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Biomedical subjects

K Tabayashi

Publications and source records attributed to K Tabayashi.

At least 19 recordsLinked to original sources
PubMed2006

[Aortic root enlargement in elderly patients].

From January 2003 to June 2005, 12 elderly patients with severe aortic stenosis underwent aortic root enlargement (ARE) by Nicks procedure. Their ages ranged from 74 to 87 with a mean of 79.3. Stented bioprosthesis were used in 11 cases. There was no death. Cardiothoracic ratio on chest X-ray decreased from 59.4 to 53.6% and New York Heart Association (NYHA) functional class improved from 3.4 to 1.3. Echocardiography also showed remarkable improvement, in peak pressure gradient (PG) from 98.3 to 20.7 mmHg, in left ventricular mass index (LVMI) 181 to 137 g/m2. LVM and LVMI regression rates were 25.3 and 22.3%, respectively. Comparative study of those with ARE alone and those with combined operation showed much hazardous effect in the latter, but no significant difference in echocardiographic findings postoperatively. ARE by Nicks procedure, if it could be performed without concomitant procedure, is a safe and effective option also in elderly patients with small aortic annulus.

Aged↗
PubMed2005

Production of methyl-oxonium ion and its complexes in the core-excited (HC(O)OCH3)n clusters: H/H+ transfer from the alpha carbonyl.

Dissociation of free methyl-formate (MF), HC(O)OCH3, and its clusters (MF)n, (HC(O)OCH3)n, induced by core-level excitation was studied near the oxygen K edge by time-of-flight fragment-mass spectroscopy. Besides the protonated clusters, (MF)nH+ with n < or = 15, we identified the production for another series of (MF)mCH3OH2+ with m < or = 14 as well as methyl-oxonium ion, CH3OH2+, characteristic of hydrogen transfer reactions in the cationic clusters. Here; specifically labeled methyl-formate-d (MFD), DC(O)OCH3 was also used to examine the core-excited dissociation mechanisms. Deuterium-labeled experiments indicated that MFD+ with low internal energies, partially generated after the core excitation, produces CH3OD+ via a site-specific deuterium transfer from the alpha carbonyl in the molecular cation and that CH3OD2+ can be formed via the successive transfer of another deuterium from the neighbor molecule in the clusters. The deuteron (proton) transfer was also found to take place preferentially from the alpha carbonyl of the neighbor molecule for the production of deuteronated (MFD)nD+, (protonated (MF)nH+), clusters. The minimal energy requirement paths were examined for dimer (MF)2+ cation to support the present dissociation mechanisms of core-excited (MF)n clusters using ab initio molecular-orbital calculations.

Journal Article↗
PubMed2004

Safety and efficacy of epidural cooling for regional spinal cord hypothermia during thoracoabdominal aneurysm repair.

Twenty-four consecutive patients underwent epidural cooling as an adjunct to elective thoracoabdominal aortic repair under moderate systemic hypothermia. One patient suffered from postoperative paraplegia (4%), and another died from subarachnoidal hemorrhage (4%). Details of the technique, the associated care, and the pitfalls will be discussed.

Aortic Aneurysm, Abdominal↗
PubMed2004

[Spinal cord protection during most or all of descending thoracic or thoracoabdominal aneurysm repair].

OBJECTIVES: The purpose of this study is to evaluate usefulness of perfusion cooling for regional spinal cord hypothermia during most or all of thoracic or thoracoabdominal aneurysm repair. METHODS: From 1987 to 2003, 103 patients underwent most or all of thoracic or thoracoabdominal aneurysm repair. Forty-eight patients underwent operation using distal aortic perfusion, mild hypothermia and segment sequential repair (group MH). Fifty-five patients underwent the same operation as group MH except epidural perfusion cooling and drainage of cerebrospinal fluid (CSF) [group EC & CSFD]. The aorta was replaced sequentially in segment and several paris of intercostal and lumbar arteries were reconstructed in 2 groups. RESULTS: Cardiopulmonary bypass time of group MH and group EC & CSFD was averaged 235 and 241 minutes, respectively. The lowest CSF temperature in group EC & CSFD was averaged 24.7 degrees C, and the difference between nasopharyngeal and CSF temperature was averaged 6.4 degrees C. The rate of spinal cord injury of group MH and EC & CSFD was 10.4% and 3.6%, respectively. Hospital mortality of group MH and EC & CSFD was 8.3% and 5.5%, respectively. The incidence of spinal cord injury and hospital mortality of group EC & CSFD were decreased compared to them of group MH. CONCLUSION: We conclude that the perfusion cooling of epidural space and CSF drainage are effective method in reducing postoperative spinal cord injury.

