Role of rotational wave packets in strong field experiments.

Complex revival features of rotational wave packets are obtained from the interplay of a molecular rotational distribution and a measured physical observable. The analysis of the measured temporal behavior can be used to retrieve either one or both quantities. We show here the first observation of high order fractional revival (up to 1/12 in CO2) using time-of-flight measurements of ion yields leading to the information required for full reconstruction of the rotational wave packet. We further show via an analysis of higher order fractional revivals in high harmonic generation that new information on the participating ionic channels can be clearly identified, showing the general implication of our results.

Element- and enantiomer-selective visualization of molecular motion in real-time.

Ultrafast optical-domain spectroscopies allow to monitor in real time the motion of nuclei in molecules. Achieving element-selectivity had to await the advent of time resolved X-ray spectroscopy, which is now commonly carried at X-ray free electron lasers. However, detecting light element that are commonly encountered in organic molecules, remained elusive due to the need to work under vacuum. Here, we present an impulsive stimulated Raman scattering (ISRS) pump/carbon K-edge absorption probe investigation, which allowed observation of the low-frequency vibrational modes involving specific selected carbon atoms in the Ibuprofen RS dimer. Remarkably, by controlling the probe light polarization we can preferentially access the enantiomer of the dimer to which the carbon atoms belong.

Effect of oral organic nitrates on expression and activity of vascular soluble guanylyl cyclase.

BACKGROUND AND PURPOSE: The regulation of vascular soluble guanylyl cyclase (sGC) expression by nitric oxide (NO) is still under discussion. In vitro, NO has been shown to downregulate the expression of sGC but it is unclear if this mechanism is operative in vivo and occurs during nitrate treatment. EXPERIMENTAL APPROACH: We investigated whether high dose isosorbide mononitrate (ISMN) or pentaerythrityl tetranitrate (PETN) treatment changes vascular sGC expression and activity in vivo. New Zealand White rabbits received a standard diet, 2 or 200 mg ISMN kg(-1) d(-1) for 16 weeks, and C57BL/6 mice received a standard diet, 6, 60 or 300 mg PETN kg(-1) d(-1) for four weeks. Absorption was checked by measuring the plasma levels of the drug/metabolite. KEY RESULTS: Western blots of rabbit aortic rings showed similar protein levels of sGC alpha1- (P=0.2790) and beta1-subunits (P=0.6900) in all groups. Likewise, ANOVA showed that there was no difference in the expression of sGC in lungs of PETN-treated mice (P=0.0961 for alpha1 and P=0.3709 for beta1). The activities of isolated sGC in response to SNAP (1 microM-1 mM) were identical in aortae of ISMN-treated rabbits (P=0.0775) and lungs of PETN-treated mice (P=0.6348). The aortic relaxation response to SNAP slightly decreased at high ISMN but not at high PETN. CONCLUSIONS AND IMPLICATIONS: These data refute the hypothesis that therapeutic treatment with long acting NO donors has a significant impact on the regulation of vascular sGC expression and activity in vivo.

Weight gain adequacy and pregnancy outcomes in gestational diabetes: a meta-analysis.

The Institute of Medicine updated guidelines for gestational weight gain in 2009, with no special recommendations for gestational diabetes. Our objectives were to describe the prevalence of weight gain adequacy and their association with adverse pregnancy outcomes in gestational diabetes. We searched MEDLINE, EMBASE, COCHRANE and SCOPUS. We calculated the pooled prevalence of gain adequacy and relative risks for pregnancy outcomes within Institute of Medicine categories. Thirty-three studies/abstracts (88,599 women) were included. Thirty-one studies provided data on the prevalence of weight gain adequacy; it was adequate in 34% (95% CI: 29-39%) of women, insufficient in 30% (95% CI: 27-34%) and excessive in 37% (95% CI: 33-41%). Excessive gain was associated with increased risks of pharmacological treatment, hypertensive disorders of pregnancy, caesarean section, large for gestational age and macrosomic babies, compared to adequate or non-excessive gain. Weight gain below the guidance had a protective effect on large babies (RR: 0.71; 95% CI: 0.56-0.90) and macrosomia (RR 0.57; 95% CI 0.40-0.83), and did not increase the risk of small babies (RR 1.40; 95% CI 0.86-2.27). Less than recommended weight gain would be beneficial, while effective prevention of excessive gain is of utmost importance, in gestational diabetes pregnancies. Nevertheless, no ideal range for weight gain could be established.

