A CD200FC immunoadhesin prolongs rat islet xenograft survival in mice

BACKGROUND

A solubilized form of the CD200 molecule, CD200Fc, has been shown to suppress allograft rejection and development of collagen-induced arthritis in mice. We investigated whether the same molecule could prolong survival of rat islet xenografts.

METHODS

Streptozocin-treated mice, receiving injections with anti-asialo-GM1 antibody, received rat islets ( approximately 400/mouse) under the kidney capsule or injected into the portal vein, along with rapamycin treatment. Thereafter mice received injections of CD200Fc (10 microg/mouse/injection) or control mouse IgG2. Blood glucose was monitored daily. Some mice received additional injections of anti-CD200/-CD200R monoclonal antibodies.

RESULTS

Portal vein delivery of islets led to more extended resolution of diabetes than did transplantation under the kidney capsule. CD200Fc further prolonged survival in either case, an effect abolished by anti-CD200 or F(ab')2 anti-CD200R mAbs, but not by whole anti-CD200R (anti-CD200R Ig). Spleen cells taken from CD200Fc-treated mice showed polarization to type-2 cytokine production (interleukin-4, interleukin-10) on restimulation with rat splenocytes in culture, in comparison to cells from control mice (type-1 cytokines, interlulin-2, interferon-gamma).

CONCLUSION

CD200:CD200R interactions are important in regulating rat islet xenograft survival.

Protein kinase CK2 mediates TGF-beta1-stimulated type IV collagen gene transcription and its reversal by estradiol

BACKGROUND

We have previously shown that the transcription factor Sp1 mediates the stimulatory effects of transforming growth factor-beta1 (TGF-beta1) on type IV collagen gene transcription and protein synthesis, and that estradiol reverses these effects by down-regulating Sp1 activity. Protein kinase casein kinase II (CK2) phosphorylates Egr-1 and prevents its binding to Sp1. We hypothesized that TGF-beta1 stimulates CK2 activity, which in turn activates type IV collagen gene transcription via increased availability of free Sp1.

METHODS

The effects of TGF-beta1 and of estradiol on murine mesangial cell type IV collagen gene transcription were measured using a reporter mini gene construct and on collagen IV protein synthesis by Western blotting. Nuclear Egr-1, phosphorylated Egr-1, Sp1, Egr-1/Sp1 complexes and unbound Sp1 were measured using co-immunoprecipitation and Western blotting techniques.

RESULTS

TGF-beta1 stimulated CK2 activity in murine mesangial cells. Although TGF-beta1 failed to alter total Egr-1 protein, it increased phosphorylated Egr-1. This led to decreased Egr-1/Sp1 complex formation, increased unbound Sp1, increased binding of nuclear extracts to the collagen IV promoter, and increased type IV collagen gene transcription and protein synthesis. Physiologic concentrations of estradiol reversed these effects.

CONCLUSIONS

These studies suggest that activation of CK2 mediates the stimulatory effect of TGF-beta1 on type IV collagen gene transcription. Moreover, the ability of estradiol to reverse TGF-beta1-stimulated type IV collagen synthesis is mediated by down-regulating CK2 activity, which ultimately limits the availability of unbound Sp1 to activate gene transcription.

Evidence of a role for CD200 in regulation of immune rejection of leukaemic tumour cells in C57BL/6 mice

Increased expression of the molecule CD200 in mice receiving renal allografts is associated with immunosuppression leading to increased graft survival, and altered cytokine production in lymphocytes harvested from the transplanted animals. Preferential production of IL-4, IL-10 and TGFbeta occurs on donor-specific restimulation in vitro, with decreased production of IL-2, IFNgamma and TNFalpha. These effects are enhanced by simultaneous infusion of CD200 immunoadhesin (CD200Fc) and donor CD200 receptor (CD200r) bearing macrophages to transplanted mice. C57BL/6 mice do not normally resist growth of EL4 or C1498 leukaemia tumour cells. Following transplantation of cyclophosphamide-treated C57BL/6 with T-depleted C3H bone marrow cells, or for the EL4 tumour, immunization of C57BL/6 mice with tumour cells transfected with a vector encoding the co-stimulatory molecule CD80 (EL4-CD80), mice resist growth of tumour challenge. Immunization of C57BL/6 mice with EL4 cells overexpressing CD86 (EL4-CD86) is ineffective. Protection from tumour growth in either model is suppressed by infusion of CD200Fc, an effect enhanced by co-infusion of CD200r+ macrophages. CD200Fc acts on both CD4+ and CD8+ cells to produce this suppression. These data are consistent with the hypothesis that immunosuppression following CD200-CD200r interaction can regulate a functionally important tumour growth inhibition response in mice.

