Continuous positive airway pressure versus high-flow nasal cannula oxygen therapy for acute hypoxemic respiratory failure: A randomized controlled trial.

BACKGROUND AND OBJECTIVE: The relative effectiveness of initial non-invasive respiratory strategies for acute respiratory failure using continuous positive airway pressure (CPAP) or high-flow nasal cannula (HFNC) is unclear. METHODS: We conducted a multicenter, open-label, parallel-group randomized controlled trial to compare the efficacy of CPAP and HFNC on reducing the risk of meeting the prespecified criteria for intubation and improving clinical outcomes of acute hypoxemic respiratory failure. The primary endpoint was the time taken to meet the prespecified criteria for intubation within 28 days. RESULTS: Eighty-five patients were randomly assigned to the CPAP or HFNC group. Eleven (28.9%) in the CPAP group and twenty (42.6%) in the HFNC group met the criteria for intubation within 28 days. Compared with HFNC, CPAP reduced the risk of meeting the intubation criteria (hazard ratio [HR], 0.327; 95% CI, 0.148-0.724; p = 0.006). There were no significant between-group differences in the intubation rates, in-hospital and 28-day mortality rates, ventilator-free days, duration of the need for respiratory support, or duration of hospitalization for respiratory illness. Pulmonary oxygenation was significantly better in the CPAP group, with significantly lower pH and higher partial pressure of carbon dioxide, but there were no differences in the respiratory rate between groups. CPAP and HFNC were associated with few possibly causal adverse events. CONCLUSION: CPAP is more effective than HFNC at reducing the risk of meeting the intubation criteria in patients with acute hypoxemic respiratory failure.

Findings of virtual bronchoscopic navigation can predict the diagnostic rate of primary lung cancer by bronchoscopy in patients with peripheral lung lesions.

BACKGROUND: Despite being minimally invasive, bronchoscopy does not always result in pathological specimens being obtained. Therefore, we investigated whether virtual bronchoscopic navigation (VBN) findings were associated with the rate of diagnosis of primary lung cancer by bronchoscopy in patients with peripheral lung lesions. METHODS: This study included patients with suspected malignant peripheral lung lesions who underwent bronchoscopy at St. Luke's International Hospital between October 2013 and March 2020. Patients diagnosed with primary lung cancer were grouped according to whether their pathology could be diagnosed by bronchoscopy, and their clinical factors were compared. In addition, the distance between the edge of the lesion and the nearest branch ("distance by VBN") was calculated. The distance by VBN and various clinical factors were compared with the diagnostic rates of primary lung cancer. RESULTS: The study included 523 patients with 578 lesions. After excluding 55 patients who underwent multiple bronchoscopies, 381 patients were diagnosed with primary lung cancer. The diagnostic rate by bronchoscopy was 71.1% (271/381). Multivariate analysis revealed that the lesion diameter (odds ratio [OR] 1.107), distance by VBN (OR 0.94) and lesion structure (solid lesion or ground-glass nodule; OR 2.988) influenced the risk of a lung cancer diagnosis. The area under the receiver operating characteristic curve for diagnosis based on lesion diameter and distance by VBN was 0.810. CONCLUSION: The distance by VBN and lesion diameter were predictive of the diagnostic rates of primary lung cancer by bronchoscopy in patients with peripheral lung lesions.

Elevated plasma levels of Krebs von den Lungen-6 and geographic appearance on high-resolution computed tomography are associated with diffuse alveolar damage in autopsy cases of acute respiratory distress syndrome: a retrospective study.

