Biomedical subjects

N Akasaka

Publications and source records attributed to N Akasaka.

At least 19 recordsLinked to original sources

PubMed2004

Venous blood flow through vein grafts before harvesting minimizes endothelial cell desquamation immediately after implantation.

AIM: The aim of this paper was to examine effectiveness of maintaining venous blood flow through dissected, but not harvested, grafts on prostaglandin I2 production and endothelial cell regeneration after implantation. METHODS: Using 10 dogs, 8-cm-long bilateral jugular veins were dissected; 1 was harvested, and immersed in heparinized blood for 60 or 120 min. The other was left in situ with retained blood flow until harvest after 60 or 120 min. Two 1-cm-long specimens were obtained from these 4 graft types and subjected to PGI2 assay or silver nitrate staining for measurement of endothelial cell coverage area. The remaining 6-cm portions of the 120-min grafts were autogenously implanted into the abdominal aorta, retrieved after 7 days and assayed and measured. RESULTS: Comparisons between groups suggested beneficial effects of preserving venous blood flow until implantation on endothelial coverage and PGI2 production (p<0.05). CONCLUSION: Venous blood flow through dissected vein grafts effectively helps preserve PGI2 production.

Animals↗

PubMed2003

[Acute pulmonary embolism performed embolectomy under percutaneous cardiopulmonary support successfully after lung cancer operation].

We have experienced a case of acute pulmonary embolism after lung cancer operation. The case was a 74-year-old male. He underwent left upper lobectomy due to squamous cell carcinoma. He fell into shock state suddenly on the 6th day postoperatively. We diagnosted acute pulmonary embolism, performed urgent embolectomy under percutaneous cardiopulmonary support (PCPS). Postoperative course was smooth, and he has returned to normal daily life. Urgent diagnosis and management are indispensable for acute pulmonary embolism after lung cancer operation from the aspect of residual among of pulmonary vascular bed.

Acute Disease↗

PubMed2002

Lipo-prostaglandin E1 is absorbed by vascular smooth muscle cells and may enhance re-endothelialization of vein grafts.

BACKGROUND: Enhancement of re-endothelialization inhibits the progression of intimal hyperplasia. We investigated uptake of Lipoprostaglandin E(1) (LPGE(1)) by endothelial cells (ECs) and vascular smooth muscle cells (VSMCs), and effects of the LPGE(1) on re-endothelialization of vein grafts. METHODS: Primary cultured ECs and VSMCs were obtained from mongrel dogs, and incubated in mediums containing 0.5, 5, 50, and 250 ng/ml of DiI-LPGE(1) (DLPGE(1)); its uptake was visualized by the standard rhodamine excitation, and assessed by flow cytometry. In an implantation study, the bilateral femoral veins of 18 animals were implanted into the femoral artery, and the animals were given 0.2 microg/kg LPGE(1) for 2 weeks. Percentages of EC coverage area of the grafts (%EC) were measured by silver nitrate staining at intervals of 3, 7, and 21 days after implantation. RESULTS: VSMCs showed significant uptake in all of the mediums containing DLPGE(1), whereas the ECs revealed no fluorescence. In flow cytometry, histograms of VSMCs showed a specific notch of DLPGE(1), which increased the height according to the grade of the concentrations. The notch did not appear in the histograms of the ECs incubated with any concentration nor in the VSMCs incubated in control medium. These results suggested that LPGE(1) is predominantly absorbed by the VSMCs and exuded PGE(1) then acts on the VSMCs itself and on ECs alike. The %EC at 7 days was 58.4+/-1.9% in the DLPGE(1) group and 31.6+/-6.8% in controls (p<0.05) showing a significant enhancing effect of DLPGE(1) on re-endothelialization of the vein grafts. CONCLUSIONS: In an animal model, daily administration of LPGE(1) resulted in significant enhancement of vein graft re-endothelialization. LPGE(1) was absorbed by the VSMCs, whereas the ECs showed no uptake, therefore the enhancement is probably due to a paracrine effect of VSMCs.

