Search PubMed⌕ Search

Biomedical subjects

Koichi Tabayashi

Publications and source records attributed to Koichi Tabayashi.

48 records · Page 3Linked to original sources
PubMed2003

Successful weaning from inhaled nitric oxide using dipyridamole.

A 33-year-old woman with an atrial septal defect associated with severe pulmonary hypertension underwent suture closure of the defect after assessment of operability by lung biopsy. Postoperative course was complicated by suprasystemic refractory pulmonary hypertension, and she became dependent upon treatment with inhaled nitric oxide. After multiple attempts to withdraw nitric oxide, dipyridamole was administered and blunted the rebound pulmonary hypertension after subsequent nitric oxide withdrawal.

Adult↗
PubMed2003

Survival and death-promoting events after transient spinal cord ischemia in rabbits: induction of Akt and caspase3 in motor neurons.

OBJECTIVE: The mechanism of spinal cord injury has been thought to be related to the vulnerability of spinal motor neuron cells to ischemia. However, the mechanisms of such vulnerability are not fully understood. We previously reported that spinal motor neurons might be lost as a result of programmed cell death and investigated a possible mechanism of neuronal death by means of immunohistochemical analysis for CPP32 (caspase3) and serine-threonine kinase (Akt). METHODS: We used a rabbit spinal cord ischemia model with use of a balloon catheter. The spinal cord was removed at 8 hours or 1, 2, or 7 days after 15 minutes of transient ischemia, and histologic changes were studied with hematoxylin and eosin staining. Western blot analysis for Akt and caspase3, temporal profiles of Akt and caspase3 immunoreactivity, and double-label fluorescence immunocytochemical studies were performed. RESULTS: The majority of motor neurons were preserved until 2 days but were selectively lost at 7 days of reperfusion. Western blot analysis revealed no immunoreactivity for Akt and caspase3 in the sham-operated spinal cords. However, such immunoreactivity became apparent at 8 hours after transient ischemia, decreased at 1 day, and returned to the baseline level at 2 days. A double-label fluorescence immunocytochemical study revealed that both Akt and caspase3 were positive at 8 hours of reperfusion in the same motor neurons, which eventually die. CONCLUSION: These results suggests that transient spinal cord ischemia activates both cell death and survival pathways after ischemia. The activation of Akt protein at the early stage of reperfusion might be one of the factors responsible for the delay in neuronal death after spinal cord ischemia.

Animals↗
PubMed2003

Oxidative damage and reduction of redox factor-1 expression after transient spinal cord ischemia in rabbits.

OBJECTIVE: The mechanism of spinal cord injury has been thought to be related to the vulnerability of spinal motor neuron cells against ischemia. However, the mechanisms of such vulnerability are not fully understood. We previously reported that spinal motor neurons may be lost by programmed cell death and thus now investigate a possible mechanism of neuronal death with immunohistochemical analysis for 8-hydroxy-2'-deoxyguanosine (8-OHdG) and redox factor-1 (Ref-1). METHODS: We used a rabbit spinal cord ischemia model with a balloon catheter. The spinal cord was removed at 8 hours, 1, 2, or 7 days after 15 minutes of transient ischemia, and histologic changes were studied with hematoxylin-eosin staining. Western blot analysis for Ref-1, temporal profiles of 8-OHdG and Ref-1 immunoreactivity, and double-label fluorescence immunocytochemical studies were performed. RESULTS: Most motor neurons were preserved until 2 days but were selectively lost at 7 days of reperfusion. Western blot analysis of a sample from sham control spinal cord showed a characteristic 37-kDa band that was reduced after ischemia. Immunohistochemistry showed the nuclear expression of Ref-1 in motor neurons of control spinal cords, and immunoreactivity was decreased 1 day after ischemia. On the other hand, no nuclear expression was seen of 8-OHdG in motor neurons of control spinal cords, and immunoreactivity was increased 1 day after ischemia. Double-label fluorescence immunocytochemical study revealed that both 8-OHdG and Ref-1 were positive at 8 hours of reperfusion in the same motor neurons, which eventually die. CONCLUSION: These results suggest that Ref-1 decreased in motor neurons after transient spinal cord ischemia and that this reduction preceded oxidative DNA damage. The reduction of Ref-1 protein at the moderately late stage of reperfusion may be one of the factors responsible for the delay in neuronal death after spinal cord ischemia.

8-Hydroxy-2'-Deoxyguanosine↗
PubMed2002

High-level expression of viral interleukin-10 in cardiac allografts fails to prolong graft survival.

