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PubMed1995

Interleukin-2 receptor expression and function following thermal injury.

BACKGROUND/OBJECTIVE: Serious traumatic or thermal injury is associated with depression of cellular immunity, including the failure of T-lymphocyte proliferation in response to stimulation that depends both on production of interleukin-2 (IL-2) and on expression of functional IL-2 receptors (IL-2R). While decreased IL-2 production following thermal injury is undisputed, the status of IL-2R expression and function in this setting is controversial; therefore, we sought to investigate this issue. DESIGN: A total of 220 male A/J mice (n = 22 per group) were subjected to a 20% scald burn injury or sham burn, killed 4, 7, 10, 14, or 21 days later, and splenocytes harvested. In vitro parameters of both IL-2R expression and function were measured. RESULTS: On day 7, splenic lymphocyte proliferation and IL-2 production in response to mitogenic stimulation were both suppressed following burn injury to 50% and 60% of controls, respectively. Northern blot analysis revealed normal IL-2R p55 messenger RNA expression in response to mitogenic stimulation on days 7, 10, and 14 in thermally injured animals. Phenotypic IL-2R p55 expression in concanavalin A-stimulated CD3+ cells was unchanged following burn injury. Binding of fluorescein-labeled IL-2 to cell membranes was increased in burned animals at days 10 and 14. The addition of IL-2 to cultures of spleen cells from burned mice consistently restored the mitogenic response to that of the controls. CONCLUSIONS: Thermal injury in this model does not result in either quantitative or functional suppression of IL-2R. Suppression of T-cell activation and proliferation, seen following thermal injury, appears primarily related to abnormal IL-2 production.

Animals↗
PubMed1995

Aberrant levels of cytokines within the healing wound after burn injury.

OBJECTIVE: To study the effect of a burn injury on the course of cellular and cytokine changes in a wound and the relationship of these cytokines to the amounts of protein and collagen deposited at the site of the wound. DESIGN: A randomized control trial was done in which one group of rats were subjected to a severe burn injury. With the use of a sponge matrix model, the wound-healing parameters were evaluated. MATERIALS: A random sample of eight inbred albino Oxford rats per group were used in all experiments. INTERVENTIONS: Rats were subjected to a severe scald injury. Polyvinyl sponges were used as the wound-healing model. MAIN OUTCOME MEASURE: The obtained results implied that the wound-healing process is impaired after a severe burn injury. RESULTS: The wounds in these animals with burn injuries contained a lower number and an altered type of infiltrating cells with aberrant levels of cytokines, higher levels of interleukin-6, and lower levels of tumor necrosis factor and interleukin-1 in the fluids of the wounds. The parameters of healing (amounts of protein and collagen deposited at the site of the wound) were significantly lower in animals with burn injuries on days 7 and 14. CONCLUSION: The underlying mechanism of the impaired healing of a wound after burn injury could lie in the altered migration of inflammatory cells to the site of the wound and in the aberrant cytokine levels within the wound.

Animals↗
PubMed2001

Use of hair pores to determine the orientation of collagen fibers in skin.

Most people are interested in recovery of skin defects caused by burn, scald or trauma from the aesthetic and functional point of view. It will occupy an important role for successful skin graft for patients with such skin defects that the orientation of collagen fibers in the grafted skin matches to the fiber orientation in surrounding skin. There have been, to my best knowledge, no methods for determining the orientation of collagen fibers in the skin from the clinical point of view. Recently, the author has found a new method for directly determining the collagen-fiber orientation without cutting samples from a calf leather by analyzing the anisotropic shape of hair pore. Its principle is based on the quantitative evaluation of collagen-fiber orientation by approximating a hair pore to an ellipse. The results obtained by the new method using hair pores were supported by the microwave method, mechanical measurements and scanning electron microscopy. Such a method will be applicable for determining the orientational distribution of collagen fibers in skins of animals and humans and give a valuable probe for performing skin grafting based on the scientific data of hair pores.

Animals↗
PubMed1990

Effect of low dose recombinant interleukin 2 plus indomethacin on mortality after sepsis in a murine burn model.

