Explaining differences between hospitals in number of organ donors.

The shortage of donor organs calls for a careful examination of all improvement options. In this study, 80 Dutch hospitals were compared. They provided 868 donors in a 5-year period, constituting 91% of all donors in that period in The Netherlands. Multilevel regression analysis was used to explain the differences between hospitals. Potential explanatory variables were hospital-specific mortality statistics, donor policy and structural hospital characteristics. Of all donors, 81% came from one quarter of the hospitals, mainly larger hospitals. A strong relationship was found between the number of donors and hospital-specific mortality statistics. Hospitals with a neurosurgery department had additional donors. Seven hospitals systematically underperformed over a period of 5 years. If these hospitals were to increase their donor efficiency to their expected value, it would lead to an increase of 10% in the number of donors. Most donors are found in large hospitals, implying that resources to improve donor-recruitment should be channelled to larger hospitals. This study presents an efficient strategy toward a benchmark for hospitals of their organ donation rates. Some larger hospitals performed less well than others. This suggests that there is still room for improvement. There is no evidence for large undiscovered and unused pools of donor organs.

Short-term impact of carbon dioxide, helium, and gasless laparoscopic donor nephrectomy on renal function and histomorphology in donor and recipient.

BACKGROUND: Laparoscopic donor nephrectomy has the potential to increase the number of living kidney donations by reducing donor morbidity. However, studies have shown that raised intraabdominal pressure can result in transient renal dysfunction. Therefore, laparoscopically procured kidneys might be at higher risk for suffering a period of ischemia during pneumoperitoneum. The objective of this study was to investigate the short-term impact of pneumoperitoneum used for laparoscopic donor nephrectomy on renal function and histomorphology in donor and recipient. METHODS: EXPERIMENT 1: KIDNEY DONOR: Initially, 36 brown Norway (BN) rats were randomized for three procedures: 2 h of carbon dioxide (CO2) insufflation (8 mmHg), 2 h of helium insufflation (8 mmHg), and 2 h of gasless technique (0 mmHg). After this, a unilateral nephrectomy was performed in all the animals. EXPERIMENT 2: RECIPIENT: Subsequently, 36 donor BN rats were subjected to a similar insufflation protocol, but after nephrectomy, a syngeneic kidney transplantation (BN-BN) was performed. Urine and blood samples were collected on postoperative days 1, 3, 7, and 14 for determination of renal function. Subsequently, donor and recipient kidneys were removed for histomorphologic and immunohistochemical analysis. RESULTS: In both donors and recipients, no significant changes in serum creatinine, proteinuria, or glomular filtration were detected between the CO2, the helium, and the gasless control groups. In both experiments, histologic analysis of Kidney specimens did not show any deleterious effects from abdominal gas insufflation. Although kidney grafts exposed to CO2 showed significantly higher numbers of CD45+ leukocytes 3 days after transplantation, immunohistochemical analysis did not show significant differences in number of infiltrating cells (CD4, CD8, ED1, OX6, OX62) between the two insufflation groups and the gasless control subjects. CONCLUSIONS: Abdominal gas insufflation does not have an adverse effect on the renal function of the kidney donor 1 week after laparoscopic donor nephrectomy. No differences in renal function or histomorphology were detected between syngeneic kidney grafts exposed to pneumoperitoneum and gasless control subjects.

Contrast in the efficacy of hDAF mouse hearts between ex vivo perfusion and transplantation into primates.

In recent experiments, in which we compared hDAF transgenic rat hearts perfused with 15% human serum in the Langendorff device and hDAF rat hearts transplanted into cynomolgus monkeys, we demonstrated that in the ex vivo heart perfusion model both homozygous and heterozygous hDAF hearts survived longer as nontransgenic controls. Surprisingly, we found that only homozygous hDAF hearts were protected against hyperacute rejection in vivo. The first aim of this study was to determine whether perfusion of mouse hearts with higher human serum concentrations or human blood might explain some of the differences found in survival time of the recently performed experiments with rat heart xenografts. Secondly, we investigated whether the observed differences in survival times of rat xenografts between in vivo and ex vivo transplantation would also hold for mouse hearts transgenic for hDAF. An ex vivo model was used to perfuse hDAF mouse hearts and controls with human serum or blood, and hDAF transgenic hearts and controls were transplanted into cynomolgus monkeys. hDAF transgenic mouse hearts survived significantly longer than their controls when perfused with 15% human serum, but no difference was found when 30% human serum was used, or when these hearts were transplanted into cynomolgus monkeys. However, in both the in vivo and ex vivo models the amount of PMNs adhering to the vascular endothelium was significantly lower in hDAF transgenes as compared with their controls. In conclusion, in the ex vivo situation, the efficacy of hDAF transgenesis in preventing HAR is limited by serum complement concentration.

