A randomized clinical trial on effects of alfaxalone combined with medetomidine and midazolam in preventing stress-related neurohormonal and metabolic responses of isoflurane-anesthetized cats undergoing surgery

OBJECTIVE

To evaluate the effects of IM and IV administration of alfaxalone alone and in combination with medetomidine, midazolam, or both on key stress-related neurohormonal and metabolic changes in isoflurane-anesthetized cats undergoing ovariohysterectomy or castration.

ANIMALS

72 client-owned mixed-breed cats undergoing ovariohysterectomy or castration between October 4, 2018, and January 10, 2020.

PROCEDURES

For each type of surgery, cats were assigned to 1 of 6 premedication protocols groups, with 6 cats/group: physiologic saline (0.9% NaCl) solution (0.5 mL, IM) and alfaxalone (5 mg/kg, IV); physiologic saline solution (0.5 mL, IM) and alfaxalone (5 mg/kg, IM); medetomidine (50 μg/kg, IM) and alfaxalone (5 mg/kg, IV); medetomidine (50 μg/kg, IM) and alfaxalone (5 mg/kg, IM); midazolam (0.5 mg/kg, IM), medetomidine (50 μg/kg, IM), and alfaxalone (5 mg/kg, IV); or midazolam (0.5 mg/kg, IM), medetomidine (50 μg/kg, IM), and alfaxalone (5 mg/kg, IM). Venous blood was taken before pretreatment, pre- and postoperatively during anesthesia with isoflurane and oxygen, and during early and complete recovery.

RESULTS

Compared with baseline concentrations, plasma adrenaline and noradrenaline concentrations decreased during anesthesia in cats premedicated with alfaxalone alone and in combination with medetomidine. The combination of medetomidine, midazolam, and alfaxalone prevented an excessive increase in catecholamines during anesthesia and surgery in cats. Postoperative plasma cortisol concentration after ovariohysterectomy was lower for cats premedicated with the combination of medetomidine and alfaxalone or the combination of medetomidine, midazolam, and alfaxalone, compared with cats premedicated with alfaxalone alone. Cats treated with combinations that included medetomidine and midazolam had hyperglycemia during anesthesia. Cats treated with medetomidine or medetomidine and midazolam in combination with alfaxalone, compared with alfaxalone alone, had lower concentrations of nonesterified fatty acids during anesthesia. Behavioral recovery scores were lower (better) for cats that received medetomidine in addition to alfaxalone, compared with alfaxalone alone.

CLINICAL RELEVANCE

Results indicated that pretreatments with medetomidine and alfaxalone or with medetomidine, midazolam, and alfaxalone were useful for preventing stress-related hormonal and metabolic responses, other than hyperglycemia, during isoflurane anesthesia and surgery in cats.

Effects of pretreatment with medetomidine, midazolam, ketamine, and their combinations on stress-related hormonal and metabolic responses in isoflurane-anesthetized cats undergoing surgery

Objective:

The purpose of this study was to compare the effects of pretreatment with medetomidine (Me), midazolam (Mi), and ketamine (Ke) on stress-related neurohormonal and metabolic responses in isoflurane-anesthetized cats undergoing ovariohysterectomy and castration.

Materials and Methods:

We prospectively recruited 112 client-owned healthy mixed-breed cats. In both surgeries, we divided the cats into seven groups (eight cats per group): non-treatment (control), Me (50 μg/kg), Mi (0.5 mg/kg), Ke (5 mg/kg), Me + Mi, Me + Ke and Me + Mi + Ke administered intramuscularly. After pretreatments, we maintained anesthesia with isoflurane and oxygen. Venous blood was taken before pretreatment, pre- and post-operatively during anesthesia, and at early- and complete-recovery.

Results:

Both plasma adrenaline and noradrenaline were reduced during anesthesia in all groups. Plasma cortisol increased during anesthesia and at early recovery in non-Me-treated groups, whereas it decreased in Me-treated groups in both surgeries. Plasma insulin and non-esterified fatty acid (NEFA) decreased, and glucose increased during anesthesia in all groups, but hyperglycemia and decrease in NEFA were greater in Me-treated groups.

