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Tsutomu Saito

Publications and source records attributed to Tsutomu Saito.

At least 19 recordsLinked to original sources
PubMed2006

Simultaneously performed mitral valve replacement and Hartmann's operation for infectious endocarditis from Streptococcus bovis and rectal cancer.

In patients with surgical indications for both cardiac surgery and a malignant neoplasm, cardiac surgery should generally be performed first; however, in some cases simultaneous surgery is recommended. We report a case of infectious endocarditis of the mitral valve caused by Streptococcus bovis with rectal cancer. Blood cultures showed a rise in coagulase-negative S. bovis, and the source of infection was thought to be the rectal cancer. The patient presented with cerebral infarction prior to surgery, and the possibility of recurrence of an infarction was predicted. The tumor of the rectum was hemorrhagic, so to avoid hemorrhagic complications due to perioperative heparinization and anticoagulant therapy and to remove the source of infection, mitral valve replacement and a Hartmann's operation were performed simultaneously. The postoperative course was uneventful.

Colectomy↗
PubMed2006

Chitosan-soyprotein interaction as determined by thermal unfolding experiments.

Chitosan interaction with soybean beta-conglycinin beta(3) was investigated by thermal unfolding experiments using CD spectroscopy. The negative ellipticity of the protein was enhanced with rising solution temperature. The transition temperature of thermal unfolding of the protein (T(m)) was 63.4 degrees C at pH 3.0 (0.15 M KCl). When chitosan was added to the protein solution, the T(m) value was elevated by 7.7 degrees C, whereas the T(m) elevation upon addition of chitosan hexamer (GlcN)(6) was 2.2 degrees C. These carbohydrates appear to interact with the protein stabilizing the protein structure, and the interaction ability could be evaluated from the T(m) elevation. Similar experiments were conducted at various pHs from 2.0 to 3.5, and the T(m) elevation was found to be enhanced in the higher pH region. We conclude that chitosan interacts with beta-conglycinin through electrostatic interactions between the positive charges of the chitosan polysaccharide and the negative charges of the protein surface.

Antigens, Plant↗
PubMed2005

Clinical features of third open-heart valve surgery at the same valve position.

OBJECTIVE: Recently, there has been an increase in case of repeated open-heart valve surgery and the clinical results of the second surgery are only slightly worse than those of the first surgery. However, clinical results of the third open-heart valve surgery at the same position are rarely reported. Clinical features of third open-heart valve surgery at the same position are discussed in this study. METHODS: Between 1995 and 2004, 16 patients underwent third open-heart valve surgery at the same valve position under cardiopulmonary bypass. The average age of the 16 patients, 12 females and 4 males, was 56 +/- 15 years. Clinical features of the 16 cases were retrospectively analyzed. RESULTS: Mechanical valve nonstructural dysfunction was the most common valve malady, followed by bioprosthetic valve dysfunction. The duration of surgery from skin incision to establishment of the cardiopulmonary bypass was 94 +/- 42 minutes. Myocardial ischemia time was 137 +/- 38 minutes and extracorporeal circulation time was 212 +/- 82 minutes. Early mortality was seen in 1 patient (6.25%) and late mortality was seen in 1 patient. CONCLUSION: Mechanical valve nonstructural valve dysfunction leads to repeated valve surgery. The clinical results of the third open-heart valve surgery at the same valve position are acceptable, and the mid-term survival is excellent.

Adult↗
PubMed2005

The CarboMedics prosthetic heart valve: experience with 180 implants.

At Jichi Medical School Hospital, three types of mechanical prosthetic valves (CarboMedics, Omnicarbon, Bicarbon) were used without randomization from 1991 to 2000. A retrospective study of valve replacements done between June 1991 and November 2000 utilizing 180 CarboMedics valves in 145 patients who had not previously undergone prosthetic valve replacement or aortic root and/or arch replacement was conducted to evaluate midterm patient outcomes to assess the future continuous use of CarboMedics valves. Women made up 47.6% of the patients and the mean age was 57.5 years (range 12-80 years). Preoperative New York Heart Association functional class was III or IV in 92.4% (134/145) of patients. Mean follow-up of 4.5 years (range 0-10.0 years) was 95.9% complete, with a total of 628 patient-years (PY). Early (within 30 postoperative days) mortality was 5.5% (8 of 145): 3 from hemorrhage, 3 from nonvalve-related heart failure, 1 from infection, and 1 from arrhythmia. There were 16 late deaths (2.54%/PY): 1 from hemorrhage, 4 from unknown causes/sudden death, 4 from nonvalve-related heart failure, and 7 from other noncardiac causes. A total of 121 patients (83.0%) were alive at the last follow-up, done in November 2000. The linearized death rate was 3.82%/year (including 1.11%/year for valve-related deaths). Linearized death rates from various causes were: bleeding, 0.96%/year; thromboembolism, 1.11%/year; thrombosis, 0.39%/year; perivalvular leak, 0.96%/year; endocarditis, 0%/year; hemolysis, 0%/year; and reoperation, 0.63%/year. No structural valve failure was observed. Comparative early mortality rates of valve replacement without aortic root replacement or arch replacement, excluding repeat valve replacement operations, in our institute, were 3.5% (12/307) for all valve types used contemporaneously, 2.6% (2/76) for Omnicarbon valves, and 2.3% (2/86) for Bicarbon valves. Although the CarboMedics valve had a rather high mortality rate of 5.5% (8/145) compared with the total early mortality rate of 3.5%, the low incidence of valve-related complications might support the continued use of the CarboMedics valve for valve replacement.

