Peritoneal Leukocytes Research Articles

Similar effects of ether phospholipids, PAF and lyso-PAF on the Ca 2+-ATPase activity of rat brain synaptosomes and leukocyte membranes

The present study is an extension of our previous work with the antineoplastic ether phospholipid ET-18-OCH 3 (edelfosine), which was shown to affect the activity of the Ca 2+-ATPase of rat brain synaptosomes and peritoneal leukocyte membranes. The effect of ET-18-OCH 3 was compared with that of the 16-carbon chain analogue ET-16-OCH 3 as well as with the structurally related 16- and 18-carbon PAFs (platelet-activating factors) and lyso-PAFs. In addition, the two alkylphosphocholines D-20166 and D-21266 (perifosine) were included in the investigation. The influence of all of the compounds followed the same pattern, i.e., the Ca 2+-ATPase activity of the synaptosomes was increased over a relatively narrow concentration range (peak at 20–30 μM) and that of the leukocyte membranes was inhibited in a concentration-dependent manner by 10–50 μM concentrations of the drugs. Ether phospholipids with an 18-carbon chain at C-1 were more potent than those with a 16-carbon chain. All of the compounds increased the activity of the synaptosomal ATPase to the same extend (ca. 50%). With the exception of lyso-PAF, all inhibited the enzyme activity of leukocyte membranes by 60–70%, whereas lyso-PAF was less effective (ca. 50% inhibition). The concentration range of activity for PAF and lyso-PAF indicates that their effect on the enzyme activity was caused by receptor-independent mechanisms. The ether phospholipids and alkylphosphocholines are suggested to act by accumulating in the membranes and thereby altering the character of the lipid environment of the enzyme rather than by a direct interaction with the Ca 2+-ATPase.

In vitro effects of E3040, a dual inhibitor of 5-lipoxygenase and thromboxane A 2 synthetase, on eicosanoid production

In vitro pharmacological profiles of E3040, 6-hydroxy-5, 7-dimethyl-2-(methylamino)-4-(3-pyridylmethyl) benzothiazole were investigated. Against the 5-lipoxygenase activity of rat basophilic leukemia cells, E3040 and zileuton (a 5-lipoxygenase inhibitor) had an IC 50 of 0.23 and 0.93 μM, respectively. Against the thromboxane A 2 synthetase activity of human platelets, E3040 had an IC 50 of 0.01 μM, which was comparable to that of OKY-1581 (sodium ( E)-3-[4-(3-pyridylmethyl) phenyl]-2-methylacrylate, a thromboxane A 2 synthetase inhibitor). Against cyclooxygenase activity of sheep seminal vesicles, E3040 showed no inhibition (IC 50, >300 μM). Sulfasalazine and 5-aminosalicylic acid, therapeutic drugs for inflammatory bowel disease, inhibited 5-lipoxygenase activity with an IC 50 of 293 and 970 μM, respectively. Sulfasalazine inhibited thromboxane A 2 synthetase activity with an IC 50 of 20 μM. In rat peritoneal leukocytes, E3040 inhibited leukotriene B 4 and thromboxane B 2 production with an IC 50 of 0.17 and 0.24 μM, respectively. E3040 inhibited leukotriene B 4 production in human neutrophils and thromboxane B 2 production in human platelets (IC 50 of 0.21 and 0.09 μM, respectively). These results indicated that E3040 potently inhibited 5-lipoxygenase and thromboxane A 2 synthetase and blocked leukotriene B 4 and thromboxane B 2 production in rat peritoneal and human blood cells.

Effect of menstruation and intrapelvic injection of endometrium on inflammatory parameters of peritoneal fluid in the baboon (Papio anubis and Papio cynocephalus )