Alprostadil↗

PubMed2001

Evaluation of an internal thoracic artery as a coronary artery bypass graft by intercostal duplex scanning ultrasonography.

OBJECTIVES: Although angiography is often used to determine whether the internal thoracic artery is appropriate as a coronary bypass graft, but use of duplex scanning ultrasonography for this purpose is not yet widespread. METHODS: The internal diameter and flow of the internal thoracic artery were measured using intercostal duplex scanning in 100 patients during April 1995. The ultrasonographic device (sonos 2000, Hewlett Packard) used had a linear probe delivering a frequency of 7.5 MHz. Bilateral internal thoracic arteries and their blood flow were imaged clearly in all subjects. Diameter was compared by angiography and duplex scanning ultrasonography in 20 patients. RESULTS: The average internal diameter of internal thoracic artery was 2.19 +/- 0.46 mm (right) or 2.13 +/- 0.32 mm (left) in men and 2.05 +/- 0.44 mm (right) or 2.09 +/- 0.42 mm (left) in women. The gender difference was statistically significant (p = 0.05). The maximum systolic blood flow velocity through the internal thoracic artery was 0.85 +/- 0.34 m/s (right) or 0.84 +/- 0.36 m/s (left) in men and 0.87 +/- 0.28 m/s (right) or 0.82 +/- 0.28 m/s (left) in women. The average internal thoracic arterial blood flow (F) was 54.6 +/- 29.0 ml/min (right) or 50.9 +/- 28.8 ml/min (left) in men and 56.8 +/- 38.2 ml/min (right) or 58.2 +/- 33.4 ml/min (left) in women. Duplex scanning ultrasonography using an intercostal approach enables easy imaging of bilateral internal thoracic arteries and visualizes entire internal thoracic artery structure by simply changing the probe position. CONCLUSION: Intercostal duplex scanning ultrasonography is thus recommended for reliable evaluation of the internal diameter and blood flow of the internal thoracic artery.

Aged↗

PubMed2001

Role of p38 MAP kinase in endothelial cell alignment induced by fluid shear stress.

The p38/mitogen-activated protein (MAP) kinase-activated protein kinase 2 (MAPKAP kinase 2)/heat shock protein (HSP)25/27 pathway is thought to play a critical role in actin dynamics. In the present study, we examined whether p38 was involved in the morphological changes seen in endothelial cells (EC) exposed to shear stress. Cultured bovine aortic EC were subjected to 14 dyn/cm(2) laminar steady shear stress. Peak activation of p38, MAPKAP kinase 2, and HSP25 were sixfold at 5 min, sixfold at 5 min, and threefold at 30 min compared with static control, respectively. SB-203580 (1 microM), a specific inhibitor of p38, abolished the activation of MAPKAP kinase 2 and HSP25 as well as EC elongation and alignment in the direction of flow elicited by shear stress. The mean orientation angle of cells subjected to shear without SB-203580, with SB-203580, or static control were 17, 50, and 43 degrees, respectively (P < 0. 05). EC transfected with the dominant negative mutant of p38-alpha aligned randomly with no stress fiber formation despite exposure to shear stress. These data suggests that the pathway of p38/MAPKAP kinase 2/HSP25/27 is activated in response to shear stress, and this pathway plays an important role in morphological changes induced by shear stress.

Animals↗

PubMed2000

Postoperative delirium in patients with chronic lower limb ischaemia: what are the specific markers?

