Publications by authors named "Shonosuke Matsushita"

25 Publications

  • Page 1 of 1

A new method for visualizing pulmonary artery microvasculature using synchrotron radiation pulmonary microangiography: the measurement of pulmonary arterial blood flow velocity in the high pulmonary blood flow rat model.

Acta Radiol 2018 Dec 19;59(12):1482-1486. Epub 2018 May 19.

1 Department of Cardiovascular Surgery, Faculty of Medicine, University of Tsukuba, Ibaraki, Japan.

Background: Increased pulmonary blood flow (PBF) and shear stress may provoke irreversible vascular remodeling, yet invasive visualization of the microvasculature complicates monitoring. A non-invasive imaging methodology would therefore safely provide mechanistic insights into the progression of high PBF-induced vascular remodeling.

Purpose: To establish a novel microvasculature visualization method using synchrotron radiation pulmonary microangiography (SRPA) that can also calculate PBF velocity in vivo.

Material And Methods: A high PBF rat model was established by making a fistula between the abdominal aorta and inferior vena cava. After eight weeks, SRPA was performed and the dynamic density changes in the right lower pulmonary artery (PA) were calculated by software. SRPA was performed with a HARP (High-Gain Avalanche Rushing amorphous Photoconductor) receiver. PBF velocity was calculated by contrast medium transit time within the PA. All data were presented as mean ± standard error (SE). Student's t-test was used for comparison between the two groups.

Results: High dynamic spatial and contrast resolution from SRPA in the PA allowed for clear pulmonary microangiography and accurate detection of higher PBF in the rat model (82.3 ± 8.5 mm/s high-PBF group vs. 46.1 ± 4.3 mm/s control group, P < 0.01).

Conclusions: These novel results demonstrate that SRPA was useful in both visualizing the dynamic flow distribution within the microvasculature and calculating PBF velocity. This newly developed, non-invasive technology may become a powerful tool in clarifying the mechanism of vascular remodeling associated with high PBF-induced shear stress.
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http://dx.doi.org/10.1177/0284185118770892DOI Listing
December 2018

Electroacupuncture Therapy for Auricular Paresthesia.

Med Acupunct 2017 Oct;29(5):331-334

Faculty of Health Science, Center for Integrative Medicine, Tsukuba University of Technology, Tsukuba City, Ibaraki, Japan.

The great auricular nerve (GAN) provides sensory innervation to the skin around the auricle. Although disorder of this nerve has been reported, great auricular neuralgia, as reported by Blumenthal in 1992, is uncommon. The authors report a case of auricular paresthesia that responded well to electroacupuncture treatment (EAT). A man in his 60s was consulted in the clinic after a 6-month history of experiencing tingling sensations of the skin around the auricle. General degenerative deformity of the cervical spine was observed using computed radiography scans and magnetic resonance imaging; tactile hyperesthesia in the skin of the GAN area was also noted. This case was diagnosed as a disturbance of the great auricular nerve (mild neuralgia). As a potential treatment, EAT was administered near the affected nerve once per week for 6 weeks. Visual analogue scale (VAS) measurements showed a marked decrease in the severity of this patient's symptoms, and the tactile hyperesthesia in the affected area had normalized. The main complaint, auricular paresthesia, had disappeared and had not recurred according to a check-up 15 months later. EAT was effective in the current case. It is hypothesized that EAT can reduce neural sensitivity via a reflex mechanism actuated by somatosensory input.
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http://dx.doi.org/10.1089/acu.2017.1239DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5653334PMC
October 2017

Renal contrast microangiography with synchrotron radiation: a novel method for visualizing structures within nephrons in vivo.

Acta Radiol 2017 Apr 22;58(4):505-510. Epub 2016 Jul 22.

4 Cardiovascular Surgery, University of Tsukuba, Tsukuba, Ibaraki, Japan.

Background No non-invasive method of observing renal microcirculation in vivo has been established as yet. Although angiography is considered to be ideally suited for the purpose, conventional X-rays cannot be used to image structures smaller than 100 µm. Purpose To develop a method for visualizing the renal arterioles, glomeruli, and proximal tubules of rats in vivo making use of synchrotron radiation. Material and Methods Male Wistar rats were anesthetized, and a catheter was inserted via laparotomy into the abdominal aorta with its tip placed above the renal arteries. The rats were paralyzed with a neuromuscular blocking agent and mechanically ventilated. An inorganic iodine contrast medium was injected via the catheter. The SR derived X-rays transmitted through the subjects were recorded with a CCD camera. Two-dimensional images with a pixel size of 9 µm were obtained. The exposure time was fixed at 50 ms, with a maximum acquisition rate of three images/s. Results Renal arterioles as small as 18 µm in diameter, glomeruli with an average diameter of 173 ± 21 µm, as well as proximal tubules, were clearly visualized. In addition, glomerular density at the peripheral renal cortex was measurable. Conclusion Rat renal microcirculation could be successfully observed in real-time, without exteriorization of the kidney in this study.
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http://dx.doi.org/10.1177/0284185116658685DOI Listing
April 2017

Association between endothelial function and micro-vascular remodeling measured by synchrotron radiation pulmonary micro-angiography in pulmonary arterial hypertension.

