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Biomedical subjects

A Trento

Publications and source records attributed to A Trento.

At least 37 records · Page 2Linked to original sources
PubMed1999

Relation between cellular repolarization characteristics and critical mass for human ventricular fibrillation.

INTRODUCTION: The critical mass for human ventricular fibrillation (VF) and its electrical determinants are unclear. The goal of this study was to evaluate the relationship between repolarization characteristics and critical mass for VF in diseased human cardiac tissues. METHODS AND RESULTS: Eight native hearts from transplant recipients were studied. The right ventricle was immediately excised, then perfused (n = 6) or superfused (n = 2) with Tyrode's solution at 36 degrees C. The action potential duration (APD) restitution curve was determined by an S1-S2 method. Programmed stimulation and burst pacing were used to induce VF. In 3 of 8 tissues, 10 microM cromakalim, an ATP-sensitive potassium channel opener, was added to the perfusate and the stimulation protocol repeated. Results show that, at baseline, VF did not occur either spontaneously or during rewarming, and it could not be induced by aggressive electrical stimulation in any tissue. The mean APD at 90% depolarization (APD90) at a cycle length of 600 msec was 227+/-49 msec, and the mean slope of the APD restitution curve was 0.22+/-0.08. Among the six tissues perfused, five were not treated with any antiarrhythmic agent. The weight of these five heart samples averaged 111+/-23 g (range 85 to 138). However, after cromakalim infusion, sustained VF (> 30 min in duration) was consistently induced. As compared with baseline in the same tissues, cromakalim shortened the APD90 from 243+/-32 msec to 55+/-18 msec (P < 0.001) and increased the maximum slope of the APD restitution curve from 0.24+/-0.11 to 1.43+/-0.10 (P < 0.01). CONCLUSION: At baseline, the critical mass for VF in diseased human hearts in vitro is > 111 g. However, the critical mass for VF can vary, as it can be reduced by shortening APD and increasing the slope of the APD restitution curve.

Action Potentials↗
PubMed1999

Video-assisted thoracoscopic surgery for patent ductus arteriosus in low birth weight neonates and infants.

BACKGROUND: Video-assisted thoracoscopic surgery (VATS) has been assuming an expanded role in the management of cardiothoracic disease. As instrumentation and experience increase, VATS is being applied to treat smaller patients. We report our experience with 34 low birth weight infants undergoing VATS interruption of patent ductus arteriosus (PDA). METHODS: VATS allows PDA interruption without the muscle cutting or rib spreading of a standard thoracotomy. Four small, 3-mm incisions are made along the line of a potential thoracotomy incision. Ports placed through these incisions admit endoscopic instruments, a camera, and a vascular clip applier. RESULTS: Median age at surgery was 15.5 days (range: 1-44 days). Median weight at surgery was 930 g (range: 575-2500 g). Twenty patients weighed <1 kg, and 13 weighed <750 g. All patients had congestive heart failure and had either failed indomethacin therapy or had contraindications to indomethacin. Median surgical time was 60 minutes (range: 31-171 minutes). Echocardiography documented elimination of ductal flow in all patients. Operative mortality was zero. Four patients (4/34 = 12%) required conversion to open thoracotomy: 1 because of difficult exposure, 1 because of pulmonary dysfunction and anasarca, 1 because of a large 1-cm duct, and 1 because of coagulopathy and poor pulmonary compliance. Two patients died before discharge: 1 patient (surgical weight: 605 g) died on postoperative day 2 because of intracranial hemorrhage, and 1 patient (surgical weight: 1725 g) died on postoperative day 88 because of multiple system organ failure. Follow-up has demonstrated no PDA murmur in any patient, but echocardiography revealed trace ductal flow in 2 patients. CONCLUSIONS: VATS offers a minimally traumatic, safe, and effective technique for PDA interruption in low birth weight neonates and infants.

Cardiac Surgical Procedures↗
PubMed1998

A 20-year experience with the Hancock porcine xenograft in the elderly.