OBJECTIVES: we determined the incidence and specific markers of postoperative delirium in elderly patients with chronic lower limb ischaemia. PATIENTS AND METHODS: since April, 1995, 110 patients aged 60 years or older (mean: 71.6+/-6.6 years) who underwent bypass surgery were assessed regarding aetiological factors of delirium: age, sex, dementia, body-mass index, hypertension, diabetes, cerebral disease, laboratory test results, severity of limb ischaemia, type of arterial occlusion, operative time, and blood transfusion. RESULTS: discriminant analysis showed statistical significance in the following five variables: age >/=70 years; critical limb ischaemia (and/or ankle pressure <40 mmHg); dementia; duration of operation >/=7 hours; low serum albumin. The overall percentage of cases correctly classified was 78.2% (Wilks>> Lambda=0.695, p<0.001); the standardized regression coefficients of the five variables were 0.648, 0.500, 0.329, 0.218, and 0.200, respectively. In logistic regression, the regression coefficients for old age and critical limb ischaemia were 2.646 (14.1 of odds ratio; 95% confidence interval, 2.7-72.0) and 1.337 (3.8; 1.3-10.9), respectively. CONCLUSIONS: the incidence of postoperative delirium in elderly patients with chronic lower-limb ischaemia was as high as 42.3%, and an age of over 70 years and critical limb ischaemia were identified as specific markers, with 14.1 times and 3.8 times the odds of suffering from delirium after bypass surgery.

Age Distribution↗

PubMed2000

Endothelial cell response to different mechanical forces.

PURPOSE: Endothelial cells (ECs) are subjected to the physical forces induced by blood flow. The aim of this study was to directly compare the EC signaling pathway in response to cyclic strain and shear stress in cultured bovine aortic ECs. MATERIALS AND METHODS: The ECs were seeded on flexible collagen I-coated silicone membranes to examine the effect of cyclic strain. The membranes were deformed with a 150-mm Hg vacuum at a rate of 60 cycle/min for up to 120 minutes. For a comparison of the effect of shear stress, ECs from the same batch as used in the strain experiments were seeded on collagen I-coated silicone sheets. The ECs were then subjected to 10 dyne/cm(2) shear with the use of a parallel flow chamber for up to 120 minutes. Activation of the mitogen- activated protein kinases was assessed by determining phosphorylation of extracellular signal-regulated kinase (ERK), c-jun N-terminal kinase (JNK), and p38 with immunoblotting. RESULTS: ERK, JNK, and p38 were activated by both cyclic strain and shear stress. Both cyclic strain and shear stress activated JNK with a similar temporal pattern and magnitude and a peak at 30 minutes. However, shear stress induced a more robust and rapid activation of ERK and p38, compared with cyclic strain. CONCLUSIONS: Our results indicate that different mechanical forces induced differential activation of mitogen-activated protein kinases. This suggests that there may be different mechanoreceptors in ECs to detect the different forces or alternative coupling pathways from a single receptor.

Animals↗

PubMed2000

An experience of a case with perforation of an aneurysm in the anterior mitral cusp developing after aortic valve replacement.

Mitral valve aneurysm is a rare disease and in Japan, cases of perforation which is considered to be mainly caused by infectious endocarditis is usually only encountered through case reports. We experienced a case who received aortic valve replacement and mitral valve annuloplasty for combined valvular heart disease of aortic insufficiency and mitral insufficiency followed by mitral valve replacement for severe mitral valve regurgitation subsequent to perforation of the anterior mitral cusp, leading to recovery.

Aneurysm, Ruptured↗

PubMed1999

Poststernotomy mediastinitis treated by rectus muscle flap plugging.

The current standard treatment of mediastinitis following median sternotomy is radical sternal curettage and plugging of the anterior mediastinal dead space with muscle flap or omentum. This paper will report our experience with a pediculated flap of the rectus muscle after mediastinal irrigation and drainage. The patient was a 75-year-old man diagnosed as having aortic arch aneurysm. The patient underwent a total aortic arch replacement with the bovine-collagen sealed vascular prosthesis (Hemashield). As an early postoperative complication, he was diagnosed with mediastinitis which was the result of infection of the drainage fluid. Mediastinal curettage and plugging of the rectus muscle flap was successfully performed. Without recurrence of infection, the wound healed completely. We conclude that early curettage and rectus muscle flap plugging are the most effective treatment of the poststernotomy mediastinitis.

Aged↗

PubMed1999

Vascular clamp for hemostasis and stabilization during minimally invasive direct coronary artery bypass.