Gen Thorac Cardiovasc Surg 2016 Oct 8;64(10):597-603. Epub 2016 Jul 8.

Department of Cardiovascular Surgery, Faculty of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, 305-8577, Japan.

Objectives: Pulmonary arterial hypertension (PAH) is a progressive disease which causes increased vascular resistance. In this study, our purpose was to quantify the micro-vascular remodeling in monocrotaline-induced PAH rats using synchrotron radiation pulmonary micro-angiography (SRPA), a method we have previously established in an in vivo rat model. To determine the relationship between endothelial function and vascular remodeling, the local expression of endothelin-1 (ET-1), endothelial nitric oxide synthase (eNOS) and vascular endothelial growth factor (VEGF) was evaluated using immunohistochemical staining.

Methods: Monocrotaline-induced PAH rats were created by subcutaneous injection of monocrotaline. After 2 weeks, SRPA was performed at the Photon Factory of the High Energy Accelerator Research Organization. The internal diameters of pulmonary arterioles were measured using SRPA images. Semi-quantified analyses of ET-1, eNOS and VEGF expression in pulmonary arterioles were performed by immunohistochemical staining.

Results: Micro-vascular density and the internal diameters of pulmonary arterioles were significantly decreased in PAH. ET-1 expression was significantly increased in PAH compared with the control (1.53 ± 0.45 vs. 0.80 ± 0.14) and eNOS expression was significantly decreased in PAH compared with the control (1.12 ± 0.59 vs. 1.91 ± 0.66), although VEGF expression did not differ between the groups.

Conclusions: SRPA can be effectively used for visualizing the decreased pulmonary micro-vasculature associated with PAH. Increased ET-1 expression and decreased eNOS expression may contribute to the proliferation and vasospasm of pulmonary arterioles induced by endothelial dysfunction due to PAH. This SRPA technology may help to identify a correlation between endothelial function and micro-vasculature remodeling in PAH.
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http://dx.doi.org/10.1007/s11748-016-0684-6DOI Listing
October 2016

A new technique of in vivo synchrotron radiation coronary microangiography in the rat.

Acta Radiol 2015 Sep 26;56(9):1105-7. Epub 2014 Sep 26.

Department of Cardiovascular Surgery, Faculty of Medicine, University of Tsukuba, Tsukuba, Japan.

Background: Previously, in our laboratory, synchrotron radiation coronary microangiography (SRCA) using Langendorff-perfused rat hearts could visualize a coronary artery of 50 µm in diameter. However, in vivo rat SRCA poses the problem of compromised temporal resolution due to the rapid heart rate of rats.

Purpose: To establish a simple method of in vivo rat SRCA with bradycardia induced by intravenous injection of adenosine triphosphate disodium hydrate (ATP).

Material And Methods: SRCA was performed at the Photon Factory of the High Energy Accelerator Research Organization (Tsukuba, Japan). Eight male Wistar rats were anesthetized. A catheter for injecting the contrast material was inserted into the carotid artery. Temporary bradycardia was induced by an intravenous bolus injection of 5 mg of ATP, and SRCA was performed immediately thereafter.

Results: After ATP administration, the average heart rate decreased from 388 to 73 beats per minute. As a result, we could detect a coronary artery as small as 45 µm in diameter.

Conclusion: Our SRCA system which has a high resolution of 9 µm per pixel could detect a coronary artery as small as 45 µm in diameter in the in vivo rat.
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http://dx.doi.org/10.1177/0284185114549570DOI Listing
September 2015

Focusing on delayed clearance for identifying small-sized metastatic lung tumors using synchrotron radiation angiography with a highly sensitive receiver.

Gen Thorac Cardiovasc Surg 2014 Sep 11;62(9):553-9. Epub 2014 Jun 11.

Department of Thoracic and Cardiovascular Surgery, Graduate School of Comprehensive Human Science, University of Tsukuba, Tsukuba, 305-8575, Japan,

Objectives: To detect metastatic lung tumors of less than 1 mm in size by focusing on the clearance of contrast material using synchrotron radiation (SR) angiography characterized by high spatial resolution and high-sensitivity receiver.

Methods: C6 cells, derived from rat glioma cells, were injected to the rat tail vein. Two weeks after injection, the rats underwent SR angiography using a high-gain avalanche rushing amorphous photoconductor (HARP) receiver of extra-high sensitivity with high contrast resolution. The 256-grayscale value was employed in the analysis of images.

Results: 19 nodules were identified in images. The tumors were confirmed histopathologically. The average tumor size was 621±193 µm. The clearance curve of the densities was expressed as a logarithm function. Tumors showed delayed clearance of contrast material, taking up to 28 s, compared with arteries, which cleared rapidly at 8 s. In 256 grayscale, the distance was 50. This gap in density clearance made it possible to identify tumors.

