Effect of different combinations of dietary additives on bacterial translocation and survival in gut-derived sepsis

BACKGROUND

Dietary arginine, glutamine, and fish oil each have been shown to improve resistance to infection. The purpose of this study was to assess the potential benefit of different combinations and amounts of these components on bacterial translocation and related mortality during gut-derived sepsis.

METHODS

Balb/c mice were fed for 10 days with an AIN-76A diet supplemented with different combinations and percentages of arginine, glutamine, glycine, fish oil, and medium-chain triglycerides. Controls were fed a complete AIN-76A diet or chow. After 10 days of feeding, all animals were transfused. On day 15, the animals were gavaged with 10(10) 111In-radiolabeled or unlabeled Escherichia coli and given a 30% burn injury. Animals gavaged with unlabeled bacteria were observed for survival (n = 317). Groups that showed the best survival as well as control groups were gavaged with labeled bacteria and killed 4 hours postburn (n = 60) for harvest of mesenteric lymph nodes, liver and spleen.

RESULTS

Mice fed diets enriched with 5% fish oil + 2% arginine, 2% arginine + 2% glutamine, or 5% fish oil + 2% glutamine had higher survival than control groups. The animals fed fish oil+glutamine had significantly reduced translocation to the liver and spleen. Animals fed arginine+glutamine had an enhanced ability to kill translocated organisms in the liver compared with other groups. Fish oil+arginine improved both barrier function and microbial killing.

CONCLUSIONS

Feeding with arginine+glutamine, fish oil+arginine, or fish oil+glutamine supplemented diets positively affects the outcome in a gut-derived sepsis model.

Bacterial translocation-related mortality may be associated with neutrophil-mediated organ damage

Balb/c mice were transfused with .2 mL of C3H/HeJ mouse blood. 5 days later, the mice were gavaged with 10(10) 14C-labeled Escherichia coli, and a 20% full thickness flame burn was inflicted. Additional animals were treated with enisoprost (prostaglandin E1 (PGE1) analog) 200 micrograms/kg/day orally for 3 days before burn. Bacterial translocation was determined by both radionuclide counts (dpm) and viable colony counts 24 h post burn. Neutrophil accumulation was evaluated by the measurement of myeloperoxidase (MPO) in the liver. In addition, splenic macrophages were separated and cultured for 24 h with or without 10 micrograms/mL of LPS. Tumor necrosis factor, interleukin-1 (IL-1), IL-6, and PGE2 were measured in the cell culture supernatants. Consistent with previous work, enisoprost significantly reduced translocation. MPO in the liver was significantly greater in the control group compared to the enisoprost group. There was a significant correlation between MPO content and the degree of bacterial translocation (p < .05). Lipopolysaccharide-stimulated macrophage production of IL-1, IL-6, and PGE2 were significantly greater in the enisoprost group.

Indefinite allograft survival induced by the combination of multiple donor-specific transfusions, cyclosporine, and an anti-T cell monoclonal antibody in a protocol relevant to cadaveric organ transplantation. The importance of prolonged posttransplant cyclosporine coverage