Adult↗
PubMed2004

[Staged total cavopulmonary connection following Starnes operation].

A three-year-old boy with Ebstein's anomaly, who had received Starnes operation in the neonate state, successfully underwent staged total cavopulmonary connection. Despite of hypoplasticity of the pulmonary artery, the postoperative cardiac catheterization showed no elevation of pulmonary artery pressure and good cardiac performance. Although he suffered from supraventricular tachycardia in the early postoperative period, subsequent course was uneventful.

Child, Preschool↗
PubMed2002

Gene transfer of Fc-fusion cytokine by in vivo electroporation: application to gene therapy for viral myocarditis.

Among a number of techniques for gene transfer in vivo, the direct injection of plasmid DNA into muscle is simple, inexpensive and safe. Although combining direct DNA injection with in vivo electroporation increases the efficiency of gene transfer into muscle, applications of this method have remained limited because of the relatively low expression level. To overcome this problem, we developed a plasmid vector that expresses a secretory protein as a fusion protein with the noncytolytic immunoglobulin Fc portion and used it for electroporation-mediated viral interleukin 10 (vIL-10) expression in vivo. The fusion cytokine vIL-10/mutFc was successfully expressed and the peak serum concentration of vIL-10 was almost 100-fold (195 ng/ml) higher than with a non-fusion vIL-10 expression plasmid. The expressed fusion cytokine suppressed the phytohemagglutinin-induced IFN-gamma production by human peripheral blood mononuclear cells and decreased the mortality in a mouse viral myocarditis model as effectively as vIL-10 expression. These results demonstrate that the transfer of plasmid DNA expressing a noncytolytic Fc-fusion cytokine is useful to deliver enhanced levels of cytokine without altering general biological activities. This simple and efficient system should provide a new approach to gene therapy for human diseases and prove very useful for investigating the function of newly discovered secretory protein genes.

Animals↗
PubMed2002

Epidural cooling for regional spinal cord hypothermia during most or all of descending thoracic or thoracoabdominal aneurysm repair.

PURPOSE: Hypothermia has some protective effect against ischemia of the spinal cord in thoracoabdominal aneurysm repair. Its method is divided into systemic or regional cooling. Several experimental studies of the regional cooling of the spinal cord have been performed, however, clinical reports are few. The purpose of this study is to evaluate the effect and safety of perfusion cooling of the epidural space during thoracic or thoracoabdominal aortic replacement. METHODS: Between January 1998 to June 2001 37 patients (True aneurysm: 18 patients, type B aortic dissection: 19 patients) underwent thoracic or thoracoabdominal aortic replacement with an aid of epidural perfusion cooling. The age ranged from 23 to 78 years old with a mean age of 61 years old. Separate perfusion of upper and lower body was used in all cases. Temperature was lowered to around a 31 degrees C or 32 degrees C. In cases where proximal cross-clamping was danger, deep hypothermic circulatory arrest was used. RESULTS: Ten patients underwent most or all of descending thoracic aneurysm repair with no spinal cord injury and hospital death. Number of patients of the Crawford type I, type II, and type III were 14, 8 and 5 patients, respectively. One Crawford type II patients was complicated with postoperative spinal cord injury (2.7%). There was one hospital death (2.7%) in Crawford type III. The mean epidural cooling time was 150 minutes, and mean infusion volume of cold saline was 981 cc. The mean lowest cerebrospinal fluid (CSF) temperature was 24.3 degrees C, and mean temperature differences between nasopharynx and CSF was 6.3 degrees C. CONCLUSION: Perfusion cooling of the epidural space during most or all of the descending thoracic or thoracoabdominal aneurysm repair was effective in reducing postoperative spinal cord injury and a safe method in clinical situations.

Adult↗
PubMed2002

Myocardial protection of the pressure overload hypertrophied heart in human cardiac surgery by acceleration of anaerobic glycolysis.

BACKGROUND: Because of the decreased tolerance to ischemia and increased reperfusion injury in hypertrophied myocardium, myocardial hypertrophy is a well known risk factor for cardiac surgery. We have previously demonstrated in a left ventricular hypertrophy (LVH) model that a highly buffered cardioplegic solution (HBS) that provided glucose as a substrate and promoted anaerobic glycolysis during ischemia afforded superior myocardial protection when compared to standard formulations. And we reported the superiority of this cardioplegia in human cardiac surgery. METHODS: In this study, 16 patients with aortic stenosis (AS) and LVH receiving HBS were reviewed and compared to another patient group with AS and LVH who received either cold blood cardioplegia (CBC; n=5) or glucose insulin potassium (GIK; n=6). RESULTS: Postoperative cardiac index was better in the HBS group than the other two groups with similar or lower catecholamine. CK-MB was lower in HBS group than GIK group, but this was not significant. Only one DC cardioversion was required in the HBS group, whereas 2 DC in the CBC group and total 7 DC in the GIK group. CONCLUSIONS: We found that histidine buffered cardioplegic solution provided comparable or better pump performance after surgery with relatively lower inotropic requirement, less DC cardioversion and homologous blood requirements for left ventricular hypertrophied heart associated with aortic stenosis.