Conclusions: SR angiography with a HARP receiver provides high sensitivity and spatial resolution and makes it possible to diagnose metastatic lung tumors of less than 1 mm in size by focusing on differences in the clearance times of contrast material.
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http://dx.doi.org/10.1007/s11748-014-0430-xDOI Listing
September 2014

Shrinkage temperature and anti-calcification property of triglycidylamine-crosslinked autologous tissue.

J Artif Organs 2014 Sep 4;17(3):265-71. Epub 2014 May 4.

Department of Cardiovascular Surgery, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, 305-8575, Japan.

Since bioprosthetic valve dysfunction may arise due to histological calcification in the crosslinking process by glutaraldehyde (GA), non-GA crosslinking reagents have been investigated. We compared the efficacy of triglycidylamine (TGA), a newly synthesized epoxy compound, and GA as crosslinking reagents for the treatment of autologous tissues. We assessed the strength of crosslinked tissues using shrinkage temperature (Ts) measured by differential scanning calorimetry. We also conducted subdermal allografting of the crosslinked pericardium and thoracic aorta in rats, and verified the anti-calcification efficacy of TGA by histological evaluations with von Kossa stain, and immunological evaluations using tenascin-C (TN-C) or matrix metalloproteinase-9 (MMP-9). TGA treatment resulted in slower increases in Ts of the pericardium, and it required 9-12 h to reach Ts achieved by GA. In subdermal implantation of rat tissues, calcium content was lower in the TGA group than in the GA groups (p < 0.005). The expression site of TN-C and MMP-9 differed from the primary location of calcium deposition in the thoracic aorta treated with TGA suggesting a different underlying mechanism in calcification between GA and TGA crosslinking. In conclusion, TGA crosslinking in the allograft showed superior anti-calcification effect as compared to brief treatment by GA, although TGA crosslinking process was slow.
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http://dx.doi.org/10.1007/s10047-014-0768-yDOI Listing
September 2014

The role of CCL5 in the ability of adipose tissue-derived mesenchymal stem cells to support repair of ischemic regions.

Stem Cells Dev 2014 Mar 14;23(5):488-501. Epub 2013 Dec 14.

1 Department of Regenerative Medicine and Stem Cell Biology, Graduate School of Comprehensive Human Sciences, University of Tsukuba , Tsukuba, Japan .

Mesenchymal stem cells (MSC) are multipotent and possess high proliferative activity, and thus are thought to be a reliable cell source for cell therapies. Here, we isolated MSC from adult tissues--bone marrow (BM-MSC), dental tissue (DT-MSC), and adipose tissue (AT-MSC)--to compare how autotransplantation of these MSC effectively supports the repair of bone fracture and ischemic tissue. An analysis by in vitro differentiation assays showed no significant difference among these MSC. The degree of calcification at the joint region of bone fracture was higher in mice transplanted with AT-MSC than in mice transplanted with BM-MSC or DT-MSC. To compare the abilities of MSC, characterize how those MSC affect the repair of ischemic tissue, vascular occlusion was performed by ligation of the femoral artery and vein. Of note, the blood flow in the ischemic region rapidly increased in mice injected with AT-MSC, as contrasted with mice injected with BM- or DT-MSC. The number of CD45- and F4/80-positive cells at the femoral region was higher in AT-MSC recipients than in recipients of BM-MSC or DT-MSC. We evaluated the mRNA expression of angiogenic and migration factors in MSC and found the expression of CCL5 mRNA was higher in AT-MSC than in BM-MSC or DT-MSC. Transplantation of AT-MSC with impaired expression of CCL5 clearly showed a significant delay in the recovery of blood flow compared with the control. These findings have fundamental implications for the modulation of AT-MSC in the repair of vasculature and bone fracture.
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http://dx.doi.org/10.1089/scd.2013.0307DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3928761PMC
March 2014

Cardiac sympathetic activity assessed by heart rate variability indicates myocardial ischemia on cold exposure in diabetes.

Ann Vasc Dis 2013 5;6(3):583-9. Epub 2013 Sep 5.

School of Medicine, University of Tsukuba, Tsukuba, Ibaraki, Japan.

Measurement of heart rate variability (HRV) is a non-invasive technique that can be used to investigate functioning of the autonomic nervous system, especially the balance between sympathetic and vagal activities. It is reported that dilatation of coronary microcirculation by augmentation of sympathetic nerve activity (SNA) caused by cold exposure was impaired in diabetes. The question of whether or not SNA in HRV could respond to coronary ischemia was evaluated by cold exposure in diabetic rats. It was found that diabetes with weight loss significantly increased SNA both in baseline and cold exposure, compared with control. A correspondence was also found with coronary ischemia. It can be concluded that measurement of HRV may provide useful information regarding the coronary risk of cold exposure in diabetes. (English translation of J Jpn Coll Angiol 2012; 52: 295-301).
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http://dx.doi.org/10.3400/avd.cr.13-00064DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3793179PMC
October 2013

Nontraditional placement of an implantable cardioverter-defibrillator in a heterotaxy patient after the completion of total cavopulmonary connection.

