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Biomedical subjects

A Barbul

Publications and source records attributed to A Barbul.

At least 73 records · Page 4Linked to original sources
PubMed1989

The wound is a possible source of posttraumatic immunosuppression.

Wound fluid from 10-day-old healing wounds in rats inhibits lymphocyte immune responses. Since severe injury is frequently complicated by immunosuppression as manifested by sepsis, we hypothesized that the wound may be a source of factors that impair host immune responses. Therefore, we studied the effect of systemic wound fluid administration on the survival of rats subjected to an acute peritonitis model. Male Sprague-Dawley rats, fitted with internal jugular catheters 48 hours previously, underwent cecal ligation and puncture with a 23-gauge needle. Immediately after the operation, rats were treated intravenously every 12 hours with either wound fluid obtained from 10-day-old healing wounds and adjusted to 10 mg of protein per milliliter or rat serum. In vitro testing of the wound fluid showed it to be highly inhibitory of thymic lymphocyte mitogenesis. Rats treated with wound fluid had significantly higher mortality after peritonitis than did control rats. The data show that the wound contains factors that can impair host immune responses to sepsis. This suggests that the wound may be the source of posttraumatic host immunosuppression.

Animals↗
PubMed1989

The effect of in vivo T helper and T suppressor lymphocyte depletion on wound healing.

The role of T lymphocytes in wound healing is still not well-defined. Because it had been previously shown that in vivo depletion of T cells leads to impaired wound healing, the effect of depleting T cell subsets on subsequent fibroplasia was studied. T helper/effector cells were depleted by the use of the monoclonal antibody GK1.5, reactive against the L3T4 antigen (CD4). T suppressor/cytotoxic lymphocytes were depleted by using the 2.43 monoclonal antibody reactive against the Lyt 2 antigen (CD8). In the first experiment, Balb/c mice were treated with the antibodies starting at 24 hours before wounding was performed, and weekly thereafter. Depletion of the T helper/effector cells had no effect on wound-breaking strength or hydroxyproline deposition in sponge granulomas, whereas depletion of T suppressor/cytotoxic cells significantly enhanced both of these healing parameters. In a second experiment, T cell subset depletion was started on Days 0, 3, 7, 10, and 14 postwounding, and treatments were continued weekly thereafter. Once again, depletion of T helper/effector cells had no effect on wound healing, whereas depletion of T suppressor/cytotoxic cells markedly increased both wound-breaking strength and collagen synthesis. In conclusion, the data show that T suppressor/cytotoxic cells have a counter-regulatory role in wound healing, whereas the T cell subset responsible for up-regulating wound healing remains to be identified.

Animals↗
PubMed1989

Wound healing in nude mice: a study on the regulatory role of lymphocytes in fibroplasia.

In order to understand the role of T cells in postinjury fibroplasia, we have studied wound healing in congenitally athymic nude mice that lack a normally developed T cell system. Healing of incisional wounds, as assessed by wound breaking strength, was significantly stronger in nude mice compared with normal thymus-bearing animals. This was accompanied by a marked increase in the amount of reparative collagen synthesized at the wound site, as assessed by the hydroxyproline content of subcutaneously implanted sponges. Because nude mice have some extrathymic T cell maturation, we used an anti-Thy-1.2 (30H12) monoclonal antibody to selectively deplete T cells in vivo. Although such treatments impaired wound healing in normal mice, they had no effect on any wound healing parameter in nude mice. In a separate experiment, T cell reconstitution of nude mice, sufficient to significantly enhance in vivo delayed hypersensitivity responses, led to a decrease in both wound breaking strength and hydroxyproline deposition in subcutaneously implanted polyvinyl sponges. The data suggest that T cells play a dual role in wound healing: an early stimulatory role on macrophages, endothelial cells, and fibroblasts, and a late counterregulatory role, which may be responsible for the orderly completion of wound repair.

Animals↗
PubMed1989

Inhibition of wound repair by thymic hormones.