A single donor specific transfusion (DST) 24 hr pretransplant and Cyclosporine (CsA) are synergistic in inducing prolongation of allograft survival. This synergy was further potentiated by giving 3 additional DSTs at weekly intervals posttransplant, or by the additional administration of a small dose of the anti-T cell monoclonal antibody OX-52 24 hr pretransplant to the above protocol. This study determined whether indefinite survival can be achieved in the ACI-to-Lewis heart allograft model by combining an anti-T cell monoclonal antibody, 4 DSTs given once 24 hr pretransplant and weekly 3 times posttransplant, and CsA. CsA was given daily for 28 days or 60 days posttransplant. The dose consisted of CsA 5 mg/kg/day starting 24 hr pretransplant and continuing until day 7 posttransplant and followed by 2.5 mg/kg/day for either 21 more days (total CsA days = 28 days) or 53 days (total CsA days = 60 days). The anti-T cell monoclonal antibody OX52 (200 micrograms i.v.) was given once 24 hr pretransplant. DST (1 ml) was given 24 hr pretransplant and on days 7, 14, and 21 posttransplant. Low-dose CsA for 28 days never induced indefinite allograft survival. CsA for 60 days, however, resulted in the occasional indefinite allograft survival (> 1 year) even in this difficult model. The addition of DST 24 hr pre- and posttransplant on days 7, 14, and 21 to both 28 days and 60 days of CsA further prolonged allograft survival. The best survival was seen in the group given DST 24 hr pre- and on days 7, 14, and 21 posttransplant and 60 days of CsA, with all the allografts surviving beyond 100 days of CsA, with all the allografts surviving beyond 100 days and more than 50% surviving indefinitely (> 1 year). The addition of a single dose of OX52 24 hr pretransplant to the multiple DSTs and 28 days of CsA protocol significantly improved indefinite allograft survival but its influence was less dramatic when given to the multiple DSTs and 60 days of CsA protocol. This beneficial interaction between CsA, DST, and an anti-T cell MoAb offers a clinically applicable protocol for both living donor and cadaveric organ transplantation in inducing donor-specific hyporesponsiveness, and further investigations are warranted.

Translocation and survival of Bacteroides fragilis after thermal injury

B. fragilis and E. coli were labeled with tritiated (3H) thymidine, and 10(10) of each were given separately by gavage in Balb/c mice immediately before a 20% burn injury was inflicted. Control groups received gavage with 3H-B. fragilis or 3H-E. coli without burn. Four hours after burn or gavage was administered, the animals were killed, and the radionuclide and colony counts were determined in the mesenteric lymph nodes, liver, and spleen. Additional groups of mice receiving gavage (B. fragilis or E. coli) and burn were observed for 10 days to study survival. The results showed that 3H-B. fragilis translocated to a greater extent than 3H-E. coli but that fewer B. fragilis than E. coli survived in tissues. Survival was 86% for animals challenged with B. fragilis versus 53% for animals challenged with E. coli. It is concluded that in this model B. fragilis translocates extensively after burn injury and that survival is closely related to the destruction of translocated bacteria.

Reduced inter- and intrasubject variability in cyclosporine pharmacokinetics in renal transplant recipients treated with a microemulsion formulation in conjunction with fasting, low-fat meals, or high-fat meals

This cross-over study compared the pharmacokinetic parameters obtained from cyclosporine (CsA) concentration-time profiles after administration of the corn oil-based soft gel cap (CsA-GC) with those with the microemulsion (CsA-ME) gel cap. Neither the fasting state nor the coadministration of a low- or high-fat breakfast affected the pharmacokinetics of CsA presented in either formulation. Comparisons of the three sets of pharmacokinetic parameters--namely, after fasting or after low-fat or after high-fat diets--demonstrated the CsA-ME formulation to display greater intraindividual reproducibility of the C0 and C12 trough levels (TLs), Cmax, tmax, and area under the concentration-time curve (AUC) than the CsA-GC formulation. Although the degree of interindividual variation in AUC, Cmax and tmax after CsA-ME administration was slightly, but significantly, less than after CsA-GC administration, there was no difference between the two formulations in terms of the customarily monitored C0 or C12 TL values. CsA-ME showed higher correlation coefficients of drug exposure (AUC) with C12 than CsA-GC (0.910 versus 0.712). However, CsA-ME administration resulted in only modest improvement over CsA-GC administration in the relationships between drug dose and C0, C12, or AUC--namely, 0.645 versus 0.496, 0.611 versus 0.517, and 0.700 versus 0.501, respectively. Correlation analysis between individual timed samples and AUC determinations revealed that CsA-ME requires significantly less frequent blood monitoring for prediction of total drug exposure than does CsA-GC. Although the clinical utility of this reproducible pharmacokinetic behavior remains to be demonstrated in the de novo transplant setting, the markedly reduced intraindividual variation produced by administration of CsA-ME will likely improve the accuracy of pretransplant prediction of, and reduce the frequency of subsequent adjustments in, CsA doses.

