Okayama City Research Articles

Presence of Microplastics in Four Types of Shellfish Purchased at Fish Markets in Okayama City, Japan.

The worldwide microplastic pollution in our environment is a matter of great concern. Harmful effects of plastics have been reported in various types of organisms including murine animals. We examined the presence of microplastics in four types of shellfish purchased from fish markets in Okayama, Japan and served to the public: short-neck clam (Ruditapes philippinarum, asari in Japanese), hard-shell clam (Meretrix lusoria, hamaguri), brackishwater clam (Cyrenidae, shijimi), and oyster (Crassostrea gigas, kaki). Our analyses demonstrated that approx. 3 pieces of microplastics were present per single shellfish, based on the division of the total number of pieces of microplastic obtained from all 4 types of shellfish by the total number of shellfish examined. Since health problems in humans due to microplastics have not yet been confirmed, further examinations of the effects of ingested microplastics are needed.

岡山県における新型コロナウイルス感染症流行の疫学的特徴

This article describes the epidemiological characteristics of coronavirus disease 2019 (COVID-19) observed in Okayama Prefecture. An epidemiological survey was performed using records from the Okayama Prefecture website and data from the newspaper Sanyo Shimbun (digital version). Infected patients were categorized into two groups: 25 patients infected during the first wave and 116 infected during the second wave. Notably, 52％ of the patients in the former group were aged ≥50 years and 66％ in the latter group were aged 20-49 years. The percentages of Okayama City residents among the infected patients were 65％ and 73％, respectively. Three clusters were identified during the second wave. The interval (mean±SD) between the polymerase chain reaction (PCR) assay results for the index case and those for the cases of secondary infection was 0.8±0.8 days (n = 6 for the cases of secondary infection) during the first wave and 2.0±1.4 days (n = 62 for the cases of secondary infection) during the second wave. As of August 24, the percentage of cumulative infected cases (7.5/100,000 patients) in Okayama Prefecture was lower than that the national level (49.3/100,000 patients). These results indicate that Okayama Prefecture has controlled the COVID-19 pandemic relatively well, primarily through the consistent implementation of public health measures, such as early case identification, careful contact tracing, and prompt PCR testing. Strict enforcement of the aforementioned measures is important to prevent or offset the effects of the third wave of COVID-19 that is expected during the influenza epidemic season.

Five dipteran species from cigarette ends in Okayama City, Japan

Five dipteran species from cigarette ends in Okayama City, Japan

A Laboratory Test of Paddy Yellowing Rate Estimation Technique for Smart Agriculture

This paper describes a laboratory test result of paddy yellowing rate estimation technique for smart agriculture. The paddy yellowing rate is important for determining the proper time of harvesting. It is required to measure the paddy yellowing rate in the field by image analysis. Since, this technological development is extremely difficult, this laboratory test was conducted as a preliminary step. The study area is Hozaki area in Akaiwa city and Shinogoze area in Okayama city, Okayama prefecture. Sampling and laboratory tests were conducted on 7th October in 2019 and 9th October in 2020, these times are 1 or 2 weeks before harvest. The number of sampling points is 47, three ears were collected from each point. The ear was photographed with Olympus digital camera, TG-5. Image data converted from raw to TIFF data. The paddy yellowing rate was calculated by dividing the number of blue seeds, means immature, by the total seeds. The explanatory variables were normalized difference vegetation index that combined two bands from blue, green and red band. As a result of the analysis using 2019 data, a linear regression model with the highest correlation coefficient (R ; 0.77) could be built by the normalized difference vegetation index using the combination of red and green band. An estimation model using 2020 data could not be constructed. It is probable that the ripening of this year was more advanced than previous year. From the result, it could be considered that the proposed method can be applied before the late ripening period.

Delay in Emergency Medical Service Transportation Responsiveness during the COVID-19 Pandemic in a Minimally Affected Region.