Conclusions:

In isoflurane-anesthetized cats undergoing surgeries, premedication with Me alone and in combination is useful for reducing the perioperative stress-related increase in cortisol and catecholamines except for hyperglycemia.

Reversal effects of atipamezole, flumazenil, and 4-aminopyridine on bradycardia and increases in blood pressures induced by medetomidine, midazolam, and ketamine in isoflurane-anesthetized cats

OBJECTIVE

To investigate the effects of a fixed dose of atipamezole (AT), flumazenil (FL), and 4-aminopyridine (AP), both alone and in combination, on changes in arterial blood pressure and heart rate induced by medetomidine (ME), midazolam (MI), and ketamine (KE) under isoflurane anesthesia with controlled ventilation in healthy cats.

DESIGN

Prospective experimental study.

SETTING

University animal research facility.

ANIMALS

Healthy adult mixed-breed cats were used for 8 investigation groups (6 cats per group), with ≥2 weeks between interventions.

INTERVENTIONS

Cats were anesthetized with an end-tidal isoflurane concentration of 2% under controlled ventilation. A catheter was inserted into the right or left femoral artery for arterial pressure monitoring and blood gas sampling, and ECG electrodes were placed. Upon completed preparations, cats were administered a mixture of ME (0.05 mg/kg) and MI (0.5 mg/kg), followed 10 minutes later by intramuscular KE (10 mg/kg). Twenty minutes after KE injection, the cats received IV injection with either a physiological saline solution at 0.1 mL/kg (control), or 1 of 7 variations of experimental drugs, alone or in combination: AT (0.2 mg/kg), FL (0.1 mg/kg), AP (0.5 mg/kg), AT+FL, FL+AP, AT+AP, and AT+FL+AP. Arterial blood pressure and heart rate were continuously measured over 120 minutes after administration of potential antagonists.

MEASUREMENTS AND MAIN RESULTS

ME+MI+KE induced an increase in blood pressure and bradycardia. Potential antagonists alone or in combination did not significantly alter the bradycardia. FL, AP alone, and FL+AP did not significantly alter the changes in blood pressures induced by ME+MI+KE. Meanwhile, administration of AT alone or in combination reversed the increase in blood pressure induced by ME+MI+KE but transiently caused excessive hypotension.

CONCLUSION

These results revealed that AT alone or in combination is effective for antagonizing hypertension induced by ME+MI+KE; however, attention should be paid to temporary hypotension in cats anesthetized with isoflurane.

Human bronchial intraepithelial T cells produce interferon-gamma and stimulate epithelial cells

Intraepithelial lymphocytes (IELs) can be identified among epithelial cells in systemic mucosal tissues. Although intestinal IELs play a crucial role in mucosal immunity, their bronchial counterparts have not been well studied. The purpose of this study was to determine the immunological functions of human bronchial IELs, which interact directly with epithelial cells, unlike lamina propria lymphocytes (LPLs). We isolated successfully bronchial IELs and LPLs using a magnetic cell separation system from the T cell suspensions extracted from bronchial specimens far from the tumours of resected lungs. Human bronchial IELs showed an apparent type 1 cytokine profile and proliferated more actively in response to CD2 signalling than did bronchial LPLs. CD8(+) IELs were identified as the most significant sources of interferon (IFN)-gamma. Human bronchial epithelial cells constitutively produced the T cell growth factors interleukin (IL)-7 and IL-15, and levels of those factors increased when cells were stimulated by IFN-gamma. Bronchial epithelial cells expressed cell surface proteins CD58 and E-cadherin, possibly enabling adhesion to IELs. In summary, human bronchial IELs have immunological functions distinct from bronchial LPLs and may interact with epithelial cells to maintain mucosal homeostasis.