Aged↗
PubMed2002

[True aneurysm of the ascending aorta and/or aortic arch; determinants of late surgical outcome].

To identify significant predictors of late mortality, multivariate analysis were applied to the clinical outcome of 150 consecutive patients with true aneurysm of the ascending aorta and/or aortic arch operated between January, 1987 and December, 2000. Mean follow-up was 53.0 months with a total of 6,682 patient-months of follow-up. Multivariate analysis revealed that operation date (before December, 1996), presence of preoperative cerebrovascular disease, rupture and postoperative phrenic nerve palsy were independent determinants of late mortality. The overall 5-year and 10-year actuarial survival rates were 66.0% and 48.2%. The 5-year and 10-year event free rate of cardiovascular and/or cerebrovascular death were 88.9% and 71.7%. Preoperative evaluation of the brain, operation prior to aneurysm rupture and phrenic nerve protection during operation is necessary to improve long-term survival rate.

Adult↗
PubMed2002

[Recurrent low output syndrome after the weaning from mechanical circulatory support for postcardiotomy cardiogenic shock].

We reviewed the cases of recurrent low output syndrome (LOS) after the weaning from mechanical circulatory support for postcardiotomy cardiogenic shock. Twelve patients were divide into 2 groups according to whether low output syndrome recurred or not, consisting of a recurrent low output syndrome (+) group [re-LOS (+) group, n = 6] and a recurrent low output syndrome (-) group [re-LOS (-) group, n = 6]. Between 2 groups, there was no statistical difference in preoperative left ventricular ejection fraction (LVEF), aortic closs-clamping time and cardiac index at the weaning from mechanical circulatory support. Only the LVEF at the weaning in the re-LOS (+) group was significantly less than that in the re-LOS (-) group (0.39 +/- 0.08 vs 0.62 +/- 0.19, p < 0.05). All patients in the re-LOS (-) group survived to discharge, while in the re-LOS (+) group, although 3 patients were re-supported by intra-aortic balloon pumping, 4 of 6 patients died of multiple organ failure and 2 survivors were in New York Heart Association class III. The results suggest that the key to survive to discharge after the weaning from mechanical circulatory support is whether the cardiac contraction could recover or not.

Aged↗
PubMed2002

[Aortobronchial fistula after replacement of descending thoracic aorta with ringed graft; report of a case].

A 79-year-old male patient complicated with aortobronchial fistula after replacement of descending thoracic aorta with ringed graft. He underwent replacement of the aortic arch using a four branched vascular graft and open stent grafting to replace the descending thoracic aorta after removing the ringed-graft through median sternotomy. This procedure is useful for patients as the left thoracotomy is risky and the distal anastomotic site of the descending thoracic aorta is too far to anastomose.

Aged↗
PubMed2001

Induction of phosphatidylinositol 3-kinase and serine-threonine kinase-like immunoreactivity in rabbit spinal cord after transient ischemia.

The mechanism of spinal cord injury has been thought to be related with tissue ischemia, and spinal motor neuron cells are suggested to be vulnerable to ischemia. To evaluate the mechanism of such vulnerability of motor neurons, we attempted to make a reproducible model of rabbit spinal cord ischemia. Using this model, the inductions of phosphatidylinositol 3-kinase (PI3-k) and serine-threonine kinase (Akt) were investigated with immunohistochemical analyses for up to 7 days of the reperfusion following 15 min of ischemia in rabbit spinal cord. It has been demonstrated that both PI3-k and its downstream effector, Akt mediate growth factor-induced neuronal survival. Spinal cord sections from animals sacrificed at 8 h, 1, 2, and 7 days following the 15 min of ischemia were immunohistochemically evaluated using monoclonal antibodies for PI3-k and Akt. Following the 15 min of ischemia, the majority of the motor neurons showed selective cell death at 7 days of reperfusion. Immunoreactivity of PI3-k and Akt were induced at 8 h of reperfusion selectively in motor neuron cells. No glial cells and inter neurons were stained in the spinal cord sections. The activation of PI3-k and Akt protein at the early stage of reperfusion may be one of the factors responsible for the delay in neuronal death after spinal cord ischemia.

