Effect of bupranolol on CGP 12177-induced relaxation and cAMP accumulation in the guinea pig taenia caecum

1. The effect of bupranolol on CGP 12177-induced relaxation and cAMP accumulation in the guinea pig taenia caecum was examined. 2. The relaxant response to CGP 12177 was unaffected by propranolol (approximately 10(-6) M), whereas that to CGP 12177 was antagonized in a concentration-dependent manner by bupranolol; Schild plot of the data revealed the pA2 value of 5.61. 3. CGP 12177 significantly increased cyclic AMP level in this preparation. Bupranolol (10(-4) M) significantly decreased the cyclic AMP level that was elicited by CGP 12177, whereas propranolol (10(-5) M) produced no effect. 4. These results suggest that bupranolol appears to be an efficient beta3-antagonist in the guinea pig taenia caecum and confirm that the response to CGP 12177 is mediated by beta3-adrenoceptors.

Receptor-mediated transfer of pSV2CAT DNA to mouse liver cells using asialofetuin-labeled liposomes

Asialofetuin-labeled liposomes (AF-liposomes) were developed as a nonviral vector having high transfection activity for receptor-mediated gene transfer to hepatocytes by systemic administration. Initially, the majority of pSV2CAT, a chloramphenicol acetyltransferase (CAT) gene expression plasmid, was associated with AF-liposomes (AF-liposome-pSV2CAT), and they were injected into the portal vein of an adult mouse. Significantly high CAT activity was observed in the liver. The CAT activity in the liver was further increased two-fold by using AF-liposomes completely encapsulating pSV2CAT. Nonlabeled control liposomes, on the other hand, showed lower CAT activity in the liver than in the spleen or lung. The level of CAT mRNA reflected the CAT activity obtained by each liposome preparation in each tissue. Immunohistochemical staining showed that CAT was produced in a large number of parenchymal cells localizing in the periportal area. The plasmid encapsulated in the internal aqueous layer of the liposomes was effectively protected from environmental degradation. Thus, by administration into the blood circulation, AF-liposomes would be successfully incorporated into hepatocytes through receptor-mediated endocytosis, and the encapsulated plasmid would be transferred to the intracellular pathway.

Adhesion molecule CD18 on polymorphonuclear cells correlates to the lung injury caused by continuous infusion of endotoxin in sheep

We investigated the mechanisms of increase in the pulmonary vascular permeability, focusing on the changes in the peripheral white blood cell (WBC) counts and the surface expression of CD18 on polymorphonuclear cells (PMNs). Anesthetized sheep with chronic lung lymph fistulas were used in this study. We infused synthetic endotoxin (LPS) at a rate of 10 ng/kg/min (i.v.) continuously for 24 hr. We measured lung lymph flow, lymph-to-plasma protein concentration ratio and WBC counts in blood and lung lymph, and the PMNs' surface expression of CD18 before and at 2, 10 and 24 hr after the start of endotoxin infusion, respectively. CD18 was analyzed by flow cytometry using monoclonal anti-CD18 antibody. We found that the pulmonary vascular permeability increased during 2-4 hr after the start of endotoxin infusion, and returned to the baseline over 10 hr. At time 2 hr period, the number of WBCs in the lung lymph increased, the number of peripheral WBCs, mostly PMNs, decreased and the surface expression of CD18 on the peripheral PMNs was up-regulated. At time 10 and 24 hr, the number of WBCs in lung lymph decreased, the number of peripheral WBCs increased and CD18 expression was down-regulated. These data indicate that up-regulation of CD18 expression promotes the PMN adherence to the pulmonary endothelium, migration into the lung and increases the pulmonary vascular permeability. We conclude that the continuous endotoxin infusion up-regulates CD18, which contributes to the PMN migration into the lung.

Perimenopausal changes in serum lipids and lipoproteins: a 7-year longitudinal study

Although cross-sectional studies suggest considerable influence of menopause on serum lipids and lipoproteins in women, it is not exactly clear. During our 7-year longitudinal study, serum concentrations of total cholesterol, high-density lipoprotein (HDL) cholesterol, triglycerides and low-density lipoprotein (LDL) cholesterol were measured in 16 healthy perimenopausal women (aged 47-56 years at menopause) who had undergone annual examinations 4 years before and 3 years after menopause under a health examinations system in Osaka. Longitudinal design enabled us to study the natural course of serum lipids and lipoproteins. The results show that from 4 years before to 1 year after menopause, the serum concentration of total cholesterol and LDL cholesterol increased on average by 25 mg/dl (14%) and 20 mg/dl (19%), respectively. Serum concentrations of triglycerides and of HDL cholesterol remained virtually unchanged during the perimenopausal and postmenopausal periods. It was concluded that serum lipids and lipoproteins are thus significantly altered as a consequence of menopause, resulting in a more atherogenic profile in the postmenopausal period.

