Prevention of yeast translocation across the gut by a single enteral feeding after burn injury

Recently, burn injury has been shown to facilitate the ability of enteric Candida albicans (CA) to penetrate the gut epithelium and translocate to the mesenteric lymph nodes (MLN) during the first 24 hr after injury. Guinea pigs were given 3 X 10(10) CA intragastrically before inflicting a 50% burn to determine if a single enteral feeding could affect CA translocation to the MLN. A bolus infusion (20 kcal/kg, 12 ml in volume) of liquid meal, consisting of 68% carbohydrate, 20% protein, and 12% lipid, was administered either at 3-hr or 12-hr postburn. Control groups received no food or a similar amount of saline by bolus infusion. All animals were allowed water ad libitum until 24-hr postburn when their MLN and intestinal segments were harvested for enumeration of viable CA. Blood was also collected for determination of serum IgG, C3, cortisol, and albumin. Compared to nonfeed animals, those with a single enteral feeding at 12-hr postburn had reduced numbers of CA translocating to the MLN (970 +/- 220 vs 7,120 +/- 2,130 CFU/g, p less than 0.02) and colonizing in the ileum (27,000 +/- 6,770 vs 104,000 +/- 23,550 CFU/g, p less than 0.01). Bolus feeding at 12 hr was associated with a lower cortisol level (237 +/- 55% of normal controls) than bolus feeding at 3 hr (310 +/- 58, p less than 0.02) or the nonfed group (326 +/- 66, p less than 0.01). Regardless of dietary treatment, serum cortisol levels correlated positively with the extent to which CA translocated to the MLN and negatively with C3 levels.

Prophylactic use of OKT3 in immunologic high-risk cadaver renal transplant recipients

Prophylactic OKT3 was administered to 27 immunologic high-risk cadaver renal transplant recipients (multiple transplant and/or panel reactive antibody greater than 50%) as part of a sequential immunosuppressive protocol consisting of OKT3, prednisone, azathioprine, and cyclosporine. The first dose of OKT3 was administered intraoperatively. Patient survival was 100% with a mean follow-up period of 13 months. Graft survival at 1 year was 70% (19 of 27). Eight grafts were lost during the first 6 weeks. Causes of graft loss were hyperacute rejection or primary nonfunction (4), irreversible rejection (2), and technical (2). After the first month, single rejection episodes occurred in four patients and multiple rejection episodes in three patients; all were successfully reversed, and no further graft losses were encountered. Mean serum creatinine level at 1 month posttransplant was 141 mumol/L (1.6 mg/dL), and the average serum creatinine has remained at that level during the follow-up period. No serious infections were encountered. Prophylactic OKT3 administration resulted in depletion of CD3+ lymphocytes from the peripheral circulation throughout therapy, as well as the development of therapeutic serum OKT3 levels. Five of the 27 (22%) patients developed antimurine antibodies during or after OKT3 therapy; four of these patients had low-titer antimurine antibody, and one had high-titer antimurine antibody. First-dose reactions were generally mild in this group of patients. Prophylactic use of OKT3 in this patient population resulted in superior graft survival when compared with a similar group of patients not receiving OKT3.

Dietary iron and recovery from peritonitis in guinea pigs

Ninety female Hartley guinea pigs underwent gastrostomy placement. One week later they underwent implantation of an osmotic pump, which allowed constant delivery of bacteria into the peritoneal cavity. Three days after pump implantation the animals were begun on enteral diets differing only in iron content (the None [no Fe], Low [1 X RDA], and High [10 X RDA] groups). When survivors were killed no differences were found in body, carcass, or organ weights among the three groups. Serum Fe and percent Fe-binding sites occupied were significantly lower in the None group although total Fe-binding capacity was similar. Mortality was not statistically different (p = 0.29): 18/32 in the None group (56%), 14/24 in the Low group (58%), and 25/34 in the High group (73%). We conclude that although deprivation of dietary sources of Fe does affect available circulating Fe, diet-induced hypoferremia does not alter mortality rates from bacterial peritonitis in the guinea pig.

