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Biomedical subjects

T Asai

Publications and source records attributed to T Asai.

At least 37 records · Page 2Linked to original sources
PubMed2005

[The correlation between flow pattern during cardiopulmonary bypass and patency of the coronary artery bypass grafts].

Recently the availability of transit time flow measurement (TTFM) is reported especially in off-pump coronary artery bypass grafting (CABG). But little is known about TTFM findings in on-pump CABG. We examined the correlation between the TTFM flow pattern and the angiography findings in on-pump CABG. The subjects consisted of 52 patients who underwent on-pump CABG and angiography early after operation. In these patients, 55 internal thoracic artery (ITA), 17 gastroepiploic artery (GEA), 13 saphenous vein graft (SVG) and 41 radial artery (RA) were tested with TTFM during cardiopulmonary bypass (CPB). TTFM demonstrated a diastolic filling pattern in 53 ITA, 16 GEA, 13 SVG and 36 RA. The angiography revealed that all these grafts were perfectly patent with the exception of a GEA with a flow competition pattern. TTFM revealed an abnormal flow pattern in 2 ITA (these 2 grafts were revised during CPB and the angiography demonstrated their perfect patency), 1 GEA (to and fro pattern), 0 SVG and 5 RA (the abnormal pattern was due to graft spasm in 3 of 5, and the angiography revealed their perfect patency, however, the angiography detected stenosis in the remaining 2 grafts). The present study found that the TTFM flow pattern during CPB correlated well with the angiography findings. TTFM during CPB was useful to detect graft failure, and grafts were revised safely during CPB.

Aged↗
PubMed2005

[Advantages of side-to-side anastomosis in the assessment and revision of coronary artery bypass grafting].

With the advent of drug eluting stents in percutaneous coronary intervention, required quality level of coronary artery bypass grafting (CABG) has been elevating. To obtain nearly perfect patency of bypass grafts, intraoperative assessment and repair of abnormal grafts are helpful. We report systematic revision and safe repair technique of arterial grafts in CABG. Side-to-side instead of commonly used end-to-side anastomosis of arterial grafts is the first step in this technique. When any abnormalities are noted in intraoperative flowmetry of a graft, the distal surgical clip is removed. Free flow of the graft is measured. A coronary probe is gently inserted into the graft and the coronary artery. Vasodilators can be injected into the graft if necessary. When direct revision of the anastomosis is indicated, the graft is cut longitudinally from the distal end up to just proximal to the anastomotic site. The shape of the anastomosis can be observed directly without removing sutures. When re-anastomosis is not indicated, the distal remnant graft tissue is folded back and utilized as a patch. Thus the graft can be easily closed without narrowing.

Anastomosis, Surgical↗
PubMed2004

Ease of insertion of the laryngeal tube during manual-in-line neck stabilisation.

The laryngeal tube has a potential role in airway management during anaesthesia or cardiopulmonary resuscitation. In patients with unstable necks, the head and neck may need to be stabilised manually (manual in-line stabilisation), but it is not known whether this procedure affects the ease of insertion of the laryngeal tube. We studied, in a cross-over study, 21 adult patients to compare the success rate of ventilation through the laryngeal tube between the Magill position (a pillow under the occiput and the head extended) or the manual in-line position of the head and neck (without a pillow under the occiput). After induction of anaesthesia and neuromuscular blockade, the laryngeal tube was inserted in turn in the two positions. The ease of insertion was scored with four categories (easy, moderately difficult, difficult and impossible), and adequacy of ventilation through the device was assessed. Ventilation was adequate in all 21 patients in the Magill position, but only in two of 21 patients during manual in-line positioning (p < 0.01; 95%CI for difference: 68-94%). In the Magill position, insertion of the laryngeal tube was easy in 16 patients and moderately difficult in the remaining five patients; in the manual in-line stabilisation position, insertion was moderately difficult in two patients and impossible in the remaining 19 patients. Stabilisation of the patient's head and neck by the manual in-line method made insertion of the laryngeal tube either difficult or impossible.

Adolescent↗
PubMed2004

Analysis for the optimal blood draw speed to collect sufficient peripheral blood mononuclear cells by COBE Spectra.

In recent years the procedures for peripheral blood mononuclear cell (PBMNC) harvests have gradually been increasing. These PBMNCs are collected for several treatments, for example, donor lymphocyte infusion (DLI), immunotherapy for solid carcinoma, and regeneration therapy for ischemic limbs. In order to analyze the optimal procedure for collecting PBMNCs safely and efficiently, we evaluated 129 PBMNC apheresis procedures from April 1996 to May 2003, without hemopoietic stem cell mobilization by G-CSF. In every case, PBMNC collections were performed with a COBE Spectra cell separator (Gambro BCT). The median apheresis volume was 5550 mL. The median of blood draw speed was 48.1 mL/min. The median TNC (total nuclear cell) number in products was 50.4 x 10(3)/ micro L. In the regression analysis, no significant correlation was seen between the blood draw speed and the concentrations of TNC in products (Y = aX + b, a = 0.842497, b = 17.11352, r = 0.222032, P = 0.012464). A positive correlation was seen between WBC on apheresis day and the concentrations of TNC (Y = aX + b, a = 0.009822, b = 3.224679, r = 0.550431, P = 2.93 x 10(-11)). A significantly higher correlation was seen between the MNC (mononuclear cells) on apheresis day and the concentrations of TNC (Y = aX + b, a = 0.028278, b = 13.09266, r = 0.696988, P = 9.486 x 10(-9)). This study has shown evidence that a higher increment of blood draw speed does not provide a higher concentration of products. An adequate apheresis speed is about 40 mL/min. If we want to obtain sufficient cell counts, it is very important to obtain sufficient volume with a moderate blood draw speed, therefore protecting against side-effects.