BACKGROUND: The availability of 20 years of follow-up data on the Hancock porcine valve (Medtronic Inc, Irvine, CA) allows determination of long-term actual and actuarial failure rates in the elderly. METHODS: We analyzed outcomes after mitral or aortic valve replacement with the Hancock porcine valve in 491 consecutive patients, comparing actual and actuarial valve failure rates in the elderly (age 65 or older) with those in younger patients. RESULTS: The average age of aortic valve replacement recipients was 68+/-14 years (N = 243) and of mitral valve replacement recipients, 64+/-12 years (N = 248). Average follow-up was 7.0 years (1,673 patient-years) for aortic valve replacement and 7.3 years (1,781 patient years) for mitral valve replacement recipients. The median time to reoperation or structural failure was 15.9 years for aortic valve replacement patients and 14.3 years for mitral valve replacement patients. However, few elderly patients survived to 15 years (22% of the elderly aortic valve replacement and 13% of the older mitral valve replacement patients). The 15-year actual reoperation rate was therefore only 10% in the elderly aortic valve replacement compared to 30% in the younger aortic valve replacement patients. For mitral valve replacement, the 15-year actual reoperation rate was 11% in the elderly and 36% in the younger patients. The lifetime reoperation risk (the maximum potential number of patients who might ever undergo reoperation during their lifetime) is the sum of actual survival and actual reoperation rates. The lifetime reoperation risk was 20% or less for elderly aortic valve replacement patients and 18% or less for elderly mitral valve replacement patients. CONCLUSION: These data suggest that about 1 in 10 elderly patients (65 years or older) receiving a Hancock valve will require reoperation within 15 years and less than one in five will ever require reoperation in their lifetimes.

Actuarial Analysis↗
PubMed1998

Characteristics of wave fronts during ventricular fibrillation in human hearts with dilated cardiomyopathy: role of increased fibrosis in the generation of reentry.

OBJECTIVES: We sought to evaluate the characteristics of wave fronts during ventricular fibrillation (VF) in human hearts with dilated cardiomyopathy (DCM) and to determine the role of increased fibrosis in the generation of reentry during VF. BACKGROUND: The role of increased fibrosis in reentry formation during human VF is unclear. METHODS: Five hearts from transplant recipients with DCM were supported by Langendorff perfusion and were mapped during VF. A plaque electrode array with 477 bipolar electrodes (1.6-mm resolution) was used for epicardial mapping. In heart no. 5, we also used 440 transmural bipolar recordings. Each mapped area was analyzed histologically. RESULTS: Fifteen runs of VF (8 s/run) recorded from the epicardium were analyzed, and 55 episodes of reentry were observed. The life span of reentry was short (one to four cycles), and the mean cycle length was 172 +/- 24 ms. In heart no. 5, transmural scroll waves were demonstrated. The most common mode of initiation of reentry was epicardial breakthrough, followed by a line of conduction block parallel to the epicardial fiber orientation (34 [62%] of 55 episodes). In the areas with lines of block, histologic examination showed significant fibrosis separating the epicardial muscle fibers and bundles along the longitudinal axis of fiber orientation. The mean percent fibrous tissue in these areas (n = 20) was significantly higher than that in the areas without block (n = 28) (24 +/- 7.5% vs. 10 +/- 3.8%, p < 0.0001). CONCLUSIONS: In human hearts with DCM, epicardial reentrant wave fronts and transmural scroll waves were present during VF. Increased fibrosis provides a site for conduction block, leading to the continuous generation of reentry.

Adolescent↗
PubMed1998

Technical considerations for partial left ventriculectomy (Batista operation).

The surgical technique for partial left ventriculectomy (Batista operation) as performed in two surgical centers is described. This surgical remodeling of the left ventricle restores the abnormal geometric configuration produced by the dilated failing heart. It accomplishes a reduction of the left ventricular end-diastolic diameter and end-diastolic volume with consequent increase in left ventricular function. This procedure represents the newest surgical approach in the management of patients with end-stage cardiomyopathy; it can be used as a bridge to transplantation or perhaps as a definitive form of therapy, particularly in those patients in whom heart transplantation is contraindicated. This report describes technical guidelines to avoid serious intraoperative and postoperative complications directly associated with this technique.