Hepatitis C virus genotypes and development of hepatocellular carcinoma

BACKGROUND

Among several genotypes of hepatitis C virus (HCV), genotypes 1b (or II) and 2a (or III) are predominant in Japan. Although it has been shown that the efficacy of interferon treatment of patients with chronic hepatitis C varies with the HCV genotype, the relationship between HCV genotype and the development of hepatocellular carcinoma (HCC) has not been well described.

METHODS

The genotypes and serum levels were determined for HCV-RNA in 72 patients with HCC and 131 patients without HCC, all of whom were positive for second-generation HCV antibody and HCV-RNA. In addition, clinical data from 34 patients with HCC who each had a history of blood transfusion were analyzed.

RESULTS

Fifty-seven (79.2%) of 72 patients with HCC had genotype 1b HCV, whereas 101 (77.1%) of 131 patients without HCC had genotype 1b, indicating that there was no significant difference in the prevalence of genotype 1b HCV between the patients with and without HCC. Furthermore, comparison of patients with HCC with genotype 1b HCV with those with genotype 2a who had a history of blood transfusion did not differ significantly in the number of years from blood transfusion to diagnosis of HCC. Levels of HCV-RNA were not significantly different among patients with liver diseases of various stages.

CONCLUSIONS

Hepatocellular carcinoma develops in patients with either genotype 2a HCV or genotype 1b HCV. A difference in genotype is not likely to be responsible for the difference in development of HCC.

Relaxation effect of an audiovisual system on dental patients. Part 2. Palus-amplitude

Dental care services include relaxation of patients to reduce their displeasure at and tension during treatment. For this purpose, it is common to use audio or audiovisual programs, that is, to let them listen to music or watch TV. However, the former utilizes only the auditory sense, and the latter is disadvantageous in that a TV set is a rather large-scale unit. In the present study, we determined the relaxation effect of an audiovisual instrument on dental patients. The instrument, which gives virtual vision, was composed of a lightweight eyeset of the snow goggle type that has a built-in TV screen, with earphone and accessories. The relaxation effect was determined using a polygraph.

Disruption of the function of tumor-suppressor gene p53 by the hepatitis B virus X protein and hepatocarcinogenesis

The X gene of the hepatitis B virus codes for a small basic protein and is able to transactivate viral and cellular genes, although the X protein exhibits no DNA-binding activity. The mechanism of transactivation by X protein has been suggested to be via protein-protein interaction(s). We first demonstrated that X protein had amino acid sequences homologous to the functionally essential domain of Kunitz-type serine protease inhibitors and that those sequences were indispensable for the transactivation function. We demonstrated that X protein exhibited an inhibitor activity against hepatic serine proteases, and subsequently found that the protein activated X gene transcription in HepG2 cells and that the X responsive element was localized in the minimal promoter of the X gene. In contrast, the tumor-suppressor gene p53, but not mutant p53, remarkably reduced transcription from the minimal promoter. This p53 repression on the X gene promoter was cancelled by X gene co-expression, probably indicating that the X protein disrupts the p53 tumor suppressor function in the nucleus. All data suggest that X protein leads to transactivation of cellular oncogenes by preventing an interaction between p53 and cellular transcription factor(s) consisting of the basal transcriptional machinery.

[Enzyme immunoassay of blood coagulation and fibrinolysis factors]

Various types of immunoassays are at present applied to inspection items in clinical aspect of blood coagulation and fibrinolysis, in which EIA is acting as one of the major methods. Commercial EIA kits, available in Japan, can be itemized into categories of blood coagulation, fibrinolysis, endothelial cell injury, and platelet activation systems, along with other types of immunoassays and enzymatic activity assays, itemized for comparison. Assay methods suitable for an objective antigen should be selected, based on its biological, biochemical characteristics, such as plasma concentrations, and even clinical demands. The matters to be solved range over making reliable standard materials, using monoclonal antibody to detect absolute concentrates of specific antigen, and then further discovery of molecular markers that specifically reflect coagulative or fibrinolytic activation, leading to thrombotic or bleeding tendency.