Glove powder promotes adhesion formation and facilitates tumour cell adhesion and growth.

BACKGROUND: The presence of foreign material in the abdominal cavity irritates the peritoneal surface, leading to an inflammatory response. This defensive mechanism can provoke adhesion formation. The same peritoneal defence cascade is thought to play a role in the process of intra-abdominal tumour recurrence. The aim of this study was to evaluate whether glove powder produced peritoneal adhesions in a rat adhesion model and whether it promoted intra-abdominal tumour recurrence in a rat tumour cell adhesion and growth model. METHODS: A reproducible model that allowed semiquantitative scoring of adhesion formation or tumour load was used in three different groups of rats. One group was treated by intra-abdominal application of powder obtained from starch-powdered gloves, one by application of pure starch and in one group no powder was used. RESULTS: Application of glove powder or pure starch on minimally and severely traumatized peritoneum gave rise to significantly greater adhesion formation and intra-abdominal tumour load than peritoneal trauma alone (both P < 0.001). CONCLUSION: Starch-induced peritoneal trauma leads not only to more adhesion formation but also to increased adhesion and growth of tumour cells. Since good powder-free alternatives are available there is no longer any justification for the use of powdered gloves during intra-abdominal surgery.

Immunological aspects of fresh and cryopreserved aortic valve transplantation in rats.

BACKGROUND: The influence of immune activation on valve allograft degeneration remains unclear. We studied the combined effect of major histocompatibility complex (MHC)-incompatibility and cryopreservation on valve performance, histomorphology, and tissue antigenicity in rats. METHODS: Fresh or cryopreserved allogeneic aortic valves from WAG (RT1u) rats were transplanted to DA (RT1a) recipients and syngenic transplants served as controls. After 7 or 21 days, valves were examined for competence and morphology. Immune reactivity of the recipient was measured by concanavalin A (conA) stimulation and analysis of donor-reactive Helper T-lymphocyte frequencies (HTLf) in peripheral blood and spleen. RESULTS: Syngenic grafts demonstrated normal competence and structure. Allografts lost their competence over time caused by destruction of the leaflets combined with cellular infiltration in the vascular wall. Cryopreservation induces early loss of competence and retrovalvular thrombosis. Cryopreserved allografts were also heavily infiltrated. ConA stimulation indices and HTLf were higher in allogeneic recipients compared to syngenic recipients (p < 0.03). Cryopreserved allografts elicited a lower immune response compared with fresh allografts (p < 0.03). CONCLUSIONS: Aortic valve allografts are able to induce a donor-reactive immune response that is related to early graft destruction and incompetence. Cryopreservation appears to diminish but not eliminate the antigenicity of the allograft.

Ureteroneocystostomy contributes to late functional and morphological changes in rat kidney transplants.