Effect of different regimens of gut decontamination on bacterial translocation and mortality in experimental acute pancreatitis

OBJECTIVE

To assess the effect of four regimens of antibiotics (compared with a control regimen of distilled water) given orally on gut decontamination, bacterial translocation, and mortality in acute necrotising pancreatitis in mice.

DESIGN

Randomised experimental study.

SETTING

University hospitals, USA and Italy.

MATERIALS

150 young Swiss Webster mice.

INTERVENTION

All mice were fed a diet deficient in choline and supplemented with ethionine. They were then randomised to be given by gavage (36 hours after starting the diet): distilled water (controls, group 1); aztreonam along (group 2); neomycin, erythromycin, metronidazole (group 3); polymyxin B and amikacin (group 4); polymyxin B, amikacin, amphotericin B (group 5). 20 Mice in each group were treated for 10 days, and the remaining 10 in each group were killed after 3 days.

MAIN OUTCOME MEASURES

Survival, and qualitative and quantitative cultures of the liver, lungs, pancreas and caecum.

RESULTS

The best survival rate during the first 7 days was in group 5, but by day 10 there was no difference among the groups. All the antibiotic regimens reduced the number of bacteria in the caecum and all but aztreonam alone (group 2) reduced the rate of translocation of both Gram negative and Gram positive bacteria to all organs studied. Translocation of yeast occurred in those animals in groups 2, 3, and 4 in which there was overgrowth of fungi in the caecum.

CONCLUSION

Gram negative and Gram positive organisms and fungi may have an important role in infective morbidity and mortality in acute pancreatitis, and selective decontamination with polymyxin B, amikacin, amphotericin B reduced the incidence of translocation related infections and early mortality in mice with acute necrotising pancreatitis.

Failure of local and systemic bacterial clearance in rats with acute pancreatitis

These studies were designed to investigate the ability of rats to clear subcutaneous bacterial abscesses following acute pancreatitis. Animals underwent subcutaneous injection of 1 x 10(9) Escherichia coli and Staphylococcus aureus and, 24 h later, were randomized into four groups to receive (A) an intravenous (i.v.) infusion of cerulein, (B) saline i.v., (C) ligation of the pancreatic head, or (D) sham ligation. After 12 h, abscess sizes were measured and blood was withdrawn for culture and assay amylase and endotoxin level assay. Animals were observed for an additional 12 h to record mortality. Both E. coli and S. aureus abscesses were larger in group C vs. group D, while only the E. coli lesion was larger in group A vs. group B. Bacteremia was detected in 60% of the animals in group A, 40% in groups B and D, and 100% in group C. Mortality was 80% in group C vs. 10% in all other groups. Amylase and endotoxin levels were higher in group C vs. all groups. In the second experiment rats were injected with bacteria as above. Four, twelve, and twenty-four hours later the abscesses were removed for quantitation of bacteria and histologic evaluation. At 24 h rats underwent procedure A, B, C, or D and the abscesses were excised 12 h later. Group C had a significantly higher number of viable bacteria inside the lesion compared to group D. Histology showed tissue necrosis and cellulitis not observed in group D. It is concluded that acute pancreatis causes failure of local and systemic bacterial clearance and that the incidence of bacteremia and mortality is proportional to the severity of the disease.

Oral glutamine decreases bacterial translocation and improves survival in experimental gut-origin sepsis

BACKGROUND

Glutamine has been shown to be an important dietary component for the maintenance of gut metabolism. The purpose of this study was to assess the potential benefit of glutamine-enriched diets on experimental gut-derived sepsis.

METHODS

BALB/c mice were fed either 2% glutamine-supplemented or 1% glycine-supplemented (near-isonitrogenous control) AIN-76A diets. Control mice received either nonsupplemented AIN-76A or regular Purina Rodent Laboratory Mouse Chow 5001 diets. After 10 days of feeding, the mice were transfused with allogeneic blood (from C3H/HeJ mice), and the feeding protocols were continued for an additional 5 days. The mice then underwent gavage with 10(10) Escherichia coli labeled with either indium-111 oxine or [14C]glucose followed immediately by a 20% burn injury. Some mice were observed 10 days postburn for survival rates. Others were killed 4 hours after burn, and the mesenteric lymph nodes, liver, and spleen were harvested to determine radionuclide and bacterial colony counts. The percentages of viable translocated E coli were also calculated.