External stabilization of the anterior cruciate ligament deficient knee during rehabilitation

Using cadaveric specimens, we studied the effect of ACL deficiency upon anterior tibial translation during extension of the knee joint. Five knees were loaded via the quadriceps mechanism until flexion angles of 10 degrees, 25 degrees, 40 degrees, and 60 degrees were attained. At each angle, the anterior-posterior position of the tibia was documented with biplane radiography, both before and after division of the ACL. In every specimen, anterior tibial translation increased with loss of the ACL and was greatest at 25 degrees of flexion, where an average displacement of 3.3 mm was observed. Subluxation was not significant at flexion angles exceeding 60 degrees, regardless of ACL deficiency. We also examined the effect of an external restraining force on tibial subluxation in the ACL deficient knee. Posteriorly directed forces of 0 N, 45 N (10 pounds), 90 N (20 pounds), 135 N (30 pounds), and 225 N (50 pounds) were applied to the tibia at the level of the tibial tubercle. Anterior subluxation was eliminated through application of forces ranging from a maximum of 106 N (23.6 pounds) at 10 degrees to only 13 N (2.9 pounds) at 60 degrees.

Immunoregulation of transfusion-induced immunosuppression with inhibitors of the arachidonic acid metabolism

To further define the role of arachidonic acid (AA) metabolites in transfusion-induced immunosuppression (TII), the effects of pharmacological manipulation of AA metabolism were examined in a rodent model. If the prostaglandins of the E series are mediators of TII, as has been recently hypothesized, then inhibition of cyclooxygenase (indomethacin) should abrogate whereas inhibition of lipoxygenase (nordihydroguaiaretic acid [NDGA]), or thromboxane synthetase (4-63557A) could potentiate the transfusion effect. Lewis rats received donor-specific transfusions from Buffalo rats in conjunction with one of the above inhibitors. Two weeks later they received intraabdominal Buffalo heart allografts or were used for one-way mixed lymphocyte reactions. Cyclooxygenase inhibition partially abrogated TII with shortened cardiac allograft survival. Lipoxygenase inhibition augmented TII, with depression of MLR and prolongation of allograft survival. Thromboxane synthetase inhibition had no effect. These results indicate that AA metabolites play a role in TII, and that immunoregulation via pharmacological manipulation of AA metabolism is possible.

The immunosuppressive effects of the in vivo administration of endotoxin as influenced by macrophages

It is well documented that endotoxin can have immunosuppressive effects on lymphocytes and induce the production and secretion of monokines which act on the lymphocytes. To delineate the interaction between macrophages and lymphocytes more clearly, 0.15 mg of lipopolysaccharide (LPS) (E. coli 0111:B4) was injected into Hartley guinea pigs intraperitoneally twice a day for 7 days (saline for control group). Seven days after the last injection, spleens were taken and lymphocyte proliferation was determined in the presence and absence of macrophages. When macrophages were present, there was a significant suppression of lymphocyte proliferation when PHA and PWM were used as mitogens. There was no suppression of proliferation when the macrophages were removed. Splenic macrophages were also cultured in the presence and absence of LPS and their supernatants analyzed for PGE2 and TXB2. There was no significant difference between the endotoxin and control groups for PGE2 or TXB2 production in the presence and absence of LPS. However, the endotoxin group had significant decreases in serum levels of C3 postinjection of endotoxin which could indicate C3 degradation by LPS. Taken together these results give further evidence that macrophage products in addition to PGE2 can inhibit lymphocyte proliferation. C3 degradation products could possibly stimulate macrophages to produce inhibitors of lymphocyte proliferation or induce suppressor cells.

Increased gut blood flow with early enteral feeding in burned guinea pigs

The hemodynamic responses to early enteral feeding were assessed with fluid-resuscitated, 30% total body surface area-burned guinea pigs fed by means of tube gastrostomies. Regional blood flow and cardiac output were determined by a reference sample method, injecting 15 microns radiolabeled microspheres. During the initial 24 hours after burn injury, animals were given the same volume by continuous infusion of either lactated Ringer's solution (LR group) or a liquid diet (20% protein, 12% lipid, and 68% carbohydrate; 175 kcal/kg/24 hr) (diet group). Although cardiac outputs in the LR and diet groups were not different from each other at 24 hours and no less than that in unburned control animals, the diet group showed higher blood flow to the jejunum (+55.7%) and cecum (+98.7%) than did the LR group. Burn injury caused little change of blood flow to tissues other than the intestine. In addition, early feeding after burn injury suppressed excessive cortisol response to burn shock. The increase in gut blood flow associated with enteral feeding could have an impact on mucosal barrier function.

