62 resultados para Tree transplantation methods


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OBJECTIVE: To assess the influence of recipient's and donor's factors as well as surgical events on the occurrence of reperfusion injury after lung transplantation. DESIGN AND SETTING: Retrospective study in the surgical intensive care unit (ICU) of a university hospital. METHODS: We collected data on 60 lung transplantation donor/recipient pairs from June 1993 to May 2001, and compared the demographic, peri- and postoperative variables of patients who experienced reperfusion injury (35%) and those who did not. RESULTS: The occurrence of high systolic pulmonary pressure immediately after transplantation and/or its persistence during the first 48[Symbol: see text]h after surgery was associated with reperfusion injury, independently of preoperative values. Reperfusion injury was associated with difficult hemostasis during transplantation (p[Symbol: see text]=[Symbol: see text]0.03). Patients with reperfusion injury were more likely to require the administration of catecholamine during the first 48[Symbol: see text]h after surgery (p[Symbol: see text]=[Symbol: see text]0.014). The extubation was delayed (p[Symbol: see text]=[Symbol: see text]0.03) and the relative odds of ICU mortality were significantly greater (OR 4.8, 95% CI: 1.06, 21.8) in patients with reperfusion injury. Our analysis confirmed that preexisting pulmonary hypertension increased the incidence of reperfusion injury (p[Symbol: see text]<[Symbol: see text]0.01). CONCLUSIONS: Difficulties in perioperative hemostasis were associated with reperfusion injury. Occurrence of reperfusion injury was associated with postoperative systolic pulmonary hypertension, longer mechanical ventilation and higher mortality. Whether early recognition and treatment of pulmonary hypertension during transplantation can prevent the occurrence of reperfusion injury needs to be investigated.

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BACKGROUND: Elevated pulmonary vascular resistance (PVR) is relevant to prognosis of congestive heart failure and heart transplantation. Proof of reversibility by pharmacologic testing in potential transplantation candidates is important because it indicates a reduced probability of right ventricular failure or death in the early post-transplant period. This study aimed to clarify the possible extent of acute reversibility of elevated PVR in a large, consecutive cohort of heart transplant candidates. METHODS: This study included 208 consecutive patients (age 52 +/- 10 years, 89% men and 11% women, ejection fraction 21 +/- 9%, Vo2max 12.6 +/- 4.2 ml/kg/min) being evaluated for heart transplantation in 7 transplant centers in Germany and Switzerland. Testing was performed with increasing intravenous doses of prostaglandin E1 (PGE1; average maximum dose 173 +/- 115 ng/kg/min for at least 10 minutes) in 92 patients exhibiting a baseline PVR of > 2.5 Wood units (WU) and/or a transpulmonary gradient (TPG) of > 12 mm Hg. RESULTS: PGE1 testing lowered PVR from 4.1 +/- 2.0 to 2.1 +/- 1.1 WU (p < 0.01), increased cardiac output from 3.8 +/- 1.0 to 5.0 +/- 1.5 liters/min (p < 0.01), and decreased TPG from 14 +/- 4 to 10 +/- 3 mm Hg (p < 0.01), mean pulmonary artery pressure (PAM) from 39 +/- 9 to 29 +/- 9 mm Hg (p < 0.01) and mean pulmonary capillary wedge pressure (PCWP) from 24 +/- 7 to 19 +/- 9 mm Hg (p < 0.01). Mean aortic pressure (MAP) decreased to 85% and systemic vascular resistance (SVR) to 65% of baseline values (p < 0.01). Symptomatic systemic hypotension was not observed. For the whole population the percentage of patients with PVR > 2.5 WU was reduced from 44.2% to 10.5% with PGE1. PVR decreased in each patient; only 2 patients (1%) remained ineligible for listing because of a final PVR of > 4.0 WU. TPG, ejection fraction and male gender were independent predictors of reversibility of PVR. CONCLUSIONS: Elevated PVR in heart transplant candidates is highly reversible and can be normalized during acute pharmacologic testing with PGE1.