Reporter gene recombination in juxtaglomerular granular and collecting duct cells by human renin promoter-Cre recombinase transgene.

To assess the feasibility of using the renin promoter for expressing Cre recombinase in juxtaglomerular (JG) cells only, we generated five independent transgenic mouse lines (designated hRen-Cre) expressing Cre recombinase under control of a 12.2-kb human renin promoter. In the kidneys of adult mice Cre mRNA (RT-PCR) was found in the renal cortex, with Cre protein (immunohistochemistry) being localized in afferent arterioles and to a lower degree in interlobular arteries. Cre mRNA levels were regulated in a renin-typical fashion by changes in oral salt intake, water restriction, or isoproterenol infusion, indicating the presence of key regulatory elements within 12.2 kb of the 5'-flanking region of the human renin gene. hRen-Cre mice were interbred with both the ROSA26-EGFP and ROSA26-lacZ reporter strains to assess renin promoter activity from Cre-mediated excision of a floxed stop cassette and subsequent enhanced green fluorescent protein (EGFP) and beta-galactosidase (beta-gal) detection. In adult mice, beta-gal staining and EGFP were observed in afferent arterioles and interlobular arteries, overlapping with Cre protein expression. In addition, intense beta-gal staining was found in cortical and medullary collecting ducts where Cre expression was minimal. In embryonic kidneys, beta-gal staining was detected in the developing collecting duct system beginning at embryonic day 12, showing substantial activity of the human renin promoter in the branching ureteric bud. Our data indicate that besides its well-known activity in JG cells and renal vessels the human renin promoter is transiently active in the collecting duct system during kidney development, complicating the use of this approach for JG cell-specific excision of floxed targets.

Overexpression of G protein-coupled receptor kinase-2 in smooth muscle cells attenuates mitogenic signaling via G protein-coupled and platelet-derived growth factor receptors.

BACKGROUND: Neointimal hyperplasia involves activation of smooth muscle cells (SMCs) by several G protein-coupled receptor (GPCR) agonists, including endothelin-1, angiotensin II, thrombin, and thromboxane A(2). Signaling of many GPCRs is diminished by GPCR kinase-2 (GRK2). We therefore tested whether overexpression of GRK2 in SMCs could diminish mitogenic signaling elicited by agonists implicated in the pathogenesis of neointimal hyperplasia. METHODS AND RESULTS: Overexpression of GRK2 was achieved in primary rabbit aortic SMCs with a recombinant adenovirus. Control SMCs were infected with an empty vector adenovirus. Inositol phosphate responses to endothelin-1, angiotensin II, thrombin agonist peptide, and platelet-derived growth factor (PDGF) were attenuated by 37% to 72% in GRK2-overexpressing cells (P<0.01), but the response to the thromboxane A(2) analogue U46619 was unaffected. GRK2 also inhibited SMC [(3)H]thymidine incorporation stimulated not only by these agonists (by 30% to 60%, P<0.01) but also by 10% FBS (by 35%, P<0. 05). However, GRK2 overexpression had no effect on epidermal growth factor-induced [(3)H]thymidine incorporation. Agonist-induced tyrosine phosphorylation of the PDGF-beta receptor, but not the epidermal growth factor receptor, was reduced in GRK2-overexpressing SMCs. GRK2 overexpression also reduced SMC proliferation in response to endothelin-1, PDGF, and 10% FBS by 62%, 51%, and 29%, respectively (P<0.01), without any effect on SMC apoptosis. CONCLUSIONS: GRK2 overexpression diminishes SMC mitogenic signaling and proliferation stimulated by PDGF or agonists for several GPCRs. Gene transfer of GRK2 may therefore be therapeutically useful for neointimal hyperplasia.

Chemokine-induced phosphorylation of CC chemokine receptor 5 (CCR5).

The CC-chemokine receptor 5 (CCR5) mediates activation of T lymphocytes and macrophages by chemokines and is a major co-receptor for macrophage-tropic HIV-1 strains. Recently, it was shown that the natural CCR5 ligands RANTES, macrophage inflammatory protein-1alpha (MIP-1alpha), MIP-1beta, and amino-terminal modifications of RANTES (Met-RANTES, AOP-RANTES) significantly differ in their abilities to induce sequestration of CCR5 from cellular surfaces. It was hypothesized that these findings may account for the observed differences between these molecules to inhibit HIV infectivity in vitro. Herein we review our work on early regulatory mechanisms that are initiated by ligand binding to CCR5 and that, conceptually, are involved in receptor endocytosis. A better understanding of these mechanisms may provide new therapeutic strategies to prevent HIV infection.