BACKGROUND: Although diffuse alveolar damage (DAD) is a histopathological hallmark of acute respiratory distress syndrome (ARDS), its detection without lung biopsy is challenging. In patients with ARDS, the specificity of the Berlin definition to diagnose DAD as a reference standard is not adequately high, making it difficult to adequately diagnose DAD. The purpose of this study was to investigate the relationship between DAD and clinical findings, including KL-6 and geographic appearance, in ARDS patients and to identify more specific diagnostic criteria for DAD. METHODS: Among all adult autopsy cases at a tertiary hospital in Japan between January 2006 and March 2021, patients with ARDS who met the Berlin definition criteria were included. The patients' conditions were classified according to histopathological patterns as DAD or non-DAD, and clinical characteristics, laboratory data, and high-resolution computed tomography (HRCT) findings were compared between the two groups. RESULTS: During the study period, 27 met the Berlin definition (median age: 79 years, 19 men), of whom 18 (67%) had DAD and 9 (33%) did not. In the non-DAD group, histopathologic findings revealed organizing pneumonia in seven patients and pulmonary hemorrhage in two patients. On HRCT at onset, patients with DAD had more geographic appearance than those without DAD (89% vs. 44%). In patients with geographic appearance and elevated KL-6 (> 500 U/mL), the sensitivity and specificity for DAD diagnosis were 56% and 100%, respectively. All three patients with no geographic appearance and normal KL-6 did not have DAD. CONCLUSIONS: Geographic appearance on HRCT combined with KL-6 levels may predict the presence of DAD in patients with ARDS.

A surgically treated case of severe upper gastrointestinal hemorrhage with gastritis cystica polyposa.

BACKGROUND: Gastritis cystica polyposa (GCP) is a recently recognized entity histologically characterized by hyperplasia and cystic dilatation of the gastric glands spreading through the submucosal layer. Its symptoms include those affecting the upper gastrointestinal tract, such as upper abdominal pain, nausea, and anorexia, although some patients might be asymptomatic. GCP rarely causes severe hemorrhage. Recently, we encountered a GCP case that exhibited severe hemorrhage. CASE PRESENTATION: A 53 year-old man visited the emergency department complaining of hematemesis. He underwent distal gastrectomy and Billroth II reconstruction for duodenal ulcers 32 years ago. Upper gastrointestinal endoscopy detected bleeding from the reddened mucosa at the anastomosis; thus, tentative endoscopic hemostasis was conducted. Despite medical treatment with transfusion, melena with significant hemodynamic impairment persisted. He was treated again with endoscopic hemostasis and interventional radiology (IVR) but remained unresponsive to these procedures. He eventually underwent partial resection of the anastomosis site with Roux-en-Y reconstruction and finally achieved excellent postoperative recovery. Histopathological examination of the resected specimen suggested a GCP bleeding. CONCLUSIONS: GCP can indeed cause severe hemorrhage. Hemorrhage caused by GCP may not respond to endoscopic hemostasis or IVR; therefore, surgical treatment should be decided without delay.

Disseminated nocardiosis due to Nocardia terpenica.

We report the first case of disseminated nocardiosis due to trimethoprim/sulfamethoxazole-resistant Nocardia terpenica successfully treated with meropenem and clarithromycin. The patient travelled to Japan from Australia via Southeast Asia, which led to differential diagnoses of multiple lung nodules including miliary tuberculosis and melioidosis as well as nocardiosis. Because of variety of susceptibility depending on the Nocardia species, clinicians need to confirm the species and investigate its susceptibility.

Thymic epithelial tumor treatment in Japan: analysis of hospital cancer registry and insurance claims data, 2012-2014.

INTRODUCTION: Thymic epithelial tumors are a rare type of neoplasm. Accordingly, it is difficult to perform phase III trials in patients with thymic epithelial tumors, and thus, no standard treatment has been established for these tumors. In this study, we aimed to investigate the current status of thymic epithelial tumor treatment in Japan. METHODS: This retrospective observational study enrolled patients with thymic epithelial tumor whose data were recorded in a nationwide Hospital-based Cancer Registry that was linked with health insurance claims data for the registered patients between 2012 and 2014. The patients' treatment details were obtained from a health insurance claims database. RESULTS: A total of 813 patients with thymoma and 547 with thymic carcinoma were included in the analysis. Overall, 549 (67.5%) thymoma patients underwent surgical resection alone. Among patients with thymic carcinoma, 230 (42.0%) underwent initial surgery, and 124 (53.9%) received subsequent radiotherapy and chemotherapy. Chemotherapy regimens varied across the hospitals; overall, 21 and 22 regimens were used to treat thymoma and thymic carcinoma, respectively. Platinum-based combination regimens were predominantly selected for both diseases. CONCLUSIONS: This study revealed the real-world patterns of thymic epithelial tumor treatment in Japan. Although the nature of this study did not enable the determination of optimal treatment strategies, the simultaneous analysis of nationwide registry, insurance, efficacy and prognostic data may contribute to the establishment of a standard treatment strategy for rarely occurring cancers such as thymic epithelial tumor.