Chemosensitisation of spontaneous multidrug resistance by a 1,4-dihydropyridine analogue and verapamil in human glioma cell lines overexpressing MRP or MDR1

Multidrug resistance phenotypes in human tumours are associated with the overexpression of the 170 kDa P-glycoprotein encoded by the multidrug resistance 1 (MDR1) gene, and also with that of the non-P-glycoprotein-mediated multidrug resistance gene, MRP, which encodes a 190 kDa membrane ATP-binding protein. We have previously reported that overexpression of MRP appears to be responsible for spontaneous multidrug resistance in some human glioma cell lines (Abe et al., Int. J. Cancer, 58, 860-864, 1994). In this study, we investigated whether chemosensitising agents of P-glycoprotein-mediated multidrug resistance such as verapamil, a biscoclaurine alkaloid (cepharanthine), and a dihydropyridine analogue (NIK250) could also reverse multidrug resistance in human glioma cells. The glioma cell lines were the two MRP-expressing cell lines, T98G and IN500, an MDR1-expressing cell line, CCF-STTG1, and the MRP1 MDR1-non-expressing cell line, IN157. Verapamil and NIK250 almost completely reversed drug resistance to vincristine, etoposide and doxorubicin in T98G cells, while they also reversed drug resistance to vincristine and etoposide, but only partially to doxorubicin in IN500 cells. Cepharanthine as well as verapamil and NIK250 reversed vincristine resistance in CCF-STTG1 cells, but cepharanthine only partially reversed drug resistance in T98G and IN500 cells. The cellular accumulation of [3H]etoposide increased about 2- and 3-fold compared with control in T98G cells in the presence of verapamil and NIK250 respectively. Furthermore, the release of doxorubicin from the nuclei of T98G cells was blocked by NIK250. However, NIK250 and verapamil caused no apparent increase in vincristine accumulation in T98G cells. NIK250 or verapamil might exert inhibitory effects upon MRP function, resulting in a reversal of MRP-mediated spontaneous multidrug resistance in cultured human glioma cells.

Receptor-mediated transfer of pSV2CAT DNA to a human hepatoblastoma cell line HepG2 using asialofetuin-labeled cationic liposomes

Asialofetuin-labeled liposomes (AF-lps) were developed as a vector for gene transfer to hepatocytes. Plasmid pSV2CAT DNA which encodes bacterial chloramphenicol acetyltransferase (CAT) was associated with (meaning, in this report, the sum of 'to be adsorbed on the surface of' and 'to be encapsulated into the internal phase of') AF-lps (AF-lps-pSV2CAT) prepared by a tandem combination of the detergent removal and freeze-thaw methods. Ninety-six percent of input pSV2CAT was associated with AF-lps containing N-(alpha-trimethylammonioacetyl)-didodecyl-D-glutamate chloride, and approx. two-thirds of the associated DNA was encapsulated into the internal phase. The uptake of AF-lps by the cultured human hepatoblastoma cell line HepG2, having asialoglycoprotein receptors (AGPR) on their plasma membrane, was decreased by the addition of free AF and cytochalasin B. AF-lps bound to HepG2 cells through specific interaction with AGPR, and were internalized into the cells by the receptor-mediated endocytotic pathway. HepG2 cells transfected by AF-lps-pSV2CAT showed a significantly higher CAT activity than those transfected by pSV2CAT associated with non-labeled control lps (N-lps-pSV2CAT) or a mixture of pSV2CAT and empty AF-lps. Pretreatment with EDTA-encapsulated AF-lps increased the transfection efficiency of AF-lps-pSV2CAT. The CAT activity in A431 and Swiss/3T3 cells transfected with AF-lps-pSV2CAT was low and almost the same as those transfected with N-lps-pSV2CAT. Since DNA encapsulated in lps is likely to be protected against digestion by nucleases in the blood circulation, AF-lps could be used as a gene transfer vector targeting the hepatocytes in vivo.