First-principle approach to dielectric behavior of nonspherical cell suspensions

We present a theoretical study of the dielectric behavior of cell suspensions by employing the Bergman-Milton spectral representation of the effective dielectric constant. By means of the spectral representation, we derive the dielectric dispersion spectrum in terms of the electrical and structure parameters of the cell models. Our results show that a better agreement with the experimental data can be obtained, provided that we introduce a conductivity contrast t=sigma(2)/(sigma(2)-sigma(1)). We find that the conductivity of the cell cytoplasm sigma(1) can be much larger than that of the suspending medium sigma(2), in contrast to the previous claim that sigma(1) approximately sigma(2).

A new cause of Zollinger-Ellison syndrome: non-small cell lung cancer

Numerous epidemiologic studies suggest a relationship between lung cancer and peptic ulcer disease. Furthermore, various lung cancers synthesize and release a number of peptides such as gastrin and gastrin-releasing peptide that could cause acid hypersecretion; however, Zollinger-Ellison syndrome (ZES), because of a lung tumor, has never been described. We report such a patient for the first time. A 60-year-old man with a non-small cell lung carcinoma (large cell type) presented with diarrhea, heartburn, abdominal pain, and duodenal ulcers. Evaluation showed ZES was present (fasting hypergastrinemia, hyperchlorhydria) and control of all symptoms by omeprazole. No abdominal or cardiac tumor, the other known locations of gastrinomas causing ZES, was found on detailed tumor imaging studies. Resection of the lung tumor resulted in a decrease in gastrin levels to normal values. Plasma radioimmunoassays showed elevated gastrin, chromogranin A and normal levels of gastrin-releasing peptide, and 9 other hormones. The tumor showed similar immunocytochemical results. The characteristics of this case are compared with 100 cases of sporadic abdominal gastrinomas, and the evidence reviewed suggests why ZES should be considered in patients with lung cancer with peptic symptoms.

[The diagnostic value and limitations of total serum bile acid determined enzymatically]

OBJECTIVE

To elucidate the diagnostic value of total serum bile acid.

METHOD

Clinical data from 913 cases was statistically analyzed with SPSS for Windows and other statistical procedures reported previously.

RESULTS

(1) The mean of TBA of healthy subjects was (4.0 +/- 3.2) micromol/L. The TBA level of liver disease group is significantly higher than other group(P < 0.01). (2) The mean of TBA of patients with acute hepatitis was (167.2 +/- 132.4) micromol/L, the highest value was 449.5 micromol/L, it was significantly higher than other groups. TBA was a sensitive mark reflecting acute hepatic injury. (3) The sensitivity of TBA in patients with cirrhosis was 85.8%, higher than routine liver function tests. TBA is a valuable mark reflecting collateral circulation. (4) The sensitivity of TBA in mild chronic hepatitis was only 30.5%, much lower than ALT and TBIL (P < 0.01). (4) There was a relationship between the level of TBA and the severity of patients' condition, but the value of TBA for evaluating the severity was not as good as TBIL.

CONCLUSION

The specificity of TBA is quite high, the sensitivity is moderate, TBA is valuable for the diagnosis of liver disease, especially for acute hepatitis and cirrhosis, but it's sensitivity for mild chronic hepatitis is only 30.5%, it is not as good as TBIL for evaluating the condition of patients.