Effect of antibiotics on CR1 receptor levels of human neutrophils and on the binding and phagocytosis of opsonized polystyrene microspheres by these leucocytes

Fourteen antibiotics were studied for their effects on the following properties or functions of normal, human neutrophils: (1) the expression of CR1 receptors; (2) the total binding of C3b.IgG-coated polystyrene microspheres in the presence of cytochalasin D to inhibit phagocytosis; (3) the net phagocytosis of the opsonized microspheres; (4) the residual, external binding after phagocytosis. Fluorescence, flow cytometric methods were used to determine binding and phagocytosis of the model target particles. Only nafcillin, a penicillin, caused a decrease (33 per cent) in phagocytic capacity of the neutrophils at a physiologically significant dose (serum level); the antifungal antibiotic, amphotericin B, caused a 30 per cent increase in phagocytic capacity. These small changes in neutrophil phagocytic capacity may not be physiologically significant. There were no significant differences in the four measured parameters caused by other antibiotics tested at physiologically significant doses.

Augmentation of donor-specific transfusion and cyclosporine effects with dietary linoleic acid

Increased prostaglandin production is a possible mechanism for the immunosuppressive effects of both cyclosporine and blood transfusions. Therefore, dietary supplementation with linoleic acid, a prostaglandin precursor, combined with either modality could act synergistically. Intraabdominal cardiac allografts were performed from Buffalo rat donors to Lewis recipients. Transplant recipients received a single donor-specific transfusion, low-dose cyclosporine (CsA, 1 mg/kd/d x 7 days), dietary supplementation with linoleic acid (LA, 16% of total calories) or a combination of the three modalities. CsA, DST or LA alone significantly prolonged allograft survival. Both CsA and LA acted synergistically with DST in further prolongation of survival--however, animals receiving all three modalities achieved 100% long-term survival. Augmentation of transfusion- and cyclosporine-induced immunosuppression with dietary prostaglandin precursor is possible.

A prospective trial of prophylactic intravenous immune globulin for the prevention of infections in severely burned patients

A prospective randomized double-blind study evaluated the efficacy of i.v. immune globulin in preventing infectious complications in severely burned patients. Fifty patients were randomized to receive either i.v. immune globulin or placebo. Each group of patients was treated with twice weekly infusions for either 5 weeks or until the patients' wounds were covered. Patients treated with the immune globulin had an immediate correction of their depressed serum IgG levels, however there was no change in the infection or mortality rates. No adverse effects were noted with the immune globulin treatments. One potential weakness of this study was the greater burn surface area and a higher incidence of inhalation injury in adult patients treated with i.v. immune globulin compared to controls.

Low protein diets improve survival from peritonitis in guinea pigs

Enteral diets with different protein content were tested to determine their effect on outcome in a model of protracted bacterial peritonitis. Hartley guinea pigs were provided with gastrostomies, and 1 week later, osmotic pumps were implanted into the peritoneal cavity to allow for continuous release of live bacteria over the course of 1 week. Three days after pump implantation, the animals began receiving isocaloric enteral diets that contained 5%, 10%, 15%, or 20% of total calories as protein. After 2 weeks of observation, the survivors were killed. All animals lost weight during the 2-weeks period, but there was no difference in weight lost. Nitrogen balance correlated with dietary protein. The mortality rate was significantly higher in the groups that received 15% and 20% of total calories compared with the group that received 5% (p less than 0.05). Although dietary protein in the 5% group was insufficient for meeting the nutritional needs of the animal, survival was best in this group. Possible explanations are that protein restriction in this model may either augment host defence or impair bacterial virulence.

A new model for studying nutrition in peritonitis. The adverse effect of overfeeding

In guinea pigs fed ad libitum, controlled intraperitoneal infusion of bacteria by an implanted 7-day osmotic pump resulted in peritonitis or abscess formation with a 50% survival 14-18 days after pump implantation. Administration of 125 kcal/kg/day of a diet found to be optimal for burned guinea pigs by continuous pump controlled feedings via a previously placed gastrostomy was well-tolerated, with a 62.5% mortality by Day 17. Administration of only 100 kcal/kg/day caused weight loss of approximately 17% after 16 days, but fewer animals died (42.8%, p = NS). Feeding either 150 kcal/kg/day or 175 kcal/kg/day caused death in all 25 animals (p less than 0.001) and their survival time was slightly shortened (p = NS) when compared with animals receiving 100 or 125 kcal/kg/day. This is the first animal model of peritonitis that permits incisive dissection of the relative influences of dietary composition on outcome, because survival can be extended to 2 weeks or more in the presence of continuing sepsis.