A soft vascular clamp was used for hemostasis and stabilization of the operative field during minimally invasive direct coronary artery bypass (MIDCAB). The instrument was gently applied so that it clamps the coronary artery by grasping the adjacent myocardium. The method offered dry and stable operative field without a special instrument or technique. The surgical results have been satisfactory. We found application of the vascular clamp to be very helpful for MIDCAB.

Arteries↗

PubMed1999

[Serial cerebral computed tomography and magnetic resonance imaging in a case of hemolytic uremic syndrome with the complication of the central nervous system due to Escherichia coli O157:H7].

We report serial cerebral computed tomography (CT) and magnetic resonance imaging (MRI) in a case of hemolytic uremic syndrome (HUS) with the complication of the central nervous system due to Escherichia coli O157:H7. Although initial brain CT was normal, follow-up CT and MRI revealed lesions in the white matter and bilateral basal ganglia, representing brain edema and infarcts, respectively. Especially, lesions in the bilateral basal ganglia were very unique. Serial CT and MRI findings are useful to understand the mechanism of the complications of the central nervous system associated with HUS.

Brain↗

PubMed1999

[Right phrenic nerve palsy in a patient with ventricular septal perforation after acute myocardial infarction].

A 77-year-old female had acute myocardial infarction and ventricular septal perforation (VSP). An operation was performed 14 days after VSP. During cardiopulmonary bypass, a patch was sutured in place on the left side of the defect under a mild hypothermia with topical cardiac cooling procedure. In the postoperative period, mechanical ventilation was continued with use of pulmonary monitor (CP-100, BICORE). When the patient was weaned of mechanical ventilation, work of breathing increased (WOBp: 1.67 J.l-1) without the change of SaO2, PaO2, PaCO2 and the respiratory state. After extubation, the chest X-ray showed elevated right diaphragmatic level and a diagnosis of unilateral diaphragmatic paralysis was made. Oral intake was started two days after extubation. SpO2 decreased after oral intake, and it was significantly improved by taking a left lateral position. The symptoms disappeared 47 days after the operation. It should be noticed that the rise of endoceliac pressure in the patient who had a unilateral phrenic nerve palsy, affected the SpO2.

Aged↗

PubMed1998

[Intraoperative coronary artery spasm treated by percutaneous cardiopulmonary support in a patient with left lung cancer].

A 53-year-old man with left lung cancer underwent left upper lobectomy and extended mediastinal lymphadenectomy. Shortly before the end of the operation, electrocardiogram showed elevation of ST wave and multiple ventricular premature contractures first, then ventricular fibrillations, and finally cardiac arrest. Coronary artery spasm was strongly suspected. The patient was resuscitated by cardiac massage and countershock immediately, however, such attacks repeated several times. As medication and cardiac pacing were not effective, percutaneous cardiopulmonary support (PCPS) was established. The hemodynamics was stabilized with PCPS. He was weaned off PCPS the next day. He was discharged and has had no attack so far. PCPS is an excellent modality for intraoperative coronary spasm which is uncontrollable by medicines and other methods.

Carcinoma, Squamous Cell↗

PubMed1997

[A case of ruptured aortic arch aneurysm with hemorrhagic cardiac tamponade].

The ruptured thoracic aortic aneurysm is still a dramatic even with very poor outcome, whereby its survival depends largely on early diagnosis and operation. We report a successful case of aortic arch replacement for ruptured aortic arch aneurysm with cardiac tamponade. Lethal hemopericardium causing cardiac tamponade is most commonly seen as a complication of acute myocardial infarction or acute aortic dissection, and subsequent rupture of the heart or ascending aorta leads to the rapid accumulation of blood within the poorly distensible pericardial sac. Our case was operated upon emergency basis due to hemopericardium. On operative findings, the aortic aneurysm located the minor curvature of aortic arch and was a huge saccular shape. In surgical procedure, the total arch replacement was completed using selective cerebral antegrade perfusion with deep hypothermia. Postoperative course was uneventful and no cerebral complication was observed after surgery.

Aortic Aneurysm, Thoracic↗

PubMed1996

Ulinastatin reduces elevation of cytokines and soluble adhesion molecules during cardiac surgery.