The Collisional Behaviour of Ba[6s5d(3DJ)] Generated Following Pulsed Dye-Laser Excitation at λ = 553.5 nm {Ba[6s6p(1P1)] ← Ba[6s2(1S0)]} in the Presence of Noble Gases and Ground State Atomic Barium by Atomic Spectroscopic Marker Emission Measurements in the Time-Domain

We present a kinetic study of the collisional behaviour of Ba[6

Evidence for persistent expression of OX2 as a necessary component of prolonged renal allograft survival following portal vein immunization

Following portal vein (pv) pretransplant immunization of C3H mice, there is an early (within 2 days) increase in expression of the molecule OX2 seen on host dendritic cells (DC), along with increased survival of C57BL/6 renal allografts transplanted within 24 h of pv immunization. In addition, there is a marked polarization in cytokine production from lymphocytes harvested from the transplanted animals, with preferential production of IL-4, IL-10, and TGFbeta on donor-specific restimulation in vitro, and decreased production of IL-2, IFN-gamma, and TNFalpha compared with non-pv-immunized control transplanted mice. Both the increased renal allograft survival and the altered cytokine production are abolished by infusion of anti-mouse OX2 monoclonal antibody (3B6), even when antibody infusion is begun as late as 10 days following transplantation. Quantitative PCR analysis independently shows that OX2 expression is increased in the spleen and liver of transplanted mice as late as 21 days following pv immunization. In vitro studies with an OX2:Fc immunoadhesion had suggested that immunosuppression induced by this soluble form of the OX2 molecule was dependent primarily upon an early (OX2-dependent) signal. This discrepancy between in vivo and in vitro data possibly reflects a role for OX2 in the in vivo recruitment of other (immunregulatory) cells. Consistent with this hypothesis, regardless of the time (posttransplantation) of in vivo infusion of anti-OX2 antibody, within 2 days we observed a decline in the functional activity of a previously characterized immunoregulatory gammadeltaTCR(+) cell population, which can be monitored by its ability to regulate cytokine production in vitro.

Selective estrogen receptor modulators suppress mesangial cell collagen synthesis

Estrogen receptor modulators (SERMs) are "designer drugs" that exert estrogen-like actions in some cells but not in others. We examined the effects of the SERMs LY-117018 (an analog of raloxifene) and tamoxifen on mesangial cells synthesis of type I and type IV collagen. We found that LY-117018 and tamoxifen suppressed mesangial cell type IV collagen gene transcription and type IV collagen protein synthesis in a dose-dependent manner, with a potency identical to that of estradiol. Type I collagen synthesis was also suppressed by LY-117018 in a dose-dependent manner with a potency identical to that of estradiol but greater than that of tamoxifen. Genistein, which selectively binds to estrogen receptor-beta in nanomolar concentrations, suppressed type I and type IV collagen synthesis, suggesting that estrogen receptor-beta mediates the effects of estrogen on collagen synthesis. Because matrix accumulation is central to the development of glomerulosclerosis, second-generation SERMs may prove clinically useful in ameliorating progressive renal disease without the adverse effects of estrogen on reproductive tissues.

Synergy in induction of increased renal allograft survival after portal vein infusion of dendritic cells transduced to express TGFbeta and IL-10, along with administration of CHO cells expressing the regulatory molecule OX-2

Dendritic cells (DC), generated from C57BL/6 mouse bone marrow cells cultured with GM-CSF and IL-4 for 9 days, were engineered to express constitutively the cytokines TGFbeta, IL-10, and IL-12, using adenovirus vectors constructed using an E1-deleted replication-deficient recombinant adenovirus carrying the appropriate cDNA for the relevant cytokines (Ad-TGFbeta, Ad-IL-12, or Ad-IL-10). C3H mice receiving nontransduced DC or pretransplant infusion of DC-Ad-LacZ showed increased survival of C57BL/6 renal grafts relative to that of control nonimmunized mice. Transfusion of Ad-IL-12-transduced DC abolished this increased survival, leading to a graft survival equivalent to that of controls with no DC. Optimal graft survival was seen in the group receiving a mixture of DC transduced with constructs for both IL-10 and TGFbeta. There was a correlation between increased graft survival and both inhibition of the induction of CTL and enhancement of a polarization to produce type-2 cytokines (IL-4, IL-10, and TGFbeta) on antigen-specific restimulation in vitro. These effects were more pronounced following concomitant infusion of CHO cells transfected with a full-length cDNA for murine OX-2.