Effect of spraying of fine water particles on facial skin moisture and viscoelasticity in adult women.

BACKGROUND/PURPOSE: It is known that the elderly and adult women with reduction in sebum secretion have reduced skin barrier function, drying of the skin in a low humidity environment is accompanied by physiological distress. As our hypothesis, when fine water particles are sprayed on the skin, the water content of the corneal layer is significantly increased. In the present study, we examined the ability of fine water particles to improve facial skin moisture levels in adult women. METHODS: We examined skin conductance, transepidermal water loss (TEWL), and skin elasticity as an index of skin barrier function at the cheek in 17 healthy adult women in the spraying of fine water particles, in the environment temperature at 24°C and 34.5% relative humidity. RESULTS: The skin conductance of stratum corneum after 120 minute of spraying, A condition (peak particle size below 0.5 µm) was 119.7 ± 25.1%, B condition (peak particle size 1.8 µm) was 100.4 ± 31.7%, C condition (peak particle size 5.4 µm) was 110.1 ± 25.0%, and the A condition was significantly higher than the B condition. Also, skin elasticity in the A condition tended to be higher value than in the other conditions. Transepidermal water loss (TEWL) after 120 minute of spraying showed a lower value in the A condition than in the other conditions. In the A condition, the skin conductance steadily maintained their initial levels up to 360 minute after spraying. CONCLUSION: Especially, by spraying smallest fine water particles, skin barrier function at the cheek was improved. These data indicated that non-charged fine water particles played an important role on moisten skin in a low humidity environment.

Effect of micro mist sauna bathing on thermoregulatory and circulatory functions and thermal sensation in humans.

To examine the effects of micro mist sauna bathing, produced by water crushing method, we exposed ten male subjects to five cases of micro mist sauna, namely (1) room temperature (RT) 38 °C with 100 % (actually 91 %) relative humidity (RH), (2) RT 41.5 °C with 80 % (actually 81 %) RH, (3) RT 41.5 °C with 100 % (actually 96 %) RH, (4) RT 45.0 °C with 64 % (actually 61 %) RH, and (5) RT 45.0 °C with 100 % (actually 86 %) RH, and measured tympanic temperature, mean skin temperature, heart rate (HR), and cheek moisture content, as well as ratings of thermal and sweating sensation tympanic temperatures at RT 45 °C were significantly higher at 86 % RH than those at 61 % RH; however, those at RT 45 °C with 61 % RH were higher than those with 86 % RH during recovery. There were no significant differences at RT 41.5 °C between with 81 % RH and with 96 % RH. Mean skin temperature was the highest at RT 45 °C 86 % RH case, followed by at RT 41.5 °C 96 % RH, RT 45 °C 61 % RH, RT 41.5 °C 81 % RH, and finally at RT 38 °C 91 % RH. HR change showed the same order as for mean skin temperature. A significant difference in cheek moisture content was observed between RT 41.5 °C with 81 % RH and RT 45 °C with 86 % RH 10 min after the micro mist bathing. There were no significant differences between ratings of thermal sensation at RT 41.5 °C with 81 % RH and at RT 45 °C with 61 % RH and RT 45 °C with 61 % RH and RT 45 °C with 86 % RH. Between RT 45 °C with 86 % RH and RT 41.5 °C with 81 % RH, there was a tendency for interaction (0.05 < p < 0.1). Other cases showed significant higher ratings of thermal sensation at higher room temperature or higher relative humidity. The ratings of sweating sensation 10 min after the mist sauna bathing were significantly higher at higher RT and RH except between RT 41.5 °C 96 % RH and RT 45 °C 86 % RH which exhibited no significant difference. We concluded that the micro mist sauna produced by water crushing method induced more moderate and effective thermal effect during micro mist sauna bathing than the conventional mist sauna bathing. In addition, micro mist sauna is as effective for heating the human subjects as bathtub bathing as well as more moderate thermal and sweating sensations.

Effects of Defecation Strain at Various Bed Reclining Angles on Intrarectal Pressure and Cardiovascular Responses.

