Neutrophil-to-Lymphocyte Ratio as a Predictor of the Need for Surgical Treatment in Children's Intussusception

OBJECTIVE

 Neutrophil-to-lymphocyte ratio (NLR) is an emerging inflammatory marker in abdominal pathologies. Ileocolic intussusception (ICI) involves a progressive intestinal inflammation, and the effectiveness of nonsurgical treatment (enema) might be related to the inflammation degree, although no previous studies have investigated this relationship. Our aim is to identify predictors of the need for surgical treatment in ICI.

MATERIALS AND METHODS

 A single-center, retrospective, case-control study was performed in children with ICI, who were treated with initial nonsurgical management between 2005 and 2019. Patients were divided in two groups: A (effective enema) and B (need for surgery). Admission demographic and clinical and laboratory data were analyzed. Specificity and sensitivity of the different parameters as predictors of the need for surgical treatment were determined by receiver operating characteristic (ROC) curves.

RESULTS

 A total of 511 patients were included (410: group A; 101: group B), without statistically significant demographic differences. Group B presented significantly higher frequency of vomiting, bloody stools, and longer median time since symptoms onset (24 vs. 8 hours; p < 0.001). Group B presented higher median laboratory inflammatory markers than group A: NLR (6.8 vs. 1.8; p < 0.001), neutrophils (10,148 vs. 7,468; p < 0.001), and C-reactive protein (CRP; 28.2 vs. 4.7; p < 0.001). In ROC curve analysis, NLR had an area under the curve of 0.925, higher than neutrophil count (0.776; p = 0.001), CRP (0.670; p = 0.001), and time since symptoms onset (0.673; p = 0.001). It was estimated a cut-off point of NLR greater than 4.52 (sensitivity: 73.2%; specificity: 94.5%).

CONCLUSION

 High NLR values imply a high degree of bowel inflammation and might anticipate the need for surgical treatment in ICI in children.

LEVEL OF EVIDENCE

 III.

Graft infusion of adipose-derived mesenchymal stromal cells to prevent rejection in experimental intestinal transplantation: A feasibility study

BACKGROUND

Mesenchymal stromal cells (MSC) have been proposed as a promising complement to standard immunosuppression in solid organ transplantation because of their immunomodulatory properties. The present work addresses the role of adipose-derived MSC (Ad-MSC) in an experimental model of acute rejection in small bowel transplantation (SBT).

MATERIAL/METHODS

Heterotopic allogeneic SBT was performed. A single dose of 1.5x106 Ad-MSC was intra-arterially delivered just before graft reperfusion. Animals were divided into CONTROL (CTRL), CONTROL+Ad-MSC (CTRL_MSC), tacrolimus (TAC), and TAC+Ad-MSC (TAC_MSC) groups. Each Ad-MSC groups was subdivided in autologous and allogeneic third-party groups.

RESULTS

Rejection rate and severity were similar in MSC-treated and untreated animals. CTRL_MSC animals showed a decrease in macrophages, T-cell (CD4, CD8, and Foxp3 subsets) and B-cell counts in the graft compared with CTRL, this decrease was attenuated in TAC_MSC animals. Pro- and anti-inflammatory cytokines and some chemokines and growth factors increased in CTRL_MSC animals, especially in the allogeneic group, whereas milder changes were seen in the TAC groups.

CONCLUSION

Ad-MSC did not prevent rejection when administered just before reperfusion. However, they showed immunomodulatory effects that could be relevant for a longer-term outcome. Interference between tacrolimus and the MSC effects should be addressed in further studies.

Difficulties, guidelines and review of developing an acute rejection model after rat intestinal transplantation

Experimental small bowel transplantation (SBT) in rats has been proven to be a useful tool for the study of ischemia-reperfusion and immunological aspects related to solid organ transplantation. However, the model is not completely refined, specialized literature is scarce and complex technical details are typically omitted or confusing. Most studies related to acute rejection (AR) use the orthotopic standard, with small sample sizes due to its high mortality, whereas those studying chronic rejection (CR) use the heterotopic standard, which allows longer term survival but does not exactly reflect the human clinical scenario. Various animal strains have been used, and the type of rejection and the timing of its analysis differ among authors. The double purpose of this study was to develop an improved unusual AR model of SBT using the heterotopic technique, and to elaborate a guide useful to implement experimental models for studying AR. We analyzed the model's technical details and expected difficulties in overcoming the learning curve for such a complex microsurgical model, identifying the potential problem areas and providing a step-by-step protocol and reference guide for future surgeons interested in the topic. We also discuss the historic and more recent options in the literature.