Under anaesthesia, 129 8-week-old male A/J mice were subjected to a 25 per cent scald or sham burn and then resuscitated. They were divided at random into two groups. Mice from the first group were allocated into two groups. Mice from the first group were allocated into four subgroups to receive 6 days intraperitoneal (I.P.) injections as follows: (i) recombinant human interleukin 2 (rhIL-2) (250 units day-1); (ii) saline; (iii) indomethacin (5 micrograms-1 day-1); or (iv) rhIL-2 (250 units) + indomethacin (5 micrograms). Sham burned mice served as no treatment controls. All animals were subjected to peritonitis induced by caecal ligation and puncture 10 days after the burn and mortality was assessed. Mice from the second group were allocated to two subgroups to receive 6 days intraperitoneal injections of: (i) rhIL-2 + indomethacin; or (ii) saline. Animals in this group did not undergo septic challenge. They were randomly killed on days 7, 9 or 10 after the burn. Their splenocytes were harvested and assayed for response to the mitogens phytohaemagglutinin (PHA) and concanavalin A (Con A), and for production of interleukin 2. Mortality rate in animals subjected to burn and septic challenge without treatment was 75 per cent; in mice receiving rhIL-2 alone it was 68 per cent, in mice receiving indomethacin alone it was 62 per cent (no significance) and in mice receiving rhIL-2 + indomethacin it was reduced to 38 per cent (P less than 0.02). Splenocytes from animals receiving combination therapy had markedly improved responses to PHA on days 7 (P = 0.01), 9 (P = 0.02), and 10 (P = 0.008), and to Con A on days 7 (P = 0.001), 9 (P = 0.002) and 10 (P = 0.001), after burn injury. Interleukin 2 production was also significantly (P = 0.004) improved by therapy with rhIL-2 + indomethacin. These data suggest that low dose rhIL-2 in combination with indomethacin may have potential use in the therapy of burn victims.

Animals↗
PubMed1987

Rat monocytes in a model of combined injury express the OX8 antigen.

We have analyzed peripheral blood mononuclear cell preparations from a rat model of combined injury (CI) [whole-body irradiation (500 cGy 60Co) followed by a thermal injury (20% body surface area, dorsal, scald burn)] for the expression of OX8 antigens. Ficoll-separated mononuclear fractions were labeled with monoclonal antibodies MRC OX8, MRC OX19, W3/13 HLK, or W3/25 for flow cytometric analysis. Combined-injury trauma resulted in decreased mononuclear cells to 6% of normal. This effect was due to the rapid decrease in radiosensitive lymphocytes from 83% to 10%. The relative numbers of monocytes increased from a normal 13% to 70% at day 4 after CI. Labeling of cells with OX8 after CI shifted to a population which was significantly larger in volume than normal lymphocytes. At the same time the mean fluorescence intensity of OX8-positive cells was considerably reduced. With the use of a F(ab) fragment of OX8 as a probe, these results could be partially explained as unspecific binding of the whole molecule of OX8 to Fc receptors expressed by activated monocytes. But double-labeling and cell-sorting experiments also revealed the expression of OX8 antigens by a subset of OX8+/OX19- monocytes after CI.

Animals↗
PubMed1997

Effects of acute ethanol exposure on cellular immune responses in a murine model of thermal injury.

To test the effects of acute ethanol exposure on immune function after thermal injury, mice with blood alcohol levels of 100 mg/dL were given a 15% total body surface area dorsal scald or sham injury. Bacterial challenge resulted in 100 and 40% mortality in burn + ethanol- and burn + vehicle-treated mice, respectively. Delayed-type hypersensitivity responses were also significantly suppressed in burn + ethanol-treated mice. At 1 and 4 days post-burn, concanavalin A (ConA) -induced total splenocyte proliferation in burn + ethanol-treated groups was significantly decreased (P < 0.01) compared with burn + vehicle- or sham-treated animals. This decrease was not observed in total splenocytes cultured with anti-CD3epsilon or among adherence-depleted splenocytes given ConA or anti-CD3epsilon. FACS analyses revealed no changes in splenocyte sub-type ratios in burn + ethanol mice. The data herein demonstrate that acute ethanol exposure before thermal injury results in enhanced susceptibility to bacterial infection and markedly suppressed cellular immunity, which appears to be macrophage dependent.