To further define the role of the thymus in wound healing, we studied the effects of two thymic hormones on fibroplasia in normal euthymic and in nude athymic mice. Groups of 10 mice underwent a 2.5 cm dorsal skin incision with subcutaneous placement of polyvinyl alcohol sponges. Starting on the day of wounding, the following daily injections were given: (1) thymopentin (TP5), an active synthetic pentapeptide of thymopoietin, a naturally occurring thymic hormone (1 microgram/day/IM); (2) thymulin or facteur thymique serique (FTS), a naturally occurring circulating thymic hormone (0.2 microgram/day/IM); (3) control saline solution (0.1 ml/day/IM). All mice were killed 4 weeks after wounding, and wound breaking strength and hydroxyproline content of the sponge granulomas were measured. The results show that both thymic hormones impaired wound breaking strength and reparative collagen synthesis in normal and athymic mice. The magnitude of the wound healing impairment induced by the two hormones was equal in the thymus-bearing and in the nude mice. The data support previous findings, which suggested that the thymus has an inhibitory effect on wound healing.

Animals↗
PubMed1988

Generation of an anti-interleukin 2 factor in healing wounds.

Previously we have noted that fluid obtained from ten-day-old healing wounds noncytotoxically inhibits the blastogenesis of lymphocytes in response to mitogens or antigens. Since these lymphocytic responses are interleukin 2 (IL-2)-mediated, we looked for a specific IL-2 inhibitor in wound fluid. We have found that wound fluid blocks the response of thymic lymphocytes and of two cloned T-helper cell lines (D10 and HT2) to exogenous human recombinant IL-2. The wound fluid enhances fibroblast proliferation, thus demonstrating that its proliferative inhibitory activity is specific for lymphocytes. The findings suggest that wound fluid contains a factor that impairs lymphocyte response to IL-2, probably at the receptor or postreceptor level.

Animals↗
PubMed1988

Stimulation of T cell immunity by arginine enhances survival in peritonitis.

T cell-mediated immunity may play a role in host responses to infection. Arginine is a known thymic and T cell stimulator which enhances host allogenic, mitogenic, and anti-tumor responses. We, therefore, examined the effect of arginine on the survival of rats with severe and lethal peritonitis induced by cecal ligation and double-needle puncture (CLP). In Experiment 1, arginine HCl (100 mg) was given bid by gavage starting immediately after CLP. In Experiment 2, the same dose of arginine was given by gavage bid for 3 days pre-CLP and continued thereafter. In Experiment 3, arginine was administered iv post-CLP (100 mg tid). Arginine had no effect on overall survival in Experiment 1. In Experiments 2 and 3, arginine therapy significantly increased survival at all times. A separate experiment was carried out to determine the reason for the differential response to arginine administered via gavage or iv post-CLP (Experiments 1 and 3). Nonseptic rats showed a 400% increase in plasma arginine 30 min after gavage with 100 mg arginine (P less than 0.001). No rise in plasma arginine was noted when arginine was administered by gavage post-CLP. The impaired intestinal absorption or markedly increased utilization of arginine in this septic model may explain why no improved survival was seen in Experiment 1. The mechanism for the improved survival with arginine therapy seen in Experiments 2 and 3 may be related to its known thymic and T cell immunostimulatory effects.

Animals↗
PubMed1988

Suppressor cell generation during normal wound healing.