Objective: Our purpose was to test the hypothesis that menstruation and intrapelvic injection of endometrium for the induction of endometriosis affect inflammatory parameters in peritoneal fluid from baboons. Study Design: In the first part of this study, 107 laparoscopies were performed in 62 female baboons with a normal pelvis during menstruation, the follicular phase, and the luteal phase. In the second part of this study, 21 baboons were studied during paired laparoscopies in the follicular phase and the luteal phase of the cycle. In the third part of this study, 11 baboons were studied by paired laparoscopies during menses and during the nonmenstrual phase of the cycle. In the fourth part of this study, paired laparoscopies were performed in 7 baboons before and after intrapelvic injection of endometrium. Peritoneal fluid was aspirated and measured in all laparoscopies and assessed for leukocyte concentration. In the third and fourth parts of the study, peritoneal fluid was analyzed for the concentrations of inflammatory cytokines and for the proportions of cells with immunohistochemical staining positive for these cytokines. Results: During menstruation, in comparison with nonmenstrual phases of the cycle, the leukocyte concentration of the peritoneal fluid was increased significantly, as were the proportions of peritoneal fluid cells with positive staining for tumor necrosis factor α, transforming growth factor β1, and intercellular adhesion molecule 1 and the peritoneal fluid concentrations of transforming growth factor β1 and interleukin 6. After intrapelvic injection of endometrium, the peritoneal fluid leukocyte concentration and the proportions of peritoneal fluid cells with positive staining for tumor necrosis factor α, transforming growth factor β1, CD3, and human leukoctye antigen (DR locus) significantly increased. Conclusion: Subclinical peritoneal inflammation occurs in baboons during menstruation and after intrapelvic injection of endometrium. (Am J Obstet Gynecol 2001;184:917-25.)

Neutrophil antiserum response to decrease in proteolytic activity in loaded rat muscle.

The leukocytes that are found in skeletal muscles after intense muscular activity have been shown to infiltrate areas of injury in skeletal muscle tissue. We believe that leukocyte enzymes, which appear in the tissue after the degranulation or destruction of leukocytes, could play a role in tissue enzyme activities. Neutrophil proteinases were investigated. Histological data provided evidence of rat muscular tissue infiltration by leukocytes after intense physical loading. To reduce the influx of leukocytes in rat muscles, a rabbit antiserum against rat peritoneal leukocytes was injected into rats after muscle loading. This resulted in a reduction in muscle cytosol proteolytic activity as compared to control animals (who received saline injections). The levels of proteolytic activities of media conditioned by the soleus muscle isolated from antiserum-treated rats were also reduced. These data provide evidence that the increase in proteolytic activity observed in rat skeletal muscles after physical loading is partially induced by neutrophil proteinases.

A role for IFN-alpha beta in virus infection-induced sensitization to endotoxin.

Underlying viral infections can heighten sensitivity and worsen cytokine-mediated disease following secondary inflammatory challenges. Mechanisms for this are poorly understood. The impact of the innate response to lymphocytic choriomeningitis virus (LCMV) infection on sensitivity to endotoxin (LPS) was investigated. Compared with uninfected mice, infection with LCMV for 2-days-sensitized mice to LPS by approximately 2-fold for lethality and by 2- to 6-fold for serum TNF-alpha levels. Priming for LPS-induced TNF-alpha was also seen with splenic and peritoneal leukocytes isolated from infected mice and challenged with LPS ex vivo. The effect on TNF-alpha production was present in the absence of IFN-gamma, its major producers NK and T cells, and the major pathways for its induction through IL-12 and the signal transducer and activator of transcription 4 (STAT4), and therefore was IFN-gamma independent. Early LCMV infection induces high concentrations of the type 1 IFNs, IFN-alphabeta. Administration of recombinant IFN-alpha alone heightened the TNF-alpha response to LPS. Innate IFN-alphabeta and IFN-gamma responses to LCMV exist in a delicate balance. To reduce priming for LPS-induced TNF-alpha during LCMV, deficiencies in both the IFN-alphabeta and IFN-gamma receptors or STAT1, a transcription factor downstream to both IFNs, were required. These data demonstrate that early viral infection can enhance sensitivity to bacterial products, and that this sensitization can occur in part as a result of endogenously expressed IFN-alphabeta. This work also raises issues about potential complications associated with IFN-alphabeta therapies.

Respiratory burst response of peritoneal leukocytes adhering to titanium and stainless steel.