Animals↗
PubMed1998

Glucocorticoids protect against suppression of T cell responses in a murine model of acute ethanol exposure and thermal injury by regulating IL-6.

Previous reports by this laboratory demonstrated that acute alcohol exposure combined with a 15% body surface area dorsal scald injury results in significant reductions in delayed-type hypersensitivity (DTH) and splenocyte proliferative responses compared to either insult alone. Previous studies by this lab have also shown that these defects are mediated, in part, by increased production of interleukin-6 (IL-6). Because both alcohol exposure and thermal injury are known to modulate glucocorticoid (CORT) levels, and CORT regulates IL-6 gene expression, the relationship between circulating CORT and IL-6 production in burn + ethanol mice was examined. At 24 and 48 h post-burn, a positive correlation existed between circulating CORT levels and measurements of cellular immune function. Administration of exogenous CORT to burn + ethanol-treated mice resulted in significant restoration (to 60% of control) of DTH and splenocyte proliferative responses. This restoration was concomitant with a down-regulation of circulating and macrophage-derived IL-6. The specificity of CORT in modulating these responses was tested by assessing cellular immune function and IL-6 levels after glucocorticoid receptor blockade with RU486. Taken together, these data strongly suggest that under normal circumstances CORT protects burned mice from severe immune dysfunction, a protection that is not afforded to burn + ethanol-treated mice. Furthermore, the immune dysfunction observed in burn + ethanol mice may be due to a lack of glucocorticoid attenuation of IL-6.

Animals↗
PubMed1995

Microbiological survey of a South African poultry processing plant.

Bacterial populations associated with poultry processing were determined on neck skin samples, equipment surfaces and environmental samples by replicate surveys. Aerobic plate counts, Enterobacteriaceae counts, Enterobacteriaceae counts and Pseudomonas counts were performed by standard procedures and the prevalence of Listeria, presumptive Salmonella and Staphylococcus aureus determined. Statistically significant (P < 0.05) increases in counts of all types of bacteria were obtained on product samples as a result of processing. Although bacterial counts on neck skin samples decreased by 0.3 to 0.4 log CFU g-1 after spray washing of carcasses, subsequent spinchilling and packaging of whole carcasses resulted in 0.7 to 1.2 log CFU g-1 increases. Bacterial numbers on equipment surfaces, however, decreased significantly from the "dirty" to the "clean" areas of the abattoir. Transport cages, "rubber fingers", defeathering curtains, shackles and conveyor belts repeatedly showed aerobic plate counts in excess of 5.0 log CFU 25 cm-2. Aerobic plate counts of scald tank and spinchiller water were 2 log CFU ml-1 higher than those of potable water samples. Bacterial numbers of the air in the "dirty" area were higher than those of the "clean" area. Listeria, presumptive Salmonella and Staphylococcus aureus were isolated from 27.6, 51.7 and 24.1% of all product samples, respectively, and Listeria and Staphylococcus aureus were also isolated from selected equipment surfaces.

Animals↗
PubMed1992

Effect of helium-neon laser irradiation on serum lipid peroxide concentrations in burnt mice.

The effect of helium-neon irradiation on serum lipid peroxide concentrations in mice following 6-7% body surface area burns was investigated in a controlled study. Immediately following injury by an 8-sec 100 degrees C scalding, 25 mice were irradiated by a helium-neon laser at 0.05 J/cm2. A control group of the same size underwent identical treatment but received only sham irradiation. Serum lipid peroxide concentrations increased markedly in the control group at 0.5-4 h (P less than 0.0001, two sample t-test). In the laser treated group, the lipid peroxide concentrations remained relatively constant and were significantly depressed relative to the control group 4 h following burning (P less than 0.0001, two-sample t-test).

Animals↗
PubMed1992

Hair growth following scalp microvascular flap transfer for baldness due to burn injury.

