Induction of donor-specific tolerance to cardiac xenografts in utero.

BACKGROUND: Problems associated with heart transplantation, such as shortage of suitable organs and the side effects of immunosuppressive therapy, are especially serious for patients in the pediatric age group. Induction of donor-specific immunologic tolerance without immunosuppressive drugs would be ideal for clinical organ transplantation. In this study, we used a vascularized cardiac xenograft model to achieve donor-specific unresponsiveness without immunosuppression by manipulating the intrauterine immune response. METHODS: Lewis rats and Golden Syrian hamsters were used as the recipients and donors, respectively. Donor bone marrow cells (15 x 10(6) in 0.05 mL) were injected into each fetus of pregnant Lewis rats on days 9 (n = 2) and 16 (n = 2) of gestation. Donor hearts were heterotopically transplanted into each surviving (n = 8, n = 5) fetus of the Lewis rats at 8 weeks of age. Donor hearts were also transplanted into untreated rats as controls (n = 8). RESULTS: The mean cardiac xenograft survival time was 2.5 +/- 0.5, 7.4 +/- 4.1, and 2.8 +/- 0.8 days in the control group, gestational day 9 group, and gestational day 16 group, respectively. Chromosomal analysis of the day 9 group showed Golden Syrian hamster chromosomes as well as Lewis rat chromosomes. CONCLUSIONS: Cardiac xenograft survival was significantly prolonged by intrauterine exposure to xenograft bone marrow cells on day 9 but not on day 16 of gestation. Cardiac xenograft survival and chromosomal analysis of the recipient bone marrow suggested that chimerism was achieved between Golden Syrian hamsters and Lewis rats. Cardiac xenotransplantation may be possible by induction of donor-specific tolerance in utero.

[Experimental study on resuscitation and salvage of myocardial function (RSMF) after normothermic ischemic arrest].

We studied in anesthetized dogs, the effects of cardiopulmonary bypass with normothermic blood, crossclamping of the aortic root, and continuous warm blood cardioplegia as a part of circulatory support on the ability of the recovery of the deteriorated myocardial function, and compared this method with the circulatory support under empty beating stage. Eleven dogs were subjected to the deteriorated myocardial function by 30 minute normothermic ischemic arrest and myocardial function was measured (baseline function). In 5 dogs (Group A), coronary perfusion of 5 ml/kg/min with normothermic blood was established under empty beating state. In other 6 dogs (Group B), the aorta was then clamped and 30 minute infusion of warm blood contained 15 mEq/l of potassium and 2 mEq/l of Magnesium was given by 2.5 ml/kg/min as a part of circulatory support. After this, aortic clamp was released and coronary perfusion of 5 ml/kg/min with normal warm blood followed under empty beating state. Cardiac function was measured at the periods of 40, 60 and 90 minutes of circulatory support and compared between the two groups. The parameters of left ventricular function (developed pressure, dp/dt, -dp/dt) were deteriorated by 30 minutes ischemia by about 50% compared with baseline function. In Group a, they improved gradually along with the duration of circulatory support and 90 minutes were required to return to the baseline function. In Group B, however, their % recovery reached 100% at the period of 40 minutes and maintained over 100% thereafter. RSMF could recover myocardial function from ischemic damage more quickly and effectively compared with circulatory support under empty beating state.

[A successful circulatory assist in acute left heart failure after a rapid two-stage arterial switch operation].

A 6-month-old female with transposition of the great arteries with intact ventricular septum successfully survived with the aid of a circulatory assist device for acute left heart failure after rapid two stage-arterial switch operation (ASO). The interval between pulmonary artery banding and ASO was 9 days. Left heart failure appeared immediately after ASO, so we started the circulatory assist with a centrifugal pump. The left ventricular function gradually recovered. After 43 hours assisted circulation, she was successfully weaned from the pump. Subsequent recovery was uneventful and the patient was discharged from the hospital on the 40th postoperative day. In case of acute left heart failure after ASO due to sudden changes in the left ventricular afterload, adaptation of the left ventricle can be expected by a relatively short period of circulatory assist with centrifugal pump.

[Mitral valve reconstruction: for ruptured chordae to the posteromedial commissural scallop].

The advantages of mitral valve repair for pure mitral incompetence are established. It is necessary for us to describe suture points more detailed. This article presents our standardized maneuver for mitral regurgitation due to ruptured chordae to the posteromedial commissural scallop. The first step in the repair is placement of a temporary suture in the annulus at attachment of posterior commissural chordae and one of posterior cleft chordae. After measuring the annular diameter and estimating coaptation, this suture is removed. Secondary, rupture of chordae tendinease and adjacent margin of posteromedial commissural scallop are resected. Then, one end of a thread is passed through the margin at end of this untethered segment of leaflet, and another end is passed through the margin of leaflet at opposite end of this segment. Finally, a mattress suture using 3-0 Prolene with pledget is placed as a temporary suture. Between April 1993 and December 1994, four patients underwent reconstruction of mitral regurgitation with ruptured chordae to the posteromedial commissural scallop. Left ventriculogram 4 weeks postoperatively showed no regurgitant jet in all patients.

[Use of intravenous hyperalimentation catheter to drainage prolonged postoperative pleural effusion after harvesting the internal thoracic artery].

Increased chest drainage, a higher incidence of pleural effusions in the postoperative period, and more chest tube drainage was found after harvesting the internal thoracic artery (ITA). Patients with these complications required thoracocentesis, or prolonged chest tube drainage. But these methods may be painful and make a limitation to activity of daily life (ADL) in these patients. We therefore sought an effective procedure for these patients, and applied pleural placement of intravenous hyperalimentation catheter. This technique could drain the effusion completely, conveniently and painlessly without a limitation to ADL. Pneumothorax, infections and other complications occurred in no patients. We concluded that this method might be useful in these patients with prolonged post operative pleural effusion after harvesting the ITA who have failed other modes of therapy.

[Clinical experience of autotransfusion of shed mediastinal blood using a new device].

Autotransfusion of shed mediastinal blood is expected to be adopted as a technique to reduce transfusion thus preventing various complications such as hepatitis, AIDS, and GVHD. We report the usefulness and problems of a new device-Solcotrans Plus, which only requires connection to wall suction. This device consists of three parts: suction, reservoir bag, and filter for autoinfusion. After setting the suction and reservoir bag primed with anticoagulant, ACD or heparin, and connecting the unit to a wall suction, we performed autotransfusion of shed blood through the filtration component in ICU after operation. Postoperative hematological and biochemical examinations revealed no complications or adverse effects of autotransfusion. This device is available, simple to handle, and is useful for returning shed blood. We believe that this device will be effective for non-blood open heart surgery or reduction of transfusion.