PURPOSE: We investigated whether the surgical technique used to reconstruct the ureter has an impact on the late function of kidney transplants by comparing ureteroneocystostomy and ureteroureterostomy. To rule out alloantigeneic mediated effects on late graft dysfunction kidney transplants were performed in a syngeneic model. MATERIALS AND METHODS: Rat kidney isografts were transplanted with simultaneous ureteroneocystostomy or ureteroureterostomy. Unilaterally nephrectomized rats served as controls. Eight weeks after transplantation intrapelvic pressure was measured during baseline diuresis, and after intravesical and intrapelvic infusion. Albuminuria was determined monthly until sacrifice at week 52. Histomorphological analysis included the degree of glomerulopathy, tubular atrophy, interstitial fibrosis and intimal hyperplasia. CD4+- and CD8+ T cells, and macrophages were identified using immunohistochemical testing. RESULTS: Eight weeks after transplantation intrapelvic pressure during baseline diuresis and after intrapelvic infusion was significantly increased in rats with ureteroneocystostomy versus those with ureterostomy and unilateral nephrectomy, whereas intravesical infusion did not change the pressure in any group. During followup albuminuria after ureteroureterostomy did not differ from that after unilateral nephrectomy. In contrast, albuminuria significantly increased after ureteroneocystostomy from week 36 onward. At week 52 the ureter and kidney after ureteroureterostomy and unilateral nephrectomy had a normal appearance, whereas all ureters were dilated after ureteroneocystostomy. Nevertheless, 6 of the 8 kidneys in the ureteroneocystostomy group had a normal appearance. However, histomorphological findings in rats with transplants and ureterovesical anastomosis demonstrated significantly more interstitial fibrosis, CD8+ T cells and macrophages than isografts ureteroureterostomy. CONCLUSIONS: As a surgical technique for restoring the urinary tract after kidney transplantation, ureteroneocystostomy contributes to the development of long-term functional and histological renal changes. Partial obstruction may be the cause of this renal impairment.

Transplantation of a single kidney per se does not lead to late graft dysfunction.

In unraveling the pathogenesis of chronic transplant dysfunction (CTD), non-alloantigen specific factors, as ischemia/reperfusion and renal mass have been suggested to play a role in the process. The aim of the present study was to investigate the effect of the transplantation procedure per se on the development of CTD in a syngeneic kidney transplant model in the rat. Kidney transplantation was performed with the BN rat as donor and recipient, the recipient kidneys having been removed. Unilaterally nephrectomized (UNx) and native BN rats served as controls. Renal function was determined monthly (proteinuria and glomerular filtration rate/100 g body weight; GFR). The follow-up period was until 52 weeks post-transplantation. Histomorphological analysis of CTD according to the BANFF criteria was carried out. Immunohistochemical staining was performed to identify infiltrating cells (CD4, CD8, and ED1) and the expression of MHC class II and ICAM-1. Isografts had a minor, constant proteinuria during follow-up, which did not differ from that of UNx: 27 +/- 10 vs. 29 +/- 2 mg/24 h at week 52. Unilateral nephrectomy led to a significant reduction of the GFR, which was about 80% of that of native rats. The GFR of isografts did not differ from that of UNx rats. Histomorphology of renal isografts was comparable to UNx and native kidneys; some glomerulopathy and tubular atrophy leading to a total BANFF-score of 2.6 +/- 0.5. In native BN kidneys, few CD4+ cells and ED-1+macrophages (mphi) were found; MHC class II was constitutively expressed on the proximal tubules and ICAM-1 on the glomeruli and peritubular capillaries. UNx-kidneys showed a similar pattern. Isografts had significantly more CD4+ cells and Mphi, mainly localized in the glomeruli, and a more intense ICAM-1 expression in the glomeruli and interstitium. Transplantation of one kidney in itself does not lead to CTD.

Cold ischemia augments allogeneic-mediated injury in rat kidney allografts.

BACKGROUND: Some clinical studies demonstrate that kidney grafts with prolonged cold ischemia experience early acute rejection more often than those with minimal ischemia. The mechanism, however, is putative. Therefore, the aim of this study was to unravel the impact of ischemia on the immune response in rat kidney allografts compared with that in isografts. METHODS: To induce ischemic injury, donor kidneys were preserved for 24 hours in 4 degrees C University of Wisconsin solution before transplantation. No immunosuppression was administered. The histomorphology according to the BANFF criteria for acute rejection and infiltrating cells were assessed at days 1, 2, 3, 4, 6, and 8 post-transplantation. RESULTS: In allografts, exposure of the kidney to ischemia led to a significantly earlier onset of interstitial cell infiltration and tubulitis compared with nonischemic allografts. The BANFF score of interstitial cell infiltration was 1 +/- 0 vs. 0.25 +/- 0.29 at day 3 and 2 +/- 0 vs. 1.25 +/- 0.25 at day 4. In contrast, in isografts, the effect of ischemia on the histology was not significant. From day 6, the histologic differences between ischemic and nonischemic grafts disappeared. Ischemia led to a more intense expression of P-selectin (day 1), intercellular adhesion molecule-1 (ICAM-1; day 2), and major histocompatibility complex (MHC) class II on endothelium and proximal tubular cells (day 2) in both allografts and isografts. Concurrently with the up-regulated ICAM-1 and MHC expression, significantly more CD4(+) cells and macrophages infiltrated the ischemic allografts at days 2 and 3 and the ischemic isografts at day 4. Importantly, the influx of these cells after ischemia was significantly greater in allografts than in isografts. CONCLUSIONS: Cold ischemia augments allogeneic-mediated cell infiltration in rat kidney allografts. The earlier onset of acute rejection in 24-hour cold preserved allografts may be prevented by better preservation or treatment using tailored immunosuppression.

