Dibutyl phthalate-mediated oxidative stress induces splenic injury in mice and the attenuating effects of vitamin E and curcumin.

Dibutyl phthalate (DBP) is a ubiquitous environmental contaminant that at certain levels can be harmful to human health. Although DBP has been widely linked to immunotoxicity, any association between DBP exposure and splenic injury remains unknown. The purpose of this study was to investigate whether DBP exposure can induce splenic injury and the antagonistic effects of two antioxidants, vitamin E (VitE) and curcumin (Cur), on DBP-induced splenic injury. The levels of ROS, GSH, T-AOC, IL-1ß, TNF-α, cytochrome C, caspase-8, caspase-9 and caspase-3 in the spleen homogenate of mice were measured. Any histopathological changes in the spleen were observed using H&E and toluidine blue staining. And the morphology of mitochondria was observed using Janus Green B staining. The results indicate that exposure to 50 mg/kg DBP could cause histopathological changes of the spleen and result in inflammation and apoptosis associated with oxidative stress, which may lead to splenic injury in mice. Moreover, both VitE and Cur could antagonize the oxidative stress induced by DBP to reduce splenic injury. These findings help to expand our understanding of DBP-mediated immunotoxicity, and to show that VitE and Cur can alleviate DBP-induced splenic injury and the possible DBP-associated decline in immune function.

The effect of naringenin on the role of nuclear factor (erythroid-derived 2)-like2 (Nrf2) and haem oxygenase 1 (HO-1) in reducing the risk of oxidative stress-related radiotoxicity in the spleen of rats.

The present study was to evaluate the radiomitigative effect of naringenin (NRG) on the modulation of ionizing radiation (IR)-induced spleen injury. Rats were exposed to 12 Gy (3Gy/two times/week). NRG (50mg/Kg), was orally given one hour after the first radiation dose, and daily continued during the irradiation period. Rats were sacrificed 1 day after the last dose of radiation. NRG showed a significant decrease of malondialdehyde, hydrogen peroxide with a significant elevation of superoxide dismutase, catalase and glutathione peroxidase activities and glutathione content. Moreover, NRG confirmed the intracellular defense mechanisms through activation of nuclear factor (erythroid-derived 2)-like2 (Nrf2) and haem oxygenase-1 (HO-1) levels and their protein expression. In addition, NRG deactivated the nuclear factor-κB (NF-κB) and reduced the pro-inflammatory cytokines. Further, NRG showed positive modulation in the haematological values (WBCs, RBCs, Hb, Hct% and PLt). In conclusion, these results suggested that NRG reversed the IR-induced redox-imbalance in the rat spleen.

Intra-arterial ampicillin and gentamicin and the incidence of splenic abscesses following splenic artery embolization: A 20-year case control study.

PURPOSE: Splenic abscesses represent a major complication following splenic artery embolization. The purpose of this study was to assess the effectiveness of intra-arterial antibiotics administered during splenic artery embolization in reducing splenic abscess formation. MATERIALS AND METHODS: 406 patients were screened. 313 (77.1%) patients who underwent splenic artery embolization and were >18 years old were included. Mean age of the cohort was 58 ±â€¯15 years (range: 18-88 years). There were 205 (65.5%) male patients and 108 (34.5%) female patients. 197 (62.9%) patients underwent embolization without intra-arterial antibiotics and 116 (37.1%) patients underwent embolization with 1 g ampicillin and 80 mg gentamicin administered in an intra-arterial fashion. Primary outcome was splenic abscess formation. Secondary outcomes included type of splenic artery embolization, embolic agent, and technical success. RESULTS: Partial splenic embolization was performed in 229 (73.1%) patients. Total splenic embolization was performed in 84 (26.8%) patients. Platinum coils were the most commonly used embolic agent overall (n = 178; 56.9%) followed by particulates (n = 114; 36.4%). Embolization technical success was achieved in 312 (99.7%) patients. 7 (3.6%) splenic abscesses were detected in the non-intra-arterial antibiotic group and 1 (0.9%) in the intra-arterial antibiotic cohort (P = 0.27). Coils were found to be statistically more likely to result in splenic abscesses than any other embolic agent (P = 0.03). Mean time to abscess identification was 74 days ±120 days (range: 9-1353 days). CONCLUSION: Splenic abscesses occurred more frequently in patients who did not receive intra-arterial antibiotics during splenic embolization; however, this did not reach statistical significance.