Few studies have investigated the influence of the Coronavirus Disease 2019 (COVID-19) pandemic on emer-gency medical service (EMS) systems, especially in areas less affected or unaffected by COVID-19. In this study, we investigated changes in prehospital EMS activity and transport times during the COVID-19 pandemic. All patients transported by EMS in the city of Okayama from March-May 2019 or March-May 2020 were included. Interfacility transports were excluded. The primary outcome was the time from a patient's first emergency call until hospital arrival (total prehospital time). Secondary outcomes included three segments of total prehospital time: the response time, on-scene time, and transportation time. Total prehospital time and the durations of each segment were compared between corresponding months in 2020 (COVID19-affected) and 2019 (control). The results showed that total prehospital times in April 2020 were significantly higher than those in 2019 (33.8 ± 11.6 vs. 32.2 ± 10.8 min, p < 0.001). Increases in total prehospital time were caused by longer response time (9.3 ± 3.8 vs. 8.7 ± 3.7 min, p < 0.001) and on-scene time (14.4 ± 7.9 vs. 13.5 ± 6.2min, p < 0.001). The COVID-19 pandemic was thus shown to affect EMS and delayed arrival/response even in a minimally affected region. A system to minimize transportation delays should be developed for emerging pandemics.

Geochemical study for utilization of groundwater heat by open heat pump system in northern Okayama and Akaiwa city areas with low precipitation in Japan

This paper examines geothermal heat from groundwater in Akaiwa City and the northeastern part of Okayama City, where precipitation is the second least in Japan. Isotopes of hydrogen and oxygen and chemical compositions of 53 groundwater samples and 6 river water samples were analyzed to investigate the origin and flow modes. To examine changes in water quality, water samples were taken in Okayama City in July 2015 and 2016 and in Akaiwa City in July 2016 and February 2017. The groundwater samples consist of a mixture of Asahi River and Yoshii River water as well as local precipitation; the chemical composition is Ca2+– HCO3−. The amount of precipitation contributing to the groundwater samples increases with an increase in distance from both rivers. To inspect groundwater quality for geothermal heat-pump systems, the calcite and goethite precipitations are examined as scales. The results demonstrate that shallow groundwater can be exploited for heat using an open-type ground-source heat-pump system (GSHP); however, in the context of scaling iron materials, such as goethite, a closed-type GSHP is recommended.

Starry sky in the abdomen

A Vietnamese woman aged 23 years with a 3-year history of intermittent abdominal pain presented to our outpatient clinic at Okayama City Hospital, Okayama, Japan. She had no previous significant cardiovascular or gastrointestinal problems. She also denied any drug abuse, lead poisoning, allergies, abdominal injury, or psychiatric disorders. Her vital signs were normal. She exhibited mild tenderness of her epigastrium without guarding or rebound tenderness. A chest x-ray showed no abnormality. Abdominal ultrasonography confirmed the presence of intermediate splenic and pelvic ascites, but there was no hepatosplenomegaly. CT showed calcified mediastinal nodes, diffuse thickening and nodularity of the omentum, mesenteric lymphadenopathy, and ascites (figure, A). We were unable to drain abdominal ascites because there was no safe route of access. A subsequent QuantiFERON-TB Gold test was positive. Exploratory laparoscopy showed numerous white, miliary nodules on the peritoneum, round ligament of the liver, and hepatic surface (figure, B). Analyses of ascitic fluid showed an adenosine deaminase concentration of 136·5 U/L. Although ascites culture and PCR for Mycobacterium tuberculosis were negative, caseating granulomas with Langhans giant cells were detected in specimens of omentum. Based on these clinical findings, we made a diagnosis of tuberculous peritonitis. The patient was given anti-tuberculous treatment with rifampicin, isoniazid, pyrazinamide, and ethambutol for 2 months, followed by rifampicin and isoniazid for 4 months. After treatment, her abdominal symptoms improved, and ascites resolved completely.