Infectious Complications Following Small Bowel Transplantation

Microbiological spectrum and outcome of infectious complications following small bowel transplantation (SBT) have not been thoroughly characterized. We performed a retrospective analysis of all patients undergoing SBT from 2004 to 2013 in Spain. Sixty-nine patients underwent a total of 87 SBT procedures (65 pediatric, 22 adult). The median follow-up was 867 days. Overall, 81 transplant patients (93.1%) developed 263 episodes of infection (incidence rate: 2.81 episodes per 1000 transplant-days), with no significant differences between adult and pediatric populations. Most infections were bacterial (47.5%). Despite universal prophylaxis, 22 transplant patients (25.3%) developed cytomegalovirus disease, mainly in the form of enteritis. Specifically, 54 episodes of opportunistic infection (OI) occurred in 35 transplant patients. Infection was the major cause of mortality (17 of 24 deaths). Multivariate analysis identified retransplantation (hazard ratio [HR]: 2.21; 95% confidence interval [CI]: 1.02-4.80; p = 0.046) and posttransplant renal replacement therapy (RRT; HR: 4.19; 95% CI: 1.40-12.60; p = 0.011) as risk factors for OI. RRT was also a risk factor for invasive fungal disease (IFD; HR: 24.90; 95% CI: 5.35-115.91; p < 0.001). In conclusion, infection is the most frequent complication and the leading cause of death following SBT. Posttransplant RRT and retransplantation identify those recipients at high risk for developing OI and IFD.

Ulcerative ileitis after proctocolectomy in children: a complication of ulcerative colitis or a disease in itself after ileoanal pullthrough?

Ulcerative ileitis (UI) after restorative proctocolectomy (RPC) and ileoanal pullthrough procedure (IAPP) is a rare condition described as inflammation of the terminal ileum proximal to the anastomosis. It is mostly observed in ulcerative colitis (UC) and is designated as prepouch ileitis; sometimes with pouchitis, but not necessarily all the time. Its incidence in adults is less than 5%, but the information in children is limited. Pathogenesis is unknown, it has been considered as a disease by itself, independently on the underlying disease. It involves additional morbidity and impacts negatively on quality of life because there is no effective treatment so far. This study aims to review the cases of UI in our institution and to summarize their clinical features and management. A descriptive retrospective study of UI patients between 1990 and 2013 was conducted. Children with RPC and IAPP with clinical and pathological diagnosis of UI were included. Sociodemographic and clinical data, diagnostic, and therapeutic procedures were collected through medical records. UI was diagnosed in eight patients (six males) after RCP; four had UC, two had total colonic aganglionosis (TCA), and two had complex anorectal malformations (one cloacal exstrophy and one omphalopagus twin with bladder exstrophy). Different surgical techniques were used in each case: UC patients underwent IAPP, 50% with J-reservoir and 50% without it; posterior sagittal pullthrough was performed in those with anorectal malformations; one Soave and one Swenson procedure in those with TCA. In summary, three patients had reservoir and five did not. The median age at the IAPP and ostomy closure was 6 years (range 2 months-8 years) and 7 years (range 6 months-9 years), respectively. UI was found after a median of 23 months (range 1-48 months), all of them after digestive tract continuity was reestablished. The leading symptom was lower GI or gastrointestinal, both of them bleeding with abdominal pain, followed by abdominopelvic abscesses and malabsorption with weight loss. Pathology showed nonspecific inflammatory changes. Treatment included antibiotics, corticosteroids and/or immunosuppressive agents with variable response, requiring a new ileostomy in five cases. Ileitis disappeared after diversion. In our experience, UI after colectomy is not an exclusive feature of UC as has been previously described. Although it appears with pouchitis, the presence of a reservoir is not a must, suggesting that this is a different entity. No medical treatment has been really effective in our patients and diversion above this level stopped the process. Further studies on its pathogenesis and treatment strategies are necessary.

Ganglioneuroma: to operate or not to operate

INTRODUCTION

Ganglioneuroma (GN) is a benign, differentiated variety of neurogenic tumor. It is often asymptomatic and may be diagnosed by serendipity. Surgical removal is the treatment of choice. However, it has been suggested that postoperative complications and sequelae might outweigh the benefits of this approach. The purpose of the present study was to examine these issues in a large experience of neural tumors.