We have previously shown that 10 day healing wounds in rats contain wound mononuclear cells (WMNC) which inhibit normal lymphocyte mitogenic and allogeneic responses. In the present study we sought to further characterize the WMNC and define their mechanism of action. Polyvinyl alcohol sponges implanted in wounds were harvested and processed 10 days postwounding. The resultant WMNC suspension contained less than 15% macrophages. By FACS analysis, 69.5 +/- 11.4% (mean +/- SD of eight separate experiments) of the cells expressed the all T cell marker (W3/13), while 47.7 +/- 11.9% stained with the T helper/effector marker (W3/25) and 49.5 +/- 18.8% expressed the T suppressor/cytotoxic phenotype (OX8) (Th/Ts ratio = 0.96 +/- 0.13). When various numbers of WMNC were cocultured with 5 X 10(5) PHA-stimulated rat thymic lymphocytes, as few as 500 WMNC inhibit normal blastogenesis. Long-term (72 or 144 hr) culture of WMNC revealed that they maintain their suppressive activity. Furthermore, the conditioned media of long-term cultures also significantly suppressed thymic lymphocyte PHA blastogenesis, suggesting that the WMNC secrete suppressive cytokines. Large doses of human recombinant IL-2 or indomethacin did not abrogate the inhibitory effect of WMNC. We conclude that the healing wound is normally infiltrated by suppressor lymphocytes which generate immune inhibitory cytokines.

Animals↗
PubMed1988

Arginine metabolism in wounds.

Arginine metabolism in wounds was investigated in the rat in 1) lambda-carrageenan-wounded skeletal muscle, 2) Schilling chambers, and 3) subcutaneous polyvinyl alcohol sponges. All showed decreased arginine and elevated ornithine contents and high arginase activity. Arginase could be brought to the wound by macrophages, which were found to contain arginase activity. However, arginase was expressed by macrophages only after cell lysis and no arginase was released by viable macrophages in vitro. Thus the extracellular arginase of wounds may derive from dead macrophages within the injured tissue. Wound and peritoneal macrophages exhibited arginase deiminase activity as demonstrated by the conversion of [guanido-14C]arginine to radiolabeled citrulline during culture, the inhibition of this reaction by formamidinium acetate, and the lack of prokaryotic contamination of the cultures. These findings and the known metabolic fates of the products of arginase and arginine deiminase in the cellular populations of the wound suggest the possibility of cooperativity among cells for the production of substrates for collagen synthesis.

Amino Acids↗
PubMed1987

Lymphocyte participation in wound healing. Morphologic assessment using monoclonal antibodies.

To investigate lymphocyte participation in wound healing, the migration of T lymphocyte subsets into healing wounds and subcutaneously implanted polyvinyl alcohol sponges was studied. Frozen sections of 5-, 7-, and 10-day-old incisional wounds and sponges from Lewis rats were stained with mouse anti-rat monoclonal antibodies. Cellular staining to OX1 (all leucocyte), W3/25 (helper/effector T lymphocytes), and OX8 (suppressor/cytotoxic T lymphocytes) was quantitated in two arbitrarily defined areas based on maximal cellular infiltration: the superficial wound, down to and including the papillary dermis, and the deep wound, the reticular dermis. Five-day wounds were significantly more cellular than 10-day wounds in the deep portion (p less than 0.05) and somewhat more cellular in the superficial section (p less than 0.10). Approximately 2:1 W3/25 to OX8 ratios were noted for wound strips on all days. At 5 and 10 days there are twice as many W3/25 and OX8 labeled cells in the deep wound as in the superficial portion. At 7 days there is a peak in surface W3/25 and OX8 lymphocytes, whereas the deep population remains constant. Seven- and 10-day sponge granulomas demonstrate ratios similar to the wound strips (5-day sponge lymphocytic infiltration was insufficient to count). The data demonstrate that lymphocyte subpopulation participation in wound healing is a dynamic and distinctive process.

Animals↗
PubMed1987

Significance of T-lymphocytes in wound healing.

