Publications by authors named "Motoyasu Nakamura"

13 Publications

  • Page 1 of 1

A novel mouse model of heatstroke accounting for ambient temperature and relative humidity.

J Intensive Care 2021 Apr 16;9(1):35. Epub 2021 Apr 16.

Department of Emergency, Critical Care and Disaster Medicine, Showa University School of Medicine, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo, 142-8555, Japan.

Background: Heatstroke is associated with exposure to high ambient temperature (AT) and relative humidity (RH), and an increased risk of organ damage or death. Previously proposed animal models of heatstroke disregard the impact of RH. Therefore, we aimed to establish and validate an animal model of heatstroke considering RH. To validate our model, we also examined the effect of hydration and investigated gene expression of cotransporter proteins in the intestinal membranes after heat exposure.

Methods: Mildly dehydrated adult male C57/BL6J mice were subjected to three AT conditions (37 °C, 41 °C, or 43 °C) at RH > 99% and monitored with WetBulb globe temperature (WBGT) for 1 h. The survival rate, body weight, core body temperature, blood parameters, and histologically confirmed tissue damage were evaluated to establish a mouse heatstroke model. Then, the mice received no treatment, water, or oral rehydration solution (ORS) before and after heat exposure; subsequent organ damage was compared using our model. Thereafter, we investigated cotransporter protein gene expressions in the intestinal membranes of mice that received no treatment, water, or ORS.

Results: The survival rates of mice exposed to ATs of 37 °C, 41 °C, and 43 °C were 100%, 83.3%, and 0%, respectively. From this result, we excluded AT43. Mice in the AT 41 °C group appeared to be more dehydrated than those in the AT 37 °C group. WBGT in the AT 41 °C group was > 44 °C; core body temperature in this group reached 41.3 ± 0.08 °C during heat exposure and decreased to 34.0 ± 0.18 °C, returning to baseline after 8 h which showed a biphasic thermal dysregulation response. The AT 41 °C group presented with greater hepatic, renal, and musculoskeletal damage than did the other groups. The impact of ORS on recovery was greater than that of water or no treatment. The administration of ORS with heat exposure increased cotransporter gene expression in the intestines and reduced heatstroke-related damage.

Conclusions: We developed a novel mouse heatstroke model that considered AT and RH. We found that ORS administration improved inadequate circulation and reduced tissue injury by increasing cotransporter gene expression in the intestines.
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http://dx.doi.org/10.1186/s40560-021-00546-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8052643PMC
April 2021

Hypovolemic shock induced by a large chest wall hematoma caused by a single rib fracture in an elderly patient.

Trauma Case Rep 2021 Apr 17;32:100459. Epub 2021 Mar 17.

Department of Emergency and Disaster Medicine, Showa University.

Displaced rib fractures can injure intercostal vessels leading to chest wall hematomas. As the bleeding occurs within the vessel, compression of the vessel wall helps in preventing further bleeding. Therefore, chest wall hematomas rarely result in shock. A thin 78-year-old man transferred to the emergency department with complaints of left dorsal pain due to an injury. He had a history of hypertension and aorta dissection. He arrived at the ED in a state of shock and presented with a large left dorsal wall mass. Subsequent imaging using computed tomography angiography revealed a large hyperdense hematoma at the left dorsal-flank wall along with rib fracture (11th intercostal artery). Moreover, a large fusiform aneurysm was detected from the abdominal aorta to the iliac arteries. Extravasation of the contrast agent was detected at the branch of the 11th intercostal artery, and hence, embolization was performed. The dermis, which comprises collagen and elastin fibers, plays an important role in vessel compression to prevent bleeding. The aortic media also comprises collagen and elastin fibers. Cell turnover, loss of collagen, and excessive elastolysis are associated with the formation of abdominal aortic aneurysms. The systemic degeneration of connecting tissue (collagen and elastin fiber) appears to be progress in patients with an aortic aneurysms and history of aortic dissection compared with other healthy older individuals. Physicians should be cognizant of the potential unexpected large hematoma complications if a risk of systemic connecting tissue degradation exists, as seen in patients with aortic aneurysm or aortic dissection.
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http://dx.doi.org/10.1016/j.tcr.2021.100459DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8010857PMC
April 2021

Diagnosis of neurofibromatosis type 1 after rupture of aneurysm and consequent fatal hemothorax.

Am J Emerg Med 2020 07 7;38(7):1543.e3-1543.e5. Epub 2020 Apr 7.

