Prior Removal Research Articles

Solid-Phase Extraction and Elution on Diamond (SPEED): A Fast and General Platform for Proteome Analysis with Mass Spectrometry

This paper presents a new solid-phase extraction and elution platform based on surface-functionalized diamond nanocrystallites. Compared with conventional methods, the platform facilitates purification and concentration of intact proteins and their enzymatic digests for ensuing sodium dodecyl sulfate-polyacrylamide gel electrophoresis or matrix-assisted laser desorption/ionization mass spectrometry analysis without prior removal of the adsorbent. One-pot work flow involving reduction of disulfide bonds, protection of free cysteine residues, washing off residual chemicals, and proteolytic digestion of adsorbed proteins can be performed directly on the particles. The utility and versatility of this protein workup platform were demonstrated with liquid chromatography-electrospray ionization tandem mass spectrometry in proteome analysis of human urine. The proteome analysis of each urine sample can be completed in 8 h.

Suboptimal Sphenoid and Sellar Exposure: A Consistent Finding in Patients Treated with Repeat Transsphenoidal Surgery for Residual Endocrine-inactive Macroadenomas

In a series of patients with residual endocrine-inactive macroadenomas who underwent repeat surgery, we assess possible reasons for prior subtotal removal, reoperative success, complication rates, and patient impressions. All patients were identified who had a prior subtotal removal of an endocrine-inactive macroadenoma and were reoperated on for residual sellar tumor via an endonasal approach. Over 6 years, of 188 consecutive patients with endocrine-inactive adenomas, 30 (16%) had repeat surgery (age, 15-77 yr; median interval between surgeries, 25 mo; median follow-up, 20 mo). Maximal tumor diameter averaged 2.4 +/- 0.9 cm. At reoperation, a suboptimal bony exposure was seen in all 30 patients: at the sphenoid keel, the sella, or both in 97, 93, and 90% of patients, respectively. Cavernous sinus invasion was seen in 16 (53%) patients and a fibrous/rubbery consistency in 12 (40%). Gross total tumor removal was achieved in 17 (57%) patients, including 12 of 14 (86%) with noninvasive tumors and 5 of 16 (31%) with invasive tumors, (P < 0.01). All six fibrous/rubbery but noninvasive tumors were totally removed. Of 16 patients with preoperative visual loss, 15 (94%) improved. Complications included one each of cerebrospinal fluid leak, delayed sinusitis, and new hypothyroidism. In 17 patients with prior sublabial surgery who completed questionnaires, the second (endonasal) surgery was associated with an easier recovery, less pain, and better nasal airflow in 82, 88, and 93%, respectively (P < 0.0001). In patients with residual sellar endocrine-inactive adenomas, a suboptimal opening at the sphenoid keel or sella at the first surgery and a high proportion of fibrous/rubbery tumors likely contributed to prior subtotal removal of otherwise accessible tumor. With a wider exposure, most noninvasive tumors can be totally removed, whereas invasive tumors can be effectively debulked. An endonasal reoperation is well tolerated with a low complication rate.

Suppression of natural killer cell-mediated bone marrow cell rejection by CD4+CD25+ regulatory T cells.

Naturally occurring CD4(+)CD25(+) T regulatory (Treg) cells have been shown to inhibit adaptive responses by T cells. Natural killer (NK) cells represent an important component of innate immunity in both cancer and infectious disease states. We investigated whether CD4(+)CD25(+) Treg cells could affect NK cell function in vivo by using allogeneic (full H2-disparate) bone marrow (BM) transplantation and the model of hybrid resistance, in which parental marrow grafts are rejected solely by the NK cells of irradiated (BALB/c x C57BL/6) F(1) recipients. We demonstrate that the prior removal of host Treg cells, but not CD8(+) T cells, significantly enhanced NK cell-mediated BM rejection in both models. The inhibitory role of Treg cells on NK cells was confirmed in vivo with adoptive transfer studies in which transferred CD4(+)CD25(+) cells could abrogate NK cell-mediated hybrid resistance. Anti-TGF-beta mAb treatment also increased NK cell-mediated BM graft rejection, suggesting that the NK cell suppression is exerted through TGF-beta. Thus, CD4(+)CD25(+) Treg cells can potently inhibit NK cell function in vivo, and their depletion may have therapeutic ramifications for NK cell function in BM transplantation and cancer therapy.

