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Dive into the research topics where Motohiro Nishiyama is active.

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Featured researches published by Motohiro Nishiyama.


European Journal of Vascular and Endovascular Surgery | 2008

Quantitative Lymph Imaging for Assessment of Lymph Function using Indocyanine Green Fluorescence Lymphography

Naoki Unno; Motohiro Nishiyama; Minoru Suzuki; Naoto Yamamoto; Kazunori Inuzuka; Daisuke Sagara; Hiroki Tanaka; Hiroyuki Konno

OBJECTIVES A new diagnostic imaging technique that can assess lymph function is needed as a screening test in daily practice. This study assessed the use of indocyanine green (ICG) fluorescence lymphography in subjects without leg oedema. METHODS 0.3ml of ICG (0.5 %) was injected subcutaneously at the dorsum of the foot. Subsequently, the movement of ICG dye from the injection site to the groin was traced by visualizing its fluorescence signal with an infrared light camera. The time for the dye to reach the knee and groin were measured (Transit time to knee: TT(K), Transit time to groin: TT(G)). TT(G) was measured while standing, lying at a supine position, standing with massage, and sitting while using a cycle ergometer exercise at an intensity of 50W at 50rpm in ten healthy volunteers at intervals of 14 days. RESULTS Mean TT(G) during standing was 357+/-289 and 653+/-564 seconds for the right and left legs respectively. Compared to TT(G) in the standing position, all other conditions shortened TT(G). In another seventeen subjects without leg oedema, we compared transit time obtained with ICG fluorescence lymphography to that with dynamic lymphoscintigraphy. A significant correlation between transit time measured with ICG lymphography and dynamic lymphoscintigraphy was identified (r(2)=0.64, p<0.01). CONCLUSIONS ICG fluorescence lymphography has the potential to become an alternative lymphatic imaging technique to assess lymph function.


Journal of Vascular Surgery | 2010

A novel method of measuring human lymphatic pumping using indocyanine green fluorescence lymphography.

Naoki Unno; Motohiro Nishiyama; Minoru Suzuki; Hiroki Tanaka; Naoto Yamamoto; Daisuke Sagara; Yuuki Mano; Hiroyuki Konno

OBJECTIVES Lymph transportation through the body is partly controlled by the intrinsic pumping of lymphatic vessels. Although an understanding of this process is important for medical application, little is currently known because it is difficult to measure. Here, we introduce an easy, safe, and cost-effective technique for measuring lymphatic pumping in leg superficial lymphatic vessels. Readings obtained with this technique were compared with values obtained with dynamic lymphoscintigraphy. Differences in lymphatic pumping between healthy volunteers and patients with lymphedema were also investigated. METHODS Indocyanine green (ICG) fluorescence lymphography was performed by subcutaneously injecting 0.3 mL of ICG (0.5%) into the dorsum of the foot. Real-time fluorescence images of lymph propulsion were obtained with an infrared-light camera system with the individual supine or sitting. A custom-made transparent sphygmomanometer cuff was wrapped around the lower leg and connected to a standard mercury sphygmomanometer. The cuff was inflated to 60 mm Hg and then gradually deflated at 5-minute intervals to lower the pressure by 10-mm Hg steps until the fluorescence contrast agent exceeded the upper border of the cuff, indicating that the lymphatic contraction had overcome the cuff pressure. Lymph pumping pressure (P(pump)) was defined as the value of the cuff pressure when the contrast agent exceeded the upper border of the cuff. We measured P(pump) among healthy volunteers who maintained a supine position and compared these values with measurements obtained from lymphoscintigraphy. P(pump) values while sitting were also compared between 30 legs from healthy volunteers and 30 legs from lymphedematous patients. RESULTS Among healthy, supine participants, P(pump) was 25.2 ± 16.7 mm Hg (mean ± standard deviation [SD]) when measured by ICG fluorescence lymphography. These values were significantly correlated with values taken using dynamic lymphoscintigraphy (r(2) = 0.54, p < .01), while 2 SDs of the mean were approximately 20 mm Hg, suggesting a substantial disagreement between the two methods (Bland-Altman plots). In the comparison of seated measurements, readings for healthy participants (P(pump) = 29.3 ± 16.0) were higher than those for lymphedematous participants (13.2 ± 14.9). CONCLUSION ICG fluorescence is an accurate-as well as a safe, easy, and economical-method of measuring lymphatic pumping. Therefore, it may develop as a vital tool for diagnosing lymphatic malfunctions even when they are only in their formative stages. Studies that use this technique may increase our knowledge of the lymphatic system as a whole, allowing us to develop better treatments for lymphatic disorders.


