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Biomedical subjects

I Yada

Publications and source records attributed to I Yada.

At least 163 records · Page 9Linked to original sources
PubMedDate not supplied

Relief of mesenteric ischemia by Z-stent placement into the superior mesenteric artery compressed by the false lumen of an aortic dissection.

In a 58-year-old man acute aortic dissection compromised the origin of the superior mesenteric artery (SMA), resulting in mesenteric ischemia. After failed balloon angioplasty a Gianturco Z-stent was placed. The stenosis improved immediately, followed by resolution of the clinical signs of mesenteric ischemia. SMA flow was well preserved 1 year after stenting.

Acute Disease↗
PubMedDate not supplied

Treatment of chronic type B aortic dissection with endovascular stent-graft placement.

A 74-year-old man with chronic aortic dissection was treated with an endovascular stent graft, fabricated from expanded polytetrafluoroethylene and a Z-stent. It was placed in the true lumen to close an entry tear. Closure was obtained immediately and thrombosis of the false lumen at the descending thoracic aorta was observed on computed tomography (CT) obtained 1 week later. No procedure-related complications developed. The patient is doing well with no adverse events including aortic rupture or aortic branch ischemia.

Aged↗
PubMedDate not supplied

The role of the protein C-thrombomodulin system in physiologic anticoagulation during cardiopulmonary bypass.

Changes in the protein C-thrombomodulin (PC-TM) system in relation to other coagulofibrinolytic parameters were examined in 25 patients undergoing open heart surgery. Although all patients were given heparin, a decrease in antithrombin III (ATIII) and progressive increase in thrombin-ATIII complex (TAT) and fibrinopeptide A (FPA) levels were noted during cardiopulmonary bypass, which indicated that heparinization did not completely inhibit the formation of thrombin and its function. C1-inactivator (INA) resistant fibrinolytic activity increased markedly during CPB, in parallel with the change of tissue plasminogen activator antigen (t-PA;Ag), which indicates that fibrinolytic activity during CPB is mainly of extrinsic origin caused by t-PA. Protein C antigen (PC;Ag), protein S antigen (PS;Ag), and thrombomodulin antigen (TM;Ag) were all decreased significantly during CPB. This is considered to reflect the activation and consumption of the PC-TM system in response to generated thrombin. Furthermore, enhancement of the extrinsic fibrinolytic system is easily explained by the action of activated PC, which counteracts plasminogen activator inhibitor (PAI-1), to cause enhancement of t-PA activity.

Adult↗
PubMedDate not supplied

Experimental evaluation of a newly developed ultrathin silicone layer coated hollow fiber oxygenator.

The authors developed a new membrane oxygenator that consists of microporous polypropylene hollow fibers coated with a 0.2 micron ultrathin silicone layer. Five venoarterial bypasses were conducted on mongrel dogs for 24 hr using these new oxygenators. The blood flow rate was maintained at 750 ml/min, and the V/Q ratio was maintained at 1:1. As a control, three venoarterial bypasses were conducted under the same conditions using an oxygenator with the same design but without the silicone coating. Eight to 16 hr after the initiation of bypass, severe plasma leakage occurred in all control experiments, so the bypasses were terminated. However, plasma leakage did not occur throughout the 24 hr of any of the experiments using the new oxygenator. The O2 transfer rate of the new oxygenators after 24 hr of perfusion was 59.7 +/- 6.6 ml/min/m2, and the plasma free hemoglobin level 8 hr after the initiation of bypass was 41.4 +/- 40.2 mg/dl, compared with 145.3 +/- 189.6 mg/dl in the control group. Scanning electron microscopic examination of the silicone coated fibers after 24 hr of bypass revealed a few scattered platelet adherents and no damage to the silicone coated surface. These results suggest that this new oxygenator has satisfactory gas transfer and good durability.

Animals↗
PubMedDate not supplied

Effect of ultrafiltration on priming solution with preserved blood for extracorporeal circulation in infants.

In pediatric cardiac surgery, the initial priming solutions of the extracorporeal circulation include preserved blood. In an effort to eliminate unfavorable effects of preserved blood on the circulation, the authors introduced the preserved blood to ultrafiltration (UF). Seventeen infants with congenital heart defects were included in this study. UF was performed with a polysulfone ultrafiltrator before extracorporeal circulation. The 1600 ml of fluid, consisting of saline, 5% glucose, and maltose, were added to 400 ml of preserved blood, and the same amount of fluid was removed by UF. The concentrations of potassium, NH3, and bradykinin in the priming blood decreased significantly after UF. In the UF group, water balance during extracorporeal circulation and max. Creatinine-phosphokinase levels after surgery were better than controls. These data suggest that UF is able to remove some substances and result in reduction of an unfavorable effect on the circulation.

Blood Preservation↗
PubMedDate not supplied

Comparative studies of glycoprotein Ib in heparin coated and nonheparin coated extracorporeal circulation circuits.