Glycosylation in the Fc domain of IgG increases resistance to proteolytic cleavage by papain

IgG antibodies (Abs) and fragments of IgG Abs are becoming major biotherapeutics to treat an assortment of human diseases. Commonly prepared fragments of IgGs include Fc, Fab, and F(ab′)2 fragments, all of which can be made using the sulfhydryl protease papain, although prolonged digestion times and/or excessive amounts of papain typically result in further cleavage of the Fc domain into smaller fragments. During our attempts to use papain to isolate Fc fragments from different IgG monoclonal Abs, it was observed that prior removal of Fc glycans resulted in a faster rate of papain-mediated degradation of the Fc domain. Subsequent time-course experiments comparing glycosylated and deglycosylated versions of IgG antibodies showed that the majority of molecules in a deglycosylated IgG sample were converted into Fab, Fc, and smaller Fc fragments in less than one hour, whereas the original glycosylated IgG required more than two hours to convert into a comparable amount of Fab and Fc fragments. Furthermore, whereas papain digestion converted almost all of a deglycosylated Fc fragment into smaller fragments of ∼10 and ∼12 kDa within 4 h, more than 40% of a glycosylated Fc fragment remained intact even after 24 h of digestion. These results indicate that the presence of CH 2 domain glycans in either IgGs or purified Fc fragments increases resistance to papain digestion. Increased sensitivity of non-glycosylated Fc domains to papain is consistent with the Fc domains lacking a defined structure, as exemplified by their inability to bind Fcγ receptors, since misfolded proteins are often degraded by proteases because of increased accessibility of their proteolytic cleavage sites. Based on these observations it is possible to use papain sensitivity as a means of assessing proper Fc structure of IgG molecules.

Donor Centrosome Regulation of Initial Spindle Formation in Mouse Somatic Cell Nuclear Transfer: Roles of Gamma-Tubulin and Nuclear Mitotic Apparatus Protein 11

During the process of spindle-chromosome complex depletion in the oocyte, it is unclear whether both gamma-tubulin and nuclear mitotic apparatus protein 1 (NUMA1), which are required for mitotic organization and spindle assembly, are removed. The role of the donor cell centrosome and donor nuclear NUMA1 in the initial spindle morphogenesis and chromosome remodeling also remains unclear. In the present study, we show that in the mouse, the level of gamma-tubulin in the poles and around the metaphase II spindle declines significantly, whereas only approximately 10% of NUMA1 is removed during spindle-chromosome complex depletion in the recipient oocyte. This process does not impede initial spindle morphogenesis and is regulated by the centrosome of the donor cumulus cell. Retaining the donor cell centrosome establishes a monopolar spindle, whereas prior removal of the centrosome by a narrow-bore micropipette leads to bipolar spindle formation. Our data show that the centrosome of the donor cell regulates initial spindle morphogenesis and that the donor cumulus cell NUMA1 compensates for the deficiency in recipient NUMA1 during the formation of metaphase-like structures after nuclear transfer. Full-term offspring of cloned mice were obtained after injection of donor cells only with a pipette having an inner diameter of 7-8 microm, which retained the donor cell centrosome. In contrast, removing the donor cell centrosome with a small pipette impaired preimplantation development and prevented full-term development. In conclusion, the initial spindle assembly of a metaphase-like spindle is regulated by the centrosome from the donor cell in the mouse.

Hydraulic Testing of Ordnance Components

This paper describes a range of hydraulic fatigue and pressure tests carried out on gun barrels and ordnance components in support of weapons research and development programs. Cyclic testing of representative sections of large caliber guns has been routinely carried out to determine safe fatigue life for operational use. Ultrasonic techniques have been developed for mapping multiple cracks within the gun barrels by which periodic examinations of barrels during testing have been used to build up histories of crack initiation and growth. In relatively unworn barrels multiple cracks, initiated along each rifling groove, are shown to form in an extremely stable array that can grow to several millimeters depth, in agreement with calculated stress intensity factors, before one crack accelerates to dominate final failure. The development of localized erosion from extensive firing is shown to significantly affect the subsequent hydraulic fatigue cycling by generation of only one or two cracks as well as the prior removal of heavily prestressed bore material. Tests on fume extractor sections of barrels show that cracking initiates in the jet holes and only grows to the bore at late stages. Introduction of different levels of autofrettage acts to bias the radial location of the cracks. An extensive experimental program of work has been carried out in support of design studies on mid-wall cooled gun barrels exploring a number of different configurations for construction of compound tubes and the results of numerical simulations of the assembly process have been compared with strain gauge measurements during the experimental procedure on scale tubes. Subsequent hydraulic cycling was used to determine the fatigue implications of the processing route.