Protective effects of resveratrol against high ambient temperature-induced spleen dysplasia in broilers through modulating splenic redox status and apoptosis.

BACKGROUND: Resveratrol has been shown to prevent high ambient temperature (HT)-induced spleen dysplasia, but the mechanisms of action are not clear. This study aims to examine the hypothesis that HT-induced spleen dysplasia may be associated with HT-induced oxidative stress and apoptosis, and resveratrol may activate the nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway, thus reducing oxidative stress and apoptosis. RESULTS: Results showed that HT caused spleen dysplasia in broilers, reflecting the lower relative weight of the spleen (P < 0.05). Compared with birds in a normal ambient temperature group, birds in the HT group exhibited higher (P < 0.05) malondialdehyde (MDA), protein carbonyl (PC), 8-hydroxydeoxyguanosine (8-OHdG) and Bcl-2 associated X protein (Bax) content, higher Bax, caspase-3 and caspase-9 mRNA levels, and caspase-3 and caspase-9 activity, and a higher Bax/B-cell lympoma/leukemia-2 (Bcl-2) ratio, but they exhibited lower (P < 0.05) glutathione (GSH) and Bcl-2 content, and lower Nrf2, glutathione peroxidase (Gpx), MnSOD, heme oxygenase 1, glutathione reductase (GR) and Bcl-2 mRNA levels, and lower total antioxidant capacity (T-AOC), T-SOD and catalase and maganese superoixide dismutase (CAT) activity, indicating HT-induced oxidative stress and apoptosis. Compared with birds in the HT group, birds in the HT + Res group exhibited higher (P < 0.05) GSH and Bcl-2 content, higher Nrf2, CAT, MnSOD, GR and Bcl-2 mRNA levels, and higher T-AOC, T-SOD and CAT activity, but lower (P < 0.05) MDA content, and Bax and caspase-3 mRNA levels, lower caspase-3 and caspase-9 activities, and Bax/Bcl-2 ratio, indicating that resveratrol activated the Nrf2 signaling pathway and decreased apoptosis in the spleen. CONCLUSION: Resveratrol was effective in ameliorating HT-induced spleen dysplasia in broilers through the activation of the Nrf2 signaling pathway, thereby decreasing apoptosis, suggesting that resveratrol may offer a potential nutritional strategy to protect against some HT-induced detriments. © 2018 Society of Chemical Industry.

Supplementation of grape seed and skin extract to orlistat therapy prevents high-fat diet-induced murine spleen lipotoxicity.

Spleen is the largest lymphoid organ and obesity is related to an elevated risk of immunity dysfunction. The mechanism whereby fat adversely affects the spleen is poorly understood. This study was designed to assess the effectiveness of grape seed and skin extract (GSSE) and orlistat (Xenical, Xe) on high-fat diet (HFD)-induced spleen lipotoxicity. Obese rats were treated either with GSSE (4 g/kg body weight) or Xe (2 mg/kg body weight) or GSSE+Xe and monitored for weight loss for 3 months. Animals were then sacrificed and their spleen used for the evaluation of lipotoxicity-induced oxidative stress and inflammation as well as the putative protection afforded by GSSE and Xe treatment. HFD induced body weight gain and glycogen accumulation into the spleen; ectopic deposition of cholesterol and triglycerides and an oxidative stress characterized by increased lipoperoxidation and carbonylation; inhibition of antioxidant enzyme activities, such as catalase, glutathione peroxidase, and superoxide dismutase; depletion of zinc and copper; and a concomitant increase in calcium. HFD also increased plasma pro-inflammatory cytokines, such as interleukin (IL)-6, IL-17A, tumour necrosis factor alpha, and C-reactive protein, and decreased plasma IL-10 and adiponectin. Importantly, GSSE counteracted all the deleterious effects of HFD on spleen (i.e., lipotoxicity, oxidative stress, and inflammation) and the best protection was obtained when combining Xe+GSSE. Combining GSSE with Xe prevented against fat-induced spleen lipotoxicity, oxidative stress, and inflammation; this combination may be beneficial in other diseases related to the spleen.