Effects of a Forest Walk on Urinary Dityrosine and Hexanoyl-Lysine in Young People: A Pilot Study.

A few studies indicate exposure to forests may alleviate oxidative stress in the body. However, more evidence is needed to support this potentiality. The purpose of the current study aimed at examining whether there is any difference in urinary levels of oxidatively modified proteins or lipids—dityrosine (DT) and hexanoyl-lysine (HEL), respectively, after a forest or urban walk. The study was performed on 29 university students who took part in forest walks (Shinjo Village) in Okayama Prefecture of Japan and on 42 university students who took part in urban walks in the downtown area of Okayama City. Urine samples before and after the walks were analyzed for DT and HEL excretion. Air phytoncides during the walks were also measured. We found a decreased tendency in urinary DT and HEL (p < 0.05) in most participants after the forest walks, but not after the urban walks. We further found the total levels of air phytoncides in the forest field were 1.50 times higher compared with those in the urban field. This study suggests the possibility that regular immersion in a forest environment might contribute toward weakening of the oxidative modifications of proteins or lipids in the body.

Long-term exposure to nitrogen dioxide and natural-cause and cause-specific mortality in Japan

BackgroundLong-term exposure to air pollution is linked with increased risk of adverse health outcomes, but the evidence for the association between nitrogen dioxide (NO2) and mortality is weak because of the inadequate adjustment of potential confounders and limited spatial resolution of the exposure assessment. Moreover, there are concerns about the independent effects of NO2. Therefore, we examined the association between NO2 long-term exposure and all-cause and cause-specific mortality. MethodsWe included participants who were enrolled in health checkups in Okayama City, Japan, in 2006 or 2007 and were followed until 2016. We used a land-use regression model to estimate the average NO2 concentrations from 2006 to 2007 and allocated them to the participants. We estimated hazard ratios (HRs) for a 10-μg/m3 increase in NO2 levels for all-cause or cause-specific mortality using Cox proportional hazard models. ResultsAfter excluding the participants who were assigned with outlier exposures, a total of 73,970 participants were included in the analyses. NO2 exposure was associated with increased risk of mortality and the HRs and their confidence intervals were 1.06 (95% CI: 1.02, 1.11) for all-cause, 1.02 (0.96, 1.09) for cardiopulmonary, and 1.36 (1.14, 1.63) for lung cancer mortality. However, the elevated risks became equivocal after the adjustment for fine particulate matter except lung cancer. ConclusionLong-term exposure to NO2 was associated with increased risk of all-cause, cardiopulmonary, and lung cancer mortality. The elevated risk for lung cancer was still observable even after adjustment for fine particulate matter.

Kominkan in Okayama City: Aiming to Achieve SDGs

Kominkan in Okayama City: Aiming to Achieve SDGs

岡山県南東部における夜間・休日の耳鼻咽喉科救急診療の実状

To clarify the scenario regarding the emergency medical treatment of patients undergoing otolaryngology in southeastern Okayama Prefecture in Japan, we evaluated the conditions in three hospitals that mainly provide emergency medical treatment to patients undergoing otorhinolaryngology at night or on holidays. The data (age, sex, type of disease, and address) of patients who visited Japanese Red Cross Okayama Hospital, Kawasaki Medical School General Medical Center, and Okayama Medical Center in 2018 were collected and compared. All three hospitals reported many cases of tonsillar abscess and nasal bleeding. In the study population, the number of patients aged ≤10 and 10-20 years were the lowest and highest, respectively. Patients residing in southern Okayama City and Tamano City tended to visit Japanese Red Cross Okayama Hospital or Kawasaki Medical School General Medical Center. Patients residing in northeastern Okayama Prefecture and northern Okayama City tended to visit Okayama Medical Center. A ceiling for the senior physicians’ capacity will be introduced in April 2020, and thus the number of otolaryngology-related treatments performed in Okayama Prefecture is expected to decrease. The otolaryngologyrelated emergency medical treatment in southeastern Okayama Prefecture may collapse. Emergency medical care systems must therefore be considered in the future.