Cardiac Surgical Procedures↗
PubMed1997

Induction of meandering functional reentrant wave front in isolated human atrial tissues.

BACKGROUND: The purpose of this study was to test the hypothesis that a single meandering functional reentrant wave front can result in rapid and irregular electrogram activity in human atrial tissues. METHODS AND RESULTS: The study used the explanted hearts of five human cardiac transplant recipients. Three right and two left atrial tissue samples, 3.4+/-0.3 mm thick, were excised and trimmed to 3.5x3.0 cm. The isolated atrium was placed endocardial surface down in a chamber with a 477 bipolar recording electrode array built into the bottom of the tissue bath. The interelectrode distance was 1.6 mm. The tissue was constantly superfused with 36.5 degrees C oxygenated Tyrode's solution at a rate of 10 mL/min. After eight baseline stimuli (S1) delivered at 400- or 600-ms cycle length from the edge of the tissue, a single premature stimulus (S2) was given at the center of the tissue to induce reentry. A total of nine episodes of reentry were induced with S1-S2 coupling intervals of 232+/-29 ms (range, 190 to 290 ms) and an S2 strength of 10+/-3 mA (range, 5 to 15 mA). In all samples, a single meandering reentrant wave front was induced, causing irregular and rapid bipolar electrogram activity. These wave fronts had a mean cycle length of 229+/-45 ms (160 to 290 ms) and persisted for 1.1+/-0.3 seconds (0.6 seconds to 2.5 seconds), or 5.2+/-1.4 (3 to 9) cycles, before spontaneous termination. CONCLUSIONS: A single meandering functional reentrant wave front can be induced in human atrial tissues and produce rapid and irregular electrical activity.

Adult↗
PubMed1997

In vivo liposome-mediated transfection of HLA-DR alpha-chain gene into pig hearts.

UNLABELLED: Scarcity of suitable donor organs remains a major problem for organ transplantation. Transfer of recipient HLA-genes into animal donor-organs during harvest could induce graft-tolerance without suppressing the recipient immune system. OBJECTIVE: This pilot study aimed to test the feasibility of an in vivo gene transfer into pig hearts by intracoronary infusion of DNA:liposome-complexes and to detect the gene product by immunohistochemistry. METHODS: The pcDV1-pL2-vector, containing the basesequence for HLA-DR alpha-chain in plasmids (1.3 kb) was selected. The plasmids were isolated with ethidiumbromide and incubated with lipofectin in a 1:3-ratio for 10 min. The DNA:lipofectin-complex was diluted to 10 cc with physiologic saline and delivered into the left anterior descending artery of 6 farm pigs over 10 min. As a control within the same animal, the same amount of lipofectin alone was infused into the first diagonal branch. Three pigs were sacrificed after 24 h, the other 3 after 48 h. Delivery of DNA:liposome-complexes was detected by oil red 0 staining, expression of HLA-DR alpha-chain-antigen with a monoclonal anti-HLA-DR alpha-antibody. RESULTS: Transfection of the HLA-class-II DR-alpha-chain occurred in endothelial cells. Infiltrating cells around capillaries stained positively for HLA-DR-alpha. These infiltrating cells were negative for the pan B- and the pan T-cell-marker L26 and UCHL-1. There was no transfection and hypercellularity in the myocardium around the first diagonal branch. CONCLUSIONS: In vivo intracoronary infusion of the HLA-DR alpha-chain-DNA:lipofectin-complex leads to expression of the corresponding antigen on pig endothelium for 48 h. The infiltrating cells require further characterization.

Animals↗
PubMed1997

Resting hemodynamics after total versus standard orthotopic heart transplantation in patients with high preoperative pulmonary vascular resistance.