J Artif Organs 2013 Dec 1;16(4):495-7. Epub 2013 Jun 1.

Department of Cardiovascular Surgery, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, 305-8577, Japan.

A 15-year-old boy with heterotaxy syndrome developed a prolonged QT interval and intractable torsade de pointes after the administration of sodium channel blockers for atrial tachyarrhythmia. Although this situation called for the placement of an implantable cardioverter-defibrillator, a conventional transvenous approach was not available since the patient had previously undergone a nonfenestrated extracardiac total cavopulmonary connection. We were urged to carry out the surgical placement of an epicardial lead for an implantable cardioverter-defibrillator using a single coil transvenous shock lead through re-do midline sternotomy. Here we describe the details of this nontraditional surgical procedure for the placement of a lead for an implantable cardioverter-defibrillator in a case without venous access into the heart.
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http://dx.doi.org/10.1007/s10047-013-0714-4DOI Listing
December 2013

Using synchrotron radiation angiography with a highly sensitive detector to identify impaired peripheral perfusion in rat pulmonary emphysema.

J Synchrotron Radiat 2013 Mar 8;20(Pt 2):376-82. Epub 2013 Feb 8.

Graduate School of Comprehensive Human Science, Department of Thoracic and Cardiovascular Surgery, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, Japan.

Owing to limitations in spatial resolution and sensitivity, it is difficult for conventional angiography to detect minute changes of perfusion in diffuse lung diseases, including pulmonary emphysema (PE). However, a high-gain avalanche rushing amorphous photoconductor (HARP) detector can give high sensitivity to synchrotron radiation (SR) angiography. SR angiography with a HARP detector provides high spatial resolution and sensitivity in addition to time resolution owing to its angiographic nature. The purpose of this study was to investigate whether this SR angiography with a HARP detector could evaluate altered microcirculation in PE. Two groups of rats were used: group PE and group C (control). Transvenous SR angiography with a HARP detector was performed and histopathological findings were compared. Peak density of contrast material in peripheral lung was lower in group PE than group C (p < 0.01). The slope of the linear regression line in scattering diagrams was also lower in group PE than C (p < 0.05). The correlation between the slope and extent of PE in histopathology showed significant negative correlation (p < 0.05, r = 0.61). SR angiography with a HARP detector made it possible to identify impaired microcirculation in PE by means of its high spatial resolution and sensitivity.
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http://dx.doi.org/10.1107/S090904951300040XDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3943542PMC
March 2013

Significant correlation between endothelial nitric oxide synthase (eNOS) expression and alveolar repair in elastase-induced rat pulmonary emphysema.

Surg Today 2013 Mar 22;43(3):293-9. Epub 2012 Aug 22.

Department of Thoracic Surgery, Graduate School of Comprehensive Human Science, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8575, Japan.

Background And Purpose: Angiogenic factors, such as endothelial nitric oxide synthase (eNOS), are thought to play an important role in the repair of pulmonary emphysema (PE); yet, the correlation of the factors involved has not been investigated. We conducted this study to clarify the positive correlation between eNOS expression and alveolar repair in PE recovery.

Methods: We used elastase to induce PE in rats, which were divided into Groups A (Control), B (G-CSF), C (PE) and D (PE + G-CSF). G-CSF was injected for 12 days, 4 weeks after which the alveolar walls, arterioles, and angiogenic factors including eNOS were examined histopathologically and by western blotting.

Results: In comparing Groups A, B, C, and D, the alveolar density was 2.4 ± 0.2, 2.4 ± 0.1, 1.8 ± 0.1, 2.5 ± 0.1 per 100 μm(2), respectively (C vs. others; p < 0.00001) and the number of arterioles was 4.5 ± 1.0, 5.6 ± 0.6, 3.2 ± 0.5, 5.5 ± 0.7/mm(2), respectively (C vs. others; p < 0.05). Immunohistochemical staining (IHC) revealed different eNOS expression in Group D versus Group C (p < 0.0001) and western blotting revealed different eNOS, VEGF, and FLT-1 expression in Group D versus Group C (p < 0.01, p < 0.05, p < 0.001), reflecting the contribution of angiogenesis to PE repair. eNOS showed a significantly positive correlation to alveolar density and arteriole repair.

Conclusion: Alveolar repair was correlated positively with eNOS expression by vascular regeneration in elastase-induced rat PE.
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http://dx.doi.org/10.1007/s00595-012-0293-7DOI Listing
March 2013

Inhibition of protein kinase C β ameliorates impaired angiogenesis in type I diabetic mice complicating myocardial infarction.

Circ J 2012 8;76(4):943-9. Epub 2012 Feb 8.

Department of Cardiovascular Surgery, Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tsukuba, Japan.