Discoidin domain receptor 1 isoform-a (DDR1alpha) promotes migration of leukocytes in three-dimensional collagen lattices

Although integrins are crucial for migration of leukocytes through endothelium, integrin-independent mechanisms appear to take over and mediate the migration of leukocytes through extracellular matrix (ECM) in a three-dimensional tissue microenvironment. Discoidin domain receptor (DDR) 1 is a receptor tyrosine kinase activated by collagen, the most abundant ECM protein. In the present study, we detected that peripheral blood mononuclear cells (PBMC) and polymorphonuclear neutrophils were induced to express DDR1 after incubation in RPMI 1640. The expression level of DDR1 in PBMC was increased further by stimulation with tumor necrosis factor-alpha, interleukin-1beta, granulocyte-macrophage colony-stimulating factor, lipopolysaccharide, or phytohemagglutinin, but not with interferon-gamma. In vivo, DDR1 mRNA was detectable in mononuclear leukocytes infiltrating human renal tumor tissue. Among three DDR1 isoforms, DDR1alpha was the major transcript in leukocytes. Functionally, overexpression of either DDR1alpha or DDR1beta in THP-1 cells resulted in increased adherence to collagen-coated plates in a beta1-integrin independent manner. However, only DDR1alpha-, but not DDR1beta-, overexpressing cells exhibited marked pseudopod extension and migrated successfully through three-dimensional collagen lattices. Consequently, we propose that the interaction of DDR1alpha with collagen of the ECM results in a requisite intracellular signaling that enables leukocytes to migrate in a tissue microenvironment and participate in host defense.

Phenotypic and functional change of cytokine-activated neutrophils: inflammatory neutrophils are heterogeneous and enhance adaptive immune responses

Polymorphonuclear leukocytes (PMN) are the most abundant leukocytes, comprising about two-thirds of peripheral blood leukocytes, and play major roles in innate immunity. In addition, PMN play critical roles in the development of adaptive immunity. Recently, defensins and other peptides pre-stored in PMN granules were shown to attract monocytes, dendritic cells, and T cells, leading to the hypothesis that the release of PMN granular peptides may link innate and adaptive immunity. During the past several years, we have focused on an alternative hypothesis that activated PMN further differentiate and acquire new phenotypes and functions that enable them to link the two responses. To test our hypothesis, we have taken local and global approaches and have shown several key findings that support the hypothesis. The findings include the requirement for priming PMN by cytokines to induce the delayed expression of MCP-1/CCL2, a signal for mononuclear cells, and the expression of new cell-surface markers by such cytokine-activated PMN. In the present manuscript, we focus on the phenotypic and functional changes that occur during PMN activation with selected cytokines. The results of our study indicate that inflammatory PMN are heterogeneous and play roles in not only innate but also adaptive immunity in response to stimuli released in injured tissues.

IL-6 and IFN-gamma regulation of IL-10 production by human colon carcinoma cells

IL-10 has been shown to play a crucial role in immunosuppression in cancer patients. We explored the regulation of IL-10 production by TNF-alpha, IL-1 beta, IL-6, IL-8, and IFN-gamma in human colon carcinoma COLO205 cells. Northern analysis revealed a marked expression of IL-10 mRNA after stimulation by IL-6, and a marginal but significant expression by TNF-alpha, IL-1 beta or IFN-gamma. No IL-10 mRNA expression was observed when cells were untreated or incubated with IL-8. IL-10 in the culture supernatants showed good agreement with mRNA expression. In addition, IFN-gamma dose-dependently inhibited this IL-6-induced production of IL-10. MTT assay revealed that low dose IFN-gamma (1-10 ng/ml) had no effect on growth of COLO205 cells, but that high dose IFN-gamma (>100 ng/ml) significantly inhibited their proliferation. Northern analysis of COLO205 cells pretreated with IFN-gamma demonstrated that the IL-6R alpha chain was down-regulated. These results suggest that, in certain colon carcinoma cells, tumor-derived IL-10 production is directly regulated by systemic or local production of pro-inflammatory cytokines, such as IL-6 and IFN-gamma.