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OBJECT: The aim of this study was to develop and characterize a new orthotopic, syngeneic, transplantable mouse brain tumor model by using the cell lines Tu-9648 and Tu-2449, which were previously isolated from tumors that arose spontaneously in glial fibrillary acidic protein (GFAP)-v-src transgenic mice. METHODS: Striatal implantation of a 1-microl suspension of 5000 to 10,000 cells from either clone into syngeneic B6C3F1 mice resulted in tumors that were histologically identified as malignant gliomas. Prior subcutaneous inoculations with irradiated autologous cells inhibited the otherwise robust development of a microscopically infiltrating malignant glioma. Untreated mice with implanted tumor cells were killed 12 days later, when the resultant gliomas were several millimeters in diameter. Immunohistochemically, the gliomas displayed both the astroglial marker GFAP and the oncogenic form of signal transducer and activator of transcription-3 (Stat3). This form is called tyrosine-705 phosphorylated Stat3, and is found in many malignant entities, including human gliomas. Phosphorylated Stat3 was particularly prominent, not only in the nucleus but also in the plasma membrane of peripherally infiltrating glioma cells, reflecting persistent overactivation of the Janus kinase/Stat3 signal transduction pathway. The Tu-2449 cells exhibited three non-random structural chromosomal aberrations, including a deletion of the long arm of chromosome 2 and an apparently balanced translocation between chromosomes 1 and 3. The GFAP-v-src transgene was mapped to the pericentromeric region of chromosome 18. CONCLUSIONS: The high rate of engraftment, the similarity to the high-grade malignant glioma of origin, and the rapid, locally invasive growth of these tumors should make this murine model useful in testing novel therapies for human malignant gliomas.

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BACKGROUND: Optimal allograft protection is essential in lung transplantation to reduce postoperative organ dysfunction. Although intravenous prostanoids are routinely used to ameliorate reperfusion injury, the latest evidence suggests a similar efficacy of inhaled prostacyclin. Therefore, we compared donor lung-pretreatment using inhaled lioprost (Ventavis) with the commonly used intravenous technique. METHODS: Five pig lungs were each preserved with Perfadex and stored for 27 hours without (group 1) or with (group-2, 100 prior aerosolized of iloprost were (group 3) or iloprost (IV). Following left lung transplantation, hemodynamics, Po(2)/F(i)o(2), compliance, and wet-to-dry ratio were monitored for 6 hours and compared to sham controls using ANOVA analysis with repeated measures. RESULTS: The mortality was 100% in group 3. All other animals survived (P < .001). Dynamic compliance and PVR were superior in the endobronchially pretreated iloprost group as compared with untreated organs (P < .05), whereas oxygenation was comparable overall W/D-ratio revealed significantly lower lung water in group 2 (P = .027) compared with group 3. CONCLUSION: Preischemic alveolar deposition of iloprost is superior to IV pretreatment as reflected by significantly improved allograft function. This strategy offers technique to optimize pulmonary preservation.

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BACKGROUND: Limited experience with bioprosthetic venous valve percutaneously inserted into femoral veins in 15 patients has been promising in short-term results only to show disappointing long-term results. Percutaneous autogenous venous valve (PAVV) transplantation was explored in an ovine model as a possible alternative treatment. METHODS: PAVV consisted of a vein segment containing a valve that was attached to a stent template. The stent templates (n = 9) were designed and hand made in our research laboratory. They consist of two stainless steel square stents 13 or 15 mm in diameter to fit the ovine jugular veins (JV), which ranges from 10 to 15 mm in diameter. A valve-containing segment of JV was harvested and attached with sutures and barbs inside the stent template (n = 9). The valve devices were then manually folded and front loaded inside the 4 cm chamber of the 13F delivery sheath and delivered into the contralateral JV by femoral vein approach. Transplanted PAVVs were studied by immediate and 3 months venograms. Animals were euthanized at 3 months, and jugular veins harvested to perform angioscopic evaluations in vitro. RESULTS: PAVV transplantation was successful in all nine animals. Good valve function with no reflux was observed on immediate and 3 months venograms in eight valves. The transplanted maximal JV diameter ranged from 10.2 mm to 15.4 mm (mean 13.1 +/- 1.5 mm). Venoscopic examination revealed intact, flexible, nonthickened valve leaflets in eight specimens. One PAVV exhibited normal function of one leaflet only; the other cusp was accidentally cut during the transplantation procedure. All transplanted autologous valves were free of thrombus and incorporated into the vein wall of the host vessel. CONCLUSION: This study demonstrated that autogenous valve transplants remained patent and competent without long-term anticoagulation for up to 3 months. The percutaneous autogenous venous valve may provide in future minimally invasive treatment for patients with chronic deep venous insufficiency, but long-term studies need to be done to document its continued patency and function.