Effect of inflammatory cytokines and growth factors on tumour cell adhesion to the peritoneum.

In this experimental study, the effect of inflammatory cytokines and growth factors on tumour cell adhesion to the peritoneum was investigated. A reproducible in vitro assay was developed to study the adhesion of CC531 colon carcinoma cells to an autologous monolayer of rat mesothelial cells. Tumour cell adhesion to mesothelium pre-incubated with interleukin-1beta (IL-1beta) and epidermal growth factor (EGF) resulted in at least 60% more tumour cell adhesion at maximal stimulation (p

Somatostatin receptor imaging, therapy and new strategies in patients with neuroendocrine tumours.

BACKGROUND: Somatostatin receptors have been found on a variety of neuroendocrine tumours, such as carcinoids and paragangliomas, as well as on most pancreatic endocrine and breast tumours. Somatostatin receptor scintigraphy with a radionuclide-labelled somatostatin analogue, [111Indium- diethylenetriaminopenta-acetic acid]octreotide, is a sensitive and specific technique for visualizing in vivo the presence of somatostatin receptors on various tumours. METHODS: Material was identified from previous review articles, references cited in original papers and a Medline search of the literature. Additional material was obtained from recently published abstracts of meetings. RESULTS AND CONCLUSION: Somatostatin receptor imaging of neuroendocrine tumours is essential in the diagnostic evaluation of most of these tumours. The expression of somatostatin receptors in vivo not only predicts the outcome of somatostatin analogue treatment but also opens the possibility of new therapeutic strategies. Because better information about spread of the disease can be obtained, more justifiable options for therapy can be proposed.

Negligible role for NK cells and macrophages in delayed xenograft rejection.

Hyperacute rejection (HAR) of a discordant xenograft can be avoided by complement manipulation, but delayed xenograft rejection (DXR) still leads to graft loss. It is generally assumed that macrophages and NK cells play key roles in DXR. In the present study the survival times and cellular infiltrate following guinea pig to rat heart transplantation was analyzed in the course of DXR, following aspecific and specific manipulation of macrophages and NK cells. HAR was overcome by a single injection of cobra venom factor 1 day before heart transplantation. To aspecifically reduce the inflammatory response dominating DXR, dexamethasone (DEXA) was given. Treatment with DEXA markedly reduced infiltration by NK cells, macrophages, and granulocytes. It also led to prolonged graft survival times (median survival of 0.4 days, n = 10, P < 0.05). In the second series of experiments the specific roles of NK cells and macrophages in DXR were further assessed. Monoclonal antibody 3.2.3 was used to selectively deplete NK cells. Liposome-encapsulated dichloromethylene biphosphonate was given to achieve macrophage depletion. Neither of these specific treatments, alone or combined, led to prolonged graft survival. Immunohistology revealed that at day 2 after transplantation no NK cells or macrophages were present in grafts from the combined treatment group. Only a mild infiltration of granulocytes was observed. Collectively, these results strongly suggest that NK cells and macrophages are not likely to be pivotal cell types in DXR.

Heart valve dysfunction resulting from cellular rejection in a novel heterotopic transplantation rat model.

