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Biomedical subjects

Kenji Okada

Publications and source records attributed to Kenji Okada.

At least 19 recordsLinked to original sources
PubMed2006

Controlled release of basic fibroblast growth factor from gelatin hydrogel sheet improves structural and physiological properties of vein graft in rat.

OBJECTIVES: Autologous vein grafts are still widely used, but their long-term patency is suboptimal. The objective of the current study was to determine whether wrapping a vein graft in gelatin hydrogel sheet incorporating basic fibroblast growth factor improves their mechanical and physiological properties. METHODS AND RESULTS: Autologous femoral vein was interposed into the abdominal aorta in rats. The rats were divided into 3 groups: nontreated grafts (group A), grafts wrapped in basic fibroblast growth factor-free gelatin hydrogel sheet (group B), and grafts wrapped in basic fibroblast growth factor-impregnated gelatin hydrogel sheet (group C). On day 1, endothelial desquamation was observed in group A, and the media in groups A and B were disrupted, staining positive in the terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling assay. In contrast, the media in group C remained intact and terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling-negative, associated with activation of MAPK. Graft dilation was significantly inhibited in groups B and C compared with group A, with those in group C showing the smallest degree of neointimal proliferation. At 8 weeks grafts in group C developed neointima with homogeneous elastic laminae, presence of rigid neoadventitia that displayed neovascularity, and the highest blood flow velocity. CONCLUSIONS: Wrapping vein grafts in basic fibroblast growth factor-impregnated gelatin hydrogel sheet improved their structural and physiological properties, and might therefore also improve long-term patency.

Anastomosis, Surgical↗
PubMed2006

Intra-aortic injection of propofol prevents spinal cord injury during aortic surgery.

OBJECTIVE: We investigated whether propofol, a widely used anesthetic, injected into clamped aortic segments quickly attenuated transcranial spinal motor-evoked potential (MEP) amplitudes and protected against spinal cord injury during thoracoabdominal aortic surgery. METHODS: Eighteen beagle dogs were divided into three groups (n=6, each group): group 1 (20 ml of saline, intra-aortic injection), group 2 (1.5 mg/kg of propofol, intravenous injection), and group 3 (1.5 mg/kg of propofol, intra-aortic injection). Aortic cross-clamping was performed for 30 min. In each group, MEP amplitudes were recorded before, during, and after aortic cross-clamping. Tarlov score and histopathological examination were used to evaluate the protective effects of intra-aortic propofol injections. RESULTS: MEP amplitudes in group 3 attenuated to a value that was 60% of the control in just a minute after aortic cross-clamping, but maintained 40% of the control value during aortic cross-clamping. However, MEP amplitudes in groups 1 and 2 gradually attenuated and almost disappeared. Groups 1 and 2 amplitudes were lower than those in group 3, 30 min after aortic cross-clamping (p<0.001). Twenty-four hours after ischemia, the Tarlov score in group 3 was 3.5+/-0.5 and was higher than scores from groups 1 and 2, which were 0.5+/-0.5 and 1.3+/-1.2 (mean+/-SD, p<0.001, and p<0.001), respectively. Histopathologically, normal spinal cord motor neurons in group 3 were preserved to a significantly greater extent than in groups 1 and 2 (p=0.0031, and p=0.0282, respectively). There was a strong correlation between Tarlov scores at 24h and the number of normal motor neurons in the anterior horns of spinal cords (r=0.897; p<0.001). CONCLUSIONS: Intra-aortic propofol injections produce the quick suppression of MEP amplitudes and protect spinal cords from ischemia during aortic cross-clamping.

Animals↗
PubMed2006

His239Arg SNP of HRAD9 is associated with lung adenocarcinoma.

BACKGROUND: It was previously reported that a functional human (h) Rad9 protein accumulated in the nuclei of non-small cell lung carcinoma (NSCLC) cells. Those experiments, however, did not examine whether the hRad9 gene was mutated in those cells. The sequence of the HRAD9 gene in NSCLC cells was investigated. METHODS: The sequence of the HRAD9 was examined in tumor and peripheral normal lung tissues obtained from 50 lung adenocarcinoma patients during surgery. The expression of its mRNA using reverse transcription polymerase chain reaction (RT-PCR) was also examined. RESULTS: No sequence alterations were detected in the HRAD9 gene, which was found to be normally transcribed in surgically resected lung carcinoma cells. However, in eight (16.0%) cases a single nucleotide polymorphism (SNP) was observed at the second position of codon 239 (His/Arg heterozygous variant) of the gene. This frequency was significantly higher than that found in the normal population. CONCLUSIONS: Whereas the capacity to produce a functional hRad9 protein was intact in lung adenocarcinoma cells, a nonsynonymous SNP of HRAD9 was detected that might be associated with the development of lung adenocarcinoma.

Adenocarcinoma↗
PubMed2006

Disruption of the vascular prosthesis caused by aortic calcification after replacement of the thoracoabdominal aortic aneurysm.