Titanium sheets, made hydrophilic by oxidative cleaning or hydrophobic by treatment with butanol, and stainless steel sheets with different patterns of pores (straight phi = 0.8 mm) were implanted into the peritoneal cavity of mice. The implants were removed after 2 h, and the surface-adhering leukocytes were stained with propidium iodide and fluorescein diacetate to quantitate cell adhesion and to indicate the presence of leaks in the cell membrane. The ability of the surface-adhering leukocytes to mount a respiratory burst response after stimulation with PMA or zymosan was measured by chemiluminiscence. The results show that stainless steel without pores induces membrane leakage in 80% of the surface-adhering leukocytes compared with 65% of cells adhering to porous steel. Hydrophilic titanium induces membrane leakage in 48% of the surface-adhering leukocytes compared with 19% of cells adhering to hydrophobic titanium. The respiratory burst response of the surface-adhering leukocytes stimulated with PMA was attenuated on stainless steel and hydrophilic titanium compared with hydrophobic titanium. Thus, butanol treatment of titanium and pores in stainless steel increase the biocompatibility of the materials.

Inhibitory effects of morphine on some inflammation-related parameters in the goldfish Carassius auratusL.

Acute peritonitis induced in the goldfish by intraperitoneal injection of a sterile Thioglycollate solution shows a typical pattern with intraperitoneal exudation of serum proteins followed by influx of leucocytes (mainly heterophils/macrophages) correlated with elevated levels of chemotactic factors in peritoneal fluid and blood plasma. Supplementation of Thioglycollate with morphine (20mg kg−1b.w.) does not affect the leakage of serum proteins into peritoneum. In contrast, it reduces the number of exudate peritoneal leucocytes (among them heterophils/macrophages) to the control level and decreases the level of peritoneal fluid/plasma chemoattractants, both effects being reversed by naltrexone pretreatment. Morphine itself acts as a chemokinetic factor for fish leucocytes as it increases their random movements. Therefore inhibitory effects of morphine on accumulation of exudate cells might be explained by inhibition of the production/release of chemotactic factors and/or reduced sensitivity of leucocytes to chemotactic signals. The effects of morphine on the goldfish peritonitis are in concordance with those described recently in Atlantic salmon and CB6 mice.

Effects of systemic and intraperitoneal chemotherapy on bacterial translocation and peritoneal defence mechanisms

Abstract Background The aim of this study was to evaluate the effects of intraperitoneal and systemic chemotherapy on peritoneal defence mechanisms and bacterial translocation. Methods Four groups of adult male Wistar Albino rats (n = 10) were used in the study. The groups consisted of intraperitoneal chemotherapy (5-fluorouracil 20 mg kg−1 day−1 for 3 days), systemic chemotherapy (5-fluorouracil 20 mg kg−1 day−1 for 3 days) and their controls (systemic and intraperitoneal isotonic saline solution). Eight hours after the last dose of chemotherapy 10 ml sodium caseinate was applied intraperitoneally and 16 h later laparotomy was done under sterile conditions. During laparotomy 10 ml phosphate-buffered saline was applied and approximately 8 ml of this solution was collected. Phagocytic activity, bactericidal activity, peritoneal total cell numbers and morphology, peripheral blood leucocyte count and bacterial translocation were studied in this peritoneal solution. Tissue samples of mesenteric lymph node, liver, spleen and caecum were taken and homogenized for culturing. Statistical analyses were done with Student's t test for independent samples. Results In the systemic chemotherapy group phagocytic activity (36 versus 52 per cent in control) and bactericidal activity (decreased in seven versus two in control) were significantly decreased. Peripheral and peritoneal leucocyte numbers were also decreased in the systemic chemotherapy group. Peritoneal cell morphology was not affected. Bacterial translocation occurred in mesenteric lymph nodes of five rats in this group. Intraperitoneal chemotherapy significantly decreased the phagocytic activity (33 versus 56 per cent in control). Peripheral and peritoneal leucocyte numbers were also decreased but the bactericidal activity and peritoneal cell morphology were not affected. In contrast to the systemic chemotherapy group, bacterial translocation was not detected. Conclusion Systemic chemotherapy caused bacterial translocation. Both systemic and intraperitoneal chemotherapy have detrimental effects on peritoneal defence mechanisms under experimental conditions.

Kinetics and dose response of the effects of heated glucose peritoneal dialysis fluids on the respiratory burst of rat peritoneal leukocytes.

