Identification of the metabolites of n-butylidenephthalide in rat and human liver microsomes by liquid chromatography-high-resolution mass spectrometry.

n-Butylidenephthalide (NBDP) is one of the bioactive constituents originally isolated from Ligusticum chuanxiong Hort. The aim of this study was to study the metabolic profiles of NBDP in rat and human liver microsomes. NBDP was individually incubated with liver microsomes of rat and human at 37°C for 1 h and the samples incubated were analyzed by ultra-high-performance liquid chromatography combined with high-resolution mass spectrometry. The identities of the metabolites were identified by accurate masses, product ions and retention times. Under the current conditions, a total of 14 metabolites were detected and identified. M12, M13 and M14 were biosynthesized and unambiguously characterized by nuclear magnetic resonance spectroscopy. All the metabolites can be detected in rat liver microsomes, whereas in human liver microsomes, M1, M3, M4, M5, M6 and M7 were not detected. Our results demonstrated that the metabolic pathways of NBDP included hydroxylation, hydration, hydrolysis and glutathione conjugation. This study provides an overview of the metabolic profiles of NBDP in vitro, which is helpful to understand the action of this compound.

Lipopolysaccharide-stimulated activation of murine DC2.4 cells is attenuated by n-butylidenephthalide through suppression of the NF-κB pathway.

Modulation of dendritic cell (DC) fate and function may be one approach for the treatment of inflammatory and autoimmune diseases. n-Butylidenephthalide (BP), derived from Angelica sinensis, at 40 µg/ml significantly decreased the secretion of interleukin-6 and tumor necrosis factor-α by lipopolysaccharide (LPS)-stimulated activation of cultured murine DC2.4 cells (P<0.01). LPS-induced major histocompatibility complex class II (P<0.05), CD86 (P<0.01) and CD40 (P<0.01) expression on DC2.4 cells was also inhibited by BP. The endocytic capacity of LPS-stimulated DC2.4 cells was increased by BP (P<0.01). The antigen-presenting capacity of LPS-stimulated DC2.4 cells was decreased by BP (P<0.05). Moreover, we confirmed BP attenuates the responses of LPS-stimulated activation of DCs via suppression of NF-κB-dependent pathways.

Construction of an amperometric ascorbate biosensor using epoxy resin membrane bound Lagenaria siceraria fruit ascorbate oxidase.

Ascorbate oxidase purified from Lagenaria siceraria fruit was immobilized onto epoxy resin "Araldite" membrane with 79.4% retention of initial activity of free enzyme. The biosensor showed optimum response within 15s at pH 5.8 and 35°C, which was directly proportional to ascorbate concentration ranging from 1-100µM. There was a good correlation (R(2) = 0.99) between serum ascorbic acid values by standard enzymic colorimetric method and the present method. The enzyme electrode was used for 200 times without considerable loss of activity during the span of 90 days when stored at 4°C.

Ginkgolide B treatment regulated intestinal flora to improve high-fat diet induced atherosclerosis in ApoE-/- mice.

Intestinal flora plays a major role in cardiovascular diseases, like atherosclerosis (AS). Ginkgolide B (GB), a natural substance extracted from Ginkgo biloba L., is recently acknowledged as a potential therapeutic drug of AS. However, the underlying mechanism of GB is not fully clear. Thus, we evaluated whether the antiatherosclerotic effect of GB was related to alterations in gut microbial structure and if so, whether specific bacterial taxa contributed to the beneficial effects of GB. We constructed a high fat diet (HFD)-induced ApoE-/- mice model to explore the antiatherosclerotic effects of GB. The effects of GB on lipid metabolism, hypoglycemia, inflammation and gut barrier integrity were also investigated. Then HFD inventories and high throughput sequencing of the V3-V4 region of the bacterial 16S ribosomal RNA gene were used to characterize how GB modulated gut microbiome composition. We found that HFD-induced dyslipidemia, inflammation, increased atherosclerotic plaque and gut barrier dysfunction were reduced by GB treatment. Moreover, GB treatment obviously inhibited the mRNA level and protein expression of FMO3, and then decreased the concentrations of TMA and TMAO, which was related to changes of gut microbiota in HFD-fed mice. Modulation of gut microbiota, specifically the increased abundance of Bacteroides and decreased abundance of Helicobacter, might contribute to the antiatherosclerotic effects of GB. Our findings first support the therapeutic value of GB on gut microbiota manipulation in treating AS, which still need to further study.

Identification of covalent binding sites of phthalic anhydride in human hemoglobin.