Corrosion resistance of AA2219 aluminium alloy: electrochemical polarisation and impedance study

The addition of copper increases the strength of aluminium, but decreases the localised corrosion resistance of the metal to seawater as the copper containing intermetallics exhibit different electrochemical properties from the matrix. The main requirement of corrosion resistance could be met through the surface modification by removing the copper rich phase. The present work involves investigations of the influence of prior copper removal treatment on the pitting and general corrosion resistance of AA2219 alloy containing a high copper content in different initial thermal tempers. Significant improvement in the pitting and general corrosion resistance after surface copper removal treatment was evident from the results of electrochemical polarisation and the impedance tests. Attempts were also was made to modify the surface further, with a conversion layer of cerium as an alternative to the chromate coating.

New low-viscosity overlay medium for viral plaque assays

BackgroundPlaque assays in cell culture monolayers under solid or semisolid overlay media are commonly used for quantification of viruses and antiviral substances. To overcome the pitfalls of known overlays, we tested suspensions of microcrystalline cellulose Avicel RC/CL™ as overlay media in the plaque and plaque-inhibition assay of influenza viruses.ResultsSignificantly larger plaques were formed under Avicel-containing media, as compared to agar and methylcellulose (MC) overlay media. The plaque size increased with decreasing Avicel concentration, but even very diluted Avicel overlays (0.3%) ensured formation of localized plaques. Due to their low viscosity, Avicel overlays were easier to use than methylcellulose overlays, especially in the 96-well culture plates. Furthermore, Avicel overlay could be applied without prior removal of the virus inoculum thus facilitating the assay and reducing chances of cross-contamination. Using neuraminidase inhibitor oseltamivir carboxylate, we demonstrated applicability of the Avicel-based plaque reduction assay for testing of antiviral substances.ConclusionPlaque assay under Avicel-containing overlay media is easier, faster and more sensitive than assays under agar- and methylcellulose overlays. The assay can be readily performed in a 96-well plate format and seems particularly suitable for high-throughput virus titrations, serological studies and experiments on viral drug sensitivity. It may also facilitate work with highly pathogenic agents performed under hampered conditions of bio-safety labs.

Administrative Versus Clinical Data for Coronary Artery Bypass Graft Surgery Report Cards

The objective of this study was to compare the performance of a risk model for isolated coronary artery bypass graft (CABG) surgery based on administrative data with that of a clinical risk model in predicting mortality and identifying hospital performance outliers. Clinical data records from the California CABG Mortality Reporting Program for 38,230 isolated CABG patients undergoing surgery in 2000-2001 were linked to records in the California patient discharge data (PDD) abstract. Risk factors based on administrative data that mirrored clinical risk factors were developed using the condition present at admission indicator in the PDD to separate preoperative acute conditions from complications of surgery. Using logistic regression, risk model performance across data sources was compared along with hospital risk-adjusted mortality ranks and quality ratings. The administrative data showed lower prevalence of risk factors when compared with the clinical data. The clinical risk model had somewhat better discrimination (C = 0.824) than the administrative model (C = 0.799). The clinical model yielded 17 outliers and the administrative model 16 with agreement on 12 hospitals' status. Performance of the administrative risk model was minimally affected by removal of information from prior admissions and removal of risk factors not confirmed in the clinical record. Unique properties of the California administrative data, including the ability to distinguish acute preoperative risk factors from complications of surgery, permitted construction of an administrative risk model that predicts mortality on par with most published clinical models. Despite this, the administrative model identified slightly different hospital outliers, which may indicate somewhat biased assessments of hospital patient risk.

Spectroscopic studies and evanescent optical fibre wave sensing of Cu2+ based on activated mesostructured silica matrix

This paper report on the synthesis and test of eriochrome cyanine R (ECR) doped mesostructured silica films as Cu2+ sensing without prior removal of the surfactant. ECR activated mesostructured silica (via sol-gel technique) coated optical fibre core were used to Cu2+ sensing by evanescent wave method. The sol was prepared via acidic hydrolysis-condensation of tetraethoxysilane (TEOS) in the presence of cetyltrimethylammonium bromide (CTAB:C16H33NCH3Br) as the structure-directing agent. Spectrophotometric investigations using doped sol-gel thin films dip-coated on glass slides were reported. Heat treatment temperature effect (optimum temperature 150°C), absorption dependence on the pH of the aqueous phase (pH = 8 seems to be the optimal absorption pH), sensitivity, reversibility and response range (0.05 mmol/l) were reported.