To determine the importance of T-lymphocytes in wound healing, we examined the effect of T-lymphocyte depletion on the healing of surgical wounds. Thirty Balb/c mice were injected intraperitoneally with 1 mg of rat anti-mouse (IgG2b) cytotoxic monoclonal antibody (30H12) against the Thy1.2 (all T) determinant. Twenty-four hours later animals showed a greater than 95% depletion of Thy1.2 cells in peripheral blood and spleen. Thirty control mice received nonspecific rat immunoglobulin (1 mg). Twenty-four hours after treatment mice underwent a 2.5 cm dorsal skin incision with subcutaneous placement of polyvinyl alcohol sponges. Injections were repeated at weekly intervals. Wound healing was assessed at 2, 3, and 4 weeks by the breaking strength of wound strips and by the hydroxyproline content of sponge granulomas (an index of wound reparative collagen deposition). Thy1.2 depletion at death was 95% to 57% in peripheral blood and 86% to 68% in the spleen. Both groups gained weight equally. We found that T cell depletion significantly impairs wound breaking strength and wound collagen deposition at all times studied. The data strongly suggest that T-lymphocytes modulate fibroblast activity during normal wound healing.

Animals↗
PubMed1986

Interleukin 2 enhances wound healing in rats.

Antigen-stimulated lymphocytes secrete lymphokines which have been shown to enhance in vitro fibroblast migration, proliferation, and protein synthesis. In the present experiments, the effect of human recombinant interleukin 2 (RIL-2) on wound healing was assessed in vivo. Groups of male Lewis rats, 225-250 g, underwent intraperitoneal insertion of osmotic pumps and a 7-cm dorsal skin incision with subcutaneous placement of polyvinyl alcohol sponges under anesthesia. The dorsal wounds were closed with stainless-steel sutures. The dose of RIL-2 administered was 60,000 u/rat/day for 7 days in experiment I, and 140,000 u/rat/day for 7 days in experiment II. Controls received equal volumes of excipient. Animals were sacrificed 10 days post wounding and wound healing was assessed by fresh breaking strength, fixed breaking strength (following 72 hr of Formalin fixation which maximally crosslinks the collagen present), and sponge hydroxyproline content (an index of reparative collagen accumulation). In vivo RIL-2 administration significantly augmented wound fresh and fixed breaking strength and wound collagen synthesis. Higher doses of RIL-2 (experiment II) did not result in further increases in the parameters studied. The data suggest that lymphocytes participate directly in the process of wound healing.

Animals↗
PubMed1985

Cocaine colitis. Is this a new syndrome?

An unusual case of colitis in a 37-year-old cocaine addict is described. The patient presented with right-sided abdominal pain and diarrhea exacerbated by his use of cocaine. Significant antibiotic ingestion was denied. At laparotomy, an edematous cecum and ascending colon were found, the cut surface of which revealed diffuse superficial ulcerations and yellowish fibrinous material. Microscopic examination demonstrated findings consistent with pseudomembranous colitis with an ischemic component. A mechanism involving catecholamine-induced mucosal ischemia is postulated to explain the findings seen in this patient.

Adult↗
PubMed1985

Intravenous hyperalimentation with high arginine levels improves wound healing and immune function.

The purpose of this study was to evaluate the effect of increased arginine levels in intravenous hyperalimentation (IVH) therapy on wound healing and thymic immune function. Groups of SD rats, 275-325 g, underwent placement of internal jugular catheter, 7-cm dorsal skin wounding, insertion of polyvinyl alcohol sponges subcutaneously, and closure of wounds with stainless-steel sutures. Twenty-four hours later, rats were started on IVH at a rate of 0.8-1 ml/100 g body wt/hr. All IVH solutions contained 20% dextrose, adequate amounts of minerals and vitamins, and two different amino acid mixtures: (A) Fre III (4.05 g ARG/liter) (n = 13); (B) experimental (7.50 g ARG/liter) (n = 11). Solutions were isonitrogenous, and contained similar amounts of essential amino acids. After 7 days of IVH, weight gain did not differ between the two groups; however, cumulative N balance was superior in group A. Wound healing was improved in group B as assessed by fresh wound strip breaking strength, fixed breaking strength, and the amount of reparative collagen deposition as assessed by the hydroxyproline content of the implanted sponges. Group B animals also had improved thymic function as assessed by thymic weight, the total number of thymic lymphocytes/gland and mitogenic reactivity of thymic lymphocytes to PHA and Con A. The experiments indicate that high arginine levels in IVH solutions improve wound healing and thymic immune function following injury.