Expression of CCR6 and CD83 by cytokine-activated human neutrophils

Polymorphonuclear leukocytes (PMNLs) are thought to be terminally differentiated, short-lived, and unable to actively synthesize new proteins or to interact with T cells. In the current study, it was found that PMNLs incubated with supernatants of phytohemagglutinin (PHA)-stimulated peripheral blood mononuclear cells (PHA-sup) expressed high levels of CCR6 mRNA. Neutralization with IgG against several cytokines revealed that tumor necrosis factor (TNF)-alpha was largely responsible for the PHA-sup-induced CCR6 mRNA expression. Among recombinant cytokines, TNF-alpha induced high levels of CCR6 mRNA expression, whereas interferon (IFN)-gamma induced low levels. The 2 cytokines together exhibited a considerable synergy. Cytokine-activated PMNLs expressed functional CCR6, as detected by the binding of sodium iodide I 125-labeled liver and activation-regulated chemokine (LARC) and dose-dependent migration toward LARC. The induction of CCR6 suggested that these cytokine-activated PMNLs have more similarities with dendritic cells (DCs) that express CCR6 in an immature stage. In fact, the activation of PMNLs with TNF-alpha and IFN-gamma induced the expression of CD83, a dominant cell-surface marker of DCs. When PMNLs were activated with granulocyte macrophage-colony-stimulating factor, TNF-alpha, and IFN-gamma, these cells expressed CD40 and HLA-DR in addition to CD83. Taken together, PMNLs, under appropriate conditions, can undergo a differentiation process characterized by the acquisition of new phenotypes and functions, and such differentiated PMNLs may play more active roles in the adaptive immune response. (Blood. 2000;96:3958-3963)

Alteration in the responsiveness to tumour necrosis factor-alpha is crucial for maximal expression of monocyte chemoattractant protein-1 in human neutrophils

We previously reported delayed expression of monocyte chemoattractant protein-1 (MCP-1) in human neutrophils cultured with a cytokine-rich crude supernatant of phytohaemagglutinin-stimulated peripheral blood mononuclear cells (PHA-sup). Tumour necrosis factor-alpha (TNF-alpha) contained in the PHA-sup played a key role in this event, but there appeared to be another factor(s) in the same supernatant that co-operated with TNF-alpha for maximal MCP-1 expression. In the present study, we reduced TNF-alpha concentrations in the PHA-sup to minimal levels using anti-TNF-alpha affinity columns (TNF-depleted-sup) and investigated the co-operation between TNF-alpha and TNF-depleted-sup. Nine hours of preincubation with TNF-depleted-sup altered the responsiveness of neutrophils to TNF-alpha and enabled TNF-alpha to increase the level of MCP-1 expression to a maximal level within 4 hr. The priming effect was not due to the increased expression of cell-surface TNF receptors. However, the activation of primed cells by TNF-alpha was clearly through TNF receptor-p55. Finally, the activity in the TNF-depleted-sup that co-operated with TNF-alpha was eluted at 60 000 MW on high-performance liquid chromatography-gel filtration. Thus, delayed neutrophil expression of MCP-1 is regulated by a cytokine-dependent mechanism that induces neutrophils to enter a 'mature' stage.

MCP-1 is selectively expressed in the late phase by cytokine-stimulated human neutrophils: TNF-alpha plays a role in maximal MCP-1 mRNA expression

Culture supernatants of phytohemagglutinin (PHA)-stimulated human peripheral blood mononuclear cells (PHA-sup) induced monocyte chemoattractant protein-1 (MCP-1) mRNA expression in human neutrophils. MCP-1 mRNA was first detected by Northern analysis at 8 h, and the peak level was detected at 16 h and sustained until 72 h. Cycloheximide and genistein, but not pertussis toxin, inhibited the expression of MCP-1 mRNA. Recombinant tumor necrosis factor alpha (TNF-alpha) induced a low level MCP-1 mRNA accumulation in neutrophils, and addition of anti-TNF-alpha IgG blocked 30-70% of MCP-1 mRNA expression induced with PHA-sup. PHA-sup-stimulated PMN synthesized and secreted 3.1+/-1.3 ng/5 x 10(6) PMN MCP-1 within the first 24 h. Hybridization of 32P-labeled cDNA preparations to an array of human cytokine cDNAs further indicated that MCP-1 mRNA was selectively up-regulated in the late phase after stimulation with the PHA-sup.