METHODS

Patients treated between 1992 and 2012 were retrospectively reviewed. Modern imaging, measurement of catecholamine metabolite excretion and metaiodobenzylguanidine were used for workup. Surgical treatment aimed at complete resection. Complications and sequelae were recorded. Literature was searched for regrowth or malignant transformation of GN.

RESULTS

Of 227 patients with neural tumors, 24 were GN patients (12 abdominal, 11 thoracic and 1 cervical with 8 dumbbell extensions). Six children were symptomatic (three with abdominal pain and mass, one with stridor or dysphonia, and one each with anisocoria and opsomyoclonus). However, 18 (75%) were asymptomatic and the diagnosis was incidental. Several tumors were large and involved more than one body space. There were no neurologic symptoms in eight cases with dumbbell extension. Complete resection was achieved in 20 children (83%) whereas gross residual was left in four. Postoperative complications were: Horner syndrome (3 patients), mild scoliosis (1 patient), adhesive bowel obstruction (1 patient) and acute urinary retention (1 patient). There was no evidence of either regrowth or malignant behavior in residual masses left in place after follow-up of 84 (1-194) months.

CONCLUSIONS

There were a limited number of general minor complications in this series that did not include cases of regrowth or malignant transformation. However, these unfavorable events were occasionally reported in the literature. Since diagnosis of GN cannot be ascertained before removal of the mass, this should remain the aim of the treatment, although limiting the chances of complications to a minimum even if incomplete resection is the price to pay. Nonoperative attitudes should not be recommended in all cases, but they are certainly justified in some.

Preservation of the native spleen in multivisceral transplantation

The native spleen is usually removed in patients undergoing MTV. The consequential asplenic state is associated with a high risk of sepsis, especially in immunosuppressed children. In contrast, the inclusion of an allogeneic spleen in multivisceral grafts has been associated with a high incidence of GVHD. We propose an alternative technique for patients undergoing MTV, consisting of the preservation of the native spleen. This approach avoids the additional risk of infection that characterizes the asplenic state without the detrimental side effects of the allogeneic spleen.

Post-transplant lymphoproliferative disorders and other malignancies after pediatric intestinal transplantation: incidence, clinical features and outcome

PTLDs are a well-recognized and potentially fatal complication after intestinal transplantation. We analyzed the incidence, clinical features, and outcome in a 63 intestinal transplantation series performed in our unit between October 1999 and July 2011. Types of graft included ISB (n = 23), LSB (n = 20), and MV (n = 20). Patients were categorized into three groups of immunosuppression: I (n = 43) received basiliximab, tacrolimus, and steroids; II (n = 11) thymoglobulin and tacrolimus, and III (n = 9) alemtuzumab and tacrolimus. EBV status was serially assessed. All PTLD cases were biopsied to establish histopathological diagnosis. The incidence of PTLD was 14.2% (9/63). Median onset of PTLD after transplant was four months (range: 0.5-28), within first postoperative year in 6 (66.6%) patients. Fever was the most common symptom. Graft removal was needed in four patients (44%). The patient survival rate was 66.6% (6/9). We have not found any association between PTLD and immunosuppression regimen or transplant type. However, there was a statistical association with EBV active infection.

Liver transplantation in children with cystic fibrosis: experience in our centre and preliminary results with a combined en bloc liver-pancreas graft

AIM OF THE STUDY

Cystic fibrosis (CF) is a multisystemic disease, with some patients developing end-stage liver disease (ESLD), requiring liver transplantation (LT). These children usually present with severe mutations of the CFTR gene. Almost 100% of patients with severe mutations develop exocrine pancreatic insufficiency, leading later to endocrine insufficiency. Immunosuppression accelerates the development of insulin-dependent diabetes (IDD) in transplanted children with CF. Our aims were: (1) to analyze our experience with CF-related ESLD children who received LT, and the relationship to the development of IDD; (2) to report our preliminary results with en bloc liver-pancreas transplantation (CLPT).

METHODS

9 children (6M/3F) with CF and ESLD underwent LT between 1993 and 2010; median age and weight were 12.3 years (range: 5.4-17.0) and 36.7 kg (range: 14.2-58.5), respectively. 4 patients received a whole graft, 4 had reduced grafts (1 split) and 1 underwent CLPT. Immunosuppression followed the protocols at the time of transplantation.