Heat sterilization of glucose containing peritoneal dialysis (PD) fluids induces the production of cytotoxic glucose degradation products (GDPs), some of which are still unidentified. The present study was performed to characterize the kinetics and the dose-response of the respiratory burst inhibition of GDPs and to compare different fluids in this respect. The zymosan-induced respiratory burst of rat peritoneal neutrophils and macrophages was measured by chemiluminescence (CL) after incubation in vitro for 1, 2, and 4 hours in different homemade and commercially available PD fluids, followed by one hour of recovery in Hanks' buffer. Heat sterilized fluids were compared with their filter sterilized equivalents at two different pH levels. The results revealed that the inhibitory effect of heat sterilized fluids on the respiratory burst of peritoneal neutrophils is additive to that of low pH, but more fast-acting and, in contrast to the pH effect, similar in magnitude to its in vivo equivalent. The effect developed within 1 hour and had a linear dose response. The low GDP fluid Gambrosol-Bio was less toxic than the conventional fluid Gambrosol, but the difference was smaller than expected in relation to measured concentrations of known GDPs. Macrophages were less sensitive than neutrophils to the GDP effect.

Spontaneous cytotoxic activity of eosinophilic granule cells separated from the normal peritoneal cavity ofDicentrarchus labrax

In this study the spontaneous in vitro cytotoxic activity to tumour cell lines, (K562), by unstimulated sea bass (Dicentrarchus labrax) leukocytes was examined by trypan blue exclusion test and lactate dehydrogenase release assay. A high anti-tumour cell line activity of resident peritoneal leukocytes was found at an effector to target ratio (E:T) of 25:1 after incubation for 2h at 18°C. Rabbit and sheep erythrocytes were not lysed. A low activity was displayed by head kidney and spleen cell populations whereas blood leukocytes revealed no significant activity. The effect of E:T ratio on cytotoxicity as well as microscopy observations suggested that the cytotoxic reaction required effector-target cell contact. Eosinophilic granule cells, isolated on a Percoll density gradient from a peritoneal wash, appeared to be responsible for the in vitro cytotoxic activity.

PSK and OK-432-Induced Immunomodulation of Inducible Nitric Oxide (NO) Synthase Gene Expression in Mouse Peritoneal Polymorphonuclear Leukocytes and NO-Mediated Cytotoxicity

We investigated whether PSK (a polysaccharide from the mycelia of Coriolus versicolor) or OK-432 (a streptococcal preparation) can up-regulate inducible nitric oxide synthase (iNOS) gene expression and nitric oxide (NO) production in mouse peritoneal polymorphonuclear leukocytes (PMNs). Six hrs after intraperitoneal injection of mice with PSK (2500 μg/mouse) or OK-432 (100 μg/mouse), mouse peritoneal PMNs were restimulated with PSK (500 μg/ml) or OK-432 (10 μg/ml) plus 100 U/ml of mouse interferon-gamma (IFN-γ) in vitro. Northern blot analysis showed strong synergism between both PSK and OK-432 and IFN-γ for the induction of iNOS gene expression. NO production by PMNs was increased up to 20 μM (2 μM/106 PMNs/24 hrs) as measured by the Griess reagent method when PMNs were restimulated with PSK or OK-432 plus IFN-γ for 24 hrs, although tumor cell killing was not detected. NO concentrations of more than 80 μM were required for P815 tumor cell killing. These results suggest that PMNs produce NO after stimulation with PSK or OK-432 in combination with IFN-γ and may regulate the immune system in vivo, although the NO production induced by these agents is insufficient for tumor cell killing in vitro.

Elucidation of the early events contributing to zymosan-induced multiple organ dysfunction syndrome using MIP-1alpha, C3 knockout, and C5-deficient mice.

Using a zymosan-induced mouse model of multiple organ dysfunction syndrome (MODS), it has been shown that the absence of MIP-1alpha increased mortality fourfold, whereas the absence of C5 decreased mortality fourfold. The purpose of the present study was to determine the early events following zymosan injection in MIP-1alpha knockout and C5-deficient mice. B10.D2/nSnJ (C5-sufficient) and B10.D2/0SnJ (C5-deficient) and genetically matched MIP-1alpha +/+ and MIP-1alpha -/- mice were divided into 3 groups: Group1 received no injection, Group 2 received intraperitoneal saline injection (1.0 mL), and Group 3 were given intraperitoneal zymosan (1 mg/gm, 1.0 mL). Two hours, 24 h, and 48 h after injection, peritoneal exudate leukocyte counts, total WBC count, lung MPO levels, and organ histology were examined for signs of changes in cellular infiltration. An acute local and systemic inflammatory response characterized by an increase in the peritoneal leukocyte count, total WBC counts, and circulating neutrophil levels was observed within 2-48 h of zymosan injection. Lack of MIP-1alpha attenuated local recruitment of phagocytes into the peritoneal cavity, and absence of MIP-1alpha or C5 caused a decrease in circulating neutrophil levels. The presence or absence of either C5 or MIP-1alpha did not affect early pulmonary neutrophil sequestration. Organ histopathology suggested early neutrophil infiltration in the lung and spleen within 48 h. These studies indicate that MIP-1alpha and C5 play a critical role in modulating cellular changes associated with lethality in a zymosan model of MODS.