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BACKGROUND: Chronic extrinsic denervation induced by small bowel transplantation (SBT) results in adrenergic hypersensitivity in rat ileum. This study evaluated the role of neuronal and/or muscular beta1-, beta2-, and beta3-adrenoceptor (AR) mechanisms on contractility. METHODS: Ileal longitudinal muscle strips from Lewis rats (n = 6 rats per group, 8 strips per rat): naive controls (NC), 4 months after sham operation (SC) or after syngeneic orthotopic SBT were studied in vitro. Spontaneous contractile activity and dose responses (10(-8)-10(-4) mol) to isoprenaline (IP), a nonspecific beta-AR agonist were studied with or without selective antagonists (10(-5) mol), for beta1- (atenolol), beta2- (ICI 118551), or beta3- (SR 59230A) AR subtypes in the presence or absence of tetrodotoxin (TTX; 10(-6) mol; nerve blocker). RESULTS: pEC50 (neg log of EC50, which is the concentration where 50% of inhibition was observed) of IP was 7.2 +/- 0.2 (mean value +/- SEM) in SBT vs 6.3 +/- 0.1 in SC and 6.3 +/- 0.2 in NC (both P < .05 vs SBT), reflecting adrenergic hypersensitivity. Beta1- and beta2-AR blockade induced a TTX-sensitive right shift of the curve only in SBT and normalized pEC50 values from 7.2 +/- 0.2 to 6.4 +/- 0.1 and 7.2 +/- 0.2 to 6.6 +/- 0.1, respectively (P < .05). Beta3-AR blockade shifted the curve independent of the presence of TTX to the right in all groups (all P < .05). CONCLUSIONS: In rat ileum, adrenergic inhibition of contractility was dependent on muscular beta3-AR pathways, whereas posttransplant hypersensitivity was due to upregulated neuronal beta1- and beta2-AR mechanisms that were inactive before SBT.

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AIM: To study prospectively patients after heart transplantation with respect to quality of life, mortality, morbidity, and clinical parameters before and up to 10 years after the operation. METHODS: Sixty patients (47.9 +/- 10.9 years, 57 men, 3 women) were transplanted at the University of Vienna Hospital, Department for Heart and Thorax Surgery and were included in this study. They were assessed when set on the waiting list, then exactly one, 5 and 10 years after the transplantation. The variables evaluated included physical and emotional complaints, well-being, mortality and morbidity. In the sample of patients who survived 10 years (n = 23), morbidity (infections, malignancies, graft arteriosclerosis, and rejection episodes) as well as quality of life were evaluated. RESULTS: Actuarial survival rates were 83.3, 66.7, 48.3% at 1, 5, and 10 years after transplantation, respectively. During the first year, infections were the most important reasons for premature death. As a cause of mortality, malignancies were found between years 1 and 5, and graft arteriosclerosis between years 5 and 10. Physical complaints diminished significantly after the operation, but grew significantly during the period from 5 to 10 years (p < 0.001). However, trembling (p < 0.05) and paraesthesies (p < 0.01) diminished continuously. Emotional complaints such as depression and dysphoria (both p < 0.05) increased until the tenth year after their nadir at year 1. In long-time survivors, 3 malignancies (lung, skin, thyroidea) were diagnosed 6 to 9 years postoperatively. Three patients (13%) had signs of graft arteriosclerosis at year 10; 9 (40%) patients suffered from rejection episodes during the course of 10 years. There were no serious rejection episodes deserving immediate therapy. Quality of life at 10 years is good in these patients. CONCLUSIONS: Heart transplantation is a successful therapy for patients with terminal heart disease. Long-term survivors feel well after 10 years and report a good quality of life.

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AIM: This study was conducted to delineate partnership-relation functioning over time and specifically matched to various organs such as heart, liver, and kidney. METHOD: Prospective, paralleled case-control-study including patients and their respective partners before and one year after organ transplantation in 23 heart-transplant recipients, 19 liver-transplant patients, and 16 kidney-transplant recipients. To assess partnership functioning, the FB-Z (family assessment measure) of Cierpka and Frevert was used. Statistics included descriptive methods, correlations, and analysis of variance including the items "organ" and "time". RESULTS: Heart-transplant recipients and their partners show significant better overall measures in their partnership ratings (sum-value) in comparison to liver or kidney patients and their partners. In all patient and partner groups, except in kidney-transplant recipients a significant deterioration over time is discernible in the subscales role performance and emotionality. In respect to the item "organ" significant differences were found in overall functioning and the subscale communication where heart-transplant recipients and their partners have significant better functioning compared to kidney or liver transplant patients. In kidney patients and their partners only communication changes to the better in the time course. CONCLUSION: In any organ transplantation the two sides of the coin are important to bear in mind, the one is the live-saving act of transplantation as such, the other is the important distress in the phase before but equally after the operation, mainly in the first year where patients and their respective partners have to be followed and treated even in respect to psychosocial and marital functioning.