Characterization of physiologic breakdown products of the complement fragment Ba.

To better characterize the activation products of factor B which are generated under physiologic conditions Ba was purified directly from human EDTA-plasma by immunoaffinity chromatography using anti-Ba Sepharose. SDS-PAGE analysis revealed the existence of degradation products of the Ba fragment which were truncated at the carboxyterminus. A monoclonal antibody (mAb D22/3) was produced by immunizing mice with a synthetic peptide which corresponds to the Ba carboxyterminus (Glu215-Arg234). This mAb was found to react with an epitope (Ba neo-epitope), which is newly formed after the generation of Ba from its precursor protein factor B. This neoantigenic determinant is absent both in factor B and the desArg/Lys Ba derivatives. The conversion of Ba by carboxypeptidases in human serum was monitored using an assay which is based on mAb D22/3, revealing a half-life of Ba in serum of 150 min. Furthermore, this assay allowed to quantitate plasma levels of intact and degraded Ba in healthy probands and in patients with chronic renal failure. The processing of the Ba carboxyterminus may be of functional relevance as the biological activity of the Ba fragment which had been shown to suppress human B lymphocyte functions in vitro resides in its carboxyterminal amino acid sequence.

Proteins separated from human IgG molecules.

Immunoglobulin G binding proteins were separated from human IgG molecules using 1 N acetic acid followed by 5 M guanidinium chloride in 0.1 M acetic acid. The proteins thus obtained were heterogeneous as demonstrated by SDS-PAGE and reverse-phase HPLC. The isolated proteins consisted of two types: the C3a and C4a complement fragments (anaphylatoxins) and immunoglobulin peptide chain fragments V kappa I and C gamma 3. Both anaphylatoxins immobilized on cellulose nitrate membranes could reassociate with intact IgG molecules. The ubiquitous presence of C3a in IgG preparations was demonstrated using monoclonal antibodies specific for C3a. Nearly all of the bound anaphylatoxin molecules were found in the Fab fragment. These findings suggest that IgG molecules can eliminate anaphylatoxins from the circulation, and thus prevent harmful effects due to these active complement components.

The contrasting mechanisms of serum resistance of Neisseria gonorrhoeae and group B Neisseria meningitidis.

Neisseria gonorrhoeae and Neisseria meningitidis have evolved intricate mechanisms to evade complement-mediated killing. Sialylation of gonococcal lipooligosaccharide (LOS) results in conversion of previously serum sensitive strains to unstable serum resistance, which is mediated by factor H binding. Porin (Por) is also instrumental in mediating stable serum resistance in gonococci. The 5th loop of certain gonococcal PorlAs binds factor H, which efficiently inactivates C3b to iC3b. Factor H glycan residues may be essential for factor H binding to certain Por1A strains. Por1A strains can also regulate the classical pathway by binding to C4b-binding protein (C4bp) probably via the 1st loop of the Por molecule. Certain serum resistant Por1 B strains can also regulate complement by binding C4bp through a loop other than loop 1. Purified C4b can inhibit binding of C4bp to Por 1B, but not Por1A, suggesting different binding sites on C4bp for the two Por types. Unlike serum resistant gonococci, resistant meningococci have abundant C3b on their surface, which is only partially processed to iC3b. The main mechanism of complement evasion by group B meningococci is inhibition of membrane attack complex (MAC) insertion by their polysaccharide capsule. LOS structure may act in concert with capsule to prevent MAC insertion. Meningococcal strains with Class 3 Por preferentially bind factor H, suggesting Class 3 Por acts as a receptor for factor H.

Increase of glucose and lactate output and decrease of flow by human anaphylatoxin C3a but not C5a in perfused rat liver.

The complement fragments C3a and C5a were purified from zymosan-activated human serum by column chromatographic procedures after the bulk of the proteins had been removed by acidic polyethylene glycol precipitation. In the isolated in situ perfused rat liver C3a increased glucose and lactate output and reduced flow. Its effects were enhanced in the presence of the carboxypeptidase inhibitor DL-mercaptomethyl-3-guanidinoethylthio-propanoic acid (MERGETPA) and abolished by preincubation of the anaphylatoxin with carboxypeptidase B or with Fab fragments of an anti-C3a monoclonal antibody. The C3a effects were partially inhibited by the thromboxane antagonist BM13505. C5a had no effect. It is concluded that locally but not systemically produced C3a may play an important role in the regulation of local metabolism and hemodynamics during inflammatory processes in the liver.