RESULTS

Liver function was restored in all patients and none of them needed re-transplantation. Median follow-up was 105 months (range: 4-206). 1 child died of respiratory failure at 23 months after transplantation while awaiting pulmonary transplantation. Survival (Kaplan-Meier) at 105 months was 87.5%. 4 children already had IDD before transplantation and 3 developed diabetes immediately after transplantation. 2 had not developed IDD at the end of the study: the youngest at the time of LT (5.4 years, follow-up 7.1 years) and the girl who had had CLPT and who recovered normal exocrine and endocrine pancreatic function after transplantation.

CONCLUSIONS

LT is a realistic option to treat CF-related ESLD children. IDD is common in these patients. En bloc liver-pancreas transplantation is an appealing option, since it simultaneously restores exocrine function and prevents IDD. This procedure has clear technical advantages over simultaneous isolated liver and pancreas transplantation.

High-risk hepatoblastoma: results in a pediatric liver transplantation center

AIM

Aim of the study was assess the results of the treatment of High-Risk Hepatoblastoma (HRH) in a tertiary center where all liver surgery facilities, including pediatric transplantation (LT), are available.

METHODS

91 primary liver tumors treated between 1991 and 2009 were retrospectively reviewed. HRHs as defined by the SIOP criteria (PRETEXT IV or any stage with venous involvement, extrahepatic disease, tumor rupture and <100 ng/ml serum AFP) were identified and imaging and biopsies were reviewed. The treatment consisted of total removal of the tumor, involving extended hepatectomies and LT if necessary, together with SIOPEL-guided chemotherapy.

RESULTS

23/57 hepatoblastomas were HRH (11F/12M). 17 were considered unresectable by standard techniques, 3 had extrahepatic disease, and 3 fulfilled both criteria. Mean age at diagnosis was 2.3 ± 2.4 years. 3 children (referred after chemotherapy) died without surgery. 4 had resections (2 left and 2 right trisegmentectomies). Primary LT was required in 15 children (7 cadaveric donors and 8 living related donor transplantations (LRDT), 2 of them with retrohepatic vena cava replacement), and 1 patient had rescue LT after recurrence. Mean follow-up was 4.8 ± 2.9 years. 2 children who had undergone liver resection developed pulmonary metastases at 1.7 and 1.6 years postoperatively and survived after surgical treatment. 2 children with LT developed EBV-related lymphoma and leukemia respectively but survived. Event-free survival (EFS) at 1, 5, and 10 years was 78.3 ± 8.6%, 63.1 ± 10.5%, and 63.1 ± 10.5%, respectively. 6 children died (3 without surgery, 1 after liver resection, 1 after primary LT and 1 after rescue LT). Overall survival at 1, 5 and 10 years was 78.3 ± 21.7%, 73.2 ± 26.8% and 73.2 ± 26.8%. Of those with primary LT, survival at 1, 5 and 10 years was 93.3 ± 6.4%, 93.3 ± 6.4% and 93.3 ± 6.4%.

CONCLUSIONS

Outstanding results in the treatment of HRH are possible in tertiary centers when referral is early (preferably at diagnosis) and specialized liver surgery and transplantation facilities are available.

Variant techniques for liver transplantation in pediatric programs

INTRODUCTION

Several variant techniques have been developed as alternatives to whole liver transplantation to improve size matching, timing, or simply to increase the pool of donors. The aim of this study was to assess the requirements of these techniques and their outcomes in a pediatric transplant program.

PATIENTS AND METHOD

A retrospective analysis of children on the waiting list in the last 4 years was carried out. Data of patients who died while on the waiting list (WL) were recorded. Transplanted patients were divided according to the type of graft: whole liver, split, living donor and reduced liver. The analyzed outcome variables were: age, weight, UNOS status, cause of liver failure, complications and graft and patient survival. Comparisons between types of graft were performed by using Kaplan-Meier, log-rank, chi (2) and Kruskal-Wallis tests.

RESULTS

During the period studied, 116 children were listed for liver transplantation. Of these 116 children, nine (7.7 %) died after a mean period of 40.5 (5-175) days waiting for a suitable graft. Their median age at inclusion was 214 (35-1607) days, and median weight was 7.2 (12.3-3.6) kg. The cause of liver failure in this group was: 1 hemochromatosis, 1 hepatoblastoma, 2 biliary atresia, 2 acute liver failure, 2 primary non-function (PNF) and 1 chronic rejection. Liver transplantation was performed in 103 children: 25 (24 %) whole livers, 17 (16.5 %) split, 29 (28 %) living donor, 32 (31 %) reduced and 4 remain on the waiting list. Recipient age and weight were significantly lower in those receiving split and living donor than in those who given whole livers. Patient and graft survival were similar in all groups although there was a trend to lower graft survival in patients receiving whole livers. More than 50 % of patients with UNOS status I received a split graft and 5/6 children with hepatoblastoma underwent living donor transplantation. There were no differences in the rate of acute vascular complications, but long-term biliary complications were more frequent in split and living donor grafts.