Unfolding the mechanism of cisplatin induced pathophysiology in spleen and its amelioration by carnosine.

cis-Diamminedichloroplatinum (cisplatin) is an effective chemotherapeutic and is widely used for the treatment of various types of solid tumors. Bio-distribution of cisplatin to other organs due to poor targeting towards only cancer cells constitutes the backbone of cisplatin-induced toxicity. The adverse effect of this drug on spleen is not well characterized so far. Therefore, we have set our goal to explore the mechanism of the cisplatin-induced pathophysiology of the spleen and would also like to evaluate whether carnosine, an endogenous neurotransmitter and antioxidant, can ameliorate this pathophysiological response. We found a dose and time-dependent increase of the pro-inflammatory cytokine, TNF-α, in the spleen tissue of the experimental mice exposed to 10 and 20 mg/kg body weight of cisplatin. The increase in inflammatory cytokine can be attributed to the activation of the transcription factor, NF-ĸB. This also aids in the transcription of other pro-inflammatory cytokines and cellular adhesion molecules. Exposure of animals to cisplatin at both the doses resulted in ROS and NO production leading to oxidative stress. The MAP Kinase pathway, especially JNK activation, was also triggered by cisplatin. Eventually, the persistence of inflammatory response and oxidative stress lead to apoptosis through extrinsic pathway. Carnosine has been found to restore the expression of inflammatory molecules and catalase to normal levels through inhibition of pro-inflammatory cytokines, oxidative stress, NF-ĸB and JNK. Carnosine also protected the splenic cells from apoptosis. Our study elucidated the detailed mechanism of cisplatin-induced spleen toxicity and use of carnosine as a protective agent against this cytotoxic response.

Ferulic acid (FA) abrogates ionizing radiation-induced oxidative damage in murine spleen.

PURPOSE: The spleen is a crucial organ manifesting immune functions. Thus, radiation-induced oxidative challenge is vulnerable for the spleen. Our major objective was to protect the spleen from radiation-induced anomalous situations and to identify the signaling pathways involved. MATERIALS AND METHODS: Swiss albino mice were treated with ferulic acid (FA) once in a day at a dose of 50 mg/kg body weight for 5 consecutive days before exposing them to single dose of 10 Gy irradiation. The ROS generation and MMP change were determined by flow cytometry. The expression of different signaling proteins was investigated by immunoblotting and immunocytochemistry. RESULTS: FA pretreatment significantly prevented radiation-induced oxidative stress by downregulating TBARS formation and by upregulating SOD and catalase activity. FA scavenged ROS, prevented the alteration of MMP and downregulated the expression of stress marker Cdc42 and apoptotic markers p53, p21, Bax and PTEN. Cell cycle analysis showed DNA damage induced arrest of cells at subG0/G1 phase. Moreover, pretreatment with FA augmented Bcl2 expression and also increased the level of p-PI3K. CONCLUSION: FA prevented the activation of apoptotic signaling events in the spleen by interfering with the free radical chain reaction and by scavenging superfluous ROS. This is perhaps the first comprehensive study with a mechanistic viewpoint that FA can protect the spleen from ionizing radiation.