Changes in iron and ferritin in anemic calves infected with Theileria sergenti

Changes in iron and ferritin in calves infected with Theileria sergenti were investigated to elucidate iron metabolism in animals with extravascular hemolytic anemia. During severe anemia, serum iron was remarkably elevated while the total iron-binding capacity remained relatively unchanged or decreased slightly in the infected calves, resulting in elevated transferrin saturation. The serum ferritin concentration gradually increased with the progress of anemia. The erythrocyte ferritin content drastically increased when mean corpuscular volume was elevated. The concentration of non-heme iron and ferritin in the liver, spleen, and bone marrow of the infected calves was markedly higher than that in the respective tissues of the control animals. In particular, the liver of the anemic calves was found to contain 23 and 35 times as much non-heme iron and ferritin, respectively, as that of the non-anemic healthy cattle. The liver type (L) to heart type (H) subunit ratio of liver ferritin was significantly higher in the protozoa-infected than in the non-infected cattle. On the other hand, the L/H ratio of marrow ferritin was significantly reduced by the anemia. These results indicate that the anemic calves infected with T. sergenti apparently present symptoms of iron overload.

[Involvement of cytokines in invasion and metastasis of colon cancer]

Despite improvement in early diagnosis, surgical techniques, and general patient care, most deaths of cancer patients result from metastases. Recent studies have revealed that cytokines produced by cancer cells or by stromal cells play an important role into development the cancer metastasis. The formation of a cancer metastasis involves several major steps: 1) extensive vascularization; 2) local invasion; 3) adherence either to capillary endothelial cells or to subendothelial basement membrane; 4) extravasation; and 5) proliferation. In colon cancer, several cytokines such as growth factors, inflammatory cytokines, and angiogenic factors have been confirmed to be involved in each step of metastasis. This paper summarizes the involvement of cytokines in the development of invasion and metastasis in colon cancer.

Surgical trauma induces group II phospholipase A2 production by neutrophils at a local site after surgery

OBJECTIVES

Group II phospholipase A2 (PLA2) regulates eicosanoids and platelet activating factor (PAF) production and plays an important role in regulating critical mediators in inflammatory diseases such as trauma, sepsis and multiple organ failure. To elucidate the local effect of surgical trauma, we investigated the production of group II PLA2 at a local site after surgery.

DESIGN AND METHODS

We utilized a radioimmunoassay to measure group II PLA2 levels in peritoneal exudates from the operative field and blood in patients who underwent gastrectomy. We also investigated the production of group II PLA2 in cells from peritoneal exudates by Northern blotting and immunocytochemistry.

RESULTS

Immunoreactive group II PLA2 levels were significantly increased from 3 h after surgery and peaked at 12 h peritoneal exudates. However, serum group II PLA2 levels peaked at 24-48 h and decreased gradually after surgery, findings similar to levels of postoperative serum C-reactive protein (CRP). There was no significant correlation between group II PLA2 levels in peritoneal exudates and those in blood. Group II PLA2 mRNA was expressed at high level in cells from peritoneal exudates, by Northern blot analysis, but not those from blood. The localization of group II PLA2 protein was intense in neutrophils, as determined by immunocytochemistry. No group II PLA2 expression was observed in corresponding peripheral blood cells.

CONCLUSIONS

After surgery, group II PLA2 is increased in peritoneal exudates prior to elevation in the blood circulation and is produced by neutrophils recruited and activated at a local site. Group II PLA2 produced in peritoneal exudates by neutrophils has an important role in the physiological and pathological states at a local site, after surgery.