BACKGROUND: There is no clear information about the optimal bed reclining angle for promoting efficient and safe defecation in bedfast patients. OBJECTIVE: The aim of this study was to examine the optimal bed reclining angle for facilitating increases in intrarectal pressure without causing marked cardiovascular changes in order to develop an efficient and safe defecation position for bedfast patients. METHODS: Twelve healthy men participated in this study. The subjects were required to strain for 15 seconds at the end stage of inspiration while their bed was reclined at 0° (supine), 15°, 30°, or 60°. During straining, the subjects were asked to maintain (a) an intrarectal pressure of 20 mm Hg or (b) the maximal intrarectal pressure. Intrarectal pressure, blood pressure, heart rate, and abdominal muscle activity (electromyographic activity) were recorded continuously throughout the study period. RESULTS: During straining, intrarectal pressure increased with the reclining angle, and a significant linear correlation was detected between the sine of the reclining angle of the bed and intrarectal pressure (η = .57, p < .01). When subjects were straining with the aim of maintaining maximal intrarectal pressure, the extent of the observed changes (delta) in blood pressure and heart rate did not differ significantly across the reclining angles. When subjects were straining with the aim of maintaining an intrarectal pressure of 20 mm Hg, the delta blood pressure decreased as the reclining angle increased 0°: M = 23.7, SD = 15.3 mm Hg, 95% CI [11.9, 35.4]; 15°: M = 25.9, SD = 10.8 mm Hg, 95% CI [17.6, 34.2]; 30°: M = 17.7, SD = 9.4 mm Hg, 95% CI [10.4, 24.9]; 60°: M = 15.5, SD = 9.5 mm Hg, 95% CI [8.1, 22.8]; 15° versus 30°: p < .05; 15° versus 60°: p < .05. The amount of muscle activity observed during straining decreased as the reclining angle increased. DISCUSSION: In bedfast patients, it is suggested that higher reclining angles may enable safer and more efficient defecation, because it decreases the amount of muscle activity required to increase the intrarectal pressure and reduces the potentially deleterious effects of straining on the cardiovascular system to develop an efficient and safe defecation position for bedfast patients.

[Safety of pemetrexed according to the duration of vitamin B12 and folic acid supplementation prior to the first dose of pemetrexed].

OBJECTIVE: Administration of vitamin B12 and folic acid for 7 days prior to the administration of the first dose of pemetrexed is recommended. However, vitamin supplementation rarely is initiated less than 7 days prior to the first dose of pemetrexed. Therefore, we analyzed the safety of pemetrexed with vitamin supplementation for less than 7 days prior to the first dose of pemetrexed. METHODS: Patients were classified into 2 groups according to the duration of vitamin supplementation prior to the first dose of pemetrexed: group A received vitamin supplementation for 7 days or more, and group B received vitamin supplementation for less than 7 days. We analyzed adverse effects, such as myelosuppression, rash, and diarrhea, after 1 cycle of pemetrexed therapy. RESULTS: A total of 70 patients were administered pemetrexed; 40 patients were men and 30 were women with a median age of 64.5 years(range, 43-86 years). A total of 57 patients were classified into group A and 13 into group B; 33 patients were administered pemetrexed as a first-line treatment. Neutropenia of Grade 3 or more was observed in 4/49(8.2%)patients in group A and 2/13(15.4%)patients in group B(p=0.60). There were no significant differences in the rates of occurrence of neutropenia, rash, and diarrhea. CONCLUSION: This retrospective study indicated that patients could be safely treated with pemetrexed if vitamin supplementation is initiated for less than 7 days prior to the first administration of pemetrexed. However, further studies are needed because of a lack of statistical power and adjustment for confounding factors.

Effects of isotonic and isometric exercises with mist sauna bathing on cardiovascular, thermoregulatory, and metabolic functions.