Does laparoscopy reduce splenic injuries during colorectal resections? An assessment from the ACS-NSQIP database.

BACKGROUND: Nearly half of all incidental splenectomies caused by iatrogenic splenic injury occur during colorectal surgery. This study evaluates factors associated with incidental splenic procedures during colorectal surgery and their impact on short-term outcomes using a nationwide database. METHODS: Patients who underwent colorectal resections between 2005 and 2012 were identified from the American College of Surgeons National Surgical Quality Improvement Program database according to Current Procedural Terminology codes. Patients were classified into two groups based on whether they underwent a concurrent incidental splenic procedure at the time of the colorectal procedure. All splenic procedures except a preoperatively intended splenectomy performed in conjunction with colon or rectal resections were considered as incidental. Perioperative and short-term (30 day) outcomes were compared between the groups. RESULTS: In total, 93633 patients who underwent colon and/or rectal resection were identified. Among these, 215 patients had incidental splenic procedures (153 open splenectomy, 17 laparoscopic splenectomy, 36 splenorraphy, and 9 partial splenectomy). Open colorectal resections were associated with a significantly increased likelihood of incidental splenic procedures (OR 6.58, p < 0.001) compared to laparoscopic surgery. Incidental splenic procedures were associated with increased length of total hospital stay (OR 1.25, p < 0.001), mechanical ventilation dependency (OR 1.62, p = 0.02), transfusion requirement (OR: 3.84, p < 0.001), re-operation requirement (OR 1.7, p = 0.005), and sepsis (OR: 2.03, p = 0.001). Short-term advantages of splenic salvage (splenorraphy or partial splenectomy) included shorter length of total hospital stay (p = 0.001) and decreased need for re-operation (p < 0.001). CONCLUSIONS: Incidental splenic procedures during colorectal resections are associated with worse short-term outcomes. Use of the laparoscopic technique decreases the need for incidental splenic procedures.

Protecting effects of a large dose of dexamethasone on spleen injury of rats with severe acute pancreatitis.

BACKGROUND AND AIMS: To explore the protecting effects and mechanisms of dexamethasone on spleen injury in rats with severe acute pancreatitis (SAP). METHODS: The rats were randomly divided into a model control group, treated group and sham-operated group. The contents of plasma endotoxin, serum NO, phospholipase A(2) enzyme (PLA(2)) and endothelin-1 (ET-1) were determined. The mortality rate, pathological changes and changes of Bax and Bcl-2 protein expression levels and apoptotic indexes in the spleen of rats were observed in all groups, respectively, at 3, 6 and 12 h after operation. RESULTS: Although the survival rate was significantly higher in the treated group than in the model control group, there was no significantly different between them (P > 0.05). The expression levels of Bax and Bcl-2 proteins and apoptotic indexes were significantly higher in the treated group than in the model control group at different time points (P < 0.05 or P < 0.01) while other blood indexes contents and pathological severity scores of spleen were significantly lower in the treated group than in the model control group (P < 0.05, P < 0.01 or P < 0.001). CONCLUSION: Dexamethasone can protect spleen from injury during SAP mainly by reducing the content of inflammatory mediators in blood.

Partial splenectomy prevents splenic sequestration crises in sickle cell disease.

PURPOSE: Acute splenic sequestrations (SSs) are potentially fatal complications in sickle cell disease (SCD). Total splenectomies in young patients may predispose them to a higher risk of overwhelming infections, whereas partial splenectomy may maintain immunocompetence. We present our series of partial splenectomies in patients with multiple SS episodes. METHODS: We retrospectively reviewed the records of 6 patients who underwent open partial splenectomies for SS. Data on their clinical courses were collected and analyzed. RESULTS: None of the 6 patients had SS postprocedure, down from 2.1 +/- 1.0 (P = .003) sequestrations per year and 3.5 +/- 1.4 (P = .002) total sequestrations per patient. The transfusion requirements were significantly reduced postoperatively (10.2 +/- 5.6 vs 2.0 +/- 3.1 per year; P = .002). There was no increase in the infection-related hospital admissions during the period of follow-up (1.5 +/- 1.8 vs 0.8 +/- 0.8 per year after partial splenectomy; P = .363). The upper pole was preserved in all cases with blood supply off the main splenic artery. CONCLUSIONS: Partial splenectomy decreases the risk of SS in SCD and reduces the need for blood transfusions. Infection rates did not increase after the procedure during the follow-up period. Partial splenectomy should be considered for patients who experience multiple acute SS crises or have long-term transfusion requirements.