Injector‐internal thermal desorption from edible oils. Part 1: Visual experiments on sample deposition on the liner wall

Injector-internal thermal desorption from edible oils or fats enables the analysis of a wide range of compounds in oils or extracts of fatty food without prior removal of the sample matrix. The oil or fat is deposited onto the wall of the injector liner. The solutes of interest are evaporated, leaving behind the sample matrix. The injector is kept at a temperature volatilizing the solutes of interest, but minimizing evaporation of the bulk material of the oil. This technique was optimized regarding sample deposition on the liner wall (Part 1) and desorption of high boiling compounds, such as migrants from food packaging materials into simulant D (olive oil) or fatty food (Part 2). The sample liquid should be transferred to the liner wall and spread to a thin film in order to facilitate the release of high boiling components. Visual experiments with perylene-containing solutions showed that the oil must be diluted to reduce the viscosity (separation from the needle tip). The oil concentration should not exceed 20% in order to rule out that squirting sample liquid drops to the bottom of the vaporizing chamber. Further dilution to about 10% oil improves spreading of the liquid to a thin film. A rather high boiling solvent should be used, such as n-butyl acetate, to prevent thermospray at the needle exit and violent evaporation from the liner wall with sputtering liquid. Using a 5-mm ID liner, 5-10-microL injections of 10-20% oil solutions were at the upper limit.

Long-term outcome of excimer laser phototherapeutic keratectomy for treatment of Salzmann's nodular degeneration

To describe the technique and evaluate the long-term success of excimer laser phototherapeutic keratectomy (PTK) for treatment of Salzmann's nodular degeneration. Department of Ophthalmology, University of Erlangen-Nürnberg, Erlangen, Germany. This retrospective study comprised 22 eyes of 14 patients who consecutively had PTK for superficial corneal opacities in Salzmann's nodular degeneration between January 1990 and November 2003. In all cases, the nodules and as much pannus tissue as possible were removed with a hockey knife. Afterward, the laser ablation (MEL 60 or 70, Carl Zeiss-Meditec) was performed with repeated application of masking fluid to remove further scar tissue and smooth the surface. Intended depth of laser ablation ranged from 10 to 100 microm (mean: 41 microm +/- 43 [SD]). In 86% of eyes, visual acuity improved after PTK, from 0.4 +/- 0.2 preoperatively to 0.7 +/- 0.3 postoperatively. The mean myopic shift was 1.5 +/- 0.7 diopters [D]. Median refractive cylinder changed from 1.0 D preoperatively to 0.7 D postoperatively. The median surface regularity index/surface asymmetry index (SRI/SAI) of the TMS-1 topography analysis system (Tomey) decreased from 2.0/1.6 preoperatively to 1.2/1.2 postoperatively. In 4 (18%) of 22 eyes, a recurrence had to be treated by repeat PTK during a mean follow-up of 2.0 +/- 1.8 years. Results indicate that PTK is an effective and safe procedure for treatment of Salzmann's nodular degeneration. Laser ablation should be combined with prior mechanical removal of nodules and excessive pannus tissue.

Remodeling of &lt;I&gt;Helicobacter pylori&lt;/I&gt; lipopolysaccharide

Modification of the lipid A domain of lipopolysaccharide (LPS) has been reported to contribute to the virulence and pathogenesis of various Gram-negative bacteria. The Kdo (3-deoxy-D-manno-octulosonic acid)-lipid A domain of Helicobacter pylori LPS shows several differences to that of Escherichia coli. It has fewer acyl chains, a reduced number of phosphate groups, much lower immunobiological activity, and only a single Kdo sugar is attached to the disaccharide backbone. However, H. pylori synthesizes a minor lipid A species resembling that of E. coli, which is both bis-phosphorylated and hexa-acylated suggesting that the major species results from the action of specific modifying enzymes. This work describes two enzymes, a lipid A phosphatase and a phosphoethanolamine transferase, involved in the periplasmic modification of the 1-position of H. pylori lipid A. Furthermore, we report a novel Kdo trimming enzyme that requires prior removal of the 1-phosphate group for enzymatic activity. Discovery of the enzymatic machinery involved in the remodeling of H. pylori LPS will help unravel the importance of these modifications in H. pylori pathogenesis.