To clarify the effects of isometric and isotonic exercise during mist sauna bathing on the cardiovascular function, thermoregulatory function, and metabolism, six healthy young men (22 ± 1 years old, height 173 ± 4 cm, weight 65.0 ± 5.0 kg) were exposed to a mist sauna for 10 min at a temperature of 40 °C, and relative humidity of 100 % while performing or not performing ∼30 W of isometric or isotonic exercise. The effect of the exercise was assessed by measuring tympanic temperature, heart rate, systolic and diastolic blood pressure, chest sweat rate, chest skin blood flow, and plasma catecholamine and cortisol, glucose, lactate, and free fatty acid levels. Repeated measures ANOVA showed no significant differences in blood pressure, skin blood flow, sweat rate, and total amount of sweating. Tympanic temperature increased more during isotonic exercise, and heart rate increase was more marked during isotonic exercise. The changes in lactate indicated that fatigue was not very great during isometric exercise. The glucose level indicated greater energy expenditure during isometric exercise. The free fatty acid and catecholamine levels indicated that isometric exercise did not result in very great energy expenditure and stress, respectively. The results for isotonic exercise of a decrease in lactate level and an increase in plasma free fatty acid level indicated that fatigue and energy expenditure were rather large while the perceived stress was comparatively low. We concluded that isotonic exercise may be a more desirable form of exercise during mist sauna bathing given the changes in glucose and free fatty acid levels.

A comparison of head-out mist bathing, with or without facial fanning, with head-out half-body low-water level bathing in humans--a pilot study.

To reduce the risks of Japanese-style bathing, half-body bathing (HBLB) has been recommended in Japan, but discomfort due to the cold environment in winter prevents its widespread adoption. The development of the mist sauna, which causes a gradual core temperature rise with sufficient thermal comfort, has reduced the demerits of HBLB. We examined head-out 42 °C mist bathing with 38 °C HBLB up to the navel to see if it could improve thermal comfort without detracting from the merits of HBLB, with and without the effects of facial fanning (FF). The subjects were seven healthy males aged 22-25 years. The following bathing styles were provided: (1) HBLB-head-out half-body low bathing of 38 °C up to the navel (20 min); (2) HOMB-head-out mist bathing of 42 °C and HBLB of 38 °C (20 min); and (3) HOMBFF-HOMB with FF (20 min). HOMB raised the core temperature gradually. HOMBFF suppressed the core temperature rise in a similar fashion to HOMB. Increases in blood pressure and heart rate usually observed in Japanese traditional-style bathing were less marked in HOMBs with no significant difference with and without FF. The greatest body weight loss was observed after Japanese traditional-style bathing, with only one-third of this amount lost after mist bathing, and one-sixth after HBLB. HOMB increased thermal sensation, and FF also enhanced post-bathing invigoration. We conclude that HOMB reduces the risks of Japanese traditional style bathing by mitigating marked changes in the core temperature and hemodynamics, and FF provides thermal comfort and invigoration.

Japanese nurses' confidence in their understanding of telenursing via e-learning: A mixed-methods study.

Objective: Telenursing e-learning courses have been shown to enhance nurses' skills and knowledge; however, the subjective learning experience is unclear. In this study, we identified meta-inferences to quantitatively and qualitatively understand this experience, as well as the types of knowledge gained through an e-learning course and how they are linked to each other, in order to enhance nurses' confidence in their understanding of telenursing. Methods: We employed a single-arm intervention with a mixed-methods convergent parallel design. We converged participants' self-reported pre- and post-course confidence scores with their reflections on the learning experience, which were reported qualitatively as improved or unimproved. A total of 143 Japanese nurses with a mean of 20 years of nursing experience participated in this study. Results: Among the participants, 72.7% demonstrated improved confidence in their understanding of telenursing after completing the e-learning course. The baseline confidence score was originally higher in the group that reported unimproved confidence (p < .001). Although there was no statistical difference in the usability and practicality scores between the two groups, the qualitative learning experience in these aspects differed in terms of the depth of knowledge of telenursing obtained. Conclusions: Nurses' quantitative confidence in their understanding of telenursing after course completion was incongruent with their qualitative perspectives of the learning experience. Nursing educators, healthcare policymakers, and other stakeholders should consider that learners' overconfidence in their understanding of telenursing and comprehension of e-learning materials may result in their failure to develop key telenursing competencies, skills, and knowledge.

Pulmonary Sclerosing Pneumocytoma: A Case Revealed During 8-Year of Follow-up with CT imaging.

Pulmonary sclerosing pneumocytoma (PSP) is a rare, benign tumor. Given the challenges of a bronchoscopic diagnosis, surgery is performed during the early stages of the disease. Therefore, little is known about the growth pattern of PSP. This case of PSP was not diagnosed despite bronchoscopy, resulting in lung resection eight years after the anomaly was first identified on computed tomography (CT). This report compares the long-term follow-up of CT and pathological findings and discusses the difficulty in making a diagnosis using a bronchoscopic forceps biopsy to aid in future PSP diagnoses and treatment planning.