Contact between blood and artificial materials has various effects on blood. Impairment of platelet function is an especially important and well known effect, but its precise mechanism is not clearly understood. The authors constructed a circulation model to investigate the effect of extracorporeal circulation on platelet membrane glycoproteins (GPs), especially GP Ib, and to compare the changes in GP Ib in heparin coated (group C) and nonheparin coated (group N) circuits. As determined by flow cytometry, GP Ib in both groups decreased on initiating circulation, but the decrease in group N was significantly larger than that in group C. There was no observed change in GP IIb/IIIa levels in either group. The extent of shear stress induced platelet aggregation significantly decreased during circulation in both groups. Decreases in the extent of shear stress induced platelet aggregation were significantly less with the use of heparin coated circuits. In addition, the amount of GP Ib in the high speed pellet decreased progressively during circulation in both groups. In contrast, the amount of GP Ib in the Triton insoluble (low speed) pellet increased dramatically during circulation. However, expression of GP Ib in the Triton soluble platelet fraction was low in both groups. From the results, it was concluded that the cause of the decrease in platelet function during extracorporeal circulation is attributable to the internalization of GP Ib from the platelet surface inside the platelet. It also can be said that a heparin coated circuit is one effective means of controlling this change.

Blood Platelets↗
PubMedDate not supplied

Histologic changes in donor bronchi may explain the reduced mucosal blood flow seen during acute lung allograft rejection.

We assessed the histologic changes in donor and recipient bronchi from 15 dogs that had received a lung transplant and related these changes to the severity of acute rejection seen in the parenchyma of these same lungs. Minimal rejection was associated with no abnormal change in either the donor or the recipient bronchi. In mild lung rejection, mononuclear cell cuffings were seen around bronchial arteries in donor bronchial adventitia, although few mononuclear cell infiltrates were seen in the submucosa. Moderate lung rejection was associated with more prominent mononuclear cell cuffings in the donor bronchial adventitia and mucosal infiltrates of mononuclear cells in the membranous portion. In cases of severe lung rejection, the mononuclear cell infiltrates were also apparent in the cartilaginous portion of the donor bronchial mucosa. Moreover, submucosal edema and detachment of bronchial epithelium were seen. These histologic changes were not observed in the recipient bronchi during acute rejection, nor were they seen in the donor and the recipient bronchi during lung infection without rejection. They might, therefore, reflect acute rejection in the donor bronchus. These results might provide the histologic support for our previous observation of decreased bronchial mucosal blood flow measured by the laser Doppler flowmeter in relation with the extent of acute lung rejection.

Acute Disease↗
PubMedDate not supplied

Administration of haptoglobin during cardiopulmonary bypass surgery.

A study was undertaken to evaluate hemolysis and subsequent renal damage in 14 patients undergoing cardiopulmonary bypass (CPB) surgery. In all patients, free haptoglobin disappeared completely 30 to 90 minutes into CPB, while free hemoglobin (Hb) levels increased progressively. The NAG index and alpha 1M index also increased progressively, indicating renal tubular injury due to hemolysis (Study 1). An additional 20 patients were monitored intraoperatively for plasma free Hb levels by a newly developed colorimetric method using a haptoglobin coated strip. Free Hb levels during CPB exceeded 30 mg/dl in 14 patients, who were immediately given haptoglobin. This treatment eliminated plasma free Hb within 30 minutes, and effectively prevented hemoglobinuria. Haptoglobin treatment brought significant decreases in the NAG index and alpha 1M index, suggesting a protective effect on renal function (Study 2).

Acetylglucosaminidase↗
PubMedDate not supplied

Nafamostat mesilate administration during cardiopulmonary bypass decreases postoperative bleeding after cardiac surgery.

The hemostatic effect of nafamostat mesilate (FUT-175) was evaluated in patients undergoing cardiopulmonary bypass (CPB) surgery. Thirty patients undergoing aortocoronary bypass grafting were divided into two groups. In the control group, anticoagulation was achieved with an initial dose of heparin (3 mg/kg). In the FUT-175-treated group, in addition to the ordinary treatment with heparin, FUT-175 was infused continuously into the circuit throughout the procedure at a rate of 100 mg/hr. Thrombin-antithrombin III complex (TAT), fibrinopeptide A (FPA), and fibrin degradation products (FDP-D) dimer increased in both groups as CPB proceeded. In the FUT-175-treated group, these parameters remained lower and decreased more rapidly after the end of CPB. Alpha 2 plasmin inhibitor/plasmin complex (PIC) increased progressively during CPB in the control group; no such significant increases were seen in the FUT-175-treated group. Postoperative blood loss was significantly lower in the FUT-175-treated group than in the control group. It was concluded that FUT-175 reduces postoperative blood loss by inhibiting both coagulation and fibrinolysis during CPB.

Adult↗
PubMedDate not supplied

Significance of bronchial mucosal blood flow for the monitoring of acute rejection in lung transplantation.