Remodeling of Helicobacter pylori lipopolysaccharide

Modification of the lipid A domain of lipopolysaccharide (LPS) has been reported to contribute to the virulence and pathogenesis of various Gram-negative bacteria. The Kdo (3-deoxy-D- manno-octulosonic acid)—lipid A domain of Helicobacter pylori LPS shows several differences to that of Escherichia coli. It has fewer acyl chains, a reduced number of phosphate groups, much lower immunobiological activity, and only a single Kdo sugar is attached to the disaccharide backbone. However, H. pylori synthesizes a minor lipid A species resembling that of E. coli, which is both bis-phosphorylated and hexa-acylated suggesting that the major species results from the action of specific modifying enzymes. This work describes two enzymes, a lipid A phosphatase and a phosphoethanolamine transferase, involved in the periplasmic modification of the 1-position of H. pylori lipid A. Furthermore, we report a novel Kdo trimming enzyme that requires prior removal of the 1-phosphate group for enzymatic activity. Discovery of the enzymatic machinery involved in the remodeling of H. pylori LPS will help unravel the importance of these modifications in H. pylori pathogenesis.

A Novel 3-Deoxy-d-manno-Octulosonic Acid (Kdo) Hydrolase That Removes the Outer Kdo Sugar ofHelicobacter pyloriLipopolysaccharide

The lipid A domain anchors lipopolysaccharide (LPS) to the outer membrane and is typically a disaccharide of glucosamine that is both acylated and phosphorylated. The core and O-antigen carbohydrate domains are linked to the lipid A moiety through the eight-carbon sugar 3-deoxy-D-manno-octulosonic acid known as Kdo. Helicobacter pylori LPS has been characterized as having a single Kdo residue attached to lipid A, predicting in vivo a monofunctional Kdo transferase (WaaA). However, using an in vitro assay system we demonstrate that H. pylori WaaA is a bifunctional enzyme transferring two Kdo sugars to the tetra-acylated lipid A precursor lipid IV(A). In the present work we report the discovery of a Kdo hydrolase in membranes of H. pylori capable of removing the outer Kdo sugar from Kdo2-lipid A. Enzymatic removal of the Kdo group was dependent upon prior removal of the 1-phosphate group from the lipid A domain, and mass spectrometric analysis of the reaction product confirmed the enzymatic removal of a single Kdo residue by the Kdo-trimming enzyme. This is the first characterization of a Kdo hydrolase involved in the modification of gram-negative bacterial LPS.

Effect of vegetation with different evolution degree on soil organic matter in a semi-arid environment (Cabo de Gata-Níjar Natural Park, SE Spain)

The organic matter of the surface horizons of soils developed below scrub vegetation in a Mediterranean semi-arid area of great environmental interest (Cabo de Gata-Níjar Natural Park, SE Spain) has been studied. The study mainly concentrates on examining the influence of two vegetation types, one evolved (according to its successional stage), and the other clearly degraded as a result of prior removal of vegetation. In spite of the homogeneity in the results obtained from the analysis of the organic matter from the soils studied, a relationship may be established between vegetation biotype and characteristics and evolution of the soil organic matter. The evolved vegetation results in the presence in the soil of a somewhat more evolved and stable organic matter (demonstrated by certain chemical and microbiological aspects), resulting in a greater degree of humification, thus favouring the protection of the soil and the ecosystem as a whole. Hence, the presence of degraded vegetation might lead to soil degradation, something that is unsustainable in semi-arid areas that are particularly fragile in nature.

Characterisation and functional properties of Australian rice protein isolates

Albumin, globulin, glutelin and prolamin fractions were isolated from an Australian rice variety (cv. Langi) and characterised by yield, protein content and molecular weight profile using both capillary electrophoresis (SDS-CE) and sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE). The influence of pre-extraction enzymatic hydrolysis of starch and heating to 70 °C was also investigated, as was the extraction of the glutelin fraction without prior removal of the albumin and globulin fractions. Pre-extraction treatment affected mainly the albumin fraction, increasing dry matter yield but reducing protein content. SDS-CE was able to separate the protein fractions over a wider molecular weight range than SDS-PAGE, and the peaks from SDS-CE showed slightly higher molecular weight compared to equivalent bands from SDS-PAGE. The glutelin fraction extracted without prior removal of albumin and globulin fractions had different characteristics compared to those obtained by conventional extraction methods. Pre-extraction hydrolysis of starch did not significantly affect the emulsifying, foaming and gelling properties of extracted protein. Although rice glutelin had poor solubility, emulsifying and foaming properties in aqueous systems, it had good gelling properties which could be important for food applications.