A female patient, 8 years of age, presented with baldness of the right scalp following deep scalds from boiling soup landing on the head, neck, and chest. The depth of the burn was severe enough to cause baldness. She was primarily advised to wear a wig to address the problem of baldness on one side. Surgery was planned to use uninjured scalp skin to offer hairy skin coverage of the bald site. A left scalp skin flap (2.5 by 7 cm) based on the superficial temporal artery and vein was transferred to the bald area, with microvascular anastomosis to the superficial temporal vessels on the right side. There was complete survival of the flap with uneventful recovery and satisfactory growth of hair. Hair growth from the flap was comparatively thicker than from the rest of the scalp. This microvascular flap has produced sufficient hair to cover the entire area of the baldness and the patient does not need to wear a wig.

Alopecia↗
PubMed1990

The slotted crossover surface coil: a detector for in vivo NMR of skin.

An elongated, narrow, slotted crossover surface coil provides surface localization capable of resolving in vivo 31P NMR spectra from skin tissues. The shallow B1 field penetration achieves localization objectives while the probe length maintains signal-to-noise requirements. Dielectric and inductive losses are minimized via the crossover design (see T. L. Nagel et al., Magn. Reson. Med. 13, xxx (1990). In vivo spectra with millimeter depth resolution were acquired in 5 min at 2 T without pulse localization sequences. Preliminary 31P NMR spectra of normal and thermally injured rat skin were completed using a 25 X 3-mm slotted probe with a 3 X 2-cm surface region of excitation. Normal rat skin tissue PCr/Pi ratios ranged from 3.8 to 4.7 for 5-, 10-, and 30-mus pulse widths, while partial- and full-thickness scald injured tissues ranged from 0 to 2.8. Evaluation of a single minor partial thickness injury 1 to 5 h postburn shows evidence of a localized hypermetabolic response associated with hyperemia. Determination of burn depth and tissue viability appears feasible using: (1) PCr/Pi ratios and (2) observation of localized hypermetabolism.

Animals↗
PubMed2000

The role of interleukin 6 in interferon-gamma production in thermally injured mice.

Following traumatic injury, patients suffer from compromised immunity increasing their susceptibility to infection. Previous studies from this laboratory demonstrated that female BALB/c mice subjected to a 15% total body surface area (TBSA) scald injury exhibit a decrease in cell-mediated immunity 10 days post-burn. Studies described herein revealed that concanavalin A (Con A; 2 microg/ml)-stimulated splenocytes from sham treated animals produced 3557+/-853 pg/ml of IFN-gamma while splenocytes from burn injured animals released two-fold more cytokine (P<0.05). To determine whether leukocyte production of IFN-gamma was under the influence of macrophages, splenic macrophage supernatants generated from burned animals were incubated with splenic lymphocytes from sham and burn animals. The amount of IFN-gamma released by lymphocytes from sham animals increased when cultured with macrophages from burned mice (P<0.05). This suggests that the increase in IFN-gamma production by unfractionated splenocytes in burned mice relative to sham treated animals is macrophage-dependent. Macrophage supernatants from burned mice released twice as much IL-6 as supernatants from sham animals (P<0.05), and when IL-6 was blocked in vivo, the amount of IFN-gamma production in burned mice decreased to sham levels (P<0.05). Thus, IL-6 mediates IFN-gamma production following burn.

Animals↗
PubMed1993

Lymphokine activated killer cells enhance IL-2 prevention of sepsis-related death in a murine model of thermal injury.

It has previously been shown by this laboratory that immunomodulation of thermally injured animals with low-dose interleukin-1 (IL-2) and indomethacin (Indo) improves survival following septic challenge. Lymphokine-activated killer (LAK) cells have been shown to be effective in certain viral infections and to act in synergy with IL-2 in the treatment of certain types of cancer. We have studied the effect of LAK cells in combination with IL-2 and Indo in a murine model of thermal injury and sepsis. Male A/J mice received a 25% scald burn injury or sham burn and were randomized into five groups: (a) sham/vehicle, (b) burn/vehicle, (c) burn/IL-2 (250 U) + Indo (5 micrograms), (d) burn/LAK cells (2 x 10(6) cells), or (e) burn/LAK cells+IL-2+Indo and were treated accordingly for 6 days following injury. LAK cells were generated by in vitro IL-2 treatment of syngeneic spleen cells for 72 hr and cytotoxic activity was confirmed by standard 51Cr release assay using natural killer (NK)-sensitive and NK-resistant targets. In the groups receiving LAK cells they were administered on Day 1 and Day 6 postinjury. On Day 10, septic challenge by cecal ligation and puncture (CLP) or splenectomy, for in vitro studies, was performed. Five-day survival after CLP was 80% in the sham/vehicle group compared to 0% in the burn/vehicle group (P < 0.01). IL-2/Indo and LAK/IL-2/Indo improved survival to 25% (P < 0.05) and 57.1% (P < 0.01), respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Cardiac contractile and calcium transport function after burn injury in adult and aged guinea pigs.

