Biomedical subjects

Suguru Kubota

Publications and source records attributed to Suguru Kubota.

6 recordsLinked to original sources

PubMed2006

Ultrastructural analysis of TiO2 nanotubes with photodecomposition of water into O2 and H2 implanted in the nude mouse.

To analyze the biocompatibility and O2 generation of TiO2 nanotubes via photodecomposition of water into O2 and H2 in vivo, samples were implanted under the inguinal skin of the nude mouse. Venous oxygen saturation (SvO2) of the inguinal skin over the implanted region was measured with a tissue oximeter and the ultrastructures were examined with an electron microscope. Four weeks after the implantation, SvO2 of the inguinal skin of the groups with TiO2 nanotubes was 30-40% higher than that of the opposite control region (54%). SvO2 of the other groups, comprising splenic autografts, fetal cardiac tissue transplantation and surgical procedure without TiO2 nanotubes, was roughly the same as that of controls. Ultrastructurally, TiO2 nanotubes were phagocytized by the macrophage and promoted filament formation in its cytoplasm. Neither death of the cell nor destruction of the tissue was recognized. These findings indicate excellent biocompatibility and O2 generation of TiO2 nanotubes in vivo.

Animals↗

PubMed2005

[Surgical treatment of ventricular and pericardial perforation by a permanent pacing lead: a case report].

An 83-year-old woman was transferred to our hospital because of pacing failure and suspected ventricular perforation by a permanent pacing lead. She had undergone permanent pacemaker implantation 5 months previously. Chest radiography showed the pacing lead running out of the cardiac shadow. Computed tomography and echocardiography confirmed the diagnosis of ventricular perforation by the pacing lead. No evidence of cardiac tamponade was found. The lead was surgically removed through a median sternotomy. Intraoperatively, the lead was found perforating the ventricle and the pericardium, and reaching into the left pleural cavity but not injuring the left lung. A pacing lead may potentially injure the heart or the lung. Regular check-up of lead position and pacing status is recommended.

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PubMed2004

Titanium oxide nanotubes for bone regeneration.

Titanium oxide nanotubes with Ca ions on their surfaces were prepared as 2 mm cylindrical inserts and placed into surgically created bone defects in the femurs of Wistar rats. On day 3, fibroblast-like cells were present on the surface of the nanotube inserts and fibers were observed by scanning electron microscopy (SEM). On day 7, cells with alkaline phosphatase activity were present and identified as osteoblasts by SEM and transmission electron microscopy. New bone matrices were observed in and around the porous nanotube inserts by light microscopy. Compared with clinically used hydroxyapatite and tricalcium phosphate, beta-titanium oxide nanotubes promote faster acquisition and development of osteoblasts and bone tissues and have better bone regenerating ability after one week.

Alkaline Phosphatase↗

PubMed2004

The risk of reoperative heart valve procedures in Octogenarian patients.

BACKGROUND AND AIM OF THE STUDY: The authors' experience is reported of cardiac reoperations for valvular heart disease in octogenarian patients. METHODS: The records of 22 consecutive patients (10 men, 12 women) aged > or =80 years (mean age 82.4+/-2.3 years) who underwent cardiac reoperation for aortic and/or mitral valvular heart disease at the authors' institution between 1991 and 2001 were retrospectively reviewed. RESULTS: Indications for reoperation were structural dysfunction of a previously implanted bioprosthetic valve in 11 patients (50%), new valvular heart disease in six (27%), progression of rheumatic valvular heart disease in four (18%), and prosthetic valve infective endocarditis in one patient (5%). Fourteen patients (64%) underwent isolated aortic valve replacement (AVR), two (9%) had AVR plus coronary artery bypass grafting (CABG), one patient (5%) had aortic root replacement plus CABG, three patients (14%) had isolated mitral valve replacement (MVR), one patient (5%) had MVR plus ascending aorta replacement, and one (5%) had AVR plus MVR. Postoperative complications occurred in 18 patients (82%). The hospital mortality rate was 32%. Actuarial survival estimates at one year, and at three and five years were 62.6%, 56.3% and 40.2%, respectively. CONCLUSION: Cardiac reoperations for valvular heart disease in octogenarians carry a high postoperative morbidity and mortality. These findings must be taken into account in the management of associated mild or moderate valvular heart disease, and in the choice of heart valve prosthesis at the initial operation in younger patients.

Aged↗

PubMed2003

Survival and function of mouse embryonic stem cell-derived cardiomyocytes in ectopic transplants.

OBJECTIVE: Embryonic stem cell-derived cardiomyocytes are a useful source for cell transplantation into the heart, as well as for tissue engineering of the extracardiac vascular system. The present study was designed to investigate the survival and contractile function of embryonic stem cell-derived cardiomyocytes around large blood vessels to assess the feasibility of their ectopic use for future engineering of cardiovascular tissues. METHODS: The mouse embryonic stem cell-derived cardiomyocytes were transplanted into the retroperitoneum of the adult nude mice, and the myocardial tissues that developed were characterized by electrophysiological and histological techniques. RESULTS: Macroscopic and electrophysiological analyses showed spontaneously contracting transplants in the host retroperitoneum 7 and 30 days after transplantation. Immunohistochemistry detected developing cardiomyocytes in the transplants on Day 7, which formed the myocardial tissues. They were positive for cardiac troponin I, cadherin, connexin 43, and proliferating cell nuclear antigen, but negative for alpha-smooth muscle actin. Vascular formation was discernible in the transplant tissues. By Day 30, more mature myocardial tissues had been established in the transplants. Electron microscopic study emphasized that the transplant tissues comprised cardiomyocytes, in which myofibrils with organized sarcomeres were observed. Desmosomes, fasciae adherens and gap junctions were evident in the cellular junctions. CONCLUSIONS: The cardiomyocytes derived from the mouse ES cells were demonstrated to be viable and function in the ectopic site of the host retroperitoneum up to Day 30, following a process of proliferation and differentiation. Vascularization and host perfusion beneficial for the survival of the cardiomyocytes occurred in the transplants.

Animals↗

PubMed2003

Immunohistochemical localization of hepatocyte growth factor activator (HGFA) in developing mouse liver tissues. Heterogeneous distribution of HGFA protein.

Hepatocyte growth factor activator (HGFA) can activate the single-chain hepatocyte growth factor (HGF) required for embryonic development. We studied the immunohistochemical (IHC) localization of HGFA in adult mouse liver and its developmental changes from embryonic day 12 to postnatal day 30. A heterogeneous distribution of HGFA was observed in adult liver tissues. The hepatocytes around the hepatic veins were preferentially positive for HGFA, whereas those in other areas were negative. Depending on the vascular diameter, the hepatic veins were bordered by a one- to three-cell-thick layer of hepatocytes positive for HGFA, which showed evidence of cell-cell heterogeneity in staining intensity. Immunoelectron microscopy detected ubiquitous distribution of the gold particle reaction product for HGFA in the cytoplasm of these hepatocytes, especially in the rough endoplasmic reticulum. Developmental analysis indicated that there was hardly any staining of HGFA until postnatal day 0 and that noticeable staining was initially detected in the pericentral hepatocytes on postnatal day 3. Subsequently, immunoreactivity increased and the distinct staining pattern had been established by postnatal day 30. These results suggest that HGFA proteins are produced in the hepatocytes surrounding the efferent hepatic veins in the mouse and that development of the unique distributing pattern takes place postnatally.

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