Dendritic cells genetically engineered to express Fas ligand induce donor-specific hyporesponsiveness and prolong allograft survival

Polarization of an immune response toward tolerance or immunity is dictated by the interactions between T cells and dendritic cells (DC), which in turn are modulated by the expression of distinct cell surface molecules, and the cytokine milieu in which these interactions are taking place. Genetic modification of DC with genes coding for specific immunoregulatory cell surface molecules and cytokines offers the potential of inhibiting immune responses by selectively targeting Ag-specific T cells. In this study, the immunomodulatory effects of transfecting murine bone marrow-derived DC with Fas ligand (FasL) were investigated. In this study, we show that FasL transfection of DC markedly augmented their capacity to induce apoptosis of Fas+ cells. FasL-transfected DC inhibited allogeneic MLR in vitro, and induced hyporesponsiveness to alloantigen in vivo. The induction of hyporesponsiveness was Ag specific and was dependent on the interaction between FasL on DC and Fas on T cells. Finally, we show that transfusion of FasL-DC significantly prolonged the survival of fully MHC-mismatched vascularized cardiac allografts. Our findings suggest that DC transduced with FasL may facilitate the development of Ag-specific unresponsiveness for the prevention of organ rejection. Moreover, they highlight the potential of genetically engineering DC to express other genes that affect immune responses.

Eliminating disulfide exchange during glutamyl endopeptidase digestion of native protein

Numerous advantages of using immobilized enzymes over free-solution protein digests have been cited in the literature. This investigation examines both the rate of hydrolysis and the extent of disulfide bond exchange in disulfide bridged dipeptide fragments formed during proteolysis of native protein. Glutamyl endopeptidase as both an immobilized enzyme and in free solution was used in these studies. It was found that extensive hydrolysis of insulin was achieved in 2 min with immobilized enzyme cartridges operated in the stopped-flow mode orders. This is orders of magnitude faster than was seen in free solution. Other advantages ranging from ease of use and reduction in sample size to the potential for automation were also noted with the immobilized enzyme cartridge. Normal free-solution proteolysis generally requires 12-24 h, based on the lower enzyme-to-substrate ratio in solution. A disturbing feature noted in these lengthy free-solution reactions was the tendency to form disulfide bridged peptide artifacts. This could lead to the erroneous conclusion that disulfide bonding in a sample was not that of the native protein. It is concluded that the advantage of immobilized enzymes over free-solution reactions will be most important in the pharmaceutical industry where proteolytic fragment "fingerprinting" of recombinant proteins is being used to confirm structure.

Expression, purification and characterization of recombinant mouse MT5-MMP protein products

We have recently identified the fifth member of the membrane-type matrix metalloproteinase subfamily, MT5-MMP/MMP24, which is expressed in a brain specific manner (Duanqing Pei (1999) J. Biol. Chem. 274, 8925-8932). To further characterize its enzymic properties, an expression construct was engineered to produce MT5-MMP as a soluble and active form by truncating its transmembrane domain. Stable expression cell lines were subsequently established from MDCK cells transfected with this construct. Unfortunately, purification of MT5-MMP from the culture media in large quantity proves to be difficult initially due to its rapid turnover via a mechanism which can be inhibited by a broad spectrum metalloproteinase inhibitor, BB94. Thus, BB94 was included in the cell culture medium and throughout the purification process except the final step of chromatography to protect MT5-MMP from destruction. Purified to homogeneity and free of the synthetic inhibitor, MT5-MMP can activate progelatinase A efficiently in a TIMP2 sensitive fashion. A preliminary screen for its potential substrates among extracellular matrix components identified the proteoglycans as the preferred substrates for MT5-MMP. Furthermore, it is determined that the stability of purified MT5-MMP is temperature dependent with rapid destruction at 37 degrees C, but being relatively stable at temperatures 4 degrees C or lower. These observations establish MT5-MMP as a proteoglycanase with a short half-life at body temperature, which may be critical for tightly controlled turnover of ECM components such as those in the brain.