Determination of the epitope specificities of monoclonal antibodies using unprocessed supernatants of hybridoma cultures.

A double monoclonal antibody (mAb) ELISA has been developed to determine the epitope specificities of murine monoclonal (mAbs). It permits the mAbs which bind to the same or adjacent epitopes to be distinguished from those which bind to separate epitopes on soluble monomeric proteins. The assay is designed for the early evaluation of mAbs in hybridoma culture supernatants when purified or labeled mAbs are not available. It does not rely on chemical or enzymatic fragmentation of the antigen and does not generate results which may be due to differences in the affinities of the mAbs. Moreover the characteristic multiple binding of polyclonal antibodies to the same epitope is also avoided. A further advantage is the accessibility of epitopes on a given antigen since the antigen is presented by a solid-phase mAb, in contrast to assays in which the antigen itself is adsorbed onto the solid phase. The test was evaluated using culture supernatants from hybridomas which produced mAbs against the complement proteins C3a, C6 or C7.

Quantitation of components of the alternative pathway of complement (APC) by enzyme-linked immunosorbent assays.

Sensitive enzyme-linked immunosorbent assays (ELISA) using monoclonal antibodies have been developed to specifically detect components of the alternative pathway of complement in human blood plasma. Normal values of the factor B split products Ba (1.01 +/- 0.30 micrograms/ml, mean +/- SD), Bb (0.65 +/- 0.23 micrograms/ml), of the C3-fragments C3b/iC3b/C3dg (17.9 +/- 5.7 micrograms/ml), native factor B (238 +/- 48 micrograms/ml), factor D (1.05 +/- 0.27 micrograms/ml), and factor H (702 +/- 292 micrograms/ml) were determined in the EDTA-plasma of healthy probands (n = 55). The simultaneous quantitation of the main cleavage products and of control proteins in the plasma samples permits precise analysis of the activation of the alternative pathway of complement in various disease states. In addition, we describe a method for the specific depletion of factor B prior to fragment-specific assays utilizing monoclonal antibodies conjugated to paramagnetic beads. The latter should permit the quantitation of other complement split products.

Association of pulmonary inflammation and increased microvascular permeability during the development of bronchopulmonary dysplasia: a sequential analysis of inflammatory mediators in respiratory fluids of high-risk preterm neonates.

OBJECTIVE: Bronchopulmonary dysplasia (BPD) of preterm neonates is associated with an increased recruitment of inflammatory cells into the airways. To evaluate further the role of inflammation in the pathogenesis of BPD, tracheobronchial aspirate fluid of neonates with birth weight < 1200 g (n = 59) was sequentially analyzed in a prospective study. METHODS: Tracheobronchial aspirate fluid was assessed for chemotactic activity, neutrophil cell count, concentrations of elastase-alpha 1-proteinase inhibitor and activity of free elastase, concentrations of chemoattractants (complement component C5-derived anaphylatoxin, leukotriene B4, interleukin-8), and albumin concentrations as well as alpha 1-proteinase inhibitor activity. The secretory component for immunoglobulin A was used as reference protein. Only specimens without evidence of microbiological colonization were studied. RESULTS: In neonates with prolonged respiratory disease (BPD-risk neonates, n = 24, fraction of inspired oxygen > or = 0.3 and/or peak inspiratory pressure > or = 16 cm H2O at day 10 postnatal age, birth weight 892 +/- 36 g, gestational age 27.2 +/- 0.3 weeks) chemotactic activity, cell count, concentrations of the chemoattractants complement component C5-derived anaphylatoxin, leukotriene B4, interleukin-8, as well as levels of elastase-alpha 1-proteinase inhibitor were significantly higher at day 10 and/or day 15 of postnatal age compared with neonates without chronic pulmonary disease (total n = 35; day 10, n = 11; day 15, n = 8). There was no difference in free elastolytic activity. Concentrations of albumin as well as alpha 1-proteinase inhibitor activity were higher in BPD-risk patients on day 15, indicating an increased pulmonary leak. CONCLUSION: We conclude that preterm neonates at risk for the development of BPD show an enhanced inflammatory reaction in the lungs and an associated increase in pulmonary microvascular permeability. We speculate that inflammation may play an important role in the pathogenesis of BPD.