The gene encoding human 2-oxoglutarate dehydrogenase: structural organization and mapping to chromosome 7p13-p14

Genomic clones covering the entire sequence of the gene encoding human 2-oxoglutarate dehydrogenase (OGDH) were isolated by screening leukocyte and placenta genomic libraries with radio- and digoxigenin (DIG)-labeled human OGDH cDNAs. The human OGDH gene contains 22 exons spanning approx. 85 kb. All exon/intron splice junctions follow the GT/AG rule. The results of primer extension analysis imply that the OGDH transcription start point is a thymine residue 55 bp upstream from the ATG start codon. The 5'-flanking region of OGDH lacked canonical TATA or CAAT boxes. Using DNAs from human x rodent somatic cell hybrids that segregate human chromosomes in conjunction with fluorescence in situ hybridization, human OGDH was assigned to chromosome arm 7p, an area that corresponds to the boundary between bands 7p13 and 7p14.

Establishment and structural analysis of human mAb to the E2 component of the 2-oxoglutarate dehydrogenase complex generated from a patient with primary biliary cirrhosis

We established one Epstein-Barr virus-transformed B cell hybrid clone producing human mAb of the IgG class to the 2-oxoglutarate dehydrogenase complex (OGDC) for the first time from the peripheral B lymphocytes of a patient with primary biliary cirrhosis (PBC). This mAb, designated mAbM37GO37, specifically bound to OGDC and its dissociation constant with OGDC was calculated to be 3.70 x 10(-10) mol/l. mAbM37GO37 stained murine stomach/kidney cryostat sections in a typical immunofluorescence pattern of antimitochondrial antibody (AMA). Western blotting analysis revealed that mAbM37GO37 reacted with an E2 component of OGDC but not with other components of OGDC nor pyruvate dehydrogenase complex (PDC). Furthermore, mAbM37GO37 completely inhibited the enzymatic activity of OGDC. In order to determine the structure and genetic origin of anti-OGDC autoantibody, we cloned and sequenced the Ig heavy and light chain variable regions of mAbM37GO37. This mAb used the VHIII family member, V3-7, and the V kappa IV family member. The amino acid difference between the expressed V genes of this mAb and respective putative germline genes was concentrated within the complementarity determining regions (CDR) rather than the framework regions (FR). The R:S mutation ratio was high in the CDR and low in the FR. These features suggested that the immune response to OGDC is similar to that to exogenous antigen, and that the heavy and light chain variable regions of the anti-OGDC antibody undergo somatic hypermutation through antigen-driven clonal selection. This human mAb to OGDC, which was established for the first time from a patient with PBC and characterized at the molecular level, would be a valuable tool to study the B cell autoepitopes of OGDC, to clone as yet undetermined full length cDNA encoding OGDC and to dissect the autoimmune response to mitochondrial antigens in PBC.

Purification and properties of an alkaline protease from alkalophilic Bacillus sp. KSM-K16

Alkaline protease (EC 3.4.21.14) activity, suitable for use in detergents, was detected in the alkaline culture medium of Bacillus sp. KSM-K16, which was originally isolated from soil. The enzyme, designated M protease, was purified to homogeneity from the culture broth by column chromatographies. The N-terminal amino acid sequence was Ala-Gln-Ser-Val-Pro-Trp-Gly-Ile-Ser-Arg- Val-Gln-Ala-Pro-Ala-Ala-His-Asn-Arg-Gly-Leu-Thr-Gly. The molecular mass of the protease was 28 kDa, and its isoelectric point was close to pH 10.6. Maximum activity toward casein was observed at 55 degrees C and at pH 12.3 in 50 mM phosphate/NaOH buffer. The activity was inhibited by phenylmethylsulfonyl fluoride and chymostatin. The enzyme was very stable in long-term incubation with liquid detergents at 40 degrees C. The enzyme cleaved the oxidized insulin B chain initially at Leu15-Tyr16 and efficiently at ten more sites. Among various oligopeptidyl p-nitro-anilides (pNA) tested, N-succinyl-Ala-Ala-Pro-Phe-pNA was efficiently hydrolyzed by M protease. M protease was precipitated in (NH4)2SO4-saturated acetate buffer (pH 5.0) as plank-like crystals.