European Journal of Vascular and Endovascular Surgery | 2010

Imaging Mass Spectrometry Reveals Unique Lipid Distribution in Primary Varicose Veins

Hiroki Tanaka; Nobuhiro Zaima; Naoto Yamamoto; Daisuke Sagara; Masako Suzuki; Motohiro Nishiyama; Yuuki Mano; Masaki Sano; Takahiro Hayasaka; Naoko Goto-Inoue; Takeshi Sasaki; Hiroyuki Konno; Naoki Unno; Mitsutoshi Setou

BACKGROUND The lipid metabolism of varicose veins (VVs) remains unknown. To elucidate the pathogenesis of VV, we utilized the novel technique of imaging mass spectrometry (IMS). MATERIALS AND METHODS We obtained VV tissues from 10 limbs of 10 VV patients who underwent great saphenous vein stripping. As control vein samples, we harvested segmental vein tissues from 6 limbs of 6 patients with peripheral artery occlusive disease who underwent infra-inguinal bypass with reversed saphenous vein grafting. To identify the localisation of lipid molecules in the VV tissues, we performed matrix-assisted laser desorption/ionization IMS (MALDI-IMS). We also performed MS/MS analyses to identify the structure of each molecule. RESULTS We obtained mass spectra directly from control vein tissues and VV tissues and found a unique localisation of lipid molecules in the VV tissues. We localised lysophosphatidylcholine (LPC) (1-acyl 16:0), phosphatidylcholine (PC) (1-acyl 36:4) and sphingomyelin (SM) (d18:1/16:0) at the site of the VV valve. CONCLUSION MALDI-IMS revealed the distribution of various lipid molecules in normal veins and VVs both. Accumulation of LPC (1-acyl 16:0), PC (1-acyl 36:4) and SM (d18:1/16:0) in the VV tissues suggested that inflammation associated with abnormal lipid metabolism may contribute to the development of VV.


Journal of Vascular Surgery | 2009

Impaired lymphatic function recovered after great saphenous vein stripping in patients with varicose vein: Venodynamic and lymphodynamic results

Minoru Suzuki; Naoki Unno; Naoto Yamamoto; Motohiro Nishiyama; Daisuke Sagara; Hiroki Tanaka; Yuuki Mano; Hiroyuki Konno

OBJECTIVES Venodynamics and lymphodynamics may interact as an inseparable and mutually dependent dual outflow system. This study investigated the effect of surgical treatment on lower limb lymph flow in patients with varicose veins. METHODS Thirty-nine patients with varicose veins in the lower limb (28 patients with unilateral limb, 11 patients with bilateral limb), who demonstrated great saphenous vein reflux, were investigated with air-plethysmography and indocyanine green (ICG) fluorescence lymphography before surgical treatment and 6 months later. Fifteen healthy volunteers participated in this study as a control. With air-plethysmography, venous volume (VV) and venous filling time were measured. Venous filling index (VFI) was calculated. For ICG lymphography, 0.3 mL of ICG (0.5%) was subcutaneously injected at the dorsum of the foot. After the injection, fluorescent image of ICG dye was traced on real-time video images using a near-infrared camera system. The interval until the dye reached the knee was measured (transit time [TT]) in a standing position, which was previously demonstrated to correlate with the interval measured using dynamic isotope lymphoscintigraphy. RESULTS In CEAP clinical stage venous disease, TT in patients with C4 approximately 6 and C2 approximately 3 was significantly longer than that in the control group (587 +/- 97 seconds, 484 +/- 82 seconds, 252 +/- 29 seconds, respectively, mean +/- SD, P < .01). Among all limbs with varicose veins, there were correlations between TT and VV (Pearson r = 0.31, P < .01), between TT and VFI (Pearson r = 0.48, P < .01). All patients underwent great saphenous vein stripping. Six months later, the venous clinical severity score significantly improved with significant reductions in both VV and VFI values. TT 6 months postoperatively was also significantly shorter than that before surgical treatment (501 +/- 67 seconds, 340 +/- 38 seconds, respectively, mean +/- SD, P < .01). CONCLUSIONS Varicose veins could affect lymphatic function and delay lymphatic flow in the lower limbs. Derangement of lymph flow may correlate with the severity of clinical venous disease and/or the magnitude of venous reflux, which could be reversible with surgical treatment of venous incompetence.