RESULTS

Mice fed glutamine-enriched diets had a lower degree of translocation (as measured by both radionuclide and bacterial counts) to the tissues than did the other groups and had an improvement in the ability to kill translocated E coli (as measured by the percentage of viable bacteria). Survival was significantly higher in the group fed 2% glutamine (81%) compared with the groups fed 1% glycine (36%), AIN-76A (35%), and Purina Rodent Laboratory Mouse Chow 5001 (36%) diets (p < .004).

CONCLUSIONS

Glutamine-supplemented enteral diets may exert important benefits in preventing gut-origin sepsis after trauma.

Posterior cruciate function following total knee arthroplasty. A biomechanical study

The strain developed in the posterior cruciate ligament (PCL) of eight fresh cadaveric knees was measured before and after total knee arthroplasty using a loading technique that simulated stair ascent and descent. Each knee was instrumented with a Hall Effect strain gauge (Micro-Strain, Burlington, VT) in the PCL, a load cell in the quadriceps tendon, an electrogoniometer, and an array of linear displacement transducers to measure femoral rollback. Testing was undertaken with each knee in its normal state with the anterior cruciate cut and with a cruciate-retaining prosthesis, a cruciate-excising prosthesis, and a cruciate-substituting prosthesis. Normal PCL strain levels were produced in only 37% of the trials following implantation of the cruciate-retaining knee arthroplasties. With a cruciate-retaining prosthesis, femoral rollback decreased by an average of 36% and was associated with a 15% loss in extensor efficiency. In the procedures performed with excision of the PCL, rollback decreased by 70% and extensor efficiency by 19%. Cruciate substitution resulted in a 12% loss in rollback and an 11% decrease in extensor efficiency. The strain developed within the PCL during knee flexion was found to be extremely sensitive to the thickness of the polymeric tibial insert. In the majority of cases, it was not possible to restore normal ligament loading with flexion while simultaneously maintaining acceptable varus/valgus stability of the knee joint. Using a range of contemporary knee arthroplasties, the authors were unable to consistently reproduce normal function of the PCL.

Biomechanical testing of pars defect repairs

STUDY DESIGN

Human lumbar vertebral bodies were used to biomechanically test three different pars interarticularis defect repair techniques. A posteriorly directed force was applied to the inferior facets so that a bending moment was created across the pars.

OBJECTIVES

The stiffness and strength of each type of repair was measured and compared with the intact values.

SUMMARY OF BACKGROUND DATA

The Buck screw provided both the stiffest and strongest repair overall and within each group of cadaveric specimens. This was followed by the Morscher hook screw. Both the screw and hook repair were statistically significantly stronger and stiffer than the wire repair. There was no statistical difference between the screw and hook repairs regarding strength or stiffness.

METHODS

Using the intact L1 vertebral body as a control for each cadaver, the three surgical techniques for pars repair could be evaluated.

RESULTS

The screw repair provided 64% of the intact stiffness and 58% of the intact strength. The hook repair provided an average of 52% of the intact stiffness and 40% of the intact strength. The wire provided only 3.5% of the intact stiffness and 12% of the intact strength.

CONCLUSIONS

The screw repair technique is the stiffest and strongest pars repair method. The wire technique restores the least stiffness and strength.