OBJECTIVE: Pretransplant pulmonary vascular resistance > or = 4 Wood-units predisposes to right ventricular failure after heart transplantation. Total orthotopic heart transplantation with bicaval and pulmonary venous anastomoses offers synchronous contractions of the atria and a normal ventricular filling pattern, but requires longer ischemic time than standard orthotopic heart transplantation. To test if total orthotopic heart transplantation improves resting hemodynamics in pts with high preoperative pulmonary vascular resistance, we analyzed 65 pts with standard and 65 with total orthotopic heart transplantation transplanted between 12/88 and 7/94. Of these, 18 with total and 15 with standard orthotopic heart transplantation had a preoperative pulmonary vascular resistance > or = 4 Wood-units. METHODS: Right heart catheterization data were obtained at each endomyocardial biopsy. All data from biopsies at both 2 weeks and 1 year posttransplant that were free from humoral or greater than 1A cellular rejection (9 versus 13 pts) were included in a two way ANOVA. Pts with postop pacemakers, atrial fib or beta-blocker therapy at the time of biopsy were excluded. RESULTS: Ischemic time was different (172 +/- 44 versus 142 +/- 28 min, P = 0.03). Demographics, NYHA class, pre-TX hemodynamics, donor age and inotropes were similar. Cardiac output and index were higher in the total orthotopic group at 2 weeks (6.5 +/- 1.7 versus 5.1 +/- 1.0 l/min; 3.4 +/- 0.9 versus 2.8 +/- 0.6 l/min per m2) and 1 year (7.1 +/- 2.0 versus 4.9 +/- 1.1 l/min, P = 0.002; 3.6 +/- 1.1 versus 2.6 +/- 0.5 l/min per m2, P = 0.009). Right atrial and pulmonary arterial mean pressure (mmHg) were lower with total orthotopic heart transplantation at 2 weeks (6 +/- 4 versus 9 +/- 5, P = 0.04; 22 +/- 3 versus 25 +/- 7, P = 0.1) and 1 year (5 +/- 2 versus 7 +/- 3, P = 0.02; 19 +/- 4 versus 25 +/- 7, P = 0.03). Pulmonary capillary wedge pressure (mmHg) was borderline nonsignificant (11 +/- 4 versus 13 +/- 7 at 2 weeks, 8 +/- 3 versus 14 +/- 5 at 1 year, P = 0.055), as well as pulmonary vascular resistance (1.9 +/- 1 versus 2.5 +/- 1 at 2 weeks, 1.5 +/- 0.6 versus 2.7 +/- 1.7 WU at 1 year, P = 0.051). CONCLUSIONS: Total orthotopic heart transplantation improves cardiac output and index in pts with high preoperative pulmonary vacular resistance. There is a lower mean RA and PA pressure perhaps due to less tricuspid and mitral regurgitation. In view of the frequently observed restrictive filling pattern after cardiac transplantation, total orthotopic heart transplantation can be beneficial until this pattern has subsided by preserving atrioventricular synchrony and offering better atrial transport.

Aged↗
PubMed1997

The duration of administration of monoclonal antibody OKT3 for induction immunosuppression after heart transplantation.

The effective treatment of refractory allograft rejection with murine antihuman monoclonal antibody muromonab-CD3 (OKT3) and of patients with renal dysfunction has led to its use as induction therapy. The optimal protocol for OKT3 prophylaxis remains to be established. We compared 59 patients consecutively transplanted with the total orthotopic technique between 1/92 and 5/94. The first 21 patients were treated with OKT3 for 14 days, the next 19 for 10 days, and the last 19 for 7 days. Patients operated with different surgical techniques or other induction treatment were excluded. We compared length of stay (total and ICU), time to first rejection, rejection incidence and infection incidence (cytomegalovirus separately), and survival. Preoperative characteristics were similar except for significantly younger age in the 10-day group (p = 0.04). Preoperative hemodynamic parameters were similar except for a significantly higher left-ventricular ejection fraction (21%) in the 7-day group. Length of stays in the ICU and hospital were similar for the three groups (p = NS). Freedom from cellular rejection was lower with the 7 days course (p = 0.02), but freedom from humoral rejection was slightly higher (p = 0.11). However, patients in the 7-day group required treatment for rejection less frequently than patients in the other two groups (95% untreated at 2 months vs. 43% in the 14-day and 53% in the 10-day group; p = 0.002). There were no differences in incidence of infections, including cytomegalovirus. Survival was similar between the groups. There was one death in the 14-day and 1 in the 10-day group, both due to rejection. In conclusion, OKT3 therapy can be reduced safely to 7 days with a higher overall incidence of rejection but no increased necessity to treat for rejection, and no difference in infection incidence.