Correlation between serum prolactin levels and hepatocellular tumorigenesis induced by 3'-methyl-4-dimethylaminoazobenzene in mice

Ovariectomy at 1 month of age promotes development of hepatocellular adenomatous nodules in female C57BL/6 x DS-F1 mice treated neonatally with 3'-methyl-4-dimethylaminoazobenzene (3'-Me-DAB). Implantation of oestradiol-17 beta (E2) pellets at 1 month of age suppresses nodule development. Since E2 increases serum levels of prolactin, high serum levels of prolactin in mice that have received implants of E2 pellets may play a role in the suppression of hepatocellular tumorigenesis. Therefore, to investigate the role of prolactin in hepatocellular tumorigenesis, we examined development of adenomatous nodules in female mice that had been treated neonatally with 3'-Me-DAB and had undergone ovariectomy at 1 month of age, under various serum levels of prolactin. Treatment of these mice with perphenazine (dopamine antagonist) from 6 months of age or transplantation of pituitary glands under the renal capsule at 6 months of age markedly increased serum levels of prolactin and significantly suppressed the incidence of adenomatous nodules at 12 months of age. Implantation of E2 pellets at 1 month of age increased serum levels of prolactin to a greater extent and further decreased the incidence of adenomatous nodules. Treatment of mice that had received implants of E2 pellets at 1 month of age with bromocriptine (dopamine agonist) from 6 months of age decreased serum levels of prolactin, and was accompanied by an increase in the incidence of nodules. The present results showed that an increase in serum levels of prolactin was accompanied by a decrease in incidence of liver tumours induced by 3'-Me-DAB in mice, suggesting a suppressive effect of prolactin on liver tumorigenesis in mice. Thus, it is possible that the suppressive effect of oestrogen on liver tumorigenesis in mice is mediated, at least in part, by prolactin.

CD11b blockade prevents lung injury despite neutrophil priming after gut ischemia/reperfusion

Gut ischemia/reperfusion (I/R) provokes lung injury via a mechanism that involves neutrophils [polymorphonuclear neutrophils (PMNs)]. CD11b/CD18 (alpha mB2) is the integrin receptor on PMNs critical for adhesion-dependent oxidative burst. The purpose of this study was to investigate the mechanistic role of CD11b in the process of gut I/R-induced lung injury. Sprague-Dawley rats underwent 45 minutes of superior mesenteric artery (SMA) occlusion with and without CD11b monoclonal antibody treatment (IB6) (1 mg/kg, i.v.), before SMA clamping. At 2-hour reperfusion, PMN presence in tissue was quantitated by myeloperoxidase activity and circulating PMN priming determined by the difference in superoxide production with and without N-formyl-methionyl-leucyl-phenylalanine, whereas lung leak was assessed by 125I-albumin lung/blood ratio. In sum, CD11b blockade prevented gut I/R-induced lung leak, but did not attenuate gut I/R-induced PMN priming or tissue PMN accumulation. In conclusion, gut I/R promotes PMN priming and PMN adhesion in both local and distant beds via receptors other than CD11b, but this B2 integrin receptor is critical for PMN-mediated endothelial injury.

Possible mechanisms of beta-adrenoceptor-mediated relaxation induced by noradrenaline in guinea pig taenia caecum

The mechanisms of the beta-adrenoceptor-mediated relaxation induced by noradrenaline in guinea pig taenia caecum were investigated. Noradrenaline caused graded relaxation of this preparation. However, the concentration-response curves for noradrenaline were unaffected by propranolol (approximately 10(-5) M) or phentolamine (approximately 10(-5) M). The responses to noradrenaline were antagonized in a concentration-dependent manner by bupranolol, and Schild plots of the data revealed a pA2 value of 5.53. Also, bupranolol antagonized responses to isoprenaline, and Schild plots of the data revealed the pA2 value to be 8.53. Noradrenaline significantly increased the cyclic AMP level in this preparation. Bupranolol (10(-4) M) significantly decreased the cyclic AMP response elicited by noradrenaline, whereas propranolol (10(-5) M) produced no effect. These results suggest that the relaxant response to noradrenaline in guinea pig taenia caecum is mainly mediated by beta 3-adrenoceptors (or atypical beta-adrenoceptors) and that in guinea pig taenia caecum noradrenaline behaves as a beta 3-selective adrenoceptor agonist.