Proteinase-Activated Receptor-2-Activating Peptides Induce Leukocyte Rolling, Adhesion, and Extravasation In Vivo

Proteinase-activated receptor 2 (PAR2) has been suggested to play a role in inflammatory reactions. Because leukocyte-endothelial cell interactions are critical events during inflammatory reactions, and because PAR2 is expressed both on endothelium and leukocytes, we have examined the effects of PAR2-activating peptides (PAR2-APs) on leukocyte rolling and adhesion in mesenteric venules and on leukocyte recruitment into the peritoneal cavity. Using intravital microscopy, leukocyte rolling, flux, and adhesion in rat mesenteric postcapillary venules were quantified. Topical addition of PAR2-APs (10 microM) for 1 min to the superfused venule induced a significant increase in leukocyte rolling and adherence. The increase in leukocyte adherence was not affected by pretreatment with a mast cell stabilizer (sodium cromoglycate) nor by prior degranulation of mast cells with compound 48/80. Nonetheless, both leukocyte rolling and adhesion were completely inhibited by pretreatment with a platelet-activating factor receptor antagonist (WEB 2086). Intraperitoneal injections of a selective PAR2-AP (SLIGRL-NH2) caused a significant increase in leukocyte migration into the peritoneal cavity. The effect of SLIGRL-NH2 on peritoneal leukocyte infiltration was completely inhibited by WEB 2086. These data suggest that PAR2 activation could contribute to several early events in the inflammatory reaction, including leukocyte rolling, adherence, and recruitment, by a mechanism dependent on platelet-activating factor release.

Novel and known constituents from Buddleja species and their activity against leukocyte eicosanoid generation.

We have undertaken a systematic survey of the genus Buddleja used in traditional Chinese medicine for antiinflammatory and other indications by testing extracts and isolated natural products for their activity against the enzymes of the arachidonate cascade. This was done by using elicited rat peritoneal leukocytes, a physiologically relevant established whole cell system that expresses both cyclo-oxygenase (COX) and 5-lipoxygenase (5-LOX) activity. Lipophilic extracts of B. globosa roots and B. myriantha stem exhibited inhibitory activities in the 5-LOX and COX enzyme assays, whereas those of B. officinalis flowers, B. yunanesis stems, and B. asiatica stems showed inhibitory activities only against COX. The phytochemical investigation of these extracts, and consequent structure elucidation of isolated compounds using spectroscopic data, led to the isolation from B. globosa of three new terpenoid compounds named dihydrobuddledin A, buddledone A, and buddledone B and four known compounds-buddledins A, B, and C and zerumbone; 12 known compounds from B. officinalis-calceolarioside, campneoside, verbascoside, echinacoside, forsythoside B, angoroside A, crocetin monogentibiosyl ester, acacetin, acacetin-7-O-alpha-L-rhamnopyranosyl (1-6)-beta-D-glucopyranoside, acacetin-7-O-alpha-L-rhamnopyranosyl (1-6)[alpha-L-rhamnopyranosyl (1-2)]-beta-D-glucopyranoside, songarosaponin A, delta-amyrone; and eight known compounds fromB. yunanesis-11,14-dihydroxy-8,11, 13-abietatrien-7-one, beta-sitosterol, verbascoside, echinacoside, forsythoside B, angoroside A, methylcatapol, and sucrose. Tests on the isolated compounds for inhibition of eicosanoid synthesis showed that buddledin A, crocetin monogentibiosyl ester, and acacetin exhibited an inhibitory effect on COX with IC(50) values of 13.7 microM, 28.2 microM, and 77.5 microM, respectively, whereas buddledin A exhibited inhibitory effect on 5-LOX with an IC(50) value of 50.4 microM.

Effects in vitro of several antioxidants on the natural killer function of aging mice.