The effect of TP-5 on the production of C3, PGE2, and TXB2 by macrophages obtained from burned guinea pigs

The effect of in vivo administration of the immunomodulator TP-5 on the in vitro synthesis and release of C3, PGE2, and TXB2 by guinea pig alveolar, splenic, and peritoneal macrophages was studied. Three groups of animals were studied: unburned control, burned, and burned + TP-5. There was no significant difference in the production of C3, PGE2, or TXB2, by alveolar macrophages of the three groups of animals or by splenic macrophages of the three groups. There was a significant difference in the production of TXB2 by peritoneal macrophages between the unburned control compared with the burned and burned plus TP-5 groups. Our conclusion is that peritoneal macrophages seem to be controlled by mechanisms that are different from those that control alveolar or splenic macrophages.

Surface aminopeptidase activity of human lymphocytes. I. Biochemical and biologic properties of intact cells

Surface aminopeptidase activity in intact lymphocytes was studied and was shown to have the following properties when alanine-p-nitroanilide was used as substrate: 1) The activity was surface associated and not secreted as determined by extracellular location of product and the effect of proteases and diazotized sulfanilic acid on enzyme activity. 2) The enzyme activity was shown to have a pH optimum of 7.4 to 8.0. 3) Enzyme activity was shown to be inhibited by amastatin, bestatin, and 1,10 phenanthroline. Inhibition by amastatin consisted of a high-affinity component (Ki = 3.5 x 10(-6) M) which accounted for approximately 20% of the total activity and a low-affinity component (Ki = 3.5 x 10(-5) M) which accounted for the remainder suggesting that two forms of aminopeptidase exist. Only a single component of inhibition was seen with bestatin (Ki = 3.5 x 10(-6) M) and 1,10 phenanthroline (Ki = 2.0 x 10(-4) M) which accounted for 80 and 90% of the total enzyme activity, respectively. Unlike the competitive inhibitors bestatin and amastatin, inhibition by 1,10 phenanthroline was shown to be non-competitive. Finally, surface aminopeptidase activity essentially doubled in the presence of PHA (10 micrograms/ml) or Con A (10 micrograms/ml), at 72 h. This enhancing effect was shown to be dose dependent, time dependent, and mitogen dependent and correlated with the cellular state of activation as determined by [3H]TdR incorporation.

Surface aminopeptidase activity of human lymphocytes. I. Biochemical and biologic properties of intact cells

Surface aminopeptidase activity in intact lymphocytes was studied and was shown to have the following properties when alanine-p-nitroanilide was used as substrate: 1) The activity was surface associated and not secreted as determined by extracellular location of product and the effect of proteases and diazotized sulfanilic acid on enzyme activity. 2) The enzyme activity was shown to have a pH optimum of 7.4 to 8.0. 3) Enzyme activity was shown to be inhibited by amastatin, bestatin, and 1,10 phenanthroline. Inhibition by amastatin consisted of a high-affinity component (Ki = 3.5 x 10(-6) M) which accounted for approximately 20% of the total activity and a low-affinity component (Ki = 3.5 x 10(-5) M) which accounted for the remainder suggesting that two forms of aminopeptidase exist. Only a single component of inhibition was seen with bestatin (Ki = 3.5 x 10(-6) M) and 1,10 phenanthroline (Ki = 2.0 x 10(-4) M) which accounted for 80 and 90% of the total enzyme activity, respectively. Unlike the competitive inhibitors bestatin and amastatin, inhibition by 1,10 phenanthroline was shown to be non-competitive. Finally, surface aminopeptidase activity essentially doubled in the presence of PHA (10 micrograms/ml) or Con A (10 micrograms/ml), at 72 h. This enhancing effect was shown to be dose dependent, time dependent, and mitogen dependent and correlated with the cellular state of activation as determined by [3H]TdR incorporation.

Production and release of C3 by cultured monocytes/macrophages isolated from burned, trauma, and septic patients

The release of C3 under various conditions by cultured monocytes/macrophages isolated from burned, trauma, and septic trauma patients was determined. When monocytes were cultured for up to 14 days there was no difference in production and release of C3 by normals and patients; C3 production rose slowly at first then rose rapidly from 8-14 days of culture. C3 production continued for up to 28 days of culture. When lymphocytes were present with the monocytes for the first 24 hr of culture there were differences in C3 production by normal and patient cells at various times of culture. There were differences in C3 release by patients' 24 hour-cultured cells at certain postburn and injury days. Macrophages from burned patients released less C3 than normal cells and macrophages from septic trauma patients released more C3 than normal cells.