Adolescent↗
PubMed2005

Abducens nerve palsy and Horner syndrome due to metastatic tumor in the cavernous sinus.

A 41-year-old man was diagnosed as having primary parotid carcinoma on the right side. After radical parotidectomy, radiation therapy and systemic chemotherapy, the primary parotid carcinoma was completely remitted. Two years later, right abducens nerve palsy and Horner syndrome appeared. Neuroimaging demonstrated a gadolinium-enhanced lesion in the posterior portion of the right cavernous sinus, and metastasis of parotid carcinoma was suspected. After radiosurgery and systemic chemotherapy, the intracavernous lesion disappeared. This is the first case of combination of abducens nerve palsy and ipsilateral Horner syndrome due to metastasis from parotid carcinoma to the cavernous sinus.

Abducens Nerve Diseases↗
PubMed2005

A proposed parent vessel geometry-based categorization of saccular intracranial aneurysms: computational flow dynamics analysis of the risk factors for lesion rupture.

OBJECT: The authors created a simple, broadly applicable classification of saccular intracranial aneurysms into three categories: sidewall (SW), sidewall with branching vessel (SWBV), and endwall (EW) according to the angiographically documented patterns of their parent arteries. Using computational flow dynamics analysis (CFDA) of simple models representing the three aneurysm categories, the authors analyzed geometry-related risk factors such as neck width, parent artery curvature, and angulation of the branching vessels. METHODS: The authors performed CFDAs of 68 aneurysmal geometric formations documented on angiograms that had been obtained in patients with 45 ruptured and 23 unruptured lesions. In successfully studied CFDA cases, the wall shear stress, blood velocity, and pressure maps were examined and correlated with aneurysm rupture points. Statistical analysis of the cases involving aneurysm rupture revealed a statistically significant correlation between aneurysm depth and both neck size (p < 0.0001) and caliber of draining arteries (p < 0.0001). Wider-necked aneurysms or those with wider-caliber draining vessels were found to be high-flow lesions that tended to rupture at larger sizes. Smaller-necked aneurysms or those with smaller-caliber draining vessels were found to be low-flow lesions that tended to rupture at smaller sizes. The incidence of ruptured aneurysms with an aspect ratio (depth/neck) exceeding 1.6 was 100% in the SW and SWBV categories, whereas the incidence was only 28.75% for the EW aneurysms. CONCLUSIONS: The application of standardized categories enables the comparison of results for various aneurysms' geometric formations, thus assisting in their management. The proposed classification system may provide a promising means of understanding the natural history of saccular intracranial aneurysms.

Aged↗
PubMed2005

[Concurrent chemoradiotherapy for advanced hypopharyngeal cancer].

INTRODUCTION: Chemotherapy has been shown to be most effective when delivered concurrently with radiation for the patients with advanced stage tumors. We conducted a concurrent chemoradiation using systemic infusion of cisplatin (CDDP) and 5-fluorouracil (5-FU). PATIENTS AND METHODS: Thirty-nine patients with advanced hypopharyngeal cancer received one or two cycles of intravenous administration of CDDP (80-100 mg/m2) followed by 120-hour continuous infusion of 5-FU (800-1000 mg/m2), and concomitant radiotherapy (200 cGy/day x 20-35 fractions) during the period from December, 1993 through December, 2001. Three of them were in stage III, 31 in stage IVA, and 5 in stage IVB. Until 1999 definitive surgery was planed in almost all the patients, however, primary tumors had pathologically disappeared in eleven out of the 20 (55%) of the surgical specimens. Based on the result, definitive surgery was reserved for residual or recurrent tumors afterwards. RESULTS: The complete response (CR) rates according to the T factor were 100% (1/1) for T1, 86% (6/7) for T2, 67% (2/3) for T3, and 50% (14/28) for T4, respectively. Two cycles of chemotherapy yielded a significantly higher CR rate than that of one cycle (P = 0.0371). One patient died of aspiration pneumonia. The rate of grade 3-4 leukocytopenia was 38%. The projected 5-year disease specific and overall survival rates were 57 and 51%, respectively. CONCLUSIONS: Concurrent chemoradiotherapy is promising as far as improving survival as well as organ preservation.