The aim of the present work is to study the change with aging in the effect in vitro of several antioxidants: thiazolidine-4-carboxylic acid or thioproline, N-acetylcysteine (NAC), ascorbic acid (AA), and alpha-tocopherol (vitamin E, VE) on the natural killer (NK) activity in mononuclear cells from axillary nodes, spleen, thymus and peritoneal leukocytes from BALB/c male mice. Young (8+/-2 weeks), adult (24+/-2 weeks). mature (48+/-2 weeks), and old (72+/-2 weeks) animals were studied. A nonradioactive cytotoxic assay with cells from the murine lymphoma YAC-1 as target cells and a relation effector cells/target cells of 10/1 were used. The concentrations of the different antioxidants were: 1 mM for thioproline and N-acetylcysteine and 5 microM for ascorbic acid and alpha-tocopherol, which induced a maximum effect in our previous dose-response experiments. The results show that, in general, the above antioxidants cause an enhancement of the NK activity at all ages studied, this stimulation being higher with thioproline and N-acetylcysteine than with ascorbic acid and alpha-tocopherol. The effects were similar for the three lymphoid organs and the peritoneum. This stimulation of the NK activity by antioxidants is an important favorable response, especially in old mice, in which age results in a decrease in NK function and, therefore, in a higher incidence of neoplasia.

Inhibition of leukocyte eicosanoid generation and radical scavenging activity by gnaphalin, a lipophilic flavonol isolated from Helichrysum picardii.

The lipophilic aglycone 5,7-dihydroxy-3,8-dimethoxyflavone (gnaphalin) isolated from the aerial flowering parts of Helichrysum picardii Boiss. & Reuter (Asteraceae) was tested for interactions with the cyclo-oxygenase and 5-lipoxygenase pathways of arachidonate metabolism in stimulated rat peritoneal leukocytes, and for its effects on leukocyte granular enzyme release, cell viability and interactions with reactive oxygen species. Gnaphalin dose-dependently inhibited generation of the cyclo-oxygenase metabolite thromboxane B2 (IC50 = 39.9 +/- 3.9 microM), and of the 5-lipoxygenase metabolite leukotriene B4, although the potency was two-fold less (IC50 = 81.8 +/- 12.9 microM). At concentrations of 6 to 320 microM, gnaphalin did not affect secretion of the pro-inflammatory enzymes lysozyme, myeloperoxidase and beta-glucuronidase from the neutrophil secretory granules, and did not scavenge hydrogen peroxide or hypochlorous acid. However, gnaphalin effectively scavenged superoxide radicals generated in the hypoxanthine/xanthine oxidase system (IC50 = 40 microM) and by PMA-stimulated leukocytes (> 60% at 500 microM), directly inhibited xanthine oxidase (85% at 395 microM) and inhibited Fe(3+)-ascorbate-induced liposomal peroxidation (IC50 = 215 microM). Thus, like some other flavonoids found in medicinal herbs, gnaphalin possesses an array of potentially beneficial anti-eicosanoid and free-radical scavenging properties which may alongside other constituents contribute to the claimed medicinal properties of the plant from which it is derived.

Leukocyte glycolysis and lactate output in animal sepsis and ex vivo human blood

Lactate is released in large quantity from sites of sepsis and inflammation. We asked whether the increased lactate production found in sepsis can be explained by the augmented glycolysis of inflammatory cells. The glycolytic metabolism of rat peritoneal leukocytes was measured following cecal ligation and perforation (CLP) or sham laparotomy. CLP augmented glucose uptake, the pentose phosphate pathway, and glucose oxidation. Lactate output increased from 1.03 ± 0.05 to 1.20 ± 0.05 fmol · cell −1 · min −1 ( P < .001). Total lactate output of peritoneal lavage fluid increased from 7.94 ± 2.59 to 28.12 ± 5.60 nmol L · min −1 ( P < .005). The effect of lipopolysaccharide (LPS) on the lactate output of whole blood from 31 critically ill patients was measured. Leukocyte lactate production was calculated by multiple linear regression analysis. Following exposure to LPS, human leukocyte lactate output increased from 0.20 ± 0.09 to 1.22 ± 0.14 fmol · cell −1, min −1 ( P < .001). This rate of production is so high that it suggests that the lactate output of different tissue beds in sepsis may be affected by their different cell populations and state of activation. This study supports the hypothesis that lactate may be more a product of inflammation than a marker of tissue hypoxia in sepsis.