Department of Emergency and Disaster Medicine, Showa University, Fujigaoka Hospital, 1-30 Fujigaoka Aoba-ku, Yokohama 227-8501, Japan; Department of Emergency and Disaster Medicine, Showa University, 1-5-8 Hatanodai Shinagawa-ku, Tokyo 142-8666, Japan.

Patients with neurofibromatosis type 1 (NF1) can develop both benign and malignant tumors throughout their lives. A 49-year-old man was transferred to the emergency department with complaints of sudden right dorsal pain and respiratory discomfort. He was in shock on arrival. On finding significantly decreased permeability of the left lung field in chest X-ray, drainage was immediately performed. Subsequent computed tomography (CT; Lammert et al., 2005) angiography revealed the extravasation of contrast media from the deep carotid artery, a branch of subclavian artery. It suggested rupture of an aneurysm located at a rare site; the ruptured aneurysm penetrated the pleura, causing shock. The patient was resuscitated. Transcatheter arterial embolization (TAE; Evans et al., 2010) was successfully performed. Immediate drainage, resuscitation, and TAE 2 improved his condition. Most NF1 patients have café-au-lait macules; café-au-lait macules tend to fade with age. Importantly, café-au-lait macules, neurofibromas, and Lisch nodules were noticed at admission. NF1 patients are likely to have a malignant neoplasm when they are young. The patient had been diagnosed with thyroid cancer when he was young. As his deceased mother was an NF1 patient, we diagnosed him with NF1. Detailed patient history and early-stage examination led to the early diagnosis. NF1 should be considered as an early differential diagnosis to improve the outcome of patients in such cases.
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http://dx.doi.org/10.1016/j.ajem.2020.04.004DOI Listing
July 2020

The enhancement of CCL2 and CCL5 by human bone marrow-derived mesenchymal stem/stromal cells might contribute to inflammatory suppression and axonal extension after spinal cord injury.

PLoS One 2020 10;15(3):e0230080. Epub 2020 Mar 10.

Department of Anatomy, Showa University School of Medicine, Shinagawa-ku, Tokyo, Japan.

Human bone marrow-derived mesenchymal stem/stromal cells (hMSCs) have shown potential in facilitating recovery from spinal cord injury (SCI) through communicating with microglia/macrophages (MG/MΦ). We here focused on chemokines as a candidate for the communication. Selected MG/MΦ-related chemokines were determined gene expression after SCI and further focused CCL2/CCR2 and CCL5/CCR5 to estimate role of the chemokines by hMSCs. Male C57/BL6 mice were subjected to spinal cord transection. Gene expression was assayed in the spinal cords following SCI for selected MG/MΦ-related chemokines and their receptors. hMSCs (5×105 cells) were then transplanted into parenchyma of the spinal cord, and the expressions of the Ccl2/Ccr2 and Ccl5/Ccr5 axes, inflammation, MG/MΦ-polarization, and axonal regeneration were evaluated to measure the influence of the hMSCs. Finally, mouse CCL5 was injected into the spinal cords. Acute increases in gene expression after SCI were observed for most chemokines, including Ccl2; chronic increases were observed for Ccl5. CCL2+-cells merged with NeuN+-neurons. CCR2+ immunoreactivity was principally observed in Ly-6G+/iNOS+-granulocytes on postoperative day (pod) 1, and CCL5+ and CCR5+ immunoreactivity overlapped with NeuN+-neurons and F4/80+-MG/MΦ on pod 14. The hMSC transplantation enhanced Ccl2 and Ccl5 and improved locomotor activity. The hMSC implantation did not alter the number of Ly-6G+/CCR2+ but decreased Il1, Elane, and Mpo on pod 3. Conversely, hMSC transplantation increased expression of Zc3h12a (encodes MCP-1-induced protein) on pod 14. Moreover, hMSC increased the Aif1, and two alternatively activated macrophage (AAM)-related genes, Arg1 and Chil3 (Ym1), as well as axonal regenerative markers, Dpysl2 and Gap43. Gene expression indicative of AAM polarization and axonal regeneration were partially recovered by CCL5 injection. These results suggest that hMSC implantation increases Ccl2 and Ccl5, improves locomotor activity, enhances MG/MΦ polarization to AAM, and increases the gene expression of axonal regenerative markers. These functions of hMSCs might be partially mediated by the CCL2/CCR2 and CCL5/CCR5 axes.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0230080PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7064230PMC
June 2020

Image findings of bisphosphonate related osteonecrosis of jaws comparing with osteoradionecrosis.