Adult↗
PubMed1997

Absence of endocardial lymphoid infiltrates (Quilty lesions) in nonheart transplant recipients treated with cyclosporine.

The clinical records and autopsy material from 14 patients treated with cyclosporine who were not recipients of cardiac allografts were reviewed to further study the nature of endocardial lymphoid infiltrates (quilty lesions). Although there was well-documented exposure to cyclosporine, no endocardial lymphoid infiltrates were identified in these cases, providing evidence that the endocardial-based Quilty lesion is not the result of the direct effect of cyclosporine and may represent a localized form of heart rejection confined to the endocardium.

Adolescent↗
PubMed1997

The effect of chronic alcohol use on the heart before and after transplantation in an experimental model in the rat.

BACKGROUND: Alcohol has potential deleterious effects on donor heart function. This study was conducted in rats to determine whether long-term alcohol ingestion produces impaired hemodynamic performance while maintaining a normal left ventricular ejection fraction in donor hearts before transplantation and whether donor cardiac function is affected after heart transplantation. METHODS: Rats fed 30% alcohol in their drinking water for 12 weeks were compared with rats fed a normal diet. Left ventricular ejection fraction was measured by echocardiography with Simpson and single plane Dodge formulas in living sedated rats after 10 and 12 weeks of alcohol feeding. Explanted heart function was assessed before and 3 days after heterotopic heart transplantation (no immunosuppression) with a Langendorff preparation. RESULTS: Blood ethanol levels at 4 and 8 weeks were 0.08 +/- 0.04 and 0.08 +/- 0.09 gm/dl. Left ventricular ejection fraction was similar in the group fed an alcohol diet for 12 weeks when compared with the control group (65.4% +/- 1.6% vs. 66.5% +/- 2.9%, p = 0.33). Explanted alcohol-fed hearts before transplantation had significantly lower maximum and developed pressures and had a blunted response to 0.1 ml 10(-9) mol/L isoproterenol. After transplantation alcohol-fed hearts had significantly lower maximum and developed pressures and decreased maximum rates of pressure rise and pressure decline. Allografts (ACI to Lewis) exhibited decreased function in comparison with isografts (ACI to ACI). CONCLUSIONS: Alcohol feeding for 12 weeks in rats does not affect pretransplantation left ventricular ejection fraction, but it impairs explanted heart function, both before and after transplantation, resulting in a subclinical cardiomyopathy that is worsened by the presence of allograft rejection. Long-term alcohol exposure and rejection have independent, additive detrimental effects on left ventricular performance of the transplanted heart. Alcohol-exposed hearts may not be suitable donors.

Animals↗
PubMed1997

Heart transplantation with bicaval and pulmonary venous anastomoses. A hemodynamic analysis of the first 117 patients.

BACKGROUND: A new surgical technique for orthotopic heart transplantation has been introduced into clinical practice. It accomplishes total atrioventricular transplantation as the recipient's atria are completely excised and the allograft is implanted using bicaval and pulmonary venous anastomoses. MATERIALS AND METHODS: We retrospectively analyzed post-transplant hemodynamic and patient survival in our first 117 patients transplanted with this new operative approach and compared them with 64 patients transplanted with the standard biatrial technique. RESULTS: Patients transplanted with the bicaval technique had a significantly lower right atrial mean, pulmonary arterial systolic, pulmonary arterial mean, and pulmonary capillary wedge pressures. In addition, a significant reduction in post-transplant tricuspid regurgitation and a trend towards less severe mitral regurgitation was observed. The need for permanent pacemaker implantation due to sinus node dysfunction after transplantation was completely eliminated with this new technique. Thirty-day operative survival and actuarial survival at 1, 2, 3, and 4 years was significantly greater in patients transplanted with the bicaval technique. CONCLUSIONS: Orthotopic heart transplantation performed with bicaval and pulmonary venous anastomoses offers improved post-transplant hemodynamics, eliminates the need for permanent pacemaker, and has improved patient survival when compared with the standard biatrial technique. These differences can be related in part to improved hemodynamic function of the cardiac allograft due to preservation of the anatomic configuration and physiologic function of the atria.