Neutrophil elastase inhibitor (ONO-5046.Na) suppresses the proliferation, motility and chemotaxis of a pancreatic carcinoma cell line, Capan-1

ONO-5046. Na is a specific neutrophil elastase inhibitor. We investigated the in vitro effect of ONO-5046. Na on the proliferation, motility and chemotaxis of a pancreatic carcinoma cell line (Capan-1, well differentiated adenocarcinoma). ONO-5046. Na significantly suppressed the proliferation, motility and chemotaxis at a concentration of more than 100, 10 and 1 microgram/ml of ONO-5040. Na, respectively (p < 0.005, p < 0.05 and p < 0.05, respectively). These results indicate that ONO-5046. Na may have a role in preventing the progression and metastasis of pancreatic carcinoma cells, suggesting that ONO-5046. Na may serve as an anti-cancer agent.

Leukemia inhibitory factor induces apoptosis and proliferation of human carcinoma cells through different oncogene pathways

Leukemia inhibitory factor (LIF) affects the growth of carcinoma cells, and we thus analyzed its underlying mechanisms. Carcinoma cells constitutively express LIF mRNA, and 23 lines (92.0%) and all (100%) of 25 lines express LIF receptor mRNAs of LIFRbeta and gp130, respectively. Exogenous addition of LIF promoted significant cell proliferation in 4 lines (MCF-7, ZR-75-1, Hs-700T and Panc-1) and suppressed cell growth in 3 lines (AZ-521, GBK-1 and HT-29). LIF significantly induced an immediate early response of genes c-fos and junB 3 hr after stimulation, but not of c-jun during the process of proliferation of MCF-7 and Hs-700T cells, with maximum levels at 30-60 min. The cell-cycle-related gene cyclin E was also induced in MCF-7 and Hs-700T cells, whereas cyclinA, cdk2, c-myc, c-myb and p53 mRNAs were not induced. On the other hand, LIF inhibited growth and increased the rate of cell death of AZ-521 and GBK-1 cells. LIF increased the number of TUNEL-positive cells in AZ-521 cells and DNA fragmentation in AZ-521 and GBK-1 cells. LIF induced apoptosis related genes c-myc and ICE during suppression of cell growth, but p53, p21, c-fos, cyclin A and cyclin E were not induced. Our results suggest that LIF is linked to cell proliferation and apoptosis in some human carcinoma cell lines. It is considered that this is related to differences in signal transduction and induction of oncogenes.

Evidence that eosinophil infiltration in the OK-432/fibrinogen-injected Meth-A tumor in mice is mediated by locally produced IL-5

It was previously demonstrated that a single injection of OK-432 (a penicillin-treated freeze-dried Streptococcus) mixed with fibrinogen into cancer tissues induces marked infiltration by eosinophils of the tumor stroma and leads to tumor necrosis. In the present study, we examined mechanisms regulating the local accumulation of eosinophils and the role of infiltrating eosinophils in tumor regression using the OK-432/fibrinogen injected Meth-A fibrosarcoma tumor. After injection of OK-432/fibrinogen into the tumor on the left flank of the BALB/c mice, eosinophil infiltration became obvious in the tumor stroma on day 3 following the accumulation of macrophages and neutrophils, was massive on day 5 and decreased by day 10. After the decrease in the infiltration of eosinophils, the tumor injected with OK-432/fibrinogen diminished markedly in size with ulceration as compared with control. Northern blot analysis revealed that expression of IL-5 mRNA in the tumor tissue was not detected on day 0, was significantly on day 3, reached the maximum on day 5, and thereafter decreased by day 10. Although intraperitoneal injection of rat anti-IL-5 monoclonal antibody in tumor bearing mice prior to OK-432 injection inhibited the infiltration of eosinophils, the antitumor effects of OK-432 persisted. In the blood, neither eosinophilia nor IL-5 activity was recognized during the course of the experiment. These results suggest that intratumoral injection of OK-432/fibrinogen induces local production of IL-5, which in turn recruits eosinophils into the tumor tissue, however, the infiltrating eosinophils do not play an important role in tumor regression.