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BACKGROUND: Many studies confirm that noncompliance or poor compliance is one of the great problems in health care as it results in waste of resources and funds. METHODS: This overview includes literature on heart, liver, and kidney transplants with emphasis on heart transplantation in adult and pediatric transplant patients and addresses the following variables as potential predictors of postoperative compliance problems: demographic variables (age, marital status, gender) psychological variables (anxiety, denial) psychiatric disorders (major depression, anxiety, and personality disorders), poor social support, pretransplant noncompliance, obesity, substance abuse, and health-related variables (distance from transplant center, indication for transplantation, required pretransplant assist device). Relevant studies on these topics that were conducted up to 1999 are included and discussed in this overview. The most important results are presented in tables. RESULTS: Unfortunately, there has not been any systematic and comprehensive review of the literature on predictors of noncompliance in organ transplant patients so far. With organ transplantation noncompliance impairs both life quality and life span as it is a major risk factor for graft rejection episodes and is responsible for up to 25% of deaths after the initial recovery period. Therefore, it might be assumed that well-informed transplant patients are a highly motivated group whose compliance is just as high. This is not the case. However, even when graft loss means loss of life as in heart or liver transplantation, noncompliance occurs. To best select potential organ recipients, it would be ideal if patients who are very likely to show noncompliant behavior could be identified already before being transplanted. CONCLUSION: The literature overview shows the necessity of preoperative psychosocial screening regarding predictors for posttransplant noncompliance.

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OBJECTIVES: To demonstrate the feasibility of time-reversed fast imaging with steady-state precession (FISP) called PSIF for diffusion-weighted imaging of cartilage and cartilage transplants in a clinical study. MATERIAL AND METHODS: In a cross-sectional study 15 patients underwent MRI using a 3D partially balanced steady-state gradient echo pulse sequence with and without diffusion weighting at two different time points after matrix-associated autologous cartilage transplantation (MACT). Mean diffusion quotients (signal intensity without diffusion-weighting divided by signal intensity with diffusion weighting) within the cartilage transplants were compared to diffusion quotients found in normal cartilage. RESULTS: The global diffusion quotient found in repair cartilage was significantly higher than diffusion values in normal cartilage (p<0.05). There was a decrease between the earlier and the later time point after surgery. CONCLUSIONS: In-vivo diffusion-weighted imaging based on the PSIF technique is possible. Our preliminary results show follow-up of cartilage transplant maturation in patients may provide additional information to morphological assessment.

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OBJECTIVES: The treatment of recurrent rejection in heart transplant recipients has been a controversial issue for many years. The intent of this retrospective study was to perform a risk-benefit analysis between treatment strategies with bolus steroids only versus anti-thymocyte globulins (RATG; 1.5 mg/kg q 4 days). METHODS: Between 1986 and 1993, 69 of 425 patients (17 male, 52 female; mean age 44 +/- 11 years) who had more than one rejection/patient per month (rej/pt per mo) in the first 3 postoperative months were defined as recurrent rejectors. RESULTS: Repetitive methylprednisolone bolus therapy (70 mg/kg q 3 days) was given in 27 patients (group M; 1.4 +/- 0.2 rej/pt per mo) and RATG therapy for one of the rejection episodes of the 42 remaining patients (group A; 1.5 +/- 0.2 rej/pt per mo). The quality of triple drug immunosuppression in the two study groups was comparable. The rejection-free interval (RFI) following RATG treatment in group A was 21.6 +/- 10 days and 22 +/- 11 in group M. In group M, 3 of 27 patients (11%) had a rejection treatment-related infection (2 bacterial; 1 viral) versus 6 of the 42 patients of group A (14.2%; bacterial 1, viral 5). During postoperative months 3-24, 0.15 +/- 0.12 rej/pat per mo were observed in group M and 0.21 +/- 0.13 rej/pat per mo in group A (n.s.). In this 21-month period cytolytic therapy for rejection was initiated in 8 of the remaining 21 patients of group M (38%) and 15 of the remaining 37 patients of group A (40.5%). The absolute survival and the individual causes of death were not affected by the type of initial treatment of recurrent rejection. The actuarial freedom of graft atherosclerosis is comparable in the two groups with 78% in group A versus 79% in group M free of graft atherosclerosis at 3 years postoperatively. CONCLUSIONS: A comparison of cytolytic therapy versus repeated applications of bolus steroids for treatment of recurrent rejection reveals no significant difference in the long-term patient outcome with respect to the incidence of future rejection episodes and survival.