Evolution of non-operative management for blunt splenic trauma in children.

Until the late 1960s, splenectomy was routinely performed in children who had sustained blunt splenic injury. There was based on the ability to perform splenectomy without obvious consequence; the cited 90-100% mortality for splenic trauma and the possibility of delayed rupture of the spleen. In contrast, contemporary findings in immunology and surgery demonstrated that non-operative management was not only feasible but desirable in view of the potential for overwhelming post-plenectomy infection. The history of universal splenectomy following blunt splenic trauma has been reviewed and we outline the findings that have resulted in the current standard of non-operative management following blunt splenic trauma.

Dietary nucleosides and nucleotides do not affect tumor incidence but reduce amyloidosis incidence in B6C3F1 mice irradiated with californium-252.

OBJECTIVE: We investigated the effects of a dietary mixture of nucleosides and nucleotides (NS) on the systemic incidence rates of postirradiation carcinogenesis and non-neoplastic lesions in mice. METHODS: Five-week-old male B6C3F1 mice were fed AIN-76B Purified Diet supplemented with NS for 1 wk and 13 mo before and after irradiation of neutron with californium-252 ((252)Cf); specifically NS was added to the AIN-76B Purified Diet (without nucleotide) to obtain a final concentration of 0%, 0.5%, or 2.5% NS. A commercial stock diet was also given to mice, and half of the mice were irradiated. Both irradiated and non-irradiated mice were used for reference controls. RESULTS: The incidence of liver tumors in each NS group was lower than that in the reference control group (P < 0.01), but there were no differences between the 0%, 0.5%, and 2.5% NS groups. In contrast, the incidence rate of mice with non-neoplastic lesions in the 0% NS group was significantly higher than the reference control group (P < 0.05). This higher incidence of mice with non-neoplastic lesions was significantly decreased upon supplementation of the nucleotide-free diet with 0.5% or 2.5% NS (P < 0.01 and P < 0.05, respectively). Of the non-neoplastic lesions observed, the incidence of amyloidosis was decreased significantly upon supplementation of the nucleotide-free diet with 0.5% NS (P < 0.05). CONCLUSION: Supplementation of a nucleotide-free diet with NS inhibits the development of non-neoplastic lesions, such as those associated with amyloidosis, without promoting the carcinogenesis induced by (252)Cf irradiation.

A single intramuscular injection with an adenovirus-expressing IL-12 protects BALB/c mice against Leishmania major infection, while treatment with an IL-4-expressing vector increases disease susceptibility in B10.D2 mice.

Experimental infection of the susceptible BALB/c (H-2d) mouse with the intracellular parasite Leishmania major induces a predominant Th2-type T cell response that eventually leads to death. In contrast, the resistant B10.D2 (H-2d) strain develops Th1 cells that control parasite replication and disease. In this study, we tested the ability of a recombinant adenovirus vector-expressing IL-12 to skew the immune response in a Th1 direction and prevent leishmaniasis in susceptible mice. We report that BALB/c mice treated with the Ad5IL-12 vector on the same day as parasitic challenge are significantly protected against leishmaniasis and acquired long-lasting immunity, because upon rechallenge with L. major parasites they were resistant to disease. The vector-derived IL-12 expression was transient and highly localized to the tissue after i.m. injection; it caused an increase in the number of Ag-specific IFN-gamma-secreting lymphocytes and enhanced NK cell activity in the draining popliteal node. In contrast, resistant B10.D2 mice given i.m. injections with a recombinant adenovirus-expressing IL-4 displayed greater susceptibility to disease, and severe lesions were produced in some of the infected animals. These results suggest the potential use of recombinant adenoviruses expressing cytokines as potent immunomodulatory agents for the generation of protective immune responses against intracellular pathogens.