Background: In recent studies, the inhibition of protein kinase C (PKC) β has been shown to improve diabetic vascular complications. However, the effect on angiogenesis in myocardial ischemia with diabetes mellitus (DM) is still unknown.

Methods And Results: Mice were divided into 3 groups: control, DM and DM+PKC-I groups (n=8, respectively). In the DM and DM+PKC-I groups, diabetes was induced by streptozotocin (STZ) (1.5mg/body i.p.) for 5 days. Next, left anterior descending artery (LAD) ligation was performed in all groups. In the DM+PKC-I group, PKC β inhibitor (Cat. No. 539654; 10 nmol/L) was administered from days 1 to 10. After 4 weeks of LAD ligation, the animals were killed. Microvascular density was significantly improved by PKC β inhibitor (control: 87.9±5.2/high-power field (HPF); DM: 51.4±6.9/HPF; PKC-I: 80.3±4.9/HPF; P<0.05). Expression of both vascular endothelial growth factor (VEGF) and endothelial nitric oxide synthase (eNOS), which was decreased in the DM group, were significantly improved by inhibition of PKC β [VEGF (DM: 0.36±0.11-fold and DM+PKC-I: 0.77±0.07-fold vs. control), eNOS (DM: 0.35±0.06-fold and DM+PKC-I: 0.73±0.08-fold vs. control); both P<0.05)].

Conclusions: Inhibition of PKC β ameliorated impaired angiogenesis by hyperglycemia in STZ-induced DM mice complicated by myocardial infarction. These results suggest a new possible indication of PKC β inhibitor for myocardial ischemia with DM.
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http://dx.doi.org/10.1253/circj.cj-11-0881DOI Listing
June 2012

Concealed infective endocarditis associated with subaortic left ventricular aneurysm.

Thorac Cardiovasc Surg 2012 Dec 3;60 Suppl 2:e9-12. Epub 2012 Jan 3.

Department of Cardiovascular Surgery, Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tsukuba, Japan.

We describe a case of subaortic left ventricular aneurysm with concealed infective endocarditis. The patient, who was diagnosed with aortic regurgitation and a subaortic left ventricular aneurysm, did not exhibit any evidence of infective endocarditis preoperatively. However, histopathological examination after an aortic valve replacement revealed neutrophil infiltration in the resected aneurysm. One year postoperatively, the infection recurred and an aortic root replacement was performed.
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http://dx.doi.org/10.1055/s-0031-1295583DOI Listing
December 2012

Surgical repair for rupture of a chronic traumatic thoracic aneurysm 14 years after injury: report of a case.

Surg Today 2012 Jan 10;42(2):191-4. Epub 2011 Nov 10.

Department of Cardiovascular Surgery, Graduate School of Comprehensive Human Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8575, Japan.

Traumatic thoracic aortic injury is a lethal condition. Because its mortality rate is extremely high in the acute phase, these patients rarely survive long enough for a chronic aneurysm to develop. We herein report a case of surgical repair for a ruptured chronic traumatic thoracic aneurysm. A 32-year-old man, who had been involved in a traffic accident 14 years earlier, was diagnosed with a rupture of a chronic traumatic thoracic aneurysm. Preoperative computed tomography showed that the ruptured aneurysm arose from the aortic isthmus and was accompanied by multiple daughter lesions. He underwent an aorta graft replacement with reconstruction of the left subclavian artery using both a median sternotomy and a left thoracotomy. The surgery was successful and the postoperative course was uneventful. Chronic traumatic thoracic aneurysm is usually a single lesion, and cases with daughter aneurysms have rarely been reported. We include a review of the previous literature and also discuss the etiology of this condition.
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http://dx.doi.org/10.1007/s00595-011-0001-zDOI Listing
January 2012

Surgical removal of infected pacemaker leads without cardiopulmonary bypass after failed extraction using the Excimer Laser Sheath Extraction System.

J Artif Organs 2012 Mar 23;15(1):94-8. Epub 2011 Sep 23.

Department of Cardiovascular Surgery and Cardiology, Graduate School of Comprehensive Human Science, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, Ibaraki 305-7565, Japan.

With the growing number of cardiac pacemakers and internal cardioverter defibrillator implantations, problems with endocardial lead infection have been increasing. The newly developed Excimer Laser Sheath Lead Extraction System has been recognized as being highly useful for removing chronic infected leads. However, serious bleeding complications are a concern when this system is used. Here we report our experience with a 67-year-old man who was diagnosed with pacemaker endocarditis. Initially, lead removal was attempted using the Excimer Laser Sheath Extraction System, though this was abandoned because of severe adhesion of the leads and the junction of the supra vena cava (SVC) with the right atrium. Surgical removal of the leads was performed without using cardiopulmonary bypass and the leads were removed without any complications. During surgery, we found there was a silent perforation of the innominate vein brought about by the Excimer Laser Sheath System. Also, the junction of the SVC with the right atrium was thought to be an area potentially at high risk of perforation, because of a lack of surrounding tissue. It is our opinion that those who carry out procedures with the Excimer Laser Sheath System should understand the potential risk of perforation based on cardiac anatomy and should be prepared for lethal bleeding complications. Also, for emergent situations, we believe that close backup by a cardiovascular surgical team should be considered essential for performing the Excimer Laser Sheath Lead Extraction safely.
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http://dx.doi.org/10.1007/s10047-011-0610-8DOI Listing
March 2012

Reducing the dose of contrast medium in angiography by use of a highly sensitive receiver and synchrotron radiation system.