CONCLUSIONS

As long as the goal of zero mortality for children on the waiting list is not achieved, variant techniques will be necessary in pediatric liver transplantation programs. Split and living donor were employed mostly to treat younger children and particularly those with a higher UNOS status. Children with tumors were treated mainly with living donor grafts. Variant techniques, which are absolutely necessary in a pediatric program, need to be improved in order to avoid long-term biliary complications.

Long-term results of the treatment of total colonic aganglionosis with two different techniques

AIM

Aim of this study was to assess the long-term results of the treatment of total colonic aganglionosis (TCA) with 2 different techniques in terms of growth, continence and quality of life (QOL).

PATIENTS AND METHODS

Forty-one patients treated for TCA between 1972 and 2007 were reviewed retrospectively with special attention paid to the length of aganglionosis, complications, growth, continence and QOL. Until 1992, patients underwent subtotal colonic resection and side-to-side ileosigmoid anastomosis (modified Martin). Since 1992, straight ileo-anal pull-through was preferred. At the end of follow-up (median 18 years, range 1-35), the height and weight, continence and QOL (scoring feeding habits, school/work performance, family life and professional development) were assessed by clinical visit or phone interview.

RESULTS

Twenty-eight patients were male and 13 female. Six had total intestinal aganglionosis and were excluded from this review together with the 2 who died before definitive treatment. The 33/41 persons in whom aganglionosis had involved less than 50 cm above the ileocecal valve and who had been considered suitable for the reestablishment of transanal fecal flow were included. Eighteen children underwent a modified Martin and 15 straight ileo-anal pull-through. Postoperative intestinal obstruction occurred in 4 cases, prolapse and prolonged TPN requirement in 2, and wound disruption and fistula in 1. Thirteen patients (39 %) had postoperative enterocolitis. Two children died after operation (1 wound disruption with sepsis and 1 pneumonia). Out of 31 survivors, 57 % and 53 % were > p50 with regard to height and weight whereas only 15 % and 19 % were <p3 respectively. Only half the patients had more than 3 bowel movements per day and the median Wildhaber continence score (normal = 14) was 11 (range 6-14). Both types of operations resulted in comparable defecation and continence patterns. QOL was rated as good in all cases but one. All patients but 2 attended high school, 8 attend university, 4 are employed and 1 is married and has 2 daughters. Social life is normal except for 1 patient who perceives his disease as a burden.

CONCLUSIONS

Patients with TCA amenable to reestablishment of the transanal fecal flow can have adequate growth, normal feeding, reasonably good continence and satisfactory QOL. However, complications and enterocolitis are frequent. A modified Martin's procedure was performed as well as straight ileo-anal pull-through with little influence on the long-term outcome.

Nutritional status after intestinal transplantation in children

INTRODUCTION

The management of children receiving small bowel grafts involves potentially life-threatening complications that affect their nutritional status. The aim of this paper was to define these factors and their influence on nutritional outcome.

PATIENTS AND METHODS

Patients with intestinal failure (IF) who received an isolated small bowel transplantation (SBT) or small bowel/liver transplantation (SBLT) at our hospital during the last 6 years were reviewed for weight Z-score, biochemical nutritional parameters, total parenteral nutrition (TPN) weaning, catheter-related sepsis, rejection and steroid treatment.

RESULTS

Twenty patients, 11 females and 9 males, received a SBT or a SBLT and survived the postoperative period; in the present study we only included 11 children with follow-up periods longer than 1 year. Seven males and 4 females with a mean age of 4.5 years (range, 1 to 20 years) received 6 SBLT and 5 SBT. Nine (82%) were weaned from TPN to an amino-acid or peptide enteral formula during the first 6 months after surgery. During the first year there was a significant increase in total protein from 5.11 +/- 1.8 mg/dl to 6.1 +/- 1.5 mg/dl (p < 0.05) and an increase in albumin from 3.8 +/- 0.9 mg/dl to 4.5 +/- 1.1 mg/dl (p < 0.05). There was an increase in weight Z-score in 9 patients (82%) during the first year. Mean Z-score improved from - 2.6 +/- 1 at transplant to - 1.0 +/- 0.6 (p < 0.05) after 1 year. Three patients (27.2%) had at least one rejection period, which was treated with steroids alone or in combination. Mean weight Z-score 1 year after surgery was - 0.9 +/- 0.6 for patients without rejection and - 1.24 +/- 0.8 for those with at least one rejection episode treated with steroids (p > 0.1). Four patients (36%) had at least one catheter-related sepsis episode. Mean weight Z-score 1 year after surgery was - 1.01 +/- 0.6 for patients without catheter-related sepsis and - 1.24 +/- 0.8 for those with at least one catheter-related sepsis episode (p > 0.1).