Polymorphism of CC chemokine receptors CCR2 and CCR5 in Crohn's disease.

Crohn's disease (CD) is a chronic inflammatory disease of the intestine that is characterized by mononuclear cell infiltration and a predominant Th1 lymphocyte response. We tested the hypothesis that CC chemokine receptors CCR2 and CCR5 might be important in the regulation of the intestinal immune response in this disease, and we speculated that carriers of a defective 32 base pair deletion mutant of CCR5, CCR5Delta32, which results in a non-functional receptor, might be protected from CD. Using polymerase chain reaction (PCR) and PCR restriction fragment length polymorphism (PCR-RFLP) gene frequencies of CCR5Delta32 and of CCR2-641 (replacement of valine-64 by isoleucine in the CCR2 gene) in healthy controls (n=346) and in CD patients (n=235) were determined. In CD patients, subgroup phenotypic analyses were performed according to the Vienna classification. The overall gene frequency of CCR5Delta32 (9.8%) and CCR2-641 (7.6%) in CD patients did not deviate significantly from healthy controls (9.2 and 8.2%, respectively), nor did we observe a significant deviation from the predicted Hardy-Weinberg distribution. No significant differences in the CD phenotype classification for the different CCR5 and CCR2 alleles were observed, except for a trend to disease sparing of the upper gastrointestinal tract (carrier frequency 0 versus 19.6%, Delta=1 9.6%, P=0.079) as well as a more stricturing disease behaviour (23.5 versus 16.2%, Delta=7.3%, P=0.136) in carriers of the mutant CCR5Delta32 allele. These results indicate that the different CCR5 but not CCR2 alleles may influence disease behaviour and thereby contribute to the observed heterogeneity of CD. However, the associations observed are limited and await replication in other datasets. CCR2 and CCR5 polymorphisms are unlikely to be important determinants of overall disease susceptibility.

Attachment of the soluble complement regulator factor H to cell and tissue surfaces: relevance for pathology.

Complement is a central element of innate immunity and this vital defense system initiates and coordinates immediate immune reactions which attack and eliminate microbes, foreign particles and altered self cells. Newly generated activation products are extremely toxic and consequently, activation is highly restricted in terms of time and space. The initial activation of the alternative complement pathway occurs continuously and the early phase acts indiscriminatoryl and forms on any surface. However, the system discriminates between self and foreign, and therefore allows activation on foreign surfaces e.g. microbes, and restricts activation on host cells. Consequently, self cells and tissues are protected from the harmful activation products. This protection is mediated by specific regulators or inhibitors, which exist in the fluid phase and/or in membrane-bound forms. Here we review a novel mechanism, i.e. the attachment of the soluble complement regulator factor H to the surface of self cells. This attachment, which is demonstrated experimentally by means of immunofluorescense microscopy and by flow cytometry, increases the inhibitory potential at the cell surface and mediates protection by reducing the local formation of toxic inflammatory products. This attachment is highly relevant and has pathophysiological consequences in several human diseases, including Factor H-associated hemolytic uremic syndrome (FH-HUS), membrano-proliferative glomerulonephritis type II, recurrent microbial infections and chronic inflammation, e.g. rheumatoid arthritis and immune evasion of tumor cells. Defects of this safeguard activity have been recently understood in patients with FH-HUS. Point mutations in the Factor H gene occurring in the C-terminus of the protein result in impaired cell binding capacity of Factor H and, consequently, during an inflammatory insult endothelial cells are not properly protected and are damaged.

Formation of C5a during cardiopulmonary bypass: inhibition by precoating with heparin.

A novel enzyme immunoassay based on direct detection of C5a by a monoclonal antibody (C17/5) specific for a neoepitope exposed in C5a/C5adesArg was used to measure in vivo and in vitro C5a formation during cardiopulmonary bypass. In vivo, we observed a significant threefold to fourfold increase in patient plasma C5a/C5adesArg levels from baseline values (5.6; 1.6 to 12.9 ng/mL) (median and range) up to 42 hours postoperatively (17.5; 6.5 to 46.0 ng/mL) when two different uncoated cardiopulmonary bypass circuits were used. Coating of the extracorporeal circuit with end-point-attached heparin completely abolished C5a formation in vitro during circulation of blood through the circuit for 120 minutes. The C5a concentration (median and range) was 3.2 (2.6 to 15.9) ng/mL at the start and 3.1 (2.7 to 15.0) ng/mL at the end of the experiment. In the uncoated setups the corresponding C5a concentrations were 10.1 (6.2 to 17.5) and 19.7 (13.1 to 24.3) ng/mL. Finally, heparin-coated cardiopulmonary bypass circuits were examined in vivo. C5a levels did not increase significantly during the cardiopulmonary bypass period in the heparin-coated group in contrast to the uncoated group, but the postoperative increase in C5a levels was similar in the two groups. We conclude that heparin coating improves biocompatibility by completely abolishing C5a formation in vitro. The discrepancy between the in vitro and the in vivo findings is probably related to the complicated biological turnover of C5a.