Prevention of splenic granuloma formation in adjuvant arthritis by 2-acetyl-4-tetrahydroxybutylimidazole (THI).

Adjuvant-induced arthritis (AA) in Lewis rats is a widely used model of chronic inflammatory arthritis. Non-articular features such as weight loss and necrotizing granulomas of the spleen and lymph nodes also occur in this model. The compound 2-acetyl-4-tetrahydroxybutylimidazole (THI) marginally delayed the development of AA. However, this agent had no effect on the incidence or severity of disease. In contrast, THI totally prevented granuloma formation in the spleen and associated splenomegaly. We conclude that THI may be a useful adjunctive agent for some inflammatory diseases.

Corynebacterium parvum- and Mycobacterium bovis bacillus Calmette-Guerin-induced granuloma formation is inhibited in TNF receptor I (TNF-RI) knockout mice and by treatment with soluble TNF-RI.

The aim of this study was to examine the role of TNF receptor I (TNF-RI) in the pathogenesis of heat-killed Corynebacterium parvum- and live bacillus Calmette-Guerin (BCG)-induced granulomas. Granuloma formation was analyzed in TNF-RI knockout mice and after treatment with soluble TNF-RI (sTNF-RI). TNF-RI knockout mice injected with C. parvum or BCG developed fewer and smaller granulomas than wild-type control mice. Mice treated with sTNF-RI from days 7 to 13 after injection of C. parvum or BCG developed fewer and smaller granulomas than saline-treated control mice. Established granulomas regressed in rats treated with sTNF-RI from days 10 to 13 after injection of C. parvum. In conclusion, TNF signaling via TNF-RI contributes to the pathogenesis of C. parvum- and BCG-induced granulomas. sTNF-RI inhibits the development of granulomas and can cause the regression of established granulomas.

Evaluation of a new hemostatic agent in experimental splenic laceration.

OBJECTIVES: To compare the effectiveness of several hemostatic agents and to evaluate a new hemostatic agent (ReClot) in controlling splenic hemorrhage. DESIGN: Rabbits were anesthetized and catheters placed. A celiotomy was performed and a splenic injury produced; hemostatic agent and compression were applied. EXPERIMENTAL GROUPS: In group 1 (n = 8), the splenic laceration was compressed with a dry sponge and 75 g of pressure until hemorrhage ceased. In groups 2, 3, and 4 (n = 10 each), splenic injury was treated with Avitene, Collastat, and ReClot, respectively. Hemostatic agent was applied to the splenic laceration and a dry sponge and pressure were applied as described for group 1. In group 5 (n = 9), a splenic laceration was produced, ReClot applied, and aggressive fluid resuscitation was initiated; the volume of crystalloid was adjusted to maintain mean arterial pressure. RESULTS: Application of a hemostatic agent reduced total blood loss compared with that measured in the control group, but there was no difference in blood loss among experimental groups treated with a hemostatic agent. The time required to achieve control of blood loss was less in the ReClot-treated group compared with the Avitene- and Collastat-treated groups. CONCLUSIONS: The hemostatic agent ReClot had a significant advantage over other hemostatic agents for the time required to achieve control of splenic bleeding. Aggressive fluid resuscitation did not limit the ability of ReClot to produce hemostasis.

Radioprotective effects of serum thymic factor in mice.