Structural failure of heart valve allografts may be related to technical factors or immunological reactions. To circumvent nonimmunological factors a new rat implantation model was developed to study whether alloreactivity results in histopathological changes and valve dysfunction. Syngeneic (WAG-WAG, DA-DA) and allogeneic (WAG-BN, WAG-DA) transplantation was carried out using this new technique, and the function of explanted valves was assessed 21 days later by retrograde competence testing. Additionally, grafts were examined using standard histological and immunohistochemical techniques. There was no leakage during retrograde injection in nine of tem syngeneic and two of ten allogeneic grafts. Microscopically, syngeneic valves appeared normal without fibrosis or intimal thickening, although CD8+ lymphocytes and macrophages were found in necrotic myocardial rim and adventitia. In contrast, allogeneic valves were deformed and noncellular, with extensive infiltration of CD4+, CD8+ and CD68+ cells in adventitia and media. Absence of fibrosis and intimal thickening in syngeneic transplanted valves indicated circumvention of nonimmunological factors. Allogeneic valve transplantation induces cellular infiltration in the graft with subsequent graft failure.

Scavenging of reactive oxygen species leads to diminished peritoneal tumor recurrence.

Previously, we demonstrated that RBCs inhibit the recurrence of perioperatively spilled tumor cells. The aim of this study was to identify on which RBC component(s) the inhibitory effect is based. By using a cell-seeding model in rats, the effect of RBC-related antioxidant scavengers [hemoglobin, catalase, and superoxide dismutase (SOD)] on peritoneal tumor recurrence was investigated. i.p. injection of hemoglobin caused 45% more tumor load (P < 0.0001). At least 40% inhibition of tumor recurrence was achieved with the use of catalase or SOD (P < 0.05). Combining SOD and catalase did not lead to additional inhibition of tumor recurrence. Inhibition of the overwhelming oxidative potential after surgical peritoneal trauma with the use of scavengers may lead to interesting new approaches for diminishing peritoneal tumor recurrence.

Peritoneal adhesions to prosthetic materials: choice of mesh for incisional hernia repair.

BACKGROUND: In many cases, incisional hernia repair requires the use of prosthetic materials. The aim of this experimental study in a rat model was to assess the role of polyglactin 910 mesh and fluoropassivated polyester mesh in preventing the formation of adhesions. METHODS: In the first experiment, the formation of peritoneal adhesions was assessed after insertion of polypropylene, polypropylene combined with polyglactin 910, or no mesh. In the second experiment, adhesion formations were compared after insertion of fluoropassivated polyester, polypropylene, and no mesh. RESULTS: The first experiment showed no significant difference in adhesion formations between the polypropylene mesh and the combined mesh; however, when no mesh was used, there were significantly fewer adhesions in both experiments (p < 0.01). The second experiment showed a significantly lower degree of adhesions and a lower Adhesion Index after insertion of fluoropassivated polyester mesh than when polypropylene mesh was used (p = 0.04). CONCLUSIONS: Adding polyglactin 910 mesh to polypropylene mesh to prevent the formation of adhesions is not an effective measure. Fluoropassivated polyester meshes appear to provide a better alternative to the use of polypropylene meshes for incisional hernia repair in humans in terms of the formation of adhesions.

Intraperitoneal tumor growth is influenced by pressure of carbon dioxide pneumoperitoneum.

BACKGROUND: Several studies have indicated that the carbon dioxide (CO(2)) pneumoperitoneum during laparoscopy plays a role in the pathogenesis of port-site metastases. An experimental animal study was performed to investigate the impact of various pneumoperitoneum pressures on peritoneal tumor growth. METHODS: In this study, 36 male WAG rats were randomized into three groups; two groups with different pneumoperitoneum pressures (16 mmHg and 4 mmHg) and one group of gasless controls. After a pneumoperitoneum of 0.5 x 10(6) ml was established, 531 tumor cells were injected intra-abdominally and the pneumoperitoneum was maintained for 60 min. Peritoneal tumor growth was assessed on day 11 at autopsy. RESULTS: Peritoneal tumor growth in the 16-mmHg group was significantly greater than in the 4-mmHg group (p = 0.039) and the gasless group (p = 0.004). CONCLUSIONS: High-pressure CO(2) pneumoperitoneum stimulates intra-abdominal tumor growth. The use of low insufflation pressures in laparoscopic cancer surgery should be considered.