Successful thoracoscopic operative approach for refractory pneumothorax in interstitial lung disease under local anaesthesia.

Refractory pneumothorax associated with interstitial lung disease (ILD) remains a challenging condition due to the patient's tolerability and lung compliance that restrict the feasibility of aggressive interventions. Additionally, many cases recur after improvement with treatment, and reports of successful management for this complicated condition are limited. Herein, we report the case of a 60-year-old man with ILD, utilizing home oxygen therapy, who experienced a successful recovery from a surgical intervention under local anaesthesia for pneumothorax. This case highlights the potential for operative intervention under local anaesthesia as a viable option for patients who do not respond to internal approaches.

Methotrexate-associated lymphoproliferative disorder: A rare pancreatic tumor diagnosed via endoscopic ultrasound-guided fine-needle biopsy.

A 73-year-old woman with a history of rheumatoid arthritis treated with methotrexate (MTX) for the last 10 years was referred to our hospital for a pancreatic tumor examination. Contrast-enhanced abdominal computed tomography revealed a 20-mm-diameter hypovascular tumor in the pancreatic tail. A hypoechoic mass with heterogeneous internal echo was found on an endoscopic ultrasound (EUS). An EUS-guided fine-needle biopsy (EUS-FNB) was performed with a 22-gauge Franseen-tip needle. Histologic examination of EUS-FNB specimens from the pancreatic tumor revealed the proliferation of atypical spindle cells. Immunohistochemical staining for CD20 and Ki-67 was positive in the atypical cells. Immunohistochemical staining for CD3 was partially positive in the atypical cells. Epstein-Barr virus-encoded RNA in situ hybridization showed positive staining. MTX-related lymphoproliferative disorder (MTX-LPD) with Epstein-Barr virus infection was diagnosed. MTX treatment was immediately discontinued, and treatment was initiated by a hematologist. However, her condition rapidly deteriorated, and she died of multiple organ failure 4 weeks after diagnosis. MTX-LPD can complicate gastrointestinal lesions. However, most lesions are localized in the stomach and rarely complicate pancreatic lesions. MTX-LPD is classified as an "iatrogenic" LPD. Therefore, immediate action, such as MTX discontinuation, is necessary. In conclusion, endoscopists should be aware that MTX-LPD lesions can occur in the pancreas and gastrointestinal tract. Moreover, EUS-FNB can be useful in the diagnosis of this rare pancreatic tumor.

Effects of water nanodroplets on skin moisture and viscoelasticity during air-conditioning.

BACKGROUND/PURPOSE: In air-conditioned rooms, dry air exacerbates some skin diseases, for example, senile xerosis, atopic dermatitis, and surface roughness. Humidifiers are used to improve air dryness, which often induces excess humidity and thermal discomfort. To address this issue, we investigated the effects of water nanodroplets (mist) on skin hydration, which may increase skin hydration by penetrating into the interstitial spaces between corneocytes of the stratum corneum (SC) without increasing air humidity. METHODS: We examined biophysical parameters, including skin conductance and transepidermal water loss (TEWL), and biomechanical parameters of skin distension/retraction before and after suction at the forehead, lateral canthus, and cheek, with or without mist, in a testing environment (24°C, 35% relative humidity) for 120 min. RESULTS: In the group without mist, TEWL values significantly decreased at all the sites after 1 h compared with the initial values. However, in the presence of mist, TEWL values were maintained at the initial values through the test, yielding significant differences vs. the group without mist. There were no significant differences between mist and mist-free groups in terms of skin conductance. Skin distension was significantly increased in the group with mist compared with that in the group without mist at the forehead and cheek, suggesting a softening effect of mist. CONCLUSION: Skin deformation of the face was improved by mist, suggesting hydration of the SC by mist. The change in TEWL was influenced by mist, suggesting supply of water to the skin, particularly the SC, by mist. These data indicated that a mist of water nanodroplets played an important role in softening skin in an air-conditioned room without increasing excess humidity.

Attenuated thermoregulatory responses with increased plasma osmolality in obese subjects during two seasons.