Dentomaxillofac Radiol 2017 Jul 16;46(5):20160281. Epub 2017 Mar 16.

6 Department of Oral Surgery, Center for Dental Clinics, Hokkaido University Hospital, Sapporo, Hokkaido, Japan.

Objectives: The aim of this study was to evaluate image characteristics of bisphosphonate-related osteonecrosis of the jaws (BRONJ) and compare these with osteoradionecrosis (ORN).

Methods: 34 patients with BRONJ and 16 patients with ORN were included in this study. We investigated the CT and dental panoramic radiograph (DPR) images for osteolysis, osteosclerosis, sequestration, periosteal reaction, pathological fracture and spread of soft tissue inflammation around the jaws.

Results: Osteolysis, osteosclerosis, sequestration and spread of soft tissue inflammation around the jaws were common radiological features in both BRONJ and ORN. Osteolysis and spreading of soft tissue inflammation around the jaws were predominant in ORN, and by contrast osteosclerosis was predominant in BRONJ. Periosteal reaction was established in 15 of the 34 BRONJ cases, but none in the ORN cases. Pathological fractures were observed in 6 of 16 ORN cases, but none in BRONJ cases. CT was better for detection than DPR for osteolysis, osteosclerosis, sequestration and periosteal reactions.

Conclusions: Image findings of BRONJ were characterized as a severe sclerotic change combined with osteolysis, sequestration, periosteal reaction and spread of soft tissue inflammation around the jaws.
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http://dx.doi.org/10.1259/dmfr.20160281DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5595031PMC
July 2017

Changes in parotid gland morphology and function in patients treated with intensity-modulated radiotherapy for nasopharyngeal and oropharyngeal tumors.

Oral Radiol 2014 25;30:135-141. Epub 2013 Aug 25.

Omni Dentix, Sapporo, Japan.

Objective: To evaluate the morphological changes of the parotid glands in patients treated with intensity-modulated radiotherapy (IMRT) for nasopharyngeal and oropharyngeal tumors and the correlations with parotid function.

Methods: Ten patients with nasopharyngeal and oropharyngeal tumors treated with IMRT between May 2009 and January 2010 at Hokkaido University Hospital were included in this study. In the morphological assessment of the parotid glands, the sizes and computed tomography (CT) numbers of the bilateral parotid glands before and after IMRT with CT were calculated. For functional assessment of the parotid glands, we conducted the Saxon test and used a visual analog scale (VAS) for xerostomia evaluation.

Results: Reductions in saliva secretion were observed in the patients treated with IMRT for nasopharyngeal and oropharyngeal tumors, and there was a significant correlation between the reduction in saliva secretion and the VAS. The reductions in the parotid gland size and CT number were larger on the ipsilateral side than on the contralateral side. The reduction in saliva secretion was not significantly correlated with the reduction in parotid gland size, but was significantly correlated with the reduction in CT number.

Conclusions: Morphological and functional changes of the parotid glands were observed after IMRT for nasopharyngeal and oropharyngeal tumors, and preservation of the contralateral parotid glands was only partly achieved. Among the morphological changes of the parotid glands, the CT number may be considered a predictor of parotid function after radiotherapy.
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http://dx.doi.org/10.1007/s11282-013-0151-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4009139PMC
August 2013

An investigation of accidental ingestion during dental procedures.

J Oral Sci 2011 Dec;53(4):495-500

Department of Dental Radiology, Hokkaido University Hospital, Sapporo, Japan.

Twenty-three cases of accidental ingestion during dental procedures, which occurred at the Center for Dental Clinics of Hokkaido University Hospital between 2006 and 2010, were analyzed retrospectively. We examined not only the objects ingested, but also details of the circumstances (treated teeth, types of treatment, professional experience of the practitioners). Except for two cases (an unidentified endodontic file and the tip of an ultrasonic scaler, which were recovered by vacuuming), the other 21 accidentally ingested objects were all found in the digestive tract, and none in the respiratory tract, by radiographic examination of the chest and abdomen. The ingested objects were mostly metal restorations (inlays or onlays) or prostheses (crowns or cores). Ingestion occurred more frequently during treatment of lower molars, and when procedures were being conducted by practitioners with less than 5 years of experience. No adverse events related to ingestion were reported. The present study found no cases of aspiration or complications related to the ingested objects. However, considering the risk of life-threatening emergencies related to accidental aspiration and ingestion, dentists must take meticulous precautions and be ready to deal with this kind of emergency during dental procedures.
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http://dx.doi.org/10.2334/josnusd.53.495DOI Listing
December 2011

A comparison of diagnostic tools for Sjögren syndrome, with emphasis on sialography, histopathology, and ultrasonography.

Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2010 Jan;109(1):129-34

Department of Dental Radiology, Hokkaido University Hospital, Sapporo, Japan.

Objective: The present study examined the reliability and correlation of sialography, salivary gland biopsy, and ultrasonography for Sjögren syndrome (SS) and evaluated the usefulness of ultrasonography as a diagnostic tool for SS compared with sialography and histopathology.

Study Design: Seventy-three patients who underwent sialography, ultrasonography, and salivary gland biopsy were included in this study. The study evaluated the diagnostic reliability and correlation of each kind of examination with SS.

Results: There was a statistically significant difference in the sensitivities of sialography and histopathology, in the specificities of sialography and ultrasonography, and in the accuracies of sialography and both ultrasonography and histopathology. The correlation coefficient (r) between sialography and ultrasonography was significantly higher than the others and indicated a good correlation.

Conclusions: Ultrasonography can be used as a diagnostic tool for SS, with its advantage of noninvasiveness and ease of use.
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http://dx.doi.org/10.1016/j.tripleo.2009.08.033DOI Listing
January 2010

Experience of high-dose-rate brachytherapy for head and neck cancer treated by a customized intraoral mold technique.

Radiat Med 2007 May 28;25(4):181-6. Epub 2007 May 28.

Department of Dental Radiology, Hokkaido University Hospital, North-13 West-6, Kita-ku, Sapporo, 060-8516, Japan.

Radiotherapy of head and neck cancer has become more successful with the advances in treatment modalities and use of a multidisciplinary approach. Higher quality treatment and a team approach to radiotherapy have thus been required for head and neck cancer. This study presents the clinical experience of high-dose-rate (HDR) brachytherapy for head and neck cancer treated by a customized intraoral mold technique. Two patients are reported for whom we created dental prostheses as the radiation carriers for HDR brachytherapy of their head and neck cancers. HDR brachytherapy with the dental prostheses reported here was feasible and effective for eradicating the head and neck cancer. It has been demonstrated that HDR brachytherapy using a customized intraoral technique can be a treatment option for patients who are not candidates for surgery or external irradiation. It is strongly suggested that specialized dentists are needed who are familiar with not only the anatomy and function of the head and neck region but also radiotherapy. Dental radiologists should take responsibility for constructing irradiation prostheses. If they do, they have the potential to improve the quality of life of patients who undergo radiotherapy for head and neck cancer.
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http://dx.doi.org/10.1007/s11604-007-0121-yDOI Listing
May 2007

Impacted teeth in the maxilla: usefulness of 3D Dental-CT for preoperative evaluation.

Eur J Radiol 2003 Sep;47(3):221-6

Department of Dental Radiology, Dental Hospital, Hokkaido University, Kita-13, Nishi-6, Kita-ku, Sapporo 060-8586, Japan.

Objective: To compare the shapes of roots of impacted teeth shown in three-dimensional computed tomographic images (3D Dental-computed tomography (CT) images) and plain radiographs and to determine whether 3D Dental-CT images are useful for examination before performing an operation for extraction of a maxillary impacted tooth.

Methods And Patients: Images obtained from patients who had impacted teeth in the maxilla, including impacted mesial supernumerary teeth in 13 patients, impacted incisors in two patients, impacted canines in 11 patients, impacted premolars in four patients and impacted molars in three patients, were used in this study. In all patients, plain radiographs and 3D Dental-CT images were retrospectively reviewed by an oral radiologist for evidence of root dilaceration before operations to extract the impacted teeth were performed. The findings in the images were compared with intraoperative findings in all cases.

Results: The mean specificity and sensitivity of plain radiographs were 95 and 8%, respectively, while those of 3D Dental-CT images were 100 and 77%, respectively. There was a statistically significant (P<0.01) difference between the depiction capabilities of plain radiographs and 3D Dental-CT images with regard to dilacerations of roots of impacted teeth.

Discussion And Conclusion: CT may enable radiologists to make a quick and accurate diagnosis of tooth impaction. 3D Dental-CT images are useful for determining the root shape of an impacted tooth in the maxilla.
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http://dx.doi.org/10.1016/s0720-048x(02)00168-7DOI Listing
September 2003

Effect of treatment time on outcome of radiotherapy for oral tongue carcinoma.