Amino Acids↗
PubMed1984

High arginine levels in intravenous hyperalimentation abrogate post-traumatic immune suppression.

Trauma victims often suffer immune system failure. Oral arginine has strong immune-enhancing properties. The metabolic, hormonal, and immune effects of increasing concentrations of arginine as part of post-trauma intravenous hyperalimentation (IVH) were studied. Groups of 11-14 rats, 275-350 g, underwent jugular vein catheterization and bilateral closed femoral fractures under anesthesia. IVH was started immediately postinjury at a rate of 0.8-1 ml/100 g body wt/hr and continued for 5 days. Twenty percent dextrose and three different amino acid mixtures were given as follows: (A) FreII (1.55 g ARG/1); (B) FreIII (4.05 g ARG/1); (C) modified FreIII (7.9 g ARG/1). All rats lost weight over the 5-day postinjury period; however, rats in groups B and C lost significantly less weight than rats in group A (-3.4 +/- 0.8% of initial body weight and -3.6 +/- 0.9% vs -6.1 +/- 1.2%, P less than 0.05). Rats in group A had negative cumulative nitrogen balance, while those in groups B and C were in highly positive balance. No significant difference in body weight change or nitrogen balance was noted between groups B and C. Trauma-induced thymic involution as assessed by thymic weight and lymphocyte content was greatest in group A, which received the lowest amount of arginine, and was linearly abrogated by increasing the amount of arginine administered (A less than B less than C). Thymocyte immune responsiveness increased with the amount of arginine given as assessed by mitogenesis in response to Con A (stimulation index: A--151.3 +/- 28.8 vs B--243.6 +/- 29.2, P less than 0.01 vs C--321.8 +/- 22.3, P less than 0.001 vs A and P less than 0.02 vs B) and PHA (A--65.0 +/- 14.3 vs B--67.7 +/- 15.3, NS, vs C--117 +/- 14.0, P less than 0.005 vs A and B).(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acids↗
PubMed1984

Inhibition of host immunity by fluid and mononuclear cells from healing wounds.

Severe trauma impairs host immunity, which in turn renders the host susceptible to infection often terminating in death. This impairment occurs 7 to 14 days after injury, a time when wound healing is at its maximum. We examined the interactions of wound healing to host immunity by studying the in vitro and in vivo immune effects of wound components (i.e., wound fluid [WF] and wound mononuclear cells [WMNC]). Lewis male rats (RT-1(1] weighing 300 to 350 gm underwent 7 cm dorsal skin incisions and subcutaneous placement of polyvinyl alcohol sponges. At 7 and 10 days after wounding, sponges were removed and WF was separated from the cellular elements. The cell suspension was purified to contain 80% to 90% WMNC. Ten percent WF from 7- and 10-day-old wounds inhibits normal thymic lymphocyte blastogenesis to concanavalin A and phytohemagglutinin. Addition of 5 X 10(4) WMNC leads to similar inhibition. WF and WMNC from 10-day-old wounds also inhibit in vitro allogeneic responses tested in one way MLR of Lewis splenocytes with inactivated ACI (RT-1a) spleen cells by 75% to 96% and 85% to 98%, respectively. The inhibitory action of WF is heat resistant (56 degrees C for 30 minutes) and noncytotoxic. In vivo allogeneic responses, tested by grafting ACI skin onto Lewis recipients, were inhibited by intraperitoneal administration of 10-day-old WF (p less than 0.01). We conclude that WF contains factor(s) that inhibit in vitro and in vivo immune responses. WMNC exhibits the same action, suggesting that they may be the source of the WF inhibitory factor(s). These findings may explain host immunosuppression after severe trauma.

Animals↗
PubMed1983

Fluid and mononuclear cells from healing wounds inhibit thymocyte immune responsiveness.