C5a receptors are detectable on mast cells in normal human skin and in psoriatic plaques but not in weal and flare reactions or in uticaria pigmentosa by immunohistochemistry.

The expression of the receptor for the anaphylatoxin C5a on mast cells was studied with three monoclonal antibodies directed to the N-terminal domain of the C5a receptor. Human skin was investigated by immunohistology applied to sequential 2 micron sections of acrylate-embedded tissues. All anti-C5a receptor antibodies stained c-kit+ or tryptase+ cells which were metachromatic after toluidine blue staining in normal human skin. The binding of anti-C5a receptor antibodies was inhibitable by a peptide representing the first 31 amino acids of the C5a receptor. A similar expression of C5a receptors was found on mast cells in chronic psoriatic plaques. However, C5a receptors were not detectable on mast cells in weal and flare reactions or in lesional skin of uticaria pigmentosa. These findings suggest that (1) anti-C5a receptor antibodies directed to the N-terminal domain of the receptor are suitable tools for the identification of mast cells in acrylate-embedded sections of human skin, (2) mast cell activation in weal and flare reactions results in C5a receptor downregulation or receptor blockade and (3) mast cells in urticaria pigmentosa lack a typical marker of normal human skin mast cells.

Morphology, histology, and ultrastructure of human C31 organ-cultured corneas.

Our objective was to evaluate corneal structural modifications induced by corneal preservation in a C31 organ culture medium. Twenty-four postmortem human corneas preserved in C31 medium (CRTS, Besançon, France) for 2-21 days and 12 fresh postmortem human corneas were studied and evaluated by means of light microscopy, morphometry, and transmission electron microscopy (TEM). Endothelial cell loss during preservation averaged 9.2% (+/- 7.2%). Endothelial morphology displayed significantly more moderate alterations in the group of fresh corneas than in the group of preserved corneas. Endothelial morphometry resulted in a higher coefficient of variation (p = 0.002) in the preserved group but showed no difference for the average figure coefficient and average cell area. The histological study showed corneal swelling and epithelial sloughing in the preserved group. TEM displayed moderate preservation injuries, such as numerous vacuoles, mitochondrial swelling, and increased cell thickness. These results are consistent with previous findings that indicated that C31 medium induces moderate preservation injuries.

Plasma levels of bactericidal/permeability-increasing protein (BPI) and lipopolysaccharide-binding protein (LBP) during hemodialysis.

Several proteins modify the biological response to lipopolysaccharide (LPS). Both bactericidal/permeability-increasing factor (BPI), a protein stored in neutrophils, and the acute phase protein LPS-binding protein (LBP) bind to LPS; however, BPI inhibits while LBP enhances binding of LPS to leukocytes and subsequent induction of cytokines. We investigated plasma levels of BPI, LBP, elastase and C5a before, during and after hemodialysis (HD). Six patients were dialysed with Cuprophane (Cup) and polysulfone (PS) low-flux dialyzers on two consecutive HD sessions. There was a significant, 10.9 +/- 2.8-fold increase in BPI after 4-hour HD compared to predialysis and a 4.4 +/- 1.6-fold increase in elastase after 4-hour HD using Cup. Plasma levels of BPI and elastase decreased rapidly after the dialysis session. HD with PS resulted in a smaller, but still significant rise in BPI (3.7 +/- 1.6-fold at 4 hours) and elastase (1.69 +/- 0.2-fold at 4 hours). Levels for BPI and elastase were similar in the arterial and venous blood lines of the dialyzer. Plasma levels of LBP did not change during or after the HD session. These data indicate that BPI, but not LBP is released during HD with Cup and to a lesser extent with PS. Activation of neutrophils and release of BPI during HD may influence the biological response to bacterial products possibly introduced during HD.