Estradiol suppresses mesangial cell type I collagen synthesis via activation of the MAP kinase cascade

We have previously shown that estradiol suppresses the synthesis of type I collagen by murine mesangial cells grown in the presence of serum via activation of the transcription factor activator protein-1 (AP-1). We hypothesized that estradiol upregulates AP-1 via activation of the mitogen-activated protein (MAP) kinase cascade, a signal transduction pathway that regulates AP-1 activity. Estradiol (10(-10) to 10(-7) M) upregulated the MAP kinase pathway in murine mesangial cells grown in the presence of serum in a dose-dependent manner. Activation was evident by 1 min, peaked at 10 min, and was completely dissipated by 2 h. In contrast, estradiol had no significant effect on total (phosphorylated + unphosphorylated) p44 extracellular signal-related protein kinase (ERK) or p42 ERK. Nuclear extracts isolated from mesangial cells treated with estradiol showed increased binding to a consensus sequence AP-1 binding oligonucleotide in gel shift assays. In contrast, nuclear extracts from cells exposed to PD-98059, a highly selective inhibitor of MAP kinase-ERK kinase 1 (MEK1) and MEK2, showed reduced binding. In addition, PD-98059 antagonizes the enhanced binding induced by estradiol. Estradiol (10(-9) M) suppressed mesangial cell type I collagen synthesis (37.8 +/- 2.4%, expressed as a percentage of control values, P < 0.001 vs. control). In contrast, PD-98059 increased type I collagen synthesis (344.6 +/- 98.8, P < 0.01) and reversed the suppression of type I collagen synthesis induced by estradiol. The effects of estradiol, PD-98059, and PD-98059 plus estradiol on type I collagen protein synthesis were closely paralleled by their effects on steady-state levels of mRNA for the alpha(1) chain of type I collagen. These data suggest that estradiol suppresses type I collagen synthesis via upregulation of the MAP kinase cascade, leading to stimulation of AP-1 activity.

Alterations in chemokine mRNA expression in animals receiving portal vein immunization and renal allo- or xenotransplantation precede altered cytokine production

We have analyzed chemokine mRNA expression in graft tissue of C3H/HEJ mice receiving allogeneic (C57BL/6) or xenogeneic [Lewis (LEW) rat donors] kidney grafts and correlated this with graft survival. Since donor-specific portal vein (pv) immunization is known to increase allo- and xenograft survival, in some cases recipients also received pretransplant pv or intravenous (iv) immunization; other animals received the antioxidant N-acetylcysteine (NAc) to examine the role of ischemia/reperfusion injury in the changes observed. Graft tissue and lymph nodes draining the respective grafts were obtained at various times posttransplantation and used for quantitative polymerase chain reaction analysis of mRNAs for different chemokines. In addition, lymphocytes were restimulated in culture with donor antigen and supernatants assayed for different cytokines. We observed that early increases in mRNA for MCP-1 preceded a polarization to type 2 cytokine production. Infusion of NAc twice daily for 4 days following transplantation further altered chemokine mRNA expression (increased MCP-1 and RANTES; decreased CINC); led to more enhanced type 2 cytokine production relative to control animals; and further increased xenograft survival. By use of heteroantibodies to different chemokines, anti-MCP-1 alone, but not antibodies to MIP-1alpha or RANTES, abolished this early polarization in cytokine production, implying a causal link between MCP-1 production and polarization in cytokine production. We conclude that manipulation of chemokine production early after transplantation might indirectly modify graft outcome by modifying cytokine production.