Antimetabolites, Antineoplastic↗
PubMed2005

Anatomical repair of partially unroofed coronary sinus syndrome through the coronary sinus orifice.

A 15-year-old girl was admitted for repair of partially unroofed coronary sinus syndrome. A preoperative echocardiographic study disclosed the dilated coronary sinus and a draining blood flow into the right atrium from both the left atrium and the end of the coronary sinus. At surgery, the distal portion of the coronary sinus roof was found to be absent. The defect was repaired through the coronary sinus orifice with a patch. No electrophysiological conduction abnormalities developed and follow-up echocardiography showed neither residual shunts nor coronary sinus blood flow disturbances.

Adolescent↗
PubMed2004

Ca2+ binding sites in calmodulin and troponin C alter interhelical angle movements.

Molecular dynamics analyses were performed to examine conformational changes in the C-domain of calmodulin and the N-domain of troponin C induced by binding of Ca(2+) ions. Analyses of conformational changes in calmodulin and troponin C indicated that the shortening of the distance between Ca(2+) ions and Ca(2+) binding sites of helices caused widening of the distance between Ca(2+) binding sites of helices on opposite sides, while the hydrophobic side chains in the center of helices hardly moved due to their steric hindrance. This conformational change acts as the clothespin mechanism.

Animals↗
PubMed2004

Experimental application of pulsed Ho:YAG laser-induced liquid jet as a novel rigid neuroendoscopic dissection device.

BACKGROUND AND OBJECTIVES: Although water jet technology has been considered as a feasible neuroendoscopic dissection methodology because of its ability to perform selective tissue dissection without thermal damage, problems associated with continuous use of water and the ensuing fountain-effect-with catapulting of the tissue-could make water jets unsuitable for endoscopic use, in terms of safety and ease of handling. Therefore, the authors experimented with minimization of water usage during the application of a pulsed holmium:yttrium-aluminum-garnet (Ho:YAG) laser-induced liquid jet (LILJ), while assuring the dissection quality and the controllability of a conventional water jet dissection device. We have developed the LILJ generator for use as a rigid neuroendoscope, discerned its mechanical behavior, and evaluated its dissection ability using the cadaveric rabbit ventricular wall. STUDY DESIGN/MATERIALS AND METHODS: The LILJ generator is incorporated into the tip of a stainless steel tube (length: 22 cm; internal diameter: 1.0 mm; external diameter: 1.4 mm), so that the device can be inserted into a commercial, rigid neuroendoscope. Briefly, the LILJ is generated by irradiating an internally supplied water column within the stainless steel tube using the pulsed Ho:YAG laser (wave length: 2.1 microm, pulse duration time: 350 microseconds) and is then ejected through the metal nozzle (internal diameter: 100 microm). The Ho:YAG laser pulse energy is conveyed through optical quartz fiber (core diameter: 400 microm), while cold water (5 degrees C) is internally supplied at a rate of 40 ml/hour. The relationship between laser energy (range: 40-433 mJ/pulse), standoff distance (defined as the distance between the tip of the optical fiber and the nozzle end; range: 10-30 mm), and the velocity, shape, pressure, and average volume of the ejected jet were analyzed by means of high-speed camera, PVDF needle hydrophone, and digital scale. The quality of the dissection plane, the preservation of blood vessels, and the penetration depth were evaluated using five fresh cadaveric rabbit ventricular walls, under neuroendoscopic vision. RESULTS: Jet velocity (7.0-19.6 m/second) and pressure (0.07-0.28 MPa) could be controlled by varying the laser energy, which determined the penetration depth in the cadaveric rabbit ventricular wall (0.07-1.30 mm/shot). The latter could be cut into desirable shapes-without thermal effects-under clear neuroendoscopic vision. The average volume of a single ejected jet could be confined to 0.42-1.52 microl/shot, and there was no accompanying generation of shock waves. Histological specimens revealed a sharp dissection plane and demonstrated that blood vessels of diameter over 100 microm could be preserved, without thermal damage. CONCLUSIONS: The present pulsed LILJ system holds promise as a safe and reliable dissection device for deployment in a rigid neuroendoscope.