Surgery Today | 2007

Hemorrhagic Shock with Delayed Retroperitoneal Hemorrhage After Deployment of an Inferior Vena Cava Filter: Report of a Case

Kazunori Inuzuka; Naoki Unno; Naoto Yamamoto; Hiroshi Mitsuoka; Daisuke Sagara; Minoru Suzuki; Motohiro Nishiyama; Hiroyuki Konno

Although inferior vena cava (IVC) filter placement has demonstrated an excellent therapeutic efficacy in preventing pulmonary embolism, several filter-related complications have been reported. Among them, retroperitoneal hemorrhage due to IVC perforation is one of the most serious complications. We report herein a female patient who underwent TrapEase IVC filter placement with anticoagulation and thrombolytic therapy for treatment of pulmonary embolism, and later demonstrated hemorrhagic shock 5 days after filter placement. The patients blood pressure stabilized after the anticoagulant therapy was stopped and she received a blood transfusion. We should therefore carefully observe patients after IVC filter placement, particularly those receiving simultaneous anticoagulation therapy.


Annals of Vascular Diseases | 2009

Two-stage Surgery for Endovascular Repair and Laparoscopic Colectomy for a Patient with Abdominal Aortic Aneurysm and Concomitant Colon Cancer: Report of a Case

Hiroki Tanaka; Naoki Unno; Toshio Nakamura; Kiyotaka Kurachi; Naoto Yamamoto; Kazunori Inuzuka; Daisuke Sagara; Minoru Suzuki; Motohiro Nishiyama; Hiroyuki Konno

Surgical management of abdominal aortic aneurysm (AAA) with concomitant malignancy remains controversial. Commercial availability of a stentgraft may change the treatment strategy for such patients. We present a case of AAA with concomitant colon cancer, in which two-stage surgery consisting of EVAR and subsequent laparoscopic colectomy was performed with an interval of six days. The patients postoperative course was uneventful. For high-risk patients, application of endovascular AAA repair and laparoscopic surgery may decrease the risk of surgical morbidity and mortality.


Surgery Today | 2010

Assessment of pelvic hemodynamics during an open repair of an infrarenal abdominal aortic aneurysm

Kazunori Inuzuka; Naoki Unno; Naoto Yamamoto; Daisuke Sagara; Minoru Suzuki; Motohiro Nishiyama; Hiroki Tanaka; Yuuki Mano; Hiroyuki Konno