Characterization of cellular response to thiol‐modified gold surfaces implanted in mouse peritoneal cavity

The early inflammatory reaction in vivo to three well defined surfaces—gold, gold coated with glutathione (GSH), and 3-mercapto-1,2-propanediol (MG)—was assessed as manifested by the adherence and activation of inflammatory cells during implantation intraperitoneally in mice. Evaluation of cell adhesion and activation was done by immunohistochemistry using specific monoclonal antibodies directed against cell differentiation antigens CD11b/CD18, CD74, and CD25 or by measurement by chemoluminescence of reactive oxygen radical species produced by adhering cells. Cell recruitment and activation was slow on the GSH-coated gold surfaces. These surfaces also had the highest percentage of adhering cells with an intact cell membrane. The MG-coated surfaces, on the other hand, rapidly recruited and activated cells and also caused cell membrane leakage to propidium iodide, suggesting cell membrane damage or cell death. The respiratory burst of adhering cells was stimulated by phorbol-myristate acetate on the GSH-coated surface but not on the MG-coated surface and by opsonized zymosan on the Mg-coated surface but only to a small degree on the GSH-coated surface. The respiratory burst following zymosan activation of cells adhering to the MG-coated surface was inhibited by treatment with 2.3-diphosphoglycerate, a phospholipase D inhibitor. The presented data suggest that peritoneal leukocytes adhering to foreign materials may raise a respiratory burst response via a phospholipase D-dependent and protein kinase C-independent pathway. © 1999 John Wiley & Sons, Inc. J Biomed Mater Res, 45, 117–124, 1999.

Characterization of cellular response to thiol-modified gold surfaces implanted in mouse peritoneal cavity.

The early inflammatory reaction in vivo to three well defined surfaces-gold, gold coated with glutathione (GSH), and 3-mercapto-1, 2-propanediol (MG)-was assessed as manifested by the adherence and activation of inflammatory cells during implantation intraperitoneally in mice. Evaluation of cell adhesion and activation was done by immunohistochemistry using specific monoclonal antibodies directed against cell differentiation antigens CD11b/CD18, CD74, and CD25 or by measurement by chemoluminescence of reactive oxygen radical species produced by adhering cells. Cell recruitment and activation was slow on the GSH-coated gold surfaces. These surfaces also had the highest percentage of adhering cells with an intact cell membrane. The MG-coated surfaces, on the other hand, rapidly recruited and activated cells and also caused cell membrane leakage to propidium iodide, suggesting cell membrane damage or cell death. The respiratory burst of adhering cells was stimulated by phorbol-myristate acetate on the GSH-coated surface but not on the MG-coated surface and by opsonized zymosan on the Mg-coated surface but only to a small degree on the GSH-coated surface. The respiratory burst following zymosan activation of cells adhering to the MG-coated surface was inhibited by treatment with 2. 3-diphosphoglycerate, a phospholipase D inhibitor. The presented data suggest that peritoneal leukocytes adhering to foreign materials may raise a respiratory burst response via a phospholipase D-dependent and protein kinase C-independent pathway.

Biologic response to passive dissolution of titanium craniofacial microplates

The effect of anodization on passive dissolution of titanium was studied by measuring titanium levels in peritoneal leukocytes and tissues of laboratory animals with titanium plates implanted into the peritoneal cavity. Fifteen Sprague–Dawley rats were assigned randomly to three treatment groups of five animals. One group served as controls, the other two groups had an anodized or an unanodized implant placed in the left paracolic gutter. Peritoneal lavage samples and blood samples, organ tissues and tissue surrounding the implants, were removed for histologic examination and titanium levels. Titanium was not detected in any distant organs or in the peritoneal lavage fluid. The capsular tissues surrounding the implants contained titanium at levels ranging from 2610 to 16 786 ng/g for unanodized plates, and 888–5933 ng/g for anodized plates. The titanium levels within the peritoneal leukocytes of animals with unanodized implants were significantly elevated ( P=0.01) over time, as compared with controls. The level of titanium in the peritoneal leukocytes of animals with anodized implants was not significantly elevated when compared with controls. Titanium levels in the trace range, as measured in the capsular tissues, are likely a result of corrosion. Surface treatment of titanium by anodization reduces passive dissolution.