Int J Radiat Oncol Biol Phys 2003 Sep;57(1):71-8

Department of Dental Radiology, Health Sciences University of Hokkaido, Tobetsu, Japan.

Purpose: To investigate the importance of total treatment time on the outcome of external beam radiotherapy (EBRT) followed by internal brachytherapy for the treatment of oral tongue carcinoma.

Methods And Materials: Ninety-four patients with T1-T2N0 squamous cell carcinoma of the oral tongue were treated using 35-40 Gy EBRT followed by 35-40 Gy interstitial (137)Cs brachytherapy between 1985 and 1995. The interval between the end of EBRT and the start of interstitial treatment varied for numerous unavoidable reasons, with a mean of 25.3 days and standard deviation of 3.5 days. The median follow-up period was 59.1 months (range 6-146).

Results: The actuarial survival rate of all cases was 78.4% at 5 years. The 5-year local control rate for those with T1 and T2 was 92.8% and 62.7%, respectively (p < 0.05). The local control rate of the primary tumor in patients with a total treatment time >43 days was statistically lower than that of patients with a total treatment time < or =43 days in all patients (p < 0.05) and in the subgroup of Stage T2 patients (p < 0.05). Multivariate analysis revealed that the local control rates in all cases were significantly related to the T stage (T2 or not), total treatment time (>43 days or not), and location of disease (posterior or not). Regression analysis for 5-year local control as a function of treatment duration showed a 2% loss of local control per day of treatment extension >30 days (r = 0.94, p < 0.01).

Conclusion: The total treatment time was associated with the local control rate in the RT of oral tongue carcinoma. The loss in local control was estimated to be 2.0% per additional day in our series for oral tongue carcinoma.
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http://dx.doi.org/10.1016/s0360-3016(03)00507-8DOI Listing
September 2003

Management of mandibular osteoradionecrosis corresponding to the severity of osteoradionecrosis and the method of radiotherapy.

Head Neck 2003 Mar;25(3):181-6

Oral Diagnosis and Medicine, Department of Oral Pathobiological Science, Hokkaido University, Graduate School of Dental Medicine, N13 W7, Kita-ku, Sapporo 060-8586, Japan.

Purpose: : To demonstrate appropriate treatment methods for mandibular osteoradionecrosis (ORN) by evaluating previous results.

Methods: : The relationship between the time interval after radiation therapy (RT) and the severity of ORN was examined. Eighty-seven patients were classified according to the extent of the lesion (grades), and the cure rates were calculated according to the RT modality, the grade, and the treatment method for ORN.

Results: : The later ORN developed and the higher the dose of irradiation, particularly among the patients who received external RT, the more it progressed. The initial cure rates for conservative management, marginal, and segmental mandibulectomy were 39.7%, 50%, and 86.7%, respectively.

Conclusions: : Conservative management should be limited to early-onset ORN after brachytherapy with or without a low dose of external irradiation. Marginal mandibulectomy is appropriate for the late-onset ORN after brachytherapy with or without low-dose external irradiation. Segmental mandibulectomy is required for late-onset ORN after a high dose of external irradiation.
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http://dx.doi.org/10.1002/hed.10171DOI Listing
March 2003

Clinical study of a spacer to help prevent osteoradionecrosis resulting from brachytherapy for tongue cancer.

Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2003 Feb;95(2):246-50

Division of Oral and Maxillofacial Disorders, Hokkaido University Dental Hospital, Sapporo, Japan.

Objective: We sought to describe a simple method to construct a spacer and to evaluate with the use of computed tomography the spacer's effectiveness in preventing osteoradionecrosis of the mandible.

Study Design: Fifty-three patients with oral tongue cancers who were treated by means of interstitial brachytherapy were included in this study. Patients underwent a computed tomography examination immediately after the implantation of radioactive sources, with the spacers in place. Distances between the radioactive sources and the lingual surfaces of the mandible were measured on transverse computed tomographs and were evaluated in terms of the development of osteoradionecrosis in the mandible.

Results: Statistically significant differences in the frequency of osteoradionecrosis were observed between patients who had received spacers equal to or thicker than 5 mm and those who had received spacers less than 5 mm thick.

Conclusion: A spacer should have a minimum thickness of 5 mm on its lingual flange to prevent the development of osteoradionecrosis of the mandible.
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http://dx.doi.org/10.1067/moe.2003.94DOI Listing
February 2003