An immunoadhesin incorporating the molecule OX-2 is a potent immunosuppressant that prolongs allo- and xenograft survival

We have established that, in mice receiving donor-specific immunization by the portal vein, the increased graft survival seen is associated with the increased expression of a molecule (OX-2) on a subpopulation of dendritic cells (DC), and polarization of cytokine production to type 2 cytokines on Ag-specific restimulation of cells from these mice. Furthermore, infusion of a mAb to OX-2 blocks both the increased graft survival and the altered cytokine production seen. We have constructed an immunoadhesin in which the extracellular domain of OX-2 is linked to the murine IgG2a Fc region, and we have expressed this molecule (OX-2:Fc) in a eukaryotic (baculovirus) expression system. Incubation of lymphocytes with 50 ng/ml OX-2:Fc inhibits a primary mixed lymphocyte reaction in vitro, as assayed by proliferation and induction of cytotoxic T cells, and also alters cytokine production with decreased IL-2 (IFN-gamma) production and increased IL-4 (IL-10) production. Similarly, in vivo infusion of OX-2:Fc promotes increased allo- and xenograft (both skin and renal grafts) survival and decreases the Ab response to sheep erythrocytes. Our data suggest this molecule might have clinical importance in allo- and xenotransplantation.

Genetic studies on a family with acute myelogenous leukemia

Seven cases of myelogenous leukemia--two acute erythroleukemia (AEL), four acute myelogenous leukemia (AML), and one acute myelomonocytic leukemia (AMMoL)--were found in 22 members of three consecutive generations of a family in the past 16 years (1973-1989). By using cytogenetic, hematologic, and biochemical analyses of those surviving in this family, we also found four members who might develop leukemia in the future. Southern blot analysis of one of the four members and her father (an acute leukemia patient) with a v-ERBB probe showed that the gene abnormalities consisted of a c-ERBB rearrangement (hereditary) and a rearrangement/amplification of the same gene.

[A clinical study on systemic inflammatory response syndrome and multiple organ dysfunction syndrome in patients with abdominal surgical emergency]

In order to analyze the development from systemic inflammatory response syndrome(SIRS) to multiple organ dysfunction syndrome (MODS) and probe the therapeutic strategies, the authors studied retrospectively the clinical data of SIRS and MODS in 1374 patients with abdominal surgical emergency. The results showed that on admission the morbidity of SIRS was 32.5%, afterwards the morbidity of MODS was 6.4%, and the mortality of the patients with SIRS was 4.8%. After 48 hours' therapy, MODS developed in 33.0% of the SIRS cases. Of all the 1374 patients, 40 developed MODS(2.9%) and 27 died (67.5%). The authors point out that the outcome of the patients with abdominal surgical emergency can be improved on condition that SIRS is early diagnosed, the cause of SIRS after 48 hours of therapy is well defined, and the body inflammatory response is properly regulated.

Estradiol suppresses type I collagen synthesis in mesangial cells via activation of activator protein-1

BACKGROUND

Estradiol suppresses the synthesis of type I collagen by murine mesangial cells. However, neither the alpha 1(I) nor the alpha 2(I) collagen gene contains an estrogen-response element. Because estradiol modulates the transcription of several genes that lack an estrogen-response element but contain a regulatory activator protein-1 (AP-1) binding motif, we hypothesized that AP-1 may mediate estradiol-induced suppression of type I collagen synthesis.

METHODS

We measured type I collagen synthesis in murine mesangial cells exposed to estradiol, phorbol 12-myristate 13-acetate (an activator of AP-1), or curcumin (an inhibitor of AP-1). We also assessed the effects of estradiol on the steady-state level of c-fos and c-jun mRNA and on the binding of mesangial cell nuclear extracts to an AP-1 consensus binding site oligonucleotide.

RESULTS

Estradiol (10(-10) M to 10(-7) M) suppressed type I collagen synthesis by murine mesangial cells in a dose-dependent manner (10(-7) M, 43.7 +/- 8.2% of control values, P < 0.001). Phorbol 12-myristate 13-acetate (10 microM, four-hr exposure) also decreased type I collagen in the media. In contrast, curcumin (1 microM) increased type I collagen. Estradiol increased the steady-state level of c-fos mRNA twofold at 30 minutes, with a return to basal levels at one hour. This was associated with a greater than threefold increase in the binding of nuclear extracts from estradiol-treated mesangial cells to an AP-1 consensus binding site oligonucleotide. Estradiol-enhanced binding of nuclear extracts to the AP-1 oligonucleotide was reversed by cycloheximide.