Cardiac dysfunction occurs after a major burn injury regardless of age; whether burn trauma causes greater myocardial contractile depression in the older subject due to reduced cardiac reserves that normally occur with adult aging is not known. The cellular basis for burn-induced cardiac dysfunction is not known, but several studies have suggested that alterations occur in the rate of Ca2+ delivery to the contractile proteins as well as in the rate of Ca2+ removal from the sarcoplasm by the sarcoplasmic reticulum (SR). To determine if age-related differences in the cardiac contractile response to burn injury are associated with differences in SR Ca2+ transport, an isolated heart preparation was used to examine mechanical function, and myocardial homogenate preparations were used to assess SR Ca2+ transport. Guinea pigs from both age groups (adult, 6-8 months, and senescent, 34-36 months of age) were divided into two subgroups--control and 45% cutaneous scald burn. Cardiac dysfunction associated with adult aging alone was indicated by lower systolic pressure and lower rates of left ventricular (LV) pressure rise and fall, as well as decreased responses to isoproterenol, exogenous Ca2+, increased coronary flow rate, and electrical pacing. Myocardial depression in senescent control hearts was accompanied by a decreased maximal Ca2+ uptake in myocardial homogenates, suggesting that altered SR calcium transport may contribute to the diminished contractile function associated with aging. Burn injury impaired cardiac function in all animals regardless of age as evidenced by a leftward shift of LV function curves and altered responses to receptor- and nonreceptor-mediated inotropic interventions. However, the percentage change in cardiac function after burn injury was similar in both age groups compared to those of their respective controls. Significant alterations in SR Ca2+ transport were observed in myocardial homogenates isolated from both adult and senescent hearts after burn injury. Our data confirm that burn injury induced cardiac contractile dysfunction as well as alterations in SR Ca2+ transport function regardless of age, and we conclude that altered SR Ca2+ transport function contributes, in part, to the diminished cardiac function after burn injury.

Aging↗
PubMed1995

Effect of burn injury on intestinal Na+/H+ exchangers.

The Na+/H+ exchangers at the brush border membrane (BBM) and the basolateral membrane (BLM) are each distinct with different kinetic and pharmacologic characteristics. At the BBM, Na+/H+ exchange provides an acid microenvironment necessary for nutrient transport. At the BLM, the Na+/H+ exchanger regulates intracellular pH and cell volume which affect cell growth and repair. This study was designed to determine the effect of burn injury on Na+/H+ exchange at the BBM and BLM of the rat enterocyte. Adolescent Sprague-Dawley rats were divided into control (n = 6) and 20% scald burn groups (n = 6). Using differential centrifugation and percoll density gradient techniques, BBM and BLM vesicles were prepared from the jejunum. 22Na+ uptake was measured using a rapid filtration technique. Initial rate uptake studies showed that the slope of Na+ uptake in BBM (y = 0.06x + 0.12, r2 = 0.99) and BLM (y = 0.075x + 0.1, r2 = 0.99) of the control group was higher (P < 0.05) than that in the burn group (y = 0.0345x + 0.06, r2 = 0.98 and y = 0.056x + 0.01, r2 = 0.99). To determine whether the changes in transport are related to the feeding pattern in burn rats, similar experiments were done in pair-fed animals. The initial rate uptake studies of BBM showed a similarily greater slope of Na+ uptake in pair-fed control animals compared to the burn group (y = 0.043x + 0.06, r2 = 0.99 and y = 0.062x + 0.008, r2 = 0.98; P < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

Dehydroepiandrosterone reduces progressive dermal ischemia caused by thermal injury.