PURPOSE: To investigate whether ulinastatin pretreatment (6000 U.kg-1 before CPB and before declamping of aorta) influenced the production of cytokines and adhesion molecules in the peripheral circulation. METHODS: This prospective randomized study was performed in 22 patients undergoing cardiac surgery. They were divided into two groups. Patients in Group I were untreated and in Group II treated with ulinastatin. The soluble intercellular adhesion molecule-1 (S-ICAM-1), soluble endothelial leukocyte adhesion molecule-1 (S-ELAM-1), interleukin 8 and 6 (IL- 8, 6) were measured using ELISA kits. RESULTS: Serum S-ICAM-1 concentration in Group I increased from the preoperative value of 297 +/- 27 ng.kg-1 to 418 +/- 106 ng.kg-1 at 60 min after declamping of the aorta (P < 0.01) but did not change in Group II. Serum S-ELAM-1 concentration did not change in either group. Serum concentration of IL-8 and IL-6 in Group I (37 +/- 44 pg.kg-1, and 59 +/- 59 pg.kg-1, preoperatively) increased to 169 +/- 86 pg.kg-1 and 436 +/- 143 pg.kg-1 at 60 min after declamping of the aorta (P < 0.001, P < 0.001). The increases were greater than those from 25 +/- 6 pg.kg-1 and 30 +/- 26 pg.kg-1 to 56 +/- 36 pg.kg-1 and 132 +/- 78 pg.kg-1 in Group II (P < 0.001, P < 0.001). The levels of S-ICAM-1 correlated with those of IL-8 (r = 0.5, P < 0.001). CONCLUSION: These results suggest that ulinastatin may suppress the increase in IL-8 production and the expression of ICAM-1 during cardiac surgery.

Adult↗

PubMed1994

Biotin production by bifidobacteria.

Biotin production and the growth of the strains of Bifidobacterium adolescentis, B. bifidum, B. breve, B. infantis, and B. longum were studied. These five strains showed heavy growth on BL medium. But when yeast extract medium (carbon source, glucose) was used, the extent of their growth was significantly decreased, one-half or less than that of the growth on BL medium. B. bifidum grew well on yeast extract medium containing oligosaccharides, such as isomaltooligosaccharide, and produced biotin extracellularly. The utilization of oligosaccharides in biotin production by these five strains was investigated.

Bifidobacterium↗

PubMed1994

[Congenital coronary arterial fistula drained to the coronary sinus--a case report].

We report a very rare case of an infant with coronary arterial fistula in whom the communication between a dilated right coronary artery and the coronary sinus was found. The patient was 1-year-old. She had pulmonary congestion and cardiomegaly due to the left-to-right shunt through the fistula, and underwent ligations of the fistula. Ligations of the fistula was indicated because the patient was too small to undergo a fistula resection and coronary arterial bypass grafting. Although the patient had a successful post-operative course, we are paying attention to the aneurysmal change of the dilated right coronary artery proximal to the site of ligations.

Arteriovenous Fistula↗

PubMed1994

[The inhibitory effects of ulinastatin on the increase of interleukin 8 and 6 during open heart surgery].

The effects of ulinastatin on the serum interleukin 8 and 6 (IL-8, 6), granulocyte elastase (GEL), creatinphosphokinase (CK) and CK-MB were studied during open heart surgery under cardiopulmonary bypass (CPB). Eleven patients (group I) did not receive ulinastatin. Thirteen patients (group II) received 600,000 units of ulinastatin intravenously before CPB and before declamping of aorta and 12 patients (group III) received 300,000 units more added in the priming solution. The serum concentration of IL-8 and 6 increased at 60, 120, 180 min. after reperfusion compared with the preoperative value in the three groups. But, at each time point after reperfusion, IL-8 and 6 levels in group II and III were significantly lower (P < 0.01) than those in group I. GEL increased progressively after reperfusion in the three groups. There was no significant difference in the three groups with CK-MB as well CK release. These results suggest that ulinastatin is useful for protection of reperfusion injury after myocardial ischemia since ulinastatin suppresses production of IL-8 and 6.

Aged↗