The 1994 Lindberg Award. The production of tumor necrosis factor, interleukin-1, interleukin-6, and prostaglandin E2 by isolated enterocytes and gut macrophages: effect of lipopolysaccharide and thermal injury

Increasing evidence shows that cells other than immune cells have the potential for producing cytokines and arachidonate metabolites. It was the purpose of this study to determine whether isolated enterocytes could produce tumor necrosis factor, interleukin-1, interleukin-6, and prostaglandin E2, to compare the production with that of isolated gut macrophages, and to determine whether a difference existed in the production of these mediators after thermal injury. Guinea pigs received a 30% total body surface area burn and were killed 24 hours after injury. Isolated enterocytes and related intestinal macrophages (5 x 10(5) cells/ml) were cultured for 24 hours in the presence and absence of endotoxin, and the supernatants were assayed for the mediators. An increase was seen in production of interleukin-6 by enterocytes and by macrophages after thermal injury. In general enterocytes and gut macrophages produced about the same amounts of the different mediators. In contrast to macrophages from other tissues, enterocytes did not produce more prostaglandin E2 after stimulation with lipopolysaccharide, and with one exception gut macrophages did not produce larger amounts of mediators after stimulation with lipopolysaccharide. Enterocytes may be a significant source of immunomediator production and could contribute to the inflammatory response.

Effects of antimurine interleukin-6 on bacterial translocation during gut-derived sepsis

BACKGROUND

Recent studies have shown that interleukin-6 (IL-6) is involved in the systemic changes that are associated with infection and tissue injury and that there is a correlation between high levels of IL-6 and poor outcome during several pathologic conditions.

OBJECTIVE

The effects of antimurine IL-6 antibody on survival and host defense were studied in a clinically relevant model of infection.

METHODS

Balb/c mice were treated with 10 micrograms of antimurine interleukin-6, a nonspecific mouse IgG, or placebo 1 hour before they underwent bacterial challenge by gavage of 10(10) Escherichia coli and burn injury. Survival and the extent of translocation of E coli were determined as well as the correlation between the IL-6 levels and survival times.

RESULTS

Survival after burn and gavage was 90% in animals treated with antimurine interleukin-6 vs 50% in animals treated with nonspecific IgG and 30% in saline-treated controls. A significant correlation between the levels of IL-6 and survival time was observed. Less translocation and better killing of bacteria were observed in the tissues of animals treated with antimurine interleukin-6.

CONCLUSIONS

Interleukin-6 appears to play a major role in both the intensity of translocation of E coli from the intestine following burn injury and the host's ability to kill translocated organisms. Improved outcome was associated with a reduction of IL-6 levels by anti-IL-6 antibody.

Heparan sulfate increases survival during gut-derived sepsis by decreasing bacterial translocation and enhancing host defense

The effect of heparan sulfate (HS) on survival rate, bacterial translocation, and host defense was studied in a model of gut-derived sepsis that included transfusion-induced immunosuppression. Balb/c mice were treated pre- and postburn injury and bacterial challenge with HS, 5 mg/kg/day, or sterile phosphate-buffered saline. The HS pre- and postburn treated animals showed a significant improvement in survival compared to control animals (80 vs. 30%, p = .004, and 60 vs. 20%, p = .02, respectively). A lower amount of translocation was observed in the spleen (p < or = .001) of the HS group compared to control group. Quantitative colony counts and the calculated percentage of viable bacteria showed that the ability to kill translocated organisms was enhanced in all tissues of the animals receiving HS. These data suggest that treatment with HS positively affects the outcome in gut-derived sepsis. The beneficial effect was related both to an improved gut barrier function and to an enhanced host defense.

Heterogeneity of Kupffer cells and splenic, alveolar, and peritoneal macrophages for the production of TNF, IL-1, and IL-6

Kupffer cells and alveolar, splenic, and peritoneal macrophages from normal rats were incubated for various periods of time in the presence of LPS, and the culture supernatants were analyzed for IL-6, IL-1, and TNF. There was very little difference in the amounts of the cytokines produced by the macrophages when stimulated with 0.01-10 micrograms/ml of LPS. The shapes of the time course curves for the production of the cytokines by the different types of macrophages were generally similar, although only Kupffer cells continued to produce IL-6 throughout the entire incubation period and splenic macrophages showed a lag period in the production of IL-1. Kupffer cells produced more IL-6 than that produced by the other populations of macrophages, and alveolar macrophages produced more IL-1 compared to that produced by splenic cells. Kupffer cells and peritoneal macrophages produced more IL-6 in 24 h than in 6 h of culture, and splenic macrophages produced more IL-1 in 24 compared to 6 h of culture. Alveolar macrophages produced more TNF than that produced by the other populations of cells but only when integrated over the entire incubation period. These results confirm and extend the observed functional heterogeneity of macrophages obtained from different tissues of the same animal. This study and future studies will lead to a better understanding of the role of cytokines in the inflammatory response.