Combined effects of body mass index and unhealthy behaviors on disability in older Japanese adults: the Okayama study

BackgroundBody mass index (BMI) is a significant predictor of functional disability in older adults. However, when evaluated, the association between BMI and incident functional disability, considering behaviors only as covariates or not, may not be appropriate. The primary purpose of the study was to investigate the combined effects of BMI and unhealthy behaviors on the risk of incident functional disability.MethodsThis was a retrospective cohort study that took place in Okayama City, Japan. Data on BMI and unhealthy behaviors were obtained using the health check-up questionnaire. The certification of Long-Term Care Insurance was used to measure functional disability. Cox proportional hazard models were used; adjusted hazard ratios (HRs) with 95% confidence interval (CI) were calculated for incidence of functional disability across categories of BMI and number of unhealthy behaviors.ResultsThe relationship between BMI and incident functional disability was U-shaped (HR = 1.18, 95% CI [1.11–1.25], among the underweight range; and 1.26 [1.19–1.34] among the obesity range), and its risk was significantly higher within the normal-to-overweight range of BMI values with co-occurring unhealthy behaviors (with normal weight range and one, 1.17 [1.01–1.21]; two, 1.29 [1.18–1.41]; and three or four unhealthy behaviors 1.38 [1.24–1.54]; as well as among overweight range and one, 1.16 [1.05–1.27]; two, 1.26 [1.15–1.38]; and three or four unhealthy behaviors, 1.47 [1.31–1.64]). In each BMI category, the risk of incident functional disability increased with increasing number of unhealthy behaviors (p < 0.05 for linear tread), with the highest risk (1.87 [1.58–2.20]) occurring in combination with at least three unhealthy behaviors with BMI ≥ 27.5, for both sexes (2.20 [1.64–2.92] in men and 1.66 [1.35–2.04] in women).ConclusionIt is necessary to consider the combined effects of BMI and behaviors on incident functional disability. Furthermore, interventions targeting multiple behaviors should be considered as such interventions may offer greater benefits than simple interventions.

Incidence of the Acute Symptom of Chronic Periodontal Disease in Patients Undergoing Supportive Periodontal Therapy: A 5-Year Study Evaluating Climate Variables.

Although patients under supportive periodontal therapy (SPT) have a stable periodontal condition, the acute symptom of chronic periodontal disease occasionally occurs without a clear reason. Therefore, in the present study, to obtain a better understanding of this relationship in patients undergoing SPT, we hypothesized that the acute symptom of chronic periodontal disease might be affected by climate factors. We conducted a questionnaire study and carried out oral examinations on patients undergoing SPT who had been diagnosed as having the acute symptom of chronic periodontal disease. We collected climate data from the local climate office in Okayama city, Japan. We predicted parameters that affect the acute symptom of chronic periodontal disease with unidentified cause and divided patients into high and low groups in terms of climate predictors. Then we defined the cut-off values of parameters showing significant differences in the incidence of the acute symptom of chronic periodontal disease. The incidence of the acute symptom of chronic periodontal disease with unidentified cause was significantly different when the cases were classified according to the maximum hourly decrease in barometric pressure (1.5 and 1.9 hPa) (p = 0.04 and p = 0.03, respectively). This suggests that climate variables could be predictors of the acute symptom of chronic periodontal disease. Therefore, gaining a better understanding of these factors could help periodontal patients undergoing SPT prepare to avoid the acute symptom of chronic periodontal disease.

Report of health checkup system for chronic kidney disease in general population in Okayama city: effect of health guidance intervention on chronic kidney disease outcome.