Phthalic anhydride (PA) is a reactive low molecular weight compound used in the chemical industry. The exposure of PA may lead to work-related airway diseases such as rhinitis, chronic bronchitis, and asthma. The exposure gives rise to an increase in hapten-specific IgG antibodies in workers but with a low presence of specific IgE antibodies. In this study, the binding of PA to human hemoglobin (Hb) in vitro was investigated. Trypsin and Pronase E digestion, LC, LC/MS/MS, GC/MS analysis, and nanoelectrospray hybrid quadrupole time-of-flight MS were used to identify the adducted amino acids of the synthesized PA-Hb conjugates. In the conjugate with the molar ratio 1:0.1, a total of six adducted amino acids were identified. N-Terminal valine was found adducted in both the alpha- and the beta-chains as well as a total of four lysines, Val 1, Lys 16, and Lys 61 on the alpha-chain and Val 1, Lys 66, and Lys 144 on the beta-chain. Two types of lysine adducts were found, a phthalamide and a phthalimide. It was also found that PA differs in its binding site as compared to hexahydrophthalic anhydride. The result of this study suggests several interesting applications of biological monitoring.

Stereoselectivity of butylidenephthalide on non-adrenergic prejunctional voltage-dependent Ca(2+) channels in prostatic portion of rat vas deferens.

The naturally occurring and synthetic butylinenephthalide (Bdph) has two geometric isomers. Z- and E-Bdph were reported to have geometric stereoselectivity for voltage-dependent calcium channels (VDCCs) in guinea-pig ileum. The aim of this study was to investigate whether the binding of Z- and E-Bdph on prejunctional VDCCs of rat vas deferens (RVD) is stereoselective. The twitch responses to electrical field stimulation (EFS, supramaximal voltage, 1 ms, 0.2Hz) were recorded on a polygraph. Z- and E-Bdph concentration-dependently inhibited the twitch responses to EFS in full tissue, prostatic portion and epididymal portion of RVD. The pIC50 value of Z-Bdph was greater than that of E-Bdph in the electrically stimulated prostatic portion of RVD, suggesting that the binding of Bdph on the non-adrenergic prejunctional VDCCs of cell membrane is stereoselective. In the prostatic portion, exogenous Ca(2+) only partially reversed the twitch inhibition by Z-Bdph, but effectively reversed those by Ca(2+) channel blockers, such as verapamil, diltiazem and aspaminol, suggesting that the action mechanisms may be different from those of Ca(2+) channel blockers. K(+) channel blockers, such as tetraethylammonium (TEA) and 4-aminopyridine (4-AP), may prolong duration of action potential to allow greater Ca(2+) entry and induced more release of transmitters. Therefore both blockers via their prejunctional actions reversed the twitch inhibition induced by Z-Bdph in all preparations of RVD by a non-specific antagonism.

Advances in acid anhydride induced occupational asthma.

The acid anhydrides have been signal occupational agents for study because of their inherent and complex biological activity and the wide range of associated occupational airway disease that is manifest in exposed workers in a variety of occupational settings. This year in review has shed light on many of the complexities of anhydride exposure, biologic reactivity and airway disease.

Binding of the potent allergen hexahydrophthalic anhydride in the mucosa of the upper respiratory and alimentary tract following single inhalation exposures in guinea pigs and rats.

Hexahydrophthalic anhydride (HHPA; CAS No. 13149-00-3) is a highly allergenic compound commonly used in the chemical industry. Guinea pigs and rats were exposed to [3H2]HHPA by inhalation for 3-8 h and were killed at various intervals during 7 days. The tissue distribution of non-volatile and covalently bound radioactivity was studied by autoradiography. Tissue bound radioactivity was mainly found in the mucosa of the upper respiratory airways, whereas negligible levels were observed in the lungs. In addition, tissue bound radioactivity was present in the gastrointestinal tract and conjunctiva. Moreover, in the cortex of the kidneys in rats, but not in guinea pigs, a low level of tissue bound radioactivity was found. The radioactivity in the tissues persisted for at least 7 days after the end of exposure. Plasma proteins and soluble proteins from trachea, lung, and kidney from [3H2]HHPA-exposed animals were separated by gel filtration. The radioactivity in dialysed plasma was mainly found in the same fractions as albumin. The soluble proteins from trachea, lung, and kidney in both rats and guinea pigs showed a similar pattern as found in blood. The radioactivity in dialysed plasma from both guinea pigs and rats seemed to decay according to a two-compartment model. The non-extractable binding of [3H2]HHPA in the upper respiratory airways and conjunctiva may be of relevance for symptoms in workers with allergy, since they mainly develop symptoms and signs from the nose and eyes.

Exposure-response relationships in the formation of specific antibodies to hexahydrophthalic anhydride in exposed workers.