Dysfunction of cGMP-mediated pulmonary vasorelaxation in endotoxin-induced acute lung injury

Endothelial-dependent and -independent cGMP-mediated mechanisms of pulmonary vasorelaxation were studied in endotoxin-induced acute lung injury in the rat. Concentration-response curves were generated (10(-9) to 10(-6) M) for acetylcholine (ACh), A23187, and sodium nitroprusside (SNP) and for 8-bromoguanosine 3',5'-cyclic monophosphate (8-BrcGMP) (10(-9) to 10(-4) M) in isolated pulmonary arterial rings preconstricted with phenylephrine 6 h after endotoxin treatment (20 mg/kg ip). Endotoxin treatment produced significantly increased lung neutrophil accumulation (myeloperoxidase assay, 28 +/- 6 units/g lung tissue vs. 1.8 +/- 1 in controls) and lung leakage (lung/blood 125I-labeled albumin ratio, 0.06 +/- 0.01 vs. 0.028 +/- 0.01 in controls) as well as histological evidence of pulmonary vascular endothelial damage. The concentration-response curves demonstrated that pulmonary vasorelaxation by mechanisms that require generation of cGMP by either endothelial-dependent (both receptor-dependent, ACh, and receptor-independent, A23187) or endothelial-independent (SNP) pathways were significantly impaired after endotoxin treatment. Relaxation by stimulation with the cGMP analogue 8-BrcGMP was not different from control. Pulmonary vascular smooth muscle is able to relax in response to cGMP after endotoxin treatment, but relaxation by endothelial-dependent and -independent pathways that require generation of cGMP is significantly impaired.

Structures of steroidal saponins from the tubers of Brodiaea californica and their inhibitory activity on tumor promoter-induced phospholipid metabolism

Phytochemical examination of the fresh tubers of Brodiaea californica resulted in the isolation of four new steroidal saponins. Their structures were determined, by extensive spectral analysis including two-dimensional (2D) NMR spectroscopy and acid-catalyzed hydrolysis, to be (25S)-spirost-5-ene-1 beta,3 beta-diol [(25S)-ryscogenin] 1-O-[O-beta-D-glucopyranosyl-(1-->3)-O-alpha-L-rhamnopyranosyl-(1-->2)- beta-D-glucopyranoside] (1), (25S)-ruscogenin 1-O-[O-beta-D-glucopyranosyl-(1-->3)-O-alpha-L-rhamnopyranosyl-(1-->2)-O -[beta-D-xylopyranosyl-(1-->3)]-beta-D-glucopyranoside] (2), the C-20 and C-22 isomer of 2 (3) and the 6'-O-acetyl derivative of 2 (4), respectively. The conformations of the tetrasaccharide moiety of 2 and 4 were inspected through molecular mechanics and molecular dynamics calculation studies, showing that the acetyl group attached to C-6 of the inner glucose was near the C-21 methyl of the aglycon in the calculated preferred conformation of 4, which must cause the downfield shift of 21-Me by 0.07 ppm in comparing the 1H-NMR of 4 with that of 2. The inhibitory activity of the isolated saponins on 12-O-tetradecanoylphorbor-13-acetate (TPA)-stimulated 32P-incorporation into phospholipids of HeLa cells was evaluated to identify new antitumor-promoter compounds.

PMNs primed for superoxide release and increased CD11b expression do not sequester in normal lung

Our previous work has implicated platelet activating factor (PAF)-induced neutrophil (PMN) priming and increased CD11b/CD18 receptor expression in the pathogenesis of lung injury following gut ischemia/reperfusion (I/R). In this model CD11b blockade abrogates lung injury but does not alter PMN priming or pulmonary leukosequestration. We, therefore, hypothesized that PAF-stimulated PMN priming and CD11b expression are insufficient to promote lung PMN sequestration. Normal rat PMNs, labeled with 51Cr, were incubated with PAF (10 ng/ml) to induce priming for superoxide (O2-) generation and enhance CD11b expression. Gut I/R animals underwent superior mesenteric artery occlusion for 45 min. 51Cr-labeled PMNs (2 x 10(7)) were injected iv. Study groups, consisting of (a) normal/control, (b) sham/laparotomy, and (c) gut I/R, were given either normal or PAF-treated PMNs. PAF-primed PMNs had increased 2- release and CD11b expression, but did not sequester in the lungs of normal rats. However, following gut I/R PAF-treated PMNs sequestered in the pulmonary bed. These data suggest that PAF priming for O2- generation and increased CD11b expression are insufficient alone to promote PMN sequestration in the lung. Rather, additional factors generated by gut I/R are necessary for this process.