CONCLUSIONS

There was a significant improvement in weight Z-score and biochemical nutritional parameters 1 year after receiving a small bowel graft. No influence of steroids or catheter-related sepsis on children's nutritional status was noted 1 year after surgery, although this point will need further evaluation.

Organ Changes and Bacterial Translocation in a Rat Model of Chronic Rejection After Small Bowel Transplantation

Rejection after small bowel transplantation (SBTx) may allow bacterial translocation damaging the liver and lungs. This study investigated these issues in a rat model of chronic rejection.

MATERIALS AND METHODS

Orthotopic SBTx was performed in syngeneic (SYN) (ACI-ACI, n=8) and allogeneic (ALLO) (ACI-Lewis, n=8) rat strain combinations. Cyclosporine was given to ALLO rats for 28 days. Animals were sacrified between 55 and 65 days. Lymph nodes and venous samples were cultured; Escherichia coli DNA was assessed by polymerase chain reaction. We measured intestine, liver, spleen, and lung protein and DNA contents. Chronic rejection was histologically confirmed.

RESULTS

Two of eight and four of eight rats died in the first week after SYN and ALLO SBTx, respectively. There were no differences in organ weights or DNA and protein contents compared with the controls. Gram-negative enteric bacteria were found in two of four ALLO and two of six SYN rats (ns), and aerobic gram-positive were found in two of four and two of six (ns), respectively. Anaerobic growth occurred in mesenteric lymph nodes in only one ALLO rat. E. coli DNA was negative in all animals. Lungs were severely emphysematous in ALLO rats with no histologic changes observed in the other phagocytic organs. Mild rejection was found in the intestine of ALLO rats.

CONCLUSIONS

Bowel lesions in ALLO rats might be consistent with chronic rejection and lung lesions could be related to bacterial translocation after SBTx. However, contrary to our expectations, no significant bacterial translocation was demonstrated in either group at the end of the experiments.

Bacterial translocation in acute rejection after small bowel transplantation in rats

Acute rejection after small bowel transplantation (SBTx) may facilitate bacterial translocation (BT) and subsequent changes in the liver, spleen, and lungs. This study investigated whether BT occurs after acute rejection and whether this is followed by changes in the structure of the intestine and the phagocytic organs interposed between the gut and the general circulation. Orthotopic SBTx was performed in allogeneic (ALLO) rat-strain combinations (BN-Wistar, n=5). For comparison we used syngeneic SBTx (SYN) (BN-BN, n=6) controls. Animals were sacrificed on postoperative day 7. Mesenteric lymph nodes and portal and caval blood were cultured for aerobes and anaerobes. Escherichia coli beta-galactosidase DNA was assessed by polymerase chain reaction in the blood samples. Intestine, liver, spleen, and lung protein and DNA contents were measured. Histologic changes were graded according to standard criteria of acute rejection. For comparisons we used chi(2) and nonparametric Mann-Whitney test with a threshold of significance of p<0.05. ALLO rats lost more weight after SBTx than SYN rats (-13.02+/-4.39% vs. -8.04+/-5.08% of preoperative weight), although the difference was not significant (ns). A variable degree of graft rejection was histologically demonstrated in all ALLO rats, and DNA/protein content in the graft was significantly higher in this group (0.245+/-0.85 vs. 0.134+/-0.21, p<0.05). Gram-negative enteric bacteria were found in 4/5 ALLO and 4/6 SYN rats (ns), and aerobic Gram-positive bacteria in 2/5 and 3/6 (ns), respectively. Anaerobic growth occurred in mesenteric lymph nodes in one ALLO rat and in the bloodstream in another one. E. coli DNA was isolated in none of the ALLO but in two SYN rats (ns). BT was frequent after SBTx in both syngeneic and allogeneic strain combinations. Contrary to our expectations, BT after SBTx was not higher in ALLO group rats. However, anaerobic germs were isolated only in this group.