PurposeTo assess the pelvic circulation during abdominal aortic aneurysm (AAA) repair by measuring the inferior mesenteric artery stump pressure (IMA-SP), penile blood flow, and gluteal blood flow.MethodsTwenty males were selected for this study. An aorto-bi-common iliac arteries (CIA) graft replacement was performed in ten patients (Group Bi-CIA). An aorto-right-CIA/left-external iliac artery (EIA) graft replacement was performed in five (Group Lt-EIA). The other five underwent an aorto-right-EIA/left-CIA anastomosis (Group Rt-EIA). The right graft limb was anastomosed first, followed by the left limb in all of the patients. Pelvic circulation was monitored during aortic reconstruction, including the IMA-SP index (IMA-SPI), penile brachial pressure index (PBI) by pulse-volume plethysmography, and gluteal tissue oxygenation metabolism with near-infrared spectroscopy by monitoring the gluteal tissue oxygenation index (TOI) bilaterally.ResultsThe PBI and bilateral gluteal TOI became depressed in all patients during proximal aortic clamping. However, there was no significant change in IMA-SPI in each group. The PBI and bilateral gluteal TOI in all groups recovered to the baseline values after completion of bilateral graft limb anastomosis.ConclusionsIMA-SPI is likely to reflect collateral circulation mainly from the superior mesenteric artery. The penile blood flow and bilateral gluteal blood flow therefore seem to be supplied via the bilateral hypogastric arteries or the profunda femoris arteries.


Annals of Vascular Diseases | 2010

Elastic Stocking-Induced Foot Necrosis in a Patient with Severe Pneumonia

Naoto Yamamoto; Naoki Unno; Daisuke Sagara; Minoru Suzuki; Motohiro Nishiyama; Hiroki Tanaka; Yuuki Mano; Hiroyuki Konno

Elastic stockings (ES) are widely used for the prevention of venous thromboembolism. Here we report a case of foot ulcers induced by ES in patients with pneumonia and hypoxia. A 94-year-old woman was admitted for the treatment of pneumonia. The patient had been wearing an ES because of a history of deep vein thrombosis of the leg. Multiple foot ulcers occurred within 24 hours after the admission despite the absence of peripheral arterial occlusive disease. The ulcers took almost 5 months to heal. For patients with hypoxia, ES may further deteriorate local tissue hypoxia and thus should be used carefully.


World Journal of Gastroenterology | 2016

Laparoscopic resection of adult colon duplication causing intussusception

Kennoki Kyo; Masaki Azuma; Kazuya Okamoto; Motohiro Nishiyama; Takahiro Shimamura; Atsushi Maema; Motoaki Shirakawa; Toshio Nakamura; Kenji Koda; Hidetaro Yokoyama

Gastrointestinal duplications are uncommon congenital malformations that can occur anywhere along the gastrointestinal tract. Most cases are recognized before the age of 2 years, and those encountered in adults are rare. We describe here a case of ascending colon duplication in a 20-year-old male that caused intussusception and was treated laparoscopically. Although computed tomography revealed a cystic mass filled with stool-like material, the preoperative diagnosis was a submucosal tumor of the ascending colon. We performed a laparoscopic right colectomy, and the postoperative pathological diagnosis was duplication of the ascending colon, both cystic and tubular components. We conclude that gastrointestinal duplications, although rare, should be considered in the differential diagnosis of all abdominal and submucosal cystic lesions and that laparoscopy is a preferred approach for the surgical treatment of gastrointestinal duplications.


Journal of Magnetic Resonance Imaging | 2012

A case of paraspinal arteriovenous fistula in the lumbar spinal body assessed with time resolved three‐dimensional phase contrast MRI

Takashi Iwakura; Yasuo Takehara; Shuhei Yamashita; Hatsuko Nasu; Naoki Unno; Motohiro Nishiyama; Naoto Yamamoto; Haruo Isoda; Marcus T. Alley; Hiroyuki Konno; Harumi Sakahara

A 93‐year‐old female with a paraspinal arteriovenous fistula (AVF) occurred within the lumbar spinal vertebral body was assessed with time resolved three‐dimensional (3D) phase‐contrast MRI (4D‐Flow) on 1.5 Tesla MR scanner (GE Healthcare). The 3D vector field, streamlines, and pathlines analyses demonstrated uni‐directional flow from the aorta to the large vascular cavity in the lumbar vertebral body by means of the lumbar artery as well as dilated paravertebral veins as drainers, which confirmed AVF, not aortic pseudoaneurysm. The 4D‐Flow also showed an added value in planned endovascular surgery concerning localization of the precise shunting point and the shunting volume quantification. J. Magn. Reson. Imaging 2012;36:1231–1233.

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