BackgroundFrom 2011, Okayama municipal government started the health checkup follow-up project to find those who were unaware of suffering chronic kidney disease and to prevent from aggravation of CKD stage. In this study, we aimed to evaluate the effect of 2 years' CKD-follow-up project regarding renal function and CKD risks.Patients and methodsThose who received a health checkup by the national health insurance in Okayama city in 2011 were recruited. The patients with lifestyle-related diseases or metabolic syndrome were excluded. Subjects who had an estimated glomerular filtration rate<50 mL/min/1.73 m2 or urinary protein positive by dipstick test were defined as compromised renal function group. They were recommended to visit a medical institution. Non-compromised renal function participants with two or more risks for CKD (hyperglycemia, higher blood pressure, dyslipidemia, hyperuricemia) were recommended to receive a health guidance (risk group). The change of renal function and CKD risks between 2011 and 2013 in each group was examined.ResultsA total of 28,309 people received a health checkup in 2011. In compromised renal function group, 39.5% (96/243) of the subjects improved their CKD stages in 2013 regardless of the visit of medical institutions or the frequency of receiving health checkup. In risk group, 63.4% (260/410) of the subjects decreased their CKD risks in 2013 independent of the reception of health guidance.ConclusionIn both compromised renal function group and risk group, more than half of subjects kept their kidney function (217/243) and decreased the number of CKD risks (260/410) in 2 years' follow-up. Receiving a health checkup itself and notification of one’s own health condition could exert a protective effect on kidney function.

Long-term exposure to fine particulate matter and natural-cause and cause-specific mortality in Japan.

A number of studies have linked long-term exposure to particulate matter with aerodynamic diameter <2.5 µm (PM2.5) with mortality, but most of these studies were conducted in Europe and North America. Studies in Asian countries had been conducted at relatively high exposures. We evaluated the association of long-term exposure to PM2.5 and natural-cause and cause-specific mortality in Japan, where PM2.5 levels are relatively low compared with levels in other Asian countries. A cohort of 75,531 participants underwent basic health checkups in Okayama City in 2006 or 2007. We followed the participants until the end of 2016. Average PM2.5 levels from 2006 to 2010 were obtained and assigned to the participants by geographical location. We used the Cox proportional hazard models to estimate hazard ratios for a 5-μg/m3 increase in PM2.5 levels for natural-cause or cause-specific mortality, adjusting for potential confounders. PM2.5 exposure was associated with increased risk of mortality; the hazard ratios were 1.29 (95% confidence interval = 1.18, 1.41) for mortality from natural causes, 1.16 (1.02, 1.32) for cardiorespiratory mortality, and 1.63 (1.13, 2.34) for lung cancer mortality. PM2.5 exposure was more strongly associated with cardiorespiratory mortality from hypertension, pneumonia and influenza, and chronic obstructive pulmonary disease than with ischemic heart disease or cerebrovascular disease. Elderly participants and smokers tended to have higher effect estimates. Long-term exposure to PM2.5 can increase the risk of natural-cause, cardiorespiratory, and lung cancer mortality in Japan.

Physical activity and incident dementia in older Japanese adults: The Okayama study.

To evaluate the association between regular physical activity and the risk of incident dementia in older Japanese adults. This was a retrospective cohort study performed in Okayama City, Japan. Overall, 51 477 older Japanese adults were followed from 2008 to 2014. A health checkup questionnaire was used to assess regular physical activity. The Dementia Scale of long-term care insurance was used as a measure of incident dementia. Cox proportional hazard models were used to calculate adjusted hazard ratios, with their 95% confidence intervals, for the incidence of dementia across the categories of physical activity. During a 7-year follow-up, 13 816 subjects were considered as having incident dementia. Compared with participants who performed physical activity less than or equal to one time per week, the multivariate adjusted hazard ratio values (95% confidence intervals) for participants who performed physical activity greater than or equal to two times per week but not every day and those who performed physical activity every day were 0.79 (0.75-0.84) and 0.94 (0.89-0.98), respectively. The interaction of physical activity and sex was statistically significant (P < .01). In subgroup analysis, the multivariate-adjusted hazard ratio values (95% confidence intervals) remained low, at 0.76 (0.70-0.84) in males and 0.81 (0.76-0.87) in females who performed physical activity greater than or equal to two times per week but not every day; they were 0.82 (0.76-0.89) in males and 1.01 (0.95-1.07) in females who performed physical activity every day. Regular physical activity could reduce the risk of incident dementia in older Japanese adults, except females who performed physical activity every day.