Adult↗
PubMed1996

Heart transplantation in patients 65 years of age and older: a comparative analysis of 40 patients.

BACKGROUND: Advanced age has traditionally been considered a relative contraindication to heart transplantation because of the potential for increased morbidity and decreased long-term survival. METHODS: We analyzed the results in 40 patients 65 years of age and older who underwent heart transplantation and compared them with those in 138 patients younger than 65 years. RESULTS: The older age group had a higher incidence of diabetes mellitus (p = 0.01), donor-recipient weight mismatch (< 0.80) (p = 0.004), lower donor-recipient weight ratio (p = 0.02), and longer allograft ischemic time (p = 0.008), among other differences. However, the 30-day operative mortality was similar in both groups (2.5% in older versus 2.2% in younger patients). Actuarial survival at 12, 24, and 36 months was not statistically different between the older and younger patients (86% +/- 6% versus 93% +/- 2%, 78% +/- 8% versus 89% +/- 3%, and 72% +/- 9% versus 81% +/- 4%, respectively; p = 0.26). The posttransplantation intensive care unit stay, total hospital stay, and associated hospital costs were also similar. The incidence of rejection during the first posttransplantation year was similar in both groups. CONCLUSIONS: Heart transplantation in selected patients 65 years of age and older can be performed successfully, with a morbidity and mortality comparable with those seen in younger patients. Advanced age should not be an exclusion criterion for heart transplantation, but selective criteria should be applied that identify risks and benefits individually.

Actuarial Analysis↗
PubMed1996

Heart transplantation in patients 70 years of age and older: initial experience.

BACKGROUND: Heart transplantation has become a highly successful therapeutic option for patients with end-stage cardiomyopathy. Consequently, the criteria for patient selection, particularly regarding recipients' upper age limits, have been expanded, with an increasing number of people older than 60 years of age now undergoing transplantation. METHODS: A retrospective analysis of 6 patients 70 years of age and older who underwent heart transplantation was done; their clinical courses and outcomes were compared with those of younger patients, with a special emphasis on their posttransplantation quality of life. RESULTS: All 6 patients are alive and clinically well at a mean follow-up of 12 months. No age-related complications have been observed, and their quality of life is excellent. There has been a very low incidence of rejection, as well as few episodes of rejection. CONCLUSIONS: Heart transplantation in selected people 70 years of age and older can be performed successfully with a morbidity comparable to that seen in younger patients and excellent short-term survival. This initial experience is encouraging, but further studies and long-term follow-up are needed to validate the more routine application of this therapy.

Age Factors↗
PubMed1996

Clinical experience with one hundred consecutive patients undergoing orthotopic heart transplantation with bicaval and pulmonary venous anastomoses.

OBJECTIVE: Our objective was to assess survival, need for pacemaker insertion, and rejection frequency with a new surgical technique of orthotopic heart transplantation using bicaval and pulmonary venous anastomoses. METHODS: We retrospectively reviewed 100 consecutive patients who had orthotopic heart transplantation with this technique between July 1991 and September 1995. RESULTS: The mean age was 57.0 +/- 11.1 years, with 51 patients being 60 years or older. The mean donor/recipient weight ratio was 0.92, and in 28 patients the ratio was less than 0.8. The early (30-day) survival was 100% and the 1- and 2-year survivals were 98% +/- 2% and 96% +/- 2%, respectively. Survival was not affected by age or by the duration of the OKT3 therapy (p > 0.2 for each of these parameters). The seven late deaths were due to infection (n = 2), graft atherosclerosis (n = 3), acute rejection (n = 1), and nonspecific graft failure (n = 1). No permanent pacemaker was required in the first 6 months after the operation, and all the patients were discharged in normal sinus rhythm. Freedom from treated rejection was significantly greater in patients with 7 days of OKT3 therapy than in patients with 14 days of therapy (p < 0.0001). CONCLUSIONS: Orthotopic heart transplantation with bicaval and pulmonary venous anastomoses offers an improved alternative to the standard biatrial technique, with a 30-day mortality of 0,% in 100 consecutive patients, excellent intermediate-term survival, and elimination of the need for pacemaker insertion. More normal anatomic configuration and synchronous function of the atria may have contributed to these results.