A new strategy for prolonging xenograft survival

A new strategy based on a clonal reduction hypothesis has been developed for prolonging concordant cardiac xenograft survival. Splenocytes from Golden Syrian hamsters were transfused intravenously into Lewis rats 14 days before the time of a donor-specific heart transplant into the recipient. Cyclophosphamide was administered from days -11 to -7 to reduce or eliminate proliferating xenoreactive clones. Low dose CsA was administered after the cyclophosphamide to prevent emergence and expression of xenoreactive cells. Finally, rapamycin 1.0 mg/kg was given for 5 days after transplant as further immunosuppression since it acts synergistically with CsA. In the group that received no immunosuppression after day +8, mean graft survival was 33.2 +/- 7.0 days with 10 of 17 xenografts surviving > 28 days. Extending either CsA therapy or rapamycin therapy after day +8 did not prolong graft survival. Each component of the therapy was found to be necessary for the effect.

Granulocyte macrophage colony-stimulating factor improves survival in two models of gut-derived sepsis by improving gut barrier function and modulating bacterial clearance

OBJECTIVE

The effect of recombinant murine granulocyte macrophage colony-stimulating factor (rmGM-CSF) on survival and host defense was studied using two clinically relevant models of infection that included transfusion-induced immunosuppression.

SUMMARY BACKGROUND DATA

Granulocyte macrophage colony-stimulating factor improves resistance in several models of infection, but its role in transfusion-induced immunosuppression and bacterial translocation (gut-derived sepsis) has not been defined.

METHODS

Balb/c mice were treated with 100 ng of rmGM-CSF or placebo for 6 days in a model of transfusion, burn, and gavage, or cecal ligation and puncture (CLP). Translocation was studied in the first model.

RESULTS

Survival after transfusion, burn, and gavage was 90% in rmGM-CSF-treated animals versus 35% in the control group (p < 0.001). After CLP, survival was 75% in the rmGM-CSF group versus 30% in the control group (p = 0.01). Less translocation and better killing of bacteria was observed in the tissues in animals treated with rmGM-CSF.

CONCLUSION

The ability of rmGM-CSF to improve gut barrier function and enhance killing of translocated organisms after burn injury-induced gut origin sepsis was associated with improved outcome. Granulocyte macrophage colony-stimulating factor also improved survival after CLP.

IFN-gamma decreases translocation and improves survival following transfusion and thermal injury

The effects of recombinant murine interferon-gamma (rmIFN-gamma) on survival and host defense were studied during gut-derived sepsis that included transfusion-induced immunosuppression. Balb/c mice (n = 153) were transfused with allogeneic blood and then treated with different doses of rmIFN-gamma: 10, 100, 1000, 10,000 U, or sterile saline as control once daily for 3 days. Five days after transfusion they were gavaged with 10(10) Escherichia coli and given a 20% TBSA burn injury. Survival was significantly higher in groups receiving 10 U compared to control and the group receiving 10,000 U (P < 0.0001 and P = 0.02, respectively). Groups receiving 100 or 1000 U also showed an improvement of survival compared to nontreated control animals (P = 0.02). The effect of rmIFN-gamma on the degree of translocation and the host's ability to kill translocated organisms was also investigated. Mice were treated as described above, except they were gavaged with 111In oxine-labeled E. coli and then subjected to a 20% TBSA burn. Mesenteric lymph nodes (MLN), liver, and spleen were harvested aseptically. Less translocation to the liver was observed compared to the nontreated group (P = 0.002) to the MLNs and spleen of the group treated with 100 U rmIFN-gamma compared to controls and the group treated with 10 U (P < 0.005). Animals receiving 1000 U showed fewer bacteria in the liver and spleen compared to the control group (P < 0.005).(ABSTRACT TRUNCATED AT 250 WORDS)