AJR Am J Roentgenol 2011 Sep;197(3):W508-13

Department of Cardiovascular Surgery, Graduate School of Comprehensive Human Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan.

Objective: Contrast medium causes side effects such as contrast-induced nephropathy, and the dose of contrast medium is a risk factor in their occurrence. To reduce doses of contrast medium, we developed an angiographic system with high definition and high sensitivity and reviewed its effectiveness. The system entails synchrotron radiation, which is characterized by high photon density and straightness of beam that together result in high resolution, and a high-gain avalanche rushing amorphous photoconductor receiver, which is 100 times more sensitive than conventional charge-coupled device cameras.

Materials And Methods: Diluted contrast medium was administered, and angiography of rat hindlimbs was performed with synchrotron radiation and the high-gain photoconductor receiver. The difference in gray-scale value between the background and contrast medium was calculated. Images were evaluated by counting of arteries.

Results: The difference in contrast at low levels was detected with the high-gain photoconductor receiver but not with the charge-coupled device camera. The photon density of synchrotron radiation with the high-gain photoconductor receiver was one-fifth that with the charge-coupled device camera. The high-gain photoconductor receiver had approximately 5 times the sensitivity of the charge-coupled device camera.

Conclusion: Use of the synchrotron radiation and high-gain photoconductor receiver makes it possible to perform angiography with an extremely low concentration of contrast medium.
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http://dx.doi.org/10.2214/AJR.10.5798DOI Listing
September 2011

Giant coronary artery aneurysm with pulmonary artery fistula in a patient on chronic hemodialysis.

Ann Thorac Surg 2010 Mar;89(3):963-5

Department of Cardiovascular Surgery, University of Tsukuba, Ibaraki, Japan.

The combination of coronary artery aneurysm and pulmonary artery fistula is extremely rare and its common cause is atherosclerosis. A 61-year-old woman presented with a giant coronary artery aneurysm with pulmonary artery fistula and intramyocardial calcifications of the left ventricle associated with progressive atherosclerosis due to chronic hemodialysis. The coronary artery aneurysm was resected under cardiopulmonary bypass because of hemodynamic instability due to restrictive cardiac dysfunction. The patient's restrictive cardiac dysfunction was improved after aneurysm resection. Surgical resection should be considered for giant coronary artery aneurysm with restrictive cardiac dysfunction.
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http://dx.doi.org/10.1016/j.athoracsur.2009.07.095DOI Listing
March 2010

Erythropoietin enhances arterioles more significantly than it does capillaries in an infarcted rat heart model.

Int Heart J 2009 Nov;50(6):801-10

Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan.

Erythropoietin (Epo) is a hormone which regulates erythrocyte production. It has recently become known that Epo enhances angiogenesis. However, since shear stress is an initiator of arteriogenesis, this increase with Epo may be due to increased shear stress from erythrocytosis. To clarify this, we compared the effects of Epo on both angiogenesis and arteriogenesis. Myocardial infarction was induced by LAD ligation in Wistar rats (Epo, G-CSF and control). Epo (1,000 IU/kg) was administered immediately after ligation of the LAD. G-CSF was administered at 100 microg/kg/day for 5 days after the coronary ligation. Four weeks later, coronary angiography was performed using synchrotron radiation coronary micro-angiography with a Langendorff apparatus. The number of vessels was investigated by microscopy. The numbers of capillaries and arterioles (> 100 microm in diameter) were measured. Microscopical examination: Capillary density in the twilight zone was 95 +/- 19 in the control group, 126 +/- 24 in the G-CSF group, and 142 +/- 32 in the EPO group (control versus Epo: P < 0.005, control versus G-CSF: P < 0.05). Arteriole numbers were 4.3 +/- 0.2 in the control group, 6.9 +/- 1.0 in the G-CSF, and 11.8 +/- 0.6 in the Epo group (control versus Epo: P < 0.00001, G-CSF versus Epo: P < 0.00001, control versus G-CSF: P < 0.00001). The ratios of arterioles and capillaries were 0.048 +/- 0.013 in the control group, 0.057 +/- 0.016 in the G-CSF group, and 0.088 +/- 0.019 in the Epo group (control versus Epo: P < 0.0005, G-CSF versus Epo: P < 0.05). Angiography: The number of crossing arterioles in the 2 mm lattice was 5.4 +/- 1.7 in the Epo group and 3.8 +/-0.4 in the control group (P < 0.05). The gray scale values for the evaluation of capillaries was 128 +/- 3.7 and 119 +/- 2.1 in the Epo and control groups, respectively (P < 0.00005). Epo enhanced arterioles more significantly than it did capillaries in this infarcted rat heart model.
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http://dx.doi.org/10.1536/ihj.50.801DOI Listing
November 2009

Sex difference in peripheral arterial response to cold exposure.