Animals↗
PubMed2004

Pulsed holmium:yttrium-aluminum-garnet laser-induced liquid jet as a novel dissection device in neuroendoscopic surgery.

OBJECT: A pressure-driven continuous jet of water has been reported to be a feasible tool for neuroendoscopic dissection owing to its superiority at selective tissue dissection in the absence of thermal effects. With respect to a safe, accurate dissection, however, continuous water flow may not be suitable for intraventricular use. The authors performed experiments aimed at solving problems associated with continuous flow by using a pulsed holmium:yttrium-aluminum-garnet (Ho:YAG) laser-induced liquid jet (LILJ). They present this candidate neuroendoscopic LILJ dissection system, having examined its mechanical characteristics and evaluated its controllability both in a tissue phantom and in a rabbit cadaveric ventricle wall. METHODS: The LILJ generator was incorporated into the tip of a No. 4 French catheter so that the LILJ could be delivered via a neuroendoscope. Briefly, the LILJ was generated by irradiating an internally supplied column of physiological saline with a pulsed Ho:YAG laser (pulse duration time 350 microsec; laser energy 250-700 mJ/pulse) within a No. 4 French catheter (internal diameter 1 mm) and ejecting it from a metal nozzle (internal diameter 100 microm). The Ho:YAG laser energy pulses were conveyed by an optical fiber (core diameter 400 microm) at 3 Hz, whereas physiological saline (4 degrees C) was supplied at a rate of 40 ml/hour. The mechanical characteristics of the pulsed LILJ were investigated using high-speed photography and pressure measurements; thermal effects and controllability were analyzed using an artificial tissue model (10% gelatin of 1 mm thickness). Finally, the ventricle wall of a rabbit cadaver was dissected using the LILJ. Jet pressure increased in accordance with laser energy from 0.1 to 2 bar; this translated into a penetration depth of 0.08 to 0.9 mm per shot in the ventricle wall of the rabbit cadaver. The gelatin phantom could be cut into the desired shape without significant thermal effects and in the intended manner, with a good surgical view. CONCLUSIONS: The present results show that the pulsed LILJ has the potential to become a safe and reliable dissecting method for endoscopic procedures.

Animals↗
PubMed2004

Computational simulation of therapeutic parent artery occlusion to treat giant vertebrobasilar aneurysm.

We applied computational fluid dynamics (CFD) analysis to assess 3D digital subtraction angiography findings in a patient with a giant vertebrobasilar aneurysm to simulate and compare the consequences of left and right vertebral artery occlusion. The balloon occlusion test suggested that occlusion of the right vertebral artery is the better way to treat this patient's aneurysm from the point of view of aneurysmal thrombosis and isolation from the circulation. The computer simulation supported this conclusion, at the same time indicating that from the point of view of pressure distribution on the wall of the aneurysm, the right vertebral occlusion may be also accompanied by an undesirable effect. A high-pressure area on the aneurysm wall in systole was revealed. This high pressure potentially could lead to subsequent aneurysmal growth, which indeed occurred, as was revealed by a follow-up examination 6 months later. This study is a good example of possible future applications of CFD in patients with cerebrovascular disease before therapeutic intervention.

Aged↗
PubMed2004

Computational replicas: anatomic reconstructions of cerebral vessels as volume numerical grids at three-dimensional angiography.

BACKGROUND AND PURPOSE: We present a relatively simple approach that physicians can use to reconstruct cerebral vessels as 3D numerical grids or computational replicas. The method accurately duplicates their geometry to provide computer simulations of their blood flow. METHODS: Initial images were obtained by using any medical imaging technique, such as MR angiography, CT angiography, or 3D digital subtraction angiography. The data were collected in DICOM format and converted by a DICOM reader into a 3D gray-scale raster image. The image was then processed by using commercial visualization and mesh generation software, which allowed extraction of the luminal surface of the blood vessel (by using the isosurfacing technique). The subsequent final output was an unstructured tetrahedral grid that can be directly used for detailed analysis of cerebral vascular geometry for patient-specific simulations of blood flow. RESULTS: Four examples of grid reconstruction and blood flow simulation for patients with ruptured aneurysms were validated with angiographic and operative findings. The ruptured areas were correlated with areas of high fluid-induced wall-shear stress. CONCLUSION: This approach promises to be a practical tool for planning treatment and follow-up of patients after neurosurgical or endovascular interventions with 3D angiography. The proposed commercial packages or conceptually similar ones seem to be relatively simple and suitable for direct use by neurosurgeons or neuroradiologists.