Animals↗
PubMed2001

Decreased expression of c-myc family genes in thymuses from myasthenia gravis patients.

The thymus is a critical organ for the elimination of autoreactive T cells by apoptosis. We studied the expression of apoptosis-associated genes, bcl-xL, bad, caspase-3, and c-myc family genes in myasthenia gravis (MG) thymuses. We observed that the mRNA levels of myc family genes, c-myc and max, were markedly reduced in MG thymuses. These results indicate that c-myc-mediated signaling is abnormal in MG thymuses. The levels of molecules whose expressions are associated with myc, such as STAM, prothymosin-alpha, and NFkappaB, were also analyzed.

Adaptor Proteins, Signal Transducing↗
PubMed2001

IL-12 plays a pathologic role at the inflammatory loci in the development of diabetes in NOD mice.

Accumulating evidence suggests that CD4(+)T helper type 1 (Th1) cells play a major role in the development of insulin-dependent diabetes mellitus (IDDM) in the non-obese diabetic (NOD) mouse model. Interleukin (IL)-12 is a potent immunoregulatory molecule that is a key determinant of T-cell differentiation into Th1 cells, and has been implicated in the development of IDDM. To investigate the role of IL-12 that is locally produced by islet-infiltrating cells in the development of IDDM, we generated transgenic NOD mice in which the IL-12 p40 homodimer, a natural antagonist of IL-12, was produced exclusively in islets without affecting the levels of IL-12 p40 in the systemic circulation. We found that the incidence of diabetes was significantly reduced in these transgenic mice. These results clearly demonstrate that IL-12 locally produced by islet-infiltrating cells plays a critical role in the development of IDDM.

Animals↗
PubMed2001

Cryopreserved aortic homograft replacement in 3 patients with noninfectious inflammatory vascular disease.

OBJECTIVE: Although mechanical prosthetic heart valves are most commonly used for aortic valve replacement in patients with aortic regurgitation due to noninfectious inflammatory vascular disease, postoperative perivalvular leakage and/or detachment of the prosthetic valve occurs due to the fragility of the aortic annulus. Aortic root replacement with cryopreserved homografts is reported to be useful in such patients. METHODS: Three patients having aortic regurgitation associated with severe long standing noninfectious inflammatory vascular disease-2 patients with Takayasu's arteritis and 1 patient with Behçet disease--had the aortic root replacement by a cryopreserved aortic homograft valve and conduit. RESULTS: All surgery was successful and the postoperative course uneventful. Echocardiography showed neither aortic regurgitation nor graft detachment at 6-39 months after operation. CONCLUSIONS: Homograft valve and conduit replacement is appropriate in patients with aortic regurgitation associated with noninfectious inflammatory vascular disease, with mid-term results favorable.

Adult↗
PubMed2001

Concomitant replacement of the aortic root and aortic arch with or without secondary thoracoabdominal aorta replacement.

OBJECTIVES: Extensive aortic replacement, such as concomitant aortic root and arch replacement, thoracoabdominal aortic repair, and complete thoracic aorta replacement, remains controversial. We studied surgical morbidity and mortality in patients undergoing concomitant aortic root and arch replacement, and those undergoing secondary replacement of the thoracoabdominal aorta after this preceding procedure. SUBJECTS AND METHODS: Between January, 1987 and March 1999, 21 patients (mean age: 52 years) underwent concomitant aortic root and arch replacement involving 3 surgical procedures--aortic root replacement with composite graft and arch (n = 12), aortic root replacement with valve sparing and arch (n = 4), or aortic root replacement with composite graft and arch and elephant trunk (n = 5). RESULTS: Overall hospital mortality was 4.8%. Six patients (mean age: 42 years) underwent secondary thoracoabdominal aorta replacement after the concomitant root and arch procedure. The mean time until secondary surgery was 9.5 months. There was 1 hospital death. CONCLUSION: Concomitant replacement of the aortic root and arch, or secondary replacement of the thoracoabdominal aorta after concomitant root and arch replacement can be conducted with low surgical morbidity and mortality.

Adolescent↗
PubMed2001

Bronchial artery aneurysm treated with percutaneous transluminal coil embolization.

We present a case with asymptomatic mediastinal bronchial artery aneurysm at the origin of the left bronchial artery. This bronchial artery aneurysm was successfully treated with percutaneous transluminal coil embolization. Complete embolization of the feeding artery and tributaries from the aneurysm is the key to successful isolation of a large bronchial artery aneurysm from the circulation. Percutaneous transluminal embolization is one of the treatment options for a patient with asymptomatic, incidentally-identified bronchial artery aneurysm.

Aneurysm↗