Adolescent↗
PubMed1996

Liposome-mediated transfer of genes containing HLA-class II alpha chain into cultured embryonic chick cardiac myocytes and COS7 cells.

Rejection remains a major problem after cardiac transplantation. One hypothesis is that transfer of recipient HLA genes could lead to expression of the antigens on the surface of donor cells and so facilitate graft acceptance. This paper describes a pilot study for relevant gene-transfer (transfection) experiments on adult cardiac myocytes, investigating the feasibility of transfection using cationic liposomes. The plasmid pcDV1-pL2 vector containing HLA-DR-alpha chain gene was incubated with Lipofectin, a DOTMA and DOPE lipid mixture, for 10 minutes. Embryonic chick cardiac myocytes (ECCM) and COS7 monkey cells were incubated with DNA: Lipofectin ratios of 1:1, 1:2, 1:4, and 1:10 for 16 hours (hrs). Using a fixed ratio of 1:4, incubation periods of 4, 8, and 16 hrs were compared. Finally, cells were incubated for 16 hrs and consecutively cultured for 6 days. Expression of the HLA-DR-alpha chain antigen was detected by indirect immunohistochemical staining. Highest transfection rates were achieved with a DNA: Lipofectin ratio of 1:4 for ECCM and COS7 cells (2.7% +/- 0.6% and 2.4% +/- 0.3% after 16 hrs incubation) and a transfection time of 4 hrs (5.8% +/- 0.6% and 5.3% +/- 1.7%). Immunohistochemically positive cells were present after 6 days (2.0% +/- 1.2% and 2.1% +/- 0.3%). We found a low level of expression of HLA-DR-alpha chain gene, influenced by transfection time and DNA: Lipofectin ratio. To increase the efficiency of liposome-mediated gene transfer and assess potential applications in cardiac transplantation, further investigation of cell properties promoting transfection is necessary.

Adult↗
PubMed1996

Resting hemodynamics after total versus standard orthotopic heart transplantation.

Total orthotopic heart transplantation (TOHT) requires longer surgery than standard orthotopic heart transplantation (SOHT), but offers normal anatomy and synchronous atrial contraction. We endeavored to test whether TOHT improves resting hemodynamics. We analyzed 60 patients with SOHT and 66 with TOHT transplanted between 12/89 and 7/94. Age, preoperative NYHA class, ejection fraction, and donor characteristics were similar. After applying exclusion criteria at 2 weeks postoperatively, 53 SOHT and 58 TOHT patients were accepted for further study. Right-heart hemodynamics were examined at 2 weeks and 6 months posttransplant. Despite a longer ischemic time (161 +/- 36 vs. 142 +/- 37 min, p = 0.004), cardiac output and index were higher in the TOHT group at 2 weeks (6.1 +/- 1.4 vs. 5.4 +/- 1.0 L/min, TOHT vs. SOHT, p = 0.01; and 3.3 +/- 0.7 vs. 2.9 +/- 0.6 L/min/m2, p = 0.005) but similar at 6 months (5.9 +/- 1.2 vs. 5.6 +/- 1.4 L/min; and 3.0 +/- 0.6 vs. 2.9 +/- 0.7 L/min/m2). Right-atrial pressure was lower with TOHT at both time points (7 +/- 4 vs. 9 +/- 4 mmHg, p = 0.02: and 5 +/- 2 vs. 7 +/- 3, p = 0.0006). Wedge pressure was similar at 2 weeks (12 +/- 5 vs. 13 +/- 5, p = 0.045). Heart rate (bpm) was higher at both time points with TOHT (84 +/- 10 vs. 75 +/- 12, p = 0.0003: and 90 +/- 12 vs. 82 +/- 9, p = 0.0006). Pulmonary vascular resistance was similar at both time points. Despite a longer ischemic time, total orthotopic heart transplantation does not impair postoperative cardiac function. There is an early improvement in cardiac output, a sustained higher heart rate reflecting preservation of donor sinus node function, and a lower right-atrial pressure.

Blood Pressure↗