OBJECTIVES: Exposure-response relationships in the formation of specific antibodies to hexahydrophthalic anhydride (HHPA) was studied in exposed workers. METHODS: The relation between exposure to HHPA and the levels of specific immunoglobin E [(radioallergosorbent test (RAST)] and immunoglobin G (enzyme-linked immunosorbent assay) antibodies was investigated in a cross-sectional study on 95 workers from two plants using epoxy resin with HHPA as a hardener; the mean time of exposure was 7 (range 0.1-25) years. RESULTS: The specific immunoglobin E and immunoglobin G was significantly increased in exposed workers when they were compared with unexposed workers or external referents. There was no significant difference in the number of RAST positives [N = 23 (24%)] between the groups of workers exposed to < 10 micrograms.m-3, 10--< 50 micrograms.m-3, or > or = 50 micrograms.m-3. No effects were found of atopy or smoking habits on the prevalence of RAST positives. Five out of seven workers positive for immunoglobulin E in the group with the lowest exposures reported frequent short-time (minutes per day) exposures exceeding 50 micrograms.m-3. A correlation was seen between specific immunoglobulin E and G antibodies (rs = 0.5). CONCLUSIONS: The results indicate that HHPA is a sensitizing compound even at low exposure levels and that short-time peak exposures may have an impact on immunoglobulin E sensitization.

External validation of structure-biodegradation relationship (SBR) models for predicting the biodegradability of xenobiotics.

Biodegradation is an important mechanism for eliminating xenobiotics by biotransforming them into simple organic and inorganic products. Faced with the ever growing number of chemicals available on the market, structure-biodegradation relationship (SBR) and quantitative structure-biodegradation relationship (QSBR) models are increasingly used as surrogates of the biodegradation tests. Such models have great potential for a quick and cheap estimation of the biodegradation potential of chemicals. The Estimation Programs Interface (EPI) Suite™ includes different models for predicting the potential aerobic biodegradability of organic substances. They are based on different endpoints, methodologies and/or statistical approaches. Among them, Biowin 5 and 6 appeared the most robust, being derived from the largest biodegradation database with results obtained only from the Ministry of International Trade and Industry (MITI) test. The aim of this study was to assess the predictive performances of these two models from a set of 356 chemicals extracted from notification dossiers including compatible biodegradation data. Another set of molecules with no more than four carbon atoms and substituted by various heteroatoms and/or functional groups was also embodied in the validation exercise. Comparisons were made with the predictions obtained with START (Structural Alerts for Reactivity in Toxtree). Biowin 5 and Biowin 6 gave satisfactorily prediction results except for the prediction of readily degradable chemicals. A consensus model built with Biowin 1 allowed the diminution of this tendency.

Metabolic conversion from co-existing ingredient leading to significant systemic exposure of Z-butylidenephthalide, a minor ingredient in Chuanxiong Rhizoma in rats.

Pharmacokinetic (PK) study of medicinal herbs is a great challenge, because which component(s) is(are) the bioactive ingredients is largely unknown. Most of the reported PK studies of herbs focused on the major ingredients regardless of their in vivo bioactivities, while PK of components with low content in herbs is often ignored. The present study demonstrates how PK study can reveal potential importance of a low content ingredient to the herbal bioactivities using Z-butylidenephthalide (BuPh), a bioactive phthalide present in a significantly low quantity in medicinal herb Chuanxiong Rhizoma, as an example. PK of BuPh was investigated in rats using Chuanxiong extract, fraction containing BuPh and ligustilide, and pure BuPh, respectively. The results demonstrated that remarkable blood concentrations of BuPh were observed after administration of the herbal extract and its systemic exposure was significantly different between BuPh given in pure and mixed forms. More interestingly, AUC of BuPh via intake of fraction (9.3-fold) and extract (4.5-fold) was significantly greater than that obtained from pure BuPh, which was further evidenced to be mainly due to metabolic conversion from ligustilide, a major component in Chuanxiong. Our findings revealed that although it naturally occurred in low amount, BuPh reached significant systemic concentrations via metabolic conversion from ligustilide. Moreover, our results demonstrated that PK study is one of crucial and inevitable steps for revealing in vivo bioactive ingredients of herbal medicines, and such studies should be more appropriate to focus on in vivo profile of the ingredients co-existing in herbs rather than only studying them individually.

Enhanced degradation and toxicity reduction of dihexyl phthalate by Fusarium oxysporum f. sp. pisi cutinase.

AIMS: This research aims to investigate the efficiency of two lipolytic enzymes--fungal cutinase and yeast esterase--upon the biodegradation of dihexyl phthalate (DHP). METHOD AND RESULTS: During the enzymatic degradation of DHP dissolved in methanol