Obese subjects may be more vulnerable to injury from heat stress, and appear to be less efficient at thermoregulation. Sweat rate, tympanic temperature and osmolality in obese subjects were investigated in Japan during two seasons. The purpose of this study was to examine the relationship between obesity, thermoregulatory response and season. Five obese (BMI, 32.0 ± 4.9 kg/m²) and five non-obese (BMI, 23.2 ± 2.9 kg/m²) men participated in this experiment at latitude 35°10' N and longitude 136°57.9'E. The average atmospheric temperature was 29.1 ± 1.0 °C in summer and 3.3 ± 1.4 °C in winter. Tympanic temperature and sweat rate were measured during leg water immersion at 42 °C for 30 min. Blood samples were analyzed for plasma osmolality. The relationship between tympanic temperature and sweat rate decreased significantly in obese compared to in non-obese subjects in both seasons, there being a lowered sweat rate for any core temperature in obese subjects. Plasma osmolality was significantly higher in obese than in non-obese subjects in both seasons. Thermal sensation increased significantly in non-obese than in obese in winter but not in summer. Our data show that thermoregulatory responses are attenuated in obese subjects compared with controls, suggesting that obese people are at increased risk of heat-related illnesses.

Seasonal differences in melatonin concentrations and heart rates during sleep in obese subjects in Japan.

During the past several decades, obesity has been increasing globally. In Japan, obesity is defined by a BMI of 25 kg/m² or over; 28.6 % of men and 20.6 % of women are obese. Obese people have an increased incidence of developing cardiovascular, renal, and hormonal diseases and sleep disorders. Obese people also have shortened sleep durations. We investigated seasonal differences in melatonin concentrations, heart rates, and heart rate variability during sleep in obese subjects in Japan. Five obese (BMI, 32.0 ± 4.9 kg/m²) and five non-obese (BMI, 23.2 ± 2.9 kg/m²) men participated in this study in the summer and winter. Electrocardiograms were measured continuously overnight in a climatic chamber at 26 °C with a relative humidity of 50 %. Saliva samples for melatonin were collected at 2300 hours, 0200 hours, and 0600 hours. We found that melatonin concentrations during sleep in obese subjects were significantly lower than those in non-obese subjects in the winter. Heart rate during sleep in winter was significantly higher than that in summer in both obese and non-obese subjects. Heart rate variability was not significantly different in the summer and winter in both obese and non-obese subjects. Our results show that decreased nocturnal melatonin concentrations during winter in obese men may be related to higher heart rates, and this may suggest that obese men are at an increased risk of a cardiovascular incident during sleep, especially in the winter.

Effects of living at two ambient temperatures on 24-h blood pressure and neuroendocrine function among obese and non-obese humans: a pilot study.

The effects of environmental temperature on blood pressure and hormones in obese subjects in Japan were compared in two seasons: summer vs winter. Five obese (BMI, 32 ± 5 kg/m(2)) and five non-obese (BMI, 23 ±3 kg/m(2)) men participated in this experiment at latitude 35°10' N and longitude 136°57.9' E. The average environmental temperature was 29 ± 1 °C in summer and 3 ± 1 °C in winter. Blood samples were analyzed for leptin, ghrelin, catecholamines, thyroid stimulating hormone (TSH), free thyroxine (fT4), free triiodothyronine (fT3), total cholesterol, triglycerides, insulin and glucose. Blood pressure was measured over the course of 24 h in summer and winter. A Japanese version of the Profile of Mood States (POMS) questionnaire was also administered each season. Systolic and diastolic blood pressures in obese men were significantly higher in winter (lower environmental temperatures) than in summer (higher environmental temperatures). Noradrenaline and dopamine concentrations were also significantly higher at lower environmental temperatures in obese subjects, but ghrelin, TSH, fT3, fT4, insulin and glucose were not significantly different in summer and winter between obese and non-obese subjects. Leptin, total cholesterol and triglyceride concentrations were significantly higher in winter in obese than non-obese men. Results from the POMS questionnaire showed a significant rise in Confusion at lower environmental temperatures (winter) in obese subjects. In this pilot study, increased blood pressure may have been due to increased secretion of noradrenaline in obese men in winter, and the results suggest that blood pressure control in obese men is particularly important in winter.