Aneurysm, Ruptured↗
PubMed2004

[Radiation therapy for brain tumors].

Brain tumors respond differently to treatment with surgery plus radiotherapy or radiotherapy alone, combined with or without chemotherapy, because they are characterized by subtypes with different histologies. Since the development of diagnostic radiology, such as computed tomography (CT) and magnetic resonance imaging (MRI), brain tumors have been easier to demonstrate and can be found at earlier stages than in the conventional situation. Furthermore, highly technical devices and equipment for radiation therapy have been developed and installed for clinical use, especially with multileaf collimator (MLC) and treatment planning systems. In the field of radiotherapy for brain tumors, it has been possible to use more precise treatment planning with conformal radiotherapy, three-dimensional treatment planning, and stereotactic radiotherapy. Dose escalation studies and the modified fractionation schedule of radiotherapy can also be designed by analyzing biological data and applying hypofractionated intensity-modulated radiotherapy (IMRT) to radioresistant tumors such as glioblastoma multiforme and anaplastic astrocytoma. Future investigation may be useful to determine which fraction size is likely to be optimal for these malignant gliomas when highly conformal radiotherapy is used in adjuvant treatment. These technological developments and newly designed radiosensitizing agents will improve local control rates and survival times, thereby enhancing the quality of life in patients suffering from various kinds of brain tumors.

Astrocytoma↗
PubMed2003

Modified Bentall operation in a patient with hemophilia A.

We detail a successful modified Bentall operation in a patient with hemophilia A. A 53-year-old man with mild hemophilia A and a history of few bleeding episodes was diagnosed with annuloaortic ectasia. Surgical repair was planned. Simple bolus infusions of factor VIII concentrate were given before and after cardiopulmonary bypass to achieve 100% blood levels and postoperatively every 12 hours for 7 days to maintain 50% levels. The patient received no transfusion other than 10 units of platelet concentrate. We used routine operative and cardiopulmonary bypass techniques. The patient recovered well postoperatively with no excessive bleeding despite warfarin therapy.

Aortic Aneurysm↗
PubMed2003

When and how does nonstructural mechanical prosthetic heart valve dysfunction occur?

OBJECTIVE: We discuss the clinical aspects related to mechanical valve dysfunction based upon 20 years' experience of our cases. METHODS: Between January 1982 and December 2001, 21 patients underwent surgical interventions because of mechanical valve dysfunction. Thirteen men and 8 women (mean age 47 +/- 20, range 3-75 years-old), were included. RESULTS: Mitral valve dysfunction was observed in 12 patients. Prosthetic valve stenosis occurred in 6 patients between 2 and 224 months, and paravalvular leaks in 4 between 1 and 71 months after surgery. The other 2 patients suffered from hemolytic anemia with mild paravalvular leaks between 102 and 104 months after surgery. Aortic valve dysfunction was observed in 8 patients including 3 stenotic lesions between 48 and 97 months and 5 paravalvular leaks between 3 and 150 months after surgery. Tricuspid regurgitation was seen in 1 patient with a huge right atrium at 42 months after surgery. Early death was seen in 1 patient. Late death occurred in 1 patient, 17 years after operation. Survival, including early death, was 95.2%, at 10 and 15 years. One valve-related complication of bioprosthetic valve endocarditis at the mitral and tricuspid positions occurred 12 years after a reoperation. The freedom from complications was 95.2% at 10 years, and 76.2% at 15 years. CONCLUSIONS: Paravalvular leaks without overt endocarditis had latency periods of up to 12 years, and pannus formation was observed 20 years after surgery. Early and late clinical results after surgery for mechanical valve dysfunction were excellent.

Adolescent↗
PubMed2003

Isolated traumatic vertebral pseudoaneurysm: report of a case.

We report a case of isolated traumatic pseudoaneurysm of the vertebral artery in a 20-year-old man who suffered blunt injury to the left foreneck and arm in a traffic accident. A chest computed tomography (CT) scan on admission showed an upper mediastinal hematoma, but the patient's vital signs were stable. A CT scan of the head and neck showed a cerebral mass, and an elective cerebral four-vessel angiography was performed, which revealed a pseudoaneurysm in the proximal portion of the left vertebral artery. At surgery, about 2 cm of the left vertebral artery was found to be lacerated, and suture ligation was done on each side of the laceration. Postoperative intravenous digital subtraction angiography showed an intact right vertebral artery with no residual pseudoaneurysm. There were no neurological complications and the patient was discharged on the 16th postoperative day.

Adult↗