Progressive ischemia and necrosis of the skin following thermal injury are reduced by postburn administration of the steroid hormone dehydroepiandrosterone (DHEA). Thermally injured animals were provided with a subcutaneous injection of DHEA, or a related species of steroid hormone, at various times after burning. During the 96 hr following administration of the scald burn, tissue necrosis was closely monitored. Subcutaneous administration of DHEA at approximately 1 mg/kg/day achieved optimal protection against the development of progressive dermal ischemia. DHEA, 17 alpha-hydroxy-pregnenelone, 16 alpha-bromo-DHEA, and androstenediol each demonstrated, a similar level of protection. Other forms of steroids, including DHEA sulfate, androstenedione, 17 beta-estradiol, or dihydrotestosterone, exhibited no protective effect under the conditions tested. Additionally, intervention therapy with DHEA could be initiated up to 4 hr, but not 6 hr, after burn without a marked reduction in therapeutic benefit. Examination of the microvasculature of thermally injured dorsal skin suggested that postburn intervention with DHEA, either directly or indirectly, maintained a normal architecture in most of the dermal capillaries and venules within burn-exposed tissue. These findings suggest that systemic intervention therapy of burn patients with DHEA or a similar acting steroid hormone may be useful in preventing the progressive tissue destruction caused by progressive ischemia.

17-alpha-Hydroxypregnenolone↗
PubMed1996

Burn injury alters coronary endothelial function.

This study examined the effects of burn injury on coronary endothelial function and coronary vascular reactivity. Adult rabbits were given a scald burn over 30% of the total body surface area (or sham burn for controls) and resuscitated with Ringer's lactate solution (4 ml/kg/% burn). Subgroups of burned (n = 6) and sham-burned (n = 6) animals were sacrificed at 2, 6, and 24 hr after injury; hearts were harvested and perfused. Changes in coronary perfusion pressure (CPP, mmHg) and coronary vascular resistance (CVR, mmHg/min) were determined at a constant preload and constant coronary flow rate. Changes in coronary endothelial function were determined by the ability of the endothelium to release cGMP as an indicator of nitric oxide production. Compared to values measured in sham burns, CPP and CVR progressively fell during the early postburn period but increased toward values measured in the sham burn group by 24 hr. Cyclic GMP, fmole/ml of coronary perfusate, was significantly lower in burned hearts (27 +/- 1) compared to values measured in effluents from sham burn hearts (310 +/- 40, P < 0.05). Alterations in coronary effluent cGMP levels after burn injury suggest that thermal injury disrupts coronary endothelial function, likely contributing to postburn changes in cardiac performance.

Acetylcholine↗
PubMed1996

Oxygen free radicals contribute to postburn cardiac cell membrane dysfunction.

This study evaluated the contribution of O2 free radicals to changes in cardiac function after burn injury. Full-thickness scald burns comprising 42% of the total body surface area were produced in rats. Mean arterial pressure, heart rate, pH, cardiac transmembrane potential (Ling Gerard electrode, Em), myocardial ATP, creatine phosphate (CP), glucose 6-phosphate, and lactate were measured enzymatically 24 hr postburn in four groups: Group 1, sham burn controls, N = 12; Group 2, untreated burn injury, N = 14; Group 3, N = 10, burn injury resuscitated with Ringer's lactate (Parkland formula); Group 4, burns pretreated with oral allopurinol (10 mg/kg) for 5 days before burn injury, N = 11. In vitro cardiac contractile function was assessed 24 hr after burn injury in additional animals (N = 8) from each of the four experimental groups. Untreated burn injury caused hypotension, bradycardia, depolarization of the cardiac cell membrane (Em fell from 78.5 +/- 0.4 to 66.8 +/- 0.4, P < 0.05), and left ventricular contractile depression despite no significant fall in cardiac ATP content. In contrast, cardiac tissue CP fell and myocardial tissue lactate rose. Allopurinol pretreatment oblated burn-induced hypotension, bradycardia, and cardiac cell membrane depolarization and improved cardiac contractile function despite no fluid resuscitation from burn injury. In contrast, aggressive fluid resuscitation from burn injury (Group 3) repolarized cardiac cell membrane but did not reverse burn-induced cardiac contractile deficits. These data suggest that xanthine oxidase-mediated free radical production contributes, in part, to postburn alterations in cardiac function.

Animals↗