A 52-year-old man underwent a replacement of the thoracoabdominal aorta. The aorta was severely calcified, and was replaced by a 24-mm woven Dacron (Vascutek, Renfrewshire, Scotland) graft wrapped with the calcificated aneurysmal wall. His postoperative course was uneventful; however, he collapsed on the 18th postoperative day. He underwent an emergent thoracotomy and the wrapped aneurysmal wall was taken down. The prosthesis graft had a 1-mm disruption in the middle portion, which did not relate to the anastomoses. Experimental study ex vivo showed that disruption of the prosthesis could have occurred after a 3-week pulsatile force caused by a seashell simulating aortic calcification.

Animals↗
PubMed2006

Perforation of the Valsalva sinus after implantation of Medtronic Freestyle aortic bioprosthesis.

We report on structural valve deterioration in patients with the Medtronic Freestyle aortic bioprosthesis (Medtronic, Inc, Minneapolis, MN), including spontaneous perforation of the Valsalva sinus. These occurred in four prosthesis in 3 patients using the modified subcoronary method or full root technique. One patient died of ruptured pseudoaneurysm and the others survived reoperation well. Careful follow-up is required after Freestyle bioprosthesis implantation.

Aortic Rupture↗
PubMed2006

Surgical experience for the pulmonary artery sarcoma.

BACKGROUND: Pulmonary sarcoma arising from the pulmonary artery is a rare disease and its prognosis is disastrous. METHODS: Five patients who underwent surgery for pulmonary artery sarcoma were reviewed. RESULTS: All patients except one were initially diagnosed with pulmonary embolism. One patient with preoperative profound shock could not wean from cardiopulmonary bypass. Two patients are still surviving for 36 and 30 months, respectively. CONCLUSIONS: Early diagnosis and complete surgical resection is perhaps the best way to improve patients with pulmonary artery sarcoma.

Aged↗
PubMed2006

Surgical treatment for Kommerell's diverticulum.

OBJECTIVE: Kommerell's diverticulum, which is a rare condition, is a congenital abnormality of the aortic arch. The strategy of surgical treatment for Kommerell's diverticulum has not been established. METHODS: Between 1994 and 2004, 6 patients underwent surgery for Kommerell's diverticulum at our institute. Diagnoses included right aortic arch with aberrant left subclavian artery in 4 patients and left aortic arch with aberrant right subclavian artery in 2 patients. Indications for surgery were dilatation of Kommerell's aneurysm (n = 4) and dysphagia (n = 2). One patient underwent total arch replacement through the median sternotomy plus right thoracotomy. Five patients underwent replacement of the descending aorta and reconstruction in situ (n = 4) or ligation (n = 1) of the stenotic aberrant subclavian artery through the right (n = 3) or left (n = 2) thoracotomy. RESULTS: There were no patient deaths or patients who required rehospitalization. Mediastinitis occurred in 1 patient. This patient required mediastinal drainage and an omentopexy. Two patients who had dysphagia became asymptomatic. Postoperative angiographies in all patients were satisfactory. The patient whose aberrant subclavian artery was ligated had no ischemic symptom of the arm. At the midterm outcomes (mean follow-up length was 55.6 +/- 42.2 months, ranging 10-114 months), all patients resumed normal activities without any complications. CONCLUSIONS: Kommerell's diverticulum can be repaired safely with graft replacement concomitant with in situ reconstruction of the aberrant subclavian artery through thoracotomy.

Aged↗
PubMed2006

Cold spinoplegia and transvertebral cooling pad reduce spinal cord injury during thoracoabdominal aortic surgery.

OBJECTIVE: We examined the protective effects of the new selective spinal cord cooling by using cold saline infusion into the cross-clamped aorta and a transvertebral cooling pad placed over the lumbar vertebral column from paraplegia caused by ischemic spinal cord injury on thoracoabdominal aortic surgery. METHODS: Eighteen rabbits were divided into three groups: groups I, II, and III (n = 6 for each group). In group I (37 degrees C; 5 mL) and group II (3 degrees C; 5 mL), saline was infused into the isolated aortic segment twice, at 0 and 5 minutes after aortic cross clamping. In group III, a 3 degrees C saline solution plus cooling pads placed just after cross clamping were combined. The infrarenal aorta was then isolated proximally and distally by vascular clamps for 12 minutes. In our preliminary study, only the abdominal aorta just distal to the left renal artery was clamped. At 48 hours after reperfusion, the groups clamped for 12 and 15 minutes were all paraplegic. The time of clamping the aorta was set at 12 minutes as the critical point when paraplegia occurred upon simple clamping of the infrarenal aorta only. The spinal cord temperature was monitored at the L4 level continuously during the procedures in all three groups. At 8, 24, and 48 hours after the operation, hind limb function was estimated by using the Tarlov score, which is often used for evaluating motor function in animals. A histopathologic study using hematoxylin and eosin stains was also performed. RESULTS: At 48 hours after the operation, the Tarlov scores in groups I, II, and III were 0 +/- 0, 2.0 +/- 1.9, and 4.0 +/- 0 (mean +/- SD), respectively. The Tarlov score and histopathologic analysis in group III were significantly superior to those of groups I (P < .01) and II (P < .05). The spinal cord temperature in groups II and III decreased by -1.8 degrees C and -4.3 degrees C at its minimum. The rabbits in group III were also protected from paraplegia. CONCLUSIONS: Selective spinal cord cooling with cold saline infusion into the isolated aortic segment and transvertebral regional cooling can reduce the neurologic damage of spinal cord ischemia.