Changes in Urinary Hydrogen Peroxide and 8-Hydroxy-2'-Deoxyguanosine Levels after a Forest Walk: A Pilot Study.

Some studies have shown that exposure to forests has positive effects on human health, although the mechanisms underlying the health benefits of a forest environment have not been elucidated yet. The current study was aimed at examining how the levels of urinary hydrogen peroxide (H2O2) and 8-hydroxy-2’deoxyguanosine (8-OHdG) change after a forest or urban walk in healthy subjects. Twenty-eight volunteers (19 men and 9 women) participated in the study. The forest walks were carried out in a forest in Okayama Prefecture, Japan, and the urban walks (15 men and 7 women) were carried out in the downtown area of Okayama city, each for two hours. Spot urine samples were collected before the walk, the next day and one week after the forest or urban walk. Compared with pre-forest walk levels, urinary H2O2 (p < 0.1) and 8-OHdG (p < 0.1) concentrations significantly decreased in the participants the day after the forest walk; furthermore, urinary 8-OHdG remained at a low level even at one week after the forest walk (p < 0.05). However, there were no significant changes in the concentrations of these oxidative biomarkers after the urban walk. These findings suggest the possibility that exposure to forests may alleviate oxidative stress in the body.

東京・岡山市・高知市方言の並列・とりたて詞と句頭の上昇

東京・岡山市・高知市方言の並列・とりたて詞と句頭の上昇

Iwatani opens first retail hydrogen station in Okayama Prefecture

Japanese fueling technology company Iwatani Corporation recently opened a hydrogen refueling station in Okayama City, Okayama Prefecture, in the southwestern part of the main island Honshu. The station, in the Minami district, is the first commercial hydrogen refueling station in Okayama Prefecture, and features packaged equipment that reduces construction costs and saves space.

Patients with osteosarcoma and soft tissue sarcoma might become "cancer refugees" in some Japanese regional cities.

Purpose“Rare cancer” is defined as malignancy with a disease prevalence (age-adjusted incidence rate) of less than six per 100,000 population. Proper treatments which these patients need cannot always be performed unless they find dedicated facilities. Patients tend to be desperate, searching for advice and care. Thus, they are called “cancer refugees”. Osteosarcoma and soft tissue sarcoma (OS/STS) are representative rare cancers in Japan. We conducted a retrospective analysis of patients with OS/STS to improve the current treatment modalities in a Japanese regional city.Patients and methodsTwenty-one patients with OS/STS who were hospitalized to receive standard chemotherapy or palliative treatment were enrolled between October 2011 and January 2017. Patients with non-Hodgkin’s lymphoma (NHL) and advanced cancer who were treated in the palliative care unit (PCU) of the Kawasaki Medical School General Medical Center were recruited as the control groups. We analyzed the difference in residential area between patients with OS/STS and the control groups.ResultsApproximately one-third of patients with OS/STS were referred from hospitals outside of Okayama prefecture. The ratio of patients with OS/STS referred from Okayama city and/or the same medical administration area of Okayama prefecture was lower than that of patients with NHL and advanced cancer who were treated in the PCU.ConclusionBecause the medical environment of patients with OS/STS in Japanese local cities has not been consolidated, completing medical care within the patient’s own medical administration area is difficult. Thus, some patients with OS/STS may become “cancer refugees” who are unable to receive standard therapy near their residence.