation and 37 doctors (71.2%) answered that the attending physicians provided the explanation alone in their hospitals. Many doctors had no rules about the target age group of patients. Only few hospitals were able to complete the treatment of hematological malignancies and fertility preservation within their own infrastructure. Several doctors referred to neighboring hospitals for fertility preservation; however, five hospitals were unable to provide fertility preservation and had no relationship with other hospitals. Doctors should give fertility preservation options to all patients at risk of infertility because of their cancer treatment. It is suggested that the local networks should be utilized and relationships with neighboring hospitals strengthened.