CONCLUSIONS

These data suggest that estradiol suppresses collagen I synthesis by murine mesangial cells via enhanced AP-1 activity.

Characterization of peroxidase:anti-peroxidase immune complexes by capillary zone electrophoresis and high-performance size-exclusion chromatography

Determination of the molecular constituents of commercial peroxidase:anti-peroxidase (PAP) preparations is necessary for the proper interpretation of PAP applications based on competitive binding assay. Capillary zone electrophoresis with field 300 V/cm, 40 cm capillary length (20 cm effective length), and high-performance size exclusion chromatography equipped with Superose 12 HR10/30 column revealed that a PAP preparation used for Fc gamma receptor studies contained multiple sizes of immune complexes, an excess amount of free peroxidase, and little or no free anti-peroxidase antibody. The antibody:antigen ratios of the three major immune complex components were 2:2, 1:2, and 1:1. These techniques provide useful methods of qualitative, as well as quantitative analysis of PAP preparations.

[Can esophagogastric anastomosis prevent gastroesophageal reflux]

OBJECTIVE

To investigate the possible anti-reflux function of esophagogastric anastomosis in the patients after receiving resection of cardiac cancer.

METHODS

One hundred and ninety-two patients were studied by video-assisted gastroscopy, manometry, 24-h pH esophageal monitoring, radioscintigraphy and scanning electron microscopy.

RESULTS

Abnormalities were found in 90.2% of patients through endoscopy. Resting pressure in esophageal body was higher than that in normal controls, and in the stomach, lower. Twenty-four hour pH monitoring demonstrated that gastroesophageal reflux (GER) did not occur when the patients slept in semi-reclining position, and occurred in all patients when slept in supine position. Scintigraphic study showed that 2/3 of the patients had reflux, occurrence of which was not affected by the length of postoperative period. Scanning electron microscopic examination showed that degeneration, exfoliation of esophageal mucosal epithelial cell, and derangement of micro-fold and inflammatory oedema of cytomembrane may be directly caused by reflux.

CONCLUSIONS

GER exists in the majority of the patients after esophagogastrectomy and esophagogastrostomy for cardiac cancer. The occurrence of GER is not affected by the length of postoperative period. Some detecting methods fail to show the existence of GER, and 24-h pH monitoring is the most reliable method for detecting GER. Sleep in semireclining position is an effective method of preventing GER in postoperative patients.

Evidence That an OX-2-Positive Cell Can Inhibit the Stimulation of Type 1 Cytokine Production by Bone Marrow-Derived B7-1 (and B7-2)-Positive Dendritic Cells

We reported that hepatic mononuclear, nonparenchymal cells (NPC) can inhibit the immune response seen when allogeneic C57BL/6 dendritic cells (DC) are incubated with C3H spleen responder cells. Cells derived from these cultures transfer increased survival of C57BL/6 renal allografts in C3H mice. We also found that increased expression of OX-2 on DC was associated with inhibition of cytokine production and renal allograft rejection. We explored whether inhibition by hepatic NPC was a function of OX-2 expression by these cells. Fresh C57BL/6 spleen-derived DC were cultured with C3H spleen responder cells and other putative coregulatory cells. The latter were derived from fresh C3H or C57BL/6 liver NPC, or from C3H or C57BL/6 mice treated for 10 days by i.v. infusion of human Flt3 ligand. Different populations of murine bone marrow-derived DC from cultures of bone marrow with IL-4 plus granulocyte-macrophage-CSF were also used as a source of putative regulator cells. Supernatants of all stimulated cultures were examined for functional expression of different cytokines (IL-2, IL-4, IFN-γ, and TGFβ). We found that fresh C57BL/6 splenic DC induced IL-2, not IL-4, production. Cells from the sources indicated inhibited IL-2 and IFN-γ production and promoted IL-4 and TGFβ production. Inhibition was associated with increased expression of OX-2 on these cells, as defined by semiquantitative PCR and FACS analysis. By size fractionation, cells expressing OX-2 were a subpopulation of NLDC145+ cells. Our data imply a role for cells expressing OX-2 in the regulation of induction of cytokine production by conventional allostimulatory DC.