It has been shown previously that fluid obtained from 7-day-old wounds noncytotoxically inhibits normal thymic lymphocyte blastogenesis and that mononuclear cells (MNC) from the same wounds lack mitogenic responsiveness. The present series of experiments studies whether wound MNC are the source of the wound inhibitory factor(s) and the effect of adult thymectomy (ATDX) on their generation. Adult male Sprague-Dawley rats (300-350 g), intact or ATDX (performed at 8-10 weeks of age), underwent dorsal wounding (7 cm) and subcutaneous implantation of sterile Ivalon sponges. Seven days later sponges were harvested, wound fluid was obtained, and the cell pellet was purified to 90% MNC. Normal rat thymocyte blastogenesis (stimulation index) to Con A and PHA evaluated in a microculture system (10 separate experiments) was 169.9 +/- 10.0 and 30.1 +/- 3.7. Addition of 10% wound fluid markedly inhibited thymocyte mitogenesis--6.3 +/- 1.0 and 2.7 +/- 0.6, respectively (P less than 0.001). Heat-inactivated wound fluid (56 degrees C, 30 min) had similar inhibitory activity--3.4 +/- 0.9 and 2.7 +/- 0.6 (P less than 0.001). Normal thymic blastogenesis could also be inhibited by the addition of 5 X 10(4) wound MNC to the microculture system--4.4 +/- 1.1 and 1.9 +/- 0.3 (P less than 0.001). Wound fluid from ATDX rats had much less inhibitory activity (77.1 +/- 22.4 and 7.2 +/- 2.1, P less than 0.01) vs control wound fluid. In addition wound MNC from ADTX animals were also less immune suppressive (30.7 +/- 4.9 and 13.5 +/- 3.7, P less than 0.001) than control MNC. Forty-eight-hour supernatants of wound MNC from intact rats, added in 25% concentration to normal thymocyte cultures, demonstrated inhibition similar to that of the wound fluid from the same animals: 4.4 +/- 0.7 and 3.9 +/- 0.6, while ATDX MNC supernatants had minimal inhibitory activity (110.1 +/- 18.2 and 25.7 +/- 6.5, P less than 0.005). No cytotoxicity could be demonstrated in any of these experiments by trypan blue exclusion. It is concluded that 7-day-old wound fluid noncytotoxically inhibits thymocyte blastogenesis; this effect is also demonstrated by wound MNC and their supernatants, suggesting immune "suppressor" lymphocytes are present in wounds; ATDX, which abrogates suppressor cell induction, leads to marked diminution of wound inhibitory activity. The data suggest that important immune events occur at the wound site; their relation to normal wound healing remains to be elucidated.

Animals↗
PubMed1983

Cyclosporine A impairs wound healing in rats.

Cellular immune responses may play an important role in the early inflammatory and cellular phases of wound healing. Cyclosporine A (CSA), a new immunosuppressive agent, impairs cellular immunity and T-cell-dependent humoral immunity. Therefore, the effect of CSA-induced immunosuppression in a rat wound-healing model was studied. Sprague-Dawley rats underwent a standardized skin incision and subcutaneous implantation of sterile polyvinyl alcohol sponges. CSA was dissolved in olive oil and given by gavage to one group of animals at a total dose of 125 mg/kg/10 days. The control group received an equivalent volume of olive oil. Ten-day-old wounds were weaker in CSA-treated animals, both in the fresh state (282 +/- 19 g vs 380 +/- 27 g, P less than 0.01), and after formalin fixation (1111 +/- 74 g vs 1419 +/- 57 g, P less than 0.01). In addition, CSA-treated rats accumulated significantly less hydroxyproline in the wound sponge granuloma, an index of reparative collagen deposition. The impairment in wound healing occurred without differences in body weight gain or organ weights. There was a profound immunosuppression in the animals receiving CSA as determined by thymic lymphocyte blastogenesis in response to Con A and PHA. These findings suggest that immunosuppression in otherwise healthy animals impairs wound healing.

Adrenal Glands↗