Circ J 2008 Aug;72(8):1367-72

Department of Cardiovascular Surgery, Graduate School of Comprehensive Human Science, University of Tsukuba, Japan.

Background: In Japan, there is a symptom commonly referred to as "Hie-sho", which is a feeling of coldness or chill in a particular part of the body, and it can sometimes be unendurable. This phenomenon is known to occur more frequently in women. The present study used synchrotron radiation micro-angiography (SRMA) to examine the hypothesis that this feeling is derived from a sex difference in the vascular response to coldness.

Methods And Results: The hind limb of male (Group M) and female (Group F) Wistar rats was exposed to cold and the tissue temperature was recorded. SRMA with a spatial resolution of 26 microm was used to measure arterial diameter. The reduction in temperature brought on by cold exposure was significantly larger in Group F than in Group M (p<0.05). SRMA showed that the arteries were dilated by cold exposure in both groups; however, the percentage dilatation in response was statistically small in Group F (69+/-40%) compared with Group M (118+/-73%) (p<0.05).

Conclusion: Arteries in the limbs of female rats did not expand as much as those of the males in response to cold exposure, which may explain why women feel the cold more than men.
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http://dx.doi.org/10.1253/circj.72.1367DOI Listing
August 2008

The minimum coronary artery diameter in which coronary spasm can be identified by synchrotron radiation coronary angiography.

Eur J Radiol 2008 Dec 30;68(3 Suppl):S84-8. Epub 2008 Jun 30.

Cardiovascular Surgery, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan.

Background: Coronary vasospasm is defined as a temporary, intense narrowing of the coronary conduit artery. It brings about ischemic chest pain and becomes one of the causes of myocardial infarction. Coronary spasms are divided into two categories. One is the coronary spasm of the conduit artery and the other is the coronary microvascular spasm. Although coronary spasms are diagnosed with the images of coronary angiography, microvascular spasms cannot be diagnosed because of the limitations of conventional angiographic systems. However, synchrotron radiation coronary angiography (SRCA) can identify coronary arteries down to 100 microm in diameter in the beating heart and 50 microm in arrested heart.

Aim: The purpose of this study was to confirm whether microvascular spasms could be identified or not using SRCA, and then down that size identification was possible.

Methods: The Langendorff perfusion system with isolated rat hearts was employed. Krebs-Henseleit solution (KH solution) was used as a perfusate. 10mM of 4-aminopyridine (4-AP: a voltage-gated potassium channel blocker; spasm inducer) was added to the KH solution and maintained for 5 min. SRCA was performed at pre-, during and 10 min after cessation of the KH solution with 4-AP. Coronary spasms were defined as a temporal 75% reduction of coronary arterial diameter.

Results And Conclusion: Multiple sizes of coronary arteries showed coronary spasms. The minimum stenosed coronary artery size was 100 microm. Since coronary microvascular spasms are seen in the arterioles (50-400 microm), coronary microvascular spasms may be diagnosed with the use of synchrotron radiation coronary angiography.
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http://dx.doi.org/10.1016/j.ejrad.2008.04.044DOI Listing
December 2008

Cigarette-smoke-induced vasoconstriction of peripheral arteries: evaluation by synchrotron radiation microangiography.

Circ J 2007 Mar;71(3):418-22

Department of Cardiovascular Surgery, Ibaraki-higashi Hospital, Ibaraki, Japan.

Background: Although cigarette smoking is thought to constrict peripheral vessels, details have not been clarified because of the limitation of spatial resolution in conventional X-ray angiography systems. Synchrotron radiation microangiography can identify small arteries down to 50 microm in diameter.

Method And Results: Male Wistar rats (n=9) were made to smoke a cigarette using the modified Griffith snout exposure system. Angiography of the rat hind limb was performed before, during, and 15 min after smoking. Arteries were classified into 3 groups based on the pre-smoking diameter: Group S: <100 microm, Group M 100-200 microm, Group L: >200 microm). In Groups M and L, arteries were constricted with smoking (mean diameter 140-106 microm; p<0.001, 260-162 microm; p<0.00001, respectively), whereas no constriction was noted in Group S (82-83 microm). Constricted arteries in Groups M and L returned to pre-smoking levels at 15 min after cessation of smoking.

Conclusion: The acute changes brought about by cigarette smoking in rat peripheral arteries could be identified by synchrotron radiation microangiography. Cigarette smoking exclusively constricted arteries greater than 100 mum in diameter, which means there is vessel-size dependency of the impairment.
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http://dx.doi.org/10.1253/circj.71.418DOI Listing
March 2007

Changes in coronary resistance related to the stages of the female life cycle.