Post injury hypermetabolic response and magnitude of translocation: prevention by early enteral nutrition

The relationship between hypermetabolism and bacterial translocation was investigated in guinea pigs receiving a 40% burn. Animals were infused intragastrically with a complete enteral diet or Ringer's solution for 48 h, given 10(10) 14C-labeled Escherichia coli intragastrically, and killed 4 h later. Resting metabolic expenditure (RME), translocation (dpm of the 14C-labeled E. coli) to the portal blood and ileal mucosa, plasma cortisol, and urinary vanillylmandelic acid (VMA) were determined. Enterally fed animals had significantly lower RME, cortisol, VMA, and dpm, but higher mucosal and body weight than the Ringer's group. Disintegrations per minute (dpm) in the blood were positively correlated with RME (r = 0.856), cortisol (r = 0.872), VMA (r = 0.759), and dpm mucosa (r = 0.836) and inversely correlated with mucosal weight (r = -0.883). We conclude that bacterial translocation is reduced by early feeding and is an important cause of hypermetabolism and stress hormone production after burn injury.

Effect of donor age on outcome of kidney transplantation. A two-year analysis of transplants reported to the United Network for Organ Sharing Registry

The shortage of cadaveric donors coupled with a rapidly growing number of potential recipients has resulted in an increased use of older donors. In 1992, 10.7% of all cadaveric kidney transplants were from donors above the age of 55 compared with 5.4% in 1988. The present investigation serves as a follow-up of a prior study of the effect of donor age on outcome with a 2-year analysis of more than 30,000 cadaveric kidney transplants performed in the United States between October 1, 1987, and December 31, 1991, that were reported to the United Network for Organ Sharing. There was no difference between the graft survival at 1 and 2 years comparing donors aged 56-65 versus 65 and older, but the older donors (aged 56 and greater) had a 1- and 2-year graft survival that was approximately 10% and 14% less than that for recipients from the ideal age group of donors (16-45 years). There was no practical adverse interaction between donor age and recipient age, gender, diabetic status, peak PRA (panel reactive antibody activity) level of mismatch, cold ischemia time, or recipient race on outcome. The kidneys from older donors had poorer graft survival than the kidneys from younger donors when transplanted into recipients of repeat transplants, though the impact of repeat transplant and donor age on graft survival are independent of one another. These data suggest that kidneys from donors over the age of 55 overall have reduced functional reserve, which has an adverse effect on long-term function. Thus, attempts should be made to better estimate functional reserve among the older age group, but age alone should not be the sole factor for exclusion of a potential donor. The use of older donors appears to present an increased but acceptable risk of graft loss 2 years after transplant.

Time course of production of cytokines and prostaglandin E2 by macrophages isolated after thermal injury and bacterial translocation

The relationship of translocation of bacteria from the gut of burned guinea pigs and the in vitro production of tumor necrosis factor (TNF), interleukin (IL)-1 and IL-6, and prostaglandin E2 (PGE2) by lipopolysaccharide (LPS)-stimulated mesenteric lymph node and splenic macrophages was investigated at two early times after thermal injury. Two hr postburn, there was a large number of translocated bacteria in the mesenteric lymph nodes and a large proportion was killed; at 24 hr postburn, there were fewer translocated bacteria, but a large proportion was viable. In some cases, there were very large differences compared to controls in the amounts of TNF, IL-6, and PGE2, but not of IL-1, produced by the macrophages at different times postburn and at different in vitro incubation times. The results suggest that the macrophages were primed by the burn or the translocated bacteria to produce in vitro different and sometimes large amounts of cytokines or PGE2 after further stimulation with LPS. Although there was no direct correlation between production of cytokines or PGE2 and time postburn, the early increased production of PGE2 by splenic macrophages could have depressed the animal's ability to kill translocated bacteria by 24 hr postburn, and could be one of the mechanisms of the cause of systemic infection after burn injury.