BACKGROUND: Viral interleukin (vIL)-10, encoded in the Epstein-Barr virus genome, shares many of the anti-inflammatory properties of cellular IL-10 but is supposed to lack IL-10's immunostimulatory properties. Thus, vIL-10 is expected to offer superior immunosuppression. METHODS: We established transgenic mice (vIL-10 Tg) that express vIL-10 systemically and transplanted their hearts as vascularized allografts into unmodified major histocompatibility complex (MHC) full-mismatch or MHC class II-disparate mice. RESULTS: The vIL-10 Tg mice revealed high-level expression of vIL-10 in major organs including the heart. However, the heart grafts from the vIL-10 Tg mice failed to exhibit prolonged survival in combination with either the MHC full-mismatch or the class II-disparate mice. In the MHC class II-disparate mice, the vIL-10 Tg heart grafts showed severe CD8 T-cell infiltration and increased interferon (IFN)-gamma mRNA expression compared with non-Tg grafts. CONCLUSION: High level expression of vIL-10 in grafts can exacerbate immunological rejection in an allogenic transplantation model.

Animals↗
PubMed2002

Safety and clinical benefits of transsubxiphoidal left ventricular puncture.

We performed a transsubxiphoidal LV puncture (TSLVP) to evaluate left ventricular function in 21 patients with both mechanical prosthetic aortic and mitral valves and successfully obtained hemodynamic information on each patient. Analyzing cardiac hemodynamic information and ventriculographic findings obtained with TSLVP, we concluded that seven of the patients required repair of their prosthetic valves. Five of these seven patients agreed to replacement of their valves, whereas two did not. TSLVP was performed adequately and safely without severe complications, suggesting that this maneuver is easier than that of transapical LV puncture and should be recommended for the assessment of left ventricular hemodynamic functions instead of the transapical LV puncture, especially in patients requiring replacement of two valves.

Adult↗
PubMed2002

Successful surgical treatment for impending rupture in acute type A dissecting aneurysm complicated with a thoracoabdominal aortic aneurysm in an octogenarian.

Emergency or urgent thoracoabdominal aortic replacement in octogenarians has high morbidity and mortality rates due to decrease in the potential of other organs because of their age and the high invasiveness. Here, report a case of an 81-year-old woman who was diagnosed as having an impending rupture in an acute type A dissecting aneurysm complicated with a thoracoabdominal aortic aneurysm, who was rescued successfully by replacement of the thoracoabdominal aorta, under epidural perfusion cooling.

Aged↗
PubMed2002

Successful surgical management of patients with infective endocarditis associated with acute neurologic deficits.

Subjects were 2 patients with neurologic deficits due to infective endocarditis. The first, a 30-year-old woman with acute ischemic stroke, was found to have vegetation from infective endocarditis as the embolic source. Two weeks after she experienced an acute ischemic stroke, we conducted elective cardiac surgery. The second, a 16-year-old girl with infective endocarditis, suffered a ruptured mycotic aneurysm in the left carotid system complicated by intracranial hemorrhage. We conducted a successful staged mitral valve replacement following craniotomy.

Adolescent↗
PubMed2002

Ascending aortic replacement through right thoracotomy.

A 62-year-old woman with a history of esophageal resection and colon interposition with anterosternal subcutaneous tunnel required replacement of the ascending aorta due to dissecting aortic aneurysm. Preoperative three-dimensional computed tomography enabled us to reveal that right thoracotomy could offer an ascending aortic operation. The patient underwent successful operation under hypothermic circulatory arrest and the right anterolateral thoracotomy provided safe exposure of the diseased ascending aorta even when the suprasternal tunnel precluded conventional median sternotomy.

Aortic Dissection↗
PubMed2002

Management of patients with intramural hematoma involving the ascending aorta.

OBJECTIVE: Although intramural hematoma of the aorta is considered a unique pathologic entity, the management of intramural hematoma involving the ascending aorta (type A) has not been well established. The purpose of this study was to establish the optimal mode of management of type A intramural hematoma. METHODS: We treated patients with type A intramural hematoma as follows. Early operation was carried out only for patients with cardiac tamponade, impending rupture, or rupture. Other patients were treated medically, but patients with progression of intramural hematoma during medical follow-up had their treatment converted to surgery. From February 1992 to March 2001, a total of 33 patients with type A intramural hematoma were treated as described here. Patients were divided according to initial treatment into an early surgery group (n = 9) and a medical treatment group (n = 24). Clinical profiles and in-hospital and long-term survival rates were compared between the groups. RESULTS: Compared with the early surgery group, the medical treatment group was younger (64.2 +/- 7.0 years vs 71.7 +/- 8.5 years, P =.0319) and had a greater number of involved segments (3.6 +/- 0.6 vs 3.0 +/- 0.9, P =.0395). Eight patients in the medical treatment group were switched to surgery during follow-up because of progression of intramural hematoma. In-hospital mortality rates in the early surgery and medical groups were 11% and 5% (P =.477), respectively. Cumulative 1- and 2-year survivals were 89% and 89%, respectively, in the early surgery group, and 92% and 81%, respectively, in the medical group (P =.49). CONCLUSION: We concluded that about 70% of type A intramural hematomas could be managed expectantly, and more than 50% could be treated medically alone.

Aged↗