Group II phospholipase A2 is increased in peritoneal and pleural effusions in patients with various types of cancer

Serum levels of group II phospholipase A2 (PLA2) have been reported to be associated with stage of disease in cancer patients. These levels are also related to the malignant potential in tissues, and are an important prognostic factor. We radioimmunoassayed group II PLA2 levels in pleural and peritoneal effusions from patients with various cancers. We also investigated the production of group II PLA2 in cells in effusions from cancer patients by Northern blotting, immunocytochemistry and in situ hybridization. Immunoreactive group II PLA2 levels were significantly higher in effusions from 47 patients with various cancers, compared with those in sera and cirrhotic ascites. There was no significant correlation between group II PLA2 levels in effusions and those in sera. Group II PLA2 mRNA was expressed at a high level in cells from effusions, by Northern blot analysis, but not in those cells from blood. The localization of group II PLA2 protein and mRNA was intense in carcinoma cells and CD68-positive macrophages, determined by immunocytochemistry and in situ hybridization. In addition, IL-6 and IL-8 levels were significantly higher in effusions, in comparison with those in sera from patients, suggesting that cancer cells and macrophages produce group II PLA2 by IL-6. These group II PLA2 levels are apparently significantly increased in effusions, and the carcinoma cells and macrophages produce group II PLA2, as noted in effusions from patients with various cancers.

IL-6 and soluble IL-6 receptor levels change differently after surgery both in the blood and in the operative field

To investigate alterations in post-operative levels of IL-6 and soluble IL-6 receptor (sIL-6R), we examined their levels in serum and samples of drainage fluids from 26 patients who underwent thoracoabdominal surgery. Serum IL-6 levels reached the maximum within the first post-operative day and decreased thereafter. The IL-6 levels in the drainage fluid were much higher than in the serum (458 +/- 101-fold; mean +/- SEM) in the early post-operative phase. A large quantity of sIL-6R levels was present in blood samples. The time course of serum sIL-6R levels in 26 patients showed no significant change. sIL-6R concentrations in the drainage fluid were significantly lower than in serum (4.5 +/- 1.1-fold; mean +/- SEM) in the early post-operative phase. We propose that IL-6 is produced in the operative field and enters the peripheral blood stream to induce elevation of serum IL-6. On the other hand, sIL-6R levels in the operative field are lower than in the serum, and the serum sIL-6R levels are not influenced by surgical trauma. These data suggest that sIL-6R is being constantly produced in areas other than the operative field, while sIL-6R level is reduced by consumption in the operative field. Mechanisms to cope with surgical stress, involving sIL-6R together with its ligand IL-6 may thus exist.

Carcinoma-cells express IL-8 and the IL-8 receptor - their inhibition attenuates the growth of carcinoma-cells

We investigated the expression of IL-8 and the IL-8 receptor (IL-8R) in human carcinoma cells and the role of IL-8 and IL-8R in the growth of carcinoma cells. IL-8 mRNA was detected in 16 of 20 (80%) carcinoma cell lines and 20 of 24 (83.3%) cancer tissues by Northern blot analysis. IL-8R mRNA was expressed in 7 of 11 (63.6%) carcinoma cell lines by reverse transcriptase polymerase chain reaction (RT-PCR). Neutrophil chemotactic activity in the culture supernatant of carcinoma cell lines correlated with immunoreactive IL-X concentration. Growth of carcinoma cells was significantly inhibited in the presence of anti-IL-8 antibody or IL-8R antisense oligonucleotide. These results revealed that IL-8 and IL-8R are expressed in the majority of carcinoma cells and suggest that they might play a role in the growth of carcinoma cells.

Human carcinoma cell lines produce biologically active leukemia inhibitory factor (LIF)

We investigated the production of leukemia inhibitory factor (LIF) by human carcinoma cell lines. LIF mRNA was detected by Northern blot analysis in all 24 carcinoma cell lines of the lung, breast, stomach, colon, liver, gallbladder, pancreas and melanocytes. Seventeen of them (70.8%) secreted LIF in the culture supernatant (range: 40.4-3990.3 pg/ml, mean +/- SEM: 611.8 +/- 262.9 pg/ml). Biologic activity of LIF was confirmed in the culture supernatant of carcinoma cell lines by the MTT assay using M1 cells. The present results showed that human carcinoma cell lines are constitutively producing biologically active LIF. The possible biological significance of LIF produced by cancer cells is discussed.