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BACKGROUND. The high rate of reperfusion injury in clinical lung transplantation mandates significant improvements in lung preservation. Innovations should be validated using standardized and low-cost experimental models. METHODS. The model introduced here is analyzed by comparing global lung function after varying ischemic times (2, 4, 8, 16, and 24 hours). A rat double-lung block is flush-perfused, and the main pulmonary artery and left atrium are connected to the left pulmonary artery and vein of a syngeneic recipient using a T-shaped stent. With pressure side ports and incorporated flow crystals, measurement of vascular resistance and graft oxygenation can be performed. The transplant is ventilated separately, and compliance and resistance are determined. RESULTS. The increase in the ischemic interval from 2 to 24 hours caused an increase in the alveolar arterial oxygen difference from 220 +/- 20 to 600 +/- 34 mm Hg, pulmonary vascular resistance from 198 +/- 76 to 638 +/- 212 mm Hg.mL-1.min-1, and resistance to airflow from 274 +/- 50 to 712 +/- 30 cm H2O/L H2O, and a decrease in pulmonary compliance from 0.4 +/- 0.05 to 0.12 +/- 0.06 mL/cm H2O. CONCLUSIONS. This in situ, syngeneic rat lung transplantation model offers an alternative to large animal models for verification of lung preservation solutions and for modification of donor or recipient treatment regimens.

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Replacement of the heart and both lungs or single lung transplantation has been performed in a few cases of terminal (cardio) pulmonary disease in childhood. It remains unclear whether pulmonary allografts will meet the demands of a growing organism. Six domestic pigs (mean body weight, 24 kg) underwent left lung transplantation from donors of equal weight. Immunosuppression consisted of cyclosporine, azathioprine, and corticosteroids. After the pigs doubled their body weight, growth of the lung was assessed by bronchography and pulmonary angiography. In transplant animals it took 11 weeks (normal animals, 6 weeks) for their weight to double. At that time, the bronchial tree showed similar growth when compared with nontransplant animals of equal weight. The diameter of the left lower lobe bronchus (9.2 +/- 0.4 mm) was significantly greater than that of animals of 24 kg body weight (7.5 +/- 0.3 mm; p less than 0.01) but comparable to that of normal pigs of similar weight (9.0 +/- 0.5 mm). The same applied for length of the left lower lobe bronchus (transplants, 95 +/- 6.7 mm; controls 24 kg, 67 +/- 2 mm [p less than 0.01]; controls 48 kg, 93 +/- 3 mm). Similar growth tendencies were observed in the pulmonary vascular tree. The diameter of the left lower lobe artery was 9.4 +/- 98 mm in 48 kg transplant pigs, compared with 9.7 +/- 1.2 mm in 24 kg control pigs and 8.5 +/- 0.8 mm in 48 kg control pigs. In one case of recurrent severe pulmonary rejection, the lung did not grow. We conclude from this study that growth is retarded by immunosuppression.(ABSTRACT TRUNCATED AT 250 WORDS)

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Heart and lung transplantation has been performed in cases of end-stage cardiopulmonary disease in infants. Nevertheless, it still remains unclear whether lung allografts adjust to a growing organism. In 6 young domestic pigs unilateral left lung allotransplantation was performed. Immunosuppression consisted of a triple drug therapy including cyclosporine, azathioprine, and corticosteroids. Lung growth was studied by using bronchography, pulmonary angiography, and lung histology. After 11 weeks the transplanted animals had doubled their body weight from 24 kg to 48 kg. Non-transplanted animals in contrast doubled their weight within only 6 weeks. The growth retardation was attributed to the immunosuppressive therapy. The bronchial tree and pulmonary vasculature of lung allografts showed a similar growth potential to non-transplanted lungs in animals of equivalent body weight. In one case of recurrent severe rejection of the lung no growth was observed. Therefore it was concluded that lung allografts grow adequately according to the development of the recipient organism. Lung transplantation in children does not seem to be restricted by a limited growth potential of the graft.

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BACKGROUND: The question whether patients suffering from end-stage emphysema who are candidates for lung transplantation should be treated with a single lung or with a double lung transplantation is still unanswered. METHODS: We reviewed 24 consecutive lung transplant procedures, comparing the results of 6 patients with an unilateral and 17 with a bilateral transplantation. PATIENTS AND RESULTS: After bilateral transplantation the patients showed a trend towards better blood gas exchange with shorter time on ventilator and intensive care compared patients after unilateral procedure. Three-year-actuarial survival was higher in the group after bilateral transplantation (83% versus 67%). There was a continuous improvement in pulmonary function in both groups during the first months after transplantation. Vital capacity and forced exspiratory ventilation therapies during the first second were significantly higher in the bilateral transplant group. CONCLUSION: Both unilateral and bilateral transplantation are feasible for patients with end-stage emphysema. Bilateral transplantation results in better pulmonary reserve capacity and faster rehabilitation.