Adolescent↗
PubMed2004

Effects of high pressure on the solubility and growth kinetics of monoclinic lysozyme crystals.

Average growth rates of the (0 1 0) and (0 1 0) faces (R<0 1 0>) of monoclinic lysozyme crystals were measured in situ under 0.1 and 100 MPa. From the dependence of the growth rates on the lysozyme concentration, we determined the solubility of the crystal as a function of temperature at 0.1 and 100 MPa. The solubility increased with an increase in pressure. From the comparison between the growth rates under 0.1 and 100 MPa at the same supersaturation level, we found that the growth rates of the monoclinic lysozyme crystals kinetically increase with an increase in pressure. Supersaturation dependencies of the growth rates under 0.1 and 100 MPa were well fitted with a two-dimensional (2D) nucleation growth model of a birth-and-spread type. The fitting results suggest that the increase in the growth rates with pressure can be explained by the decrease in the average ledge surface energy of 2D island, the average distance between the kinks on a step and the activation energies in the incorporation processes of solute molecules.

Animals↗
PubMed2003

Use of the laryngeal tube in 100 patients.

BACKGROUND: The laryngeal tube has a potential role during anaesthesia, but there have been only a few studies assessing its efficacy during the entire course of anaesthesia, and all previous studies used prototypes. We studied 100 patients to assess the efficacy of a new laryngeal tube during the entire course of anaesthesia. METHODS: After induction of anaesthesia, the laryngeal tube was inserted (up to two times) and adequacy of ventilation was assessed. The airway pressure at which gas leaked around the device was measured. The device was used during anaesthesia, while ventilation was controlled. The device was removed after the patient had opened the mouth to verbal command. Any complications during and after anaesthesia were recorded. RESULTS: Ventilation was possible at the first attempt in 90 patients, at the second attempt in another seven patients, and adequate ventilation failed after two attempts in three patients. Median (interquartile range) leak pressure was 28 (22-30) cmH2O. In all 97 patients, the laryngeal tube was used until the end of surgery. However, in two of the 97 patients the airway was partially obstructed during anaesthesia and it was necessary to reposition the device. The laryngeal tube was tolerated well during emergence from anaesthesia. No hypoxia, regurgitation, vomiting or laryngospasm occurred in any patient. On removal of the laryngeal tube, no blood was detected on the device and no apparent ischaemic changes to the tongue were observed in any patient. Post-operatively, six patients complained of a mild sore throat, and no patient complained of difficulty in swallowing or numbness of the oropharynx. CONCLUSION: The laryngeal tube can be useful for maintaining a patent airway during anaesthesia.

Adolescent↗
PubMed2003

Inhibition of NFkappaB activation using cis-element 'decoy' of NFkappaB binding site reduces neointimal formation in porcine balloon-injured coronary artery model.

Application of DNA technology to regulate the transcription of disease-related genes has important therapeutic potential. The transcription factor NFkappaB plays a pivotal role in the transactivation of inflammatory and adhesion molecule genes, leading to vascular lesion formation. Double-stranded DNA with high affinity for NFkappaB may be introduced as 'decoy' cis elements to bind NFkappaB and block the activation of genes mediating inflammation, resulting in effective drugs for treating intimal hyperplasia. In this study, we tested the feasibility of NFkappaB decoy therapy to treat neointimal formation in a porcine coronary artery balloon injury model as a pre-clinical study. An angioplasty catheter was introduced into the left anterior descending coronary artery of the pig to cause vascular injury. First, we tested the feasibility of transfection of FITC-labeled NFkappaB decoy ODN using a hydrogel balloon catheter. Fluorescence due to NFkappaB decoy ODN could be detected throughout the medial layer. Therefore, we transfected NFkappaB decoy ODN into the balloon-injured LAD using a hydrogel catheter. Histological evaluation demonstrated that the neointimal area in the balloon-injured artery was significantly reduced by NFkappaB decoy ODN as compared to scrambled decoy ODN at 1 week after single transfection, accompanied by a significant reduction in PCNA-positive stained cells (P < 0.01). Interestingly, the reduction of ICAM-positive staining was observed, accompanied by the inhibition of migration of macrophages. Of importance, intravascular ultrasound (IVUS) confirmed that neointimal area in the balloon-injured artery was significantly reduced by NFkappaB decoy ODN at 4 weeks after transfection (P < 0.01). Interestingly, the inhibition of neointimal area was only limited to the lesion transfected with NFkappaB decoy ODN, while other lesions without NFkappaB decoy ODN demonstrated a marked increase in neointimal formation. Here, we report the successful in vivo transfer of NFkappaB decoy ODN using a hydrogel catheter to inhibit vascular lesion formation in balloon-injured porcine coronary artery.

Angioplasty, Balloon, Coronary↗