Animals↗
PubMed2006

Detection and monitoring of complications associated with femoral or axillary arterial cannulation for surgical repair of aortic dissection.

OBJECTIVES: Femoral arterial perfusion can be associated with complications, and axillary arterial perfusion is not free from risk. The purpose of this study was to describe the incidence and complications of femoral versus axillary artery cannulation for surgical repair of aortic dissection and to devise a strategy for early detection and monitoring of complications using transesophageal echocardiography, near-infrared spectroscopy, and orbital Doppler. DESIGN: Retrospective and observational. SETTING: University hospital. PARTICIPANTS: Seventy-five consecutive patients with aortic dissection who underwent aortic repair between 1995 and 2004. INTERVENTIONS: Aortic surgery. MEASUREMENTS AND MAIN RESULTS: Among the 44 cases with femoral arterial perfusion, sudden onset of hypotension occurred in 3 cases but was immediately treated based on the TEE diagnosis (collapse of true lumen in the descending aorta). In another case, myocardial ischemia occurred because of occlusion of the coronary artery. These four cases comprised 57.1% of 7 patients with type III dissection with retrograde extension in whom femoral arterial perfusion was used. However, malperfusion was not encountered in 3 cases of the same type of dissection but with axillary arterial perfusion. Axillary artery perfusion (29 cases) led to malperfusion of the right frontal lobe and coronary artery in 1 case each. CONCLUSIONS: Flexible management guided by real-time information is essential. Upon initiating femoral arterial perfusion, malperfusion should first be checked for in the descending aorta and then in the coronary and visceral arteries, especially in cases of type III dissection with retrograde extension. Attention should be paid to cerebral and coronary malperfusion when initiating axillary arterial perfusion.

Adult↗
PubMed2006

An alternative for descending thoracic aortic aneurysm repair.

A simple technique termed "clamp test and spinal cord-plegia" for descending thoracic aortic aneurysm surgery is described. The clamp test is a passive method of creating ischemic conditions, whereas spinal cord-plegia is an active method of decreasing metabolism. This technique is a practical test that double-checks for critical feeding arteries and seems to have an excellent spinal cord-preserving effect.

Aged↗
PubMed2005

Perioperative diagnosis of mesenteric ischemia in acute aortic dissection by transesophageal echocardiography.

OBJECTIVE: Although computed tomography, angiography, or magnetic resonance imaging is most commonly used for diagnosing mesenteric ischemia caused by acute aortic dissection, use of these modalities is often limited in the perioperative period. Thus, we have introduced transesophageal echocardiography to cover this deficit. Purpose of this study is to report the feasibility and accuracy of transesophageal echocardiographic diagnosis on mesenteric ischemia. METHODS: The consecutive 24 cases with acute aortic dissection which involved abdominal aorta and underwent surgery were examined. The celiac artery and superior mesenteric artery was visualized with 5 MHz biplane transesophageal echocardiography and was assessed for presence of dissection and blood flow in each of true and false lumen. The transesophageal echocardiographic findings were then correlated to the clinical course, computed tomographic findings, and laboratory data. RESULTS: The celiac artery and superior mesenteric artery was successfully visualized in 24 cases (100%) and 23 cases (95.8%), respectively. Perfusion patterns in superior mesenteric artery were categorized into four patterns: (1) intact artery with adequate perfusion (type A: 14 cases); (2) dissection in the artery but with adequate perfusion in true lumen (type B: 5 cases); (3) dissection in the artery with narrowed true lumen compressed by false lumen without detectable blood flow (type C: 1 case); and (4) obstruction of arterial orifice by the intimal flap with narrowed true lumen in the proximal aorta (type D: 2 cases). One case with immediate postoperative death and another case with unsuccessful visualization of superior mesenteric artery were excluded from the analysis. Clinically apparent intestinal ischemia was present in three cases: one case with type C and two cases with type D, but in none of the remaining 19 cases with type A or type B (both sensitivity and specificity were 100%). The superior mesenteric artery was opacified in all of these three cases with ischemia. CONCLUSIONS: The transesophageal echocardiographic assessment is feasible in nearly all patients and potentially provides correct diagnosis on intestinal ischemia in the perioperative period of acute aortic dissection. Types C and D indicate significant mesenteric malperfusion.

Acute Disease↗