Serum thymic factor (FTS) reduced mortality of mice after total-body irradiation with 7.56 Gy X rays. The radioprotective effect was achieved by daily repeated subcutaneous injections of 3-100 micrograms FTS, while doses higher than 300 micrograms/day/mouse were neither radioprotective nor toxic. Similarly, degeneration of the spleen was moderated by 3-100 micrograms FTS but not by 500 micrograms FTS in sublethally (3.78 Gy) irradiated mice. Histological examination showed that hematopoiesis was enhanced in the spleen by daily injections of 10 micrograms FTS. Spleen cells from the FTS-treated mice incorporated more [3H]thymidine in culture with or without concanavalin A. The treatment with FTS increased the production of colony-stimulating factor in the spleen as well as in peritoneal macrophage-like cells, and caused a significant increase in the number of granulocyte-macrophage colony-forming cells both in the spleen and in the femoral bone marrow. Furthermore, FTS prevented a decrease in circulating neutrophils in the sublethally irradiated mice. Prominent overshoot recovery of myelopoiesis, which occurred occasionally in sublethally irradiated mice, did not occur in the FTS-treated mice. The decrease in blood erythrocytes was also significantly reduced. These observations imply that this thymic hormone has potential as a radioprotector.

Pneumatic antishock garment decreases hemorrhage and mortality from splenic injury.

The effect of the pneumatic antishock garment (PASG) in controlling hemorrhage and death from splenic injury was studied in a canine model. Twelve (two groups of 6) anesthetized dogs had their spleens crushed. Carotid blood pressure, carotid blood flow, splenic artery flow and abdominal aortic flow, as well as the death rate and blood loss, were measured. Group 1 dogs did not have PASG inflation, but group 2 dogs had PASG inflation to an intraperitoneal pressure of 60 mm Hg. All group 1 dogs died within 27 to 58 minutes, but all group 2 dogs survived. Blood loss was 9.4 +/- 1.4 mL/min in group 1 and 1.6 +/- 0.9 mL/min in group 2. In group 1 carotid artery blood pressure, carotid artery flow, splenic artery flow and abdominal aortic flow fell from 120 +/- 10 mm Hg, 284 +/- 12 mL/min, 194 +/- 18 mL/min and 285 +/- 10 mL/min respectively to 0 with death of the animals. By 2 hours in group 2 dogs the carotid artery blood pressure had dropped from 116 +/- 12 to 99 +/- 12 mm Hg, and over the same period carotid artery flow, splenic artery flow and abdominal aortic flow fell from 296 +/- 8 mL/min, 190 +/- 26 mL/min and 279 +/- 16 mL/min respectively to 259 +/- 14 mL/min, 39.0 +/- 6 mL/min and 45 +/- 11 mL/min respectively. Thus, inflation of the PASG maintained carotid artery blood pressure wh ile decreasing splenic, abdominal and aortic flow as well as splenic hemorrhage, with a decrease in the death rate, over a 2-hour period.

Modulation of granuloma formation in vitro by endogenous mediators.

We have reported previously that in vitro granulomas are inducible by culturing murine spleen cells in the presence of artificial microparticles, dextran beads, and that macrophages and macrophage-derived cytokines (monokines) including interleukin 1 (IL-1) and tumor necrosis factor-alpha (TNF-alpha) play a critical role in the initiation of bead-induced granulomas in vitro. To investigate regulatory mechanisms of granuloma formation, we examined the modulatory effects of various mediators such as IL-1, TNF-alpha, interferon-gamma (IFN-gamma), IL-4, IL-6, transforming growth factor-beta (TGF-beta), dexamethasone and prostaglandin E2 (PGE2) on the development of lesions, because these mediators are known to play a pivotal role in inflammatory responses. The lesions were suppressed by the addition of dexamethasone, PGE2 or certain T cell-derived lymphokines such as IL-4 and IFN-gamma. These results suggest that suppressive signals are different from granulomatogenic cytokines including IL-1 and TNF-alpha and that granulomas are regulated by multi-factor dependent mechanisms.