Circ J 2006 Apr;70(4):478-81

School of Medicine, University of Tsukuba, Tenoudai, Japan.

Background: Estrogen is known to dilate the coronary vascular system mainly through nitric oxide (NO) release. However, it has not been determined whether or not this effect occurs equally throughout all stages of the female life cycle. We examined the changes in coronary flow properties in adolescent, adult and ovariectomized (OVX) female rats using the endothelial NO synthetase blocker, L-N (omega) nitroarginine (L-NNA).

Methods And Results: Female rats were divided into 3 groups: adolescent (13 weeks, n=6), adult (19 weeks, n=8) and OVX (20 weeks, n=7, 12 weeks after oophorectomy). Coronary effluent was measured using the Langendorff non-working heart model before and 15 min after the use of L-NNA. In OVX rats, coronary effluent was significantly decreased in comparison with adolescent and adult rats (adolescent vs OVX: p<0.001; adult vs OVX: p<0.05). After treatment with L-NNA, coronary effluent was significantly higher in the adolescent group compared with the adult and OVX groups (adolescent vs adult: p<0.01; adolescent vs OVX: p<0.0005).

Conclusions: Oophorectomy brought about an increase in coronary vascular resistance. L-NNA exacerbated coronary vascular resistance in relation to maturation. It is suggested that the effect of estrogen on vascular dilatation in adolescents is largely dependent on a non-NO pathway, whereas adults are largely dependent on an NO pathway.
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http://dx.doi.org/10.1253/circj.70.478DOI Listing
April 2006

High-frequency QRS potentials as a marker of myocardial dysfunction after cardiac surgery.

Ann Thorac Surg 2004 Apr;77(4):1293-7

Department of Surgery, University of Tsukuba, Institute of Clinical Medicine, Tsukuba, Japan.

Background: High-frequency QRS potentials are sensitive to myocardial ischemia. The aim of this study was to evaluate the usefulness of high-frequency QRS potentials as a marker of myocardial dysfunction after cardiac surgery.

Methods: Seventy patients undergoing coronary artery bypass grafting or heart valve surgery were involved. High-frequency QRS potentials were measured by signal-averaged electrocardiogram, and calculated as the root-mean-square voltage of the total QRS duration (RMST). The postoperative RMST was expressed as a percentage of the preoperative RMST. The mean RMST at 1 to 2 hours after removing the aortic cross-clamp was compared with the cardiac index, inotropic agents, and aortic cross-clamping time. The occurrence of ventricular tachycardia within 24 hours and the RMST at 2 postoperative days were also evaluated. Patients were divided into quartile groups from highest to lowest at postoperative RMST (groups 1, 2, 3, and 4, respectively, from maximum to minimum).

Results: In postoperative states, cardiac index significantly decreased in accordance with the RMST decrease in a stepwise manner, although there were no differences in cardiac index among the four groups preoperatively. Inotropic agents and aortic cross-clamping time increased as RMST decreased. A high rate of ventricular tachycardia within 24 hours and delayed RMST recovery at 2 postoperative days were seen in group 4. The curve of sensitivity and specificity showed that severe reduction (threshold, 35%) of RMST indicated low-output syndrome.

Conclusions: The severe reduction of filtered high-frequency QRS potentials was related to myocardial dysfunction. Measurement of filtered high-frequency QRS potentials could become a useful, noninvasive, real-time monitor of myocardial dysfunction after surgery.
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http://dx.doi.org/10.1016/j.athoracsur.2003.09.088DOI Listing
April 2004

Aortic root replacement for prosthetic aortic valve detachment without regurgitation and with enlarged Valsalva's sinuses and complete atrioventricular block caused by Takayasu's aortitis.

Jpn J Thorac Cardiovasc Surg 2003 May;51(5):201-4

Department of Cardiovascular Surgery, Higashitoride Hospital, Toride, Ibaraki, Japan.

We replaced the aortic root in a 43-year-old woman with Takayasu's aortitis associated with prosthetic aortic valve detachment. The patient's aortic valve had been replaced when she was 31 years old with a mechanical prosthesis to treat aortic regurgitation. Though C-reactive protein was kept almost normal with prednisolone, complete atrioventricular block suddenly appeared 12 years after the first operation. After the implantation of an artificial pacemaker, we closely followed up aortic root status. Aortography and echocardiography showed that the valve moved up and down, probably due to enlargement of the sinuses of Valsalva, without perivalvular leakage. We removed the prosthetic aortic valve, which was partially detached from the aortic valve ring at the right- and non-coronary cusps and successfully replaced the aortic root with a mechanical prosthesis inserted into a 26 mm woven graft. Although the postoperative course was uneventful, we closely continue to observe the case and to administer of antiinflammatory medication.
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http://dx.doi.org/10.1007/s11748-003-0032-5DOI Listing
May 2003