Bronchial mucosal blood flow (BMBF) was measured with a laser-Doppler flowmeter in a canine model (n = 20), and the measurement was evaluated to see if it was a useful method for diagnosing allografted lung rejection. The ratio of the value of BMBF at the level of the donor second carina against that at the level of carina (the L/C ratio, an index of BMBF of donor bronchus) decreased in accordance with the extent of lung rejection, and it increased and entered the normal range with the reversal of lung rejection. Compared with the L/C ratio and the rejection grade by histologic changes in open-lung biopsy, the L/C ratio at grade 0 (latent phase) was 0.91 +/- 0.07; at grade Ia (early vascular phase), 0.86 +/- 0.05; at grade Ib (late vascular phase), 0.68 +/- 0.10; at grade II (early alveolar phase), 0.60 +/- 0.14; and at grade III (late alveolar phase), 0.50 +/- 0.15. A significant difference was noted between grades Ia and Ib (p less than 0.01) and between grades Ib and III (p less than 0.01). The sensitivity and the specificity in the detection of early rejection before grade Ib were 96% and 92%, with only one false-negative and two false-positives resulting from 51 measurements of BMBF. In three cases of serious lung infections, the L/C ratio did not fall, and the rejection could be distinguished from infection. These results suggest that measurement of the BMBF is useful for detecting the early rejection of transplanted lungs.

Animals↗
PubMedDate not supplied

New diagnostic method for pulmonary allograft rejection by measurement of bronchial mucosal blood flow.

We investigated the relationship between the rejection of lung allografts and the bronchial mucosal blood flow with a laser flowmeter. Nineteen mongrel dogs underwent left lung allotransplantation and were given daily oral immunosuppressive therapy with azathioprine and cyclosporine. The bronchial mucosal blood flow at the carina and the bifurcation of left upper and lower bronchi were measured on days 14, 21, and 28 after left lung transplantation. The bronchial mucosal blood flow of the transplanted lungs was expressed as the ratio of bronchial mucosal blood flow at the bifurcation of left upper and lower bronchi to the bronchial mucosal blood flow at the carina (L/C ratio) instead of the absolute value because bronchial mucosal blood flow was affected by the depth of anesthesia of the dogs. We classified the histologic appearance of the transplanted lung tissue into one of five grades: 0, 1a, 1b, 2, and 3. No rejection was in grade 0, and as the rejection process progressed the higher grades were used in order. The mean L/C ratios for grades 0, 1a, 1b, 2, and 3 were 0.95 +/- 0.03, 0.82 +/- 0.05, 0.68 +/- 0.04, 0.58 +/- 0.07, and 0.30 +/- 0.07, respectively. Thus the L/C ratio decreased as the rejection process progressed. The histologic changes of the donor main bronchus in each rejection grade were investigated. Mononuclear cell infiltration and edema around the small vessels was seen in early rejection. These same histologic changes appeared in muscular arteries as rejection progressed, and the damage to the small vessels and muscular arteries was more severe in late rejection.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMedDate not supplied

New technique for intrathoracic heart-lung transplantation in the rat.

A technique for intrathoracic heart-lung transplantation in the rat is described. The combined heart and left lung were transplanted into the recipient's thorax in place of the excised left lung. The graft's aorta was anastomosed end to side to the recipient's descending aorta. The bronchial anastomosis was made by the telescoping technique. When the aortic anastomosis was carried out, a total aortic clamp was used in group 1 (26 animals), and an internal shunt was used in group 2 (20 animals). One rat in group 1 and seven rats in group 2 survived with well-functioning grafts for more than 7 days after transplantation. This model of intrathoracic heart-lung transplantation appears to be suitable for investigations of rejection because the grafted lung is ventilated through the anastomosed bronchus. Our internal shunt method makes it possible for this system to be used as an experimental model.

Anastomosis, Surgical↗
PubMedDate not supplied

Preoperative evaluation and surgical treatment for tricuspid regurgitation associated with acquired valvular heart disease. The Kay-Boyd method vs the Carpentier-Edwards ring method.

This study compared the results of annuloplastic repair of tricuspid regurgitation (TR) using Doppler echocardiography. Sixty-three patients who underwent tricuspid annuloplasty were studied. Thirty-four patients received Kay-Boyd annuloplasty and 29 Carpentier-Edwards ring annuloplasty. A new classification of TR based on the direction and area of regurgitation flow on Doppler echocardiogram was applied preoperatively. In the Kay-Boyd group, 10 cases showed massive TR and 24 cases showed localized TR preoperatively. Localized TR was well controlled in all cases, but 8 of 9 cases of massive TR showed grade III residual TR. In the C-E group, 21 cases showed massive TR and 8 cases showed localized TR. All cases were well controlled postoperatively. We conclude that (1) although the Kay-Boyd method is acceptable for localized TR, the C-E method should be employed for massive TR; (2) analyzing the regurgitant pattern of TR by Doppler echocardiogram is useful in selecting an appropriate surgical technique.

Adult↗