Chemometric data analysis of pollutants in wastewater—a case study

In this study, chemometric techniques such as cluster analysis (CA), discriminant analysis (DA), principal component analysis (PCA) and partial least squares (PLS) were used to analyse the wastewater dataset to identify the factors which affect the composition of sewage of domestic origin, spatial and temporal variations, similarity/dissimilarity among the wastewater characteristics of cis- and trans-drains and discriminating variables. Samples collected from 24 wastewater drains in Lucknow city and from three sites on Gomti river in the month of January/February, May, August and November during the period of 5 years (1994–1999) were characterized for 32 parameters. The multivariate techniques successfully described the similarities/dissimilarities among the sewage drains on the basis of their wastewater characteristics and sources signifying the effect of routine domestic/commercial activities in respective drainage areas. Spatial and seasonal variations in wastewater composition were also determined successfully. CA generated six groups of drains on the basis of similar wastewater characteristic. PCA provided information on seasonal influence and compositional differences in sewage generated by domestic and industrial waste dominated drains and showed that drains influenced by mixed industrial effluents have high organic pollution load. DA rendered six variables (TDS, alkalinity, F, TKN, Cd and Cr) discriminating between cis- and trans-drains. PLS–DA showed dominance of Cd, Cr, NO 3, PO 4 and F in cis-drains wastewater. The results suggest that biological-process based STPs could treat wastewater both from the cis- as well as trans-drains, however, prior removal of toxic metals will be required from the cis-drains sewage. Further, seasonal variations in wastewater composition and pollution load could be the guiding factor for determining the STPs design parameters. The information generated would be useful in selection of process type and in designing of the proposed sewage treatment plants (STPs) for safe disposal of wastewater.

Impact of nano- and mesoscale particles on the performance of microcantilever-based sensors.

Microcantilever-based sensors comprise an emerging class of chemomechanical sensors. The crucial challenge for every new and promising sensing platform lies in its performance in complex mixtures. Since most biofluids are rich in particulates, we assessed the impact of particles in the liquid stream on the performance of microcantilever sensors operated in both deflection and resonance modes. For both detection modes, sensor response depends on the particle diameter, concentration, and velocity as well as the composition of a thin-film coating. The presence of particles in the fluid stream produce substantial scattering of the laser beam used to measure cantilever deflection. Thus, prior removal of particulate matter from biofluids is required for optimal performance of microcantilever-based biosensors.

Lysophosphatidic acid attenuates the cytotoxic effects and degree of peroxisome proliferator-activated receptor gamma activation induced by 15-deoxyDelta12,14-prostaglandin J2 in neuroblastoma cells.

PPARgamma (peroxisome proliferator-activated receptor gamma) is a ligand-activated transcription factor that responds to 15dPGJ2 (15-deoxy-Delta12,14-prostglandin J2). 15dPGJ2, in vitro, halts neuroblastoma cell growth, but reported mechanisms vary. Here we evaluated the modulatory effects of endogenous serum lipid mitogens upon the extent of 15dPGJ2-induced growth inhibition and on the precise cellular responses of neuroblastoma cells to PPARgamma activation. We show that 15dPGJ2 specifically inhibited cell growth in both complete and delipidated media. 15dPGJ2-induced growth inhibition was accompanied by decreased cell viability, although the effect was far more marked in delipidated medium than in complete medium. Incubation with 15dPGJ2 in complete medium resulted in cytoplasmic changes characteristic of type II programmed cell death (autophagy), while prior serum lipid removal resulted in cell death via an apoptotic mechanism. These distinct, serum lipid-dependent cellular responses to 15dPGJ2 were accompanied by increases in the expression of a reporter gene construct containing a PPAR response element of 2.3-fold in complete medium, but of 4.8-fold in delipidated medium. Restoration of the serum lysolipid LPA (lysophosphatidic acid) to cells in delipidated medium reduced 15dPGJ2-mediated PPARgamma activation, growth inhibition and cell death; following addition of S1P (sphingosine 1-phosphate), decreases were apparent but more marginal. Further, while the effects of LPA in delipidated medium were mediated through a G(i)/phosphoinositide 3-kinase/MAPK (mitogen-activated protein kinase) pathway, those of S1P did not involve the MAPK component. These data suggest that the serum lysolipid LPA modulates the degree of PPARgamma activation and the precise cellular response to 15dPGJ2 via activation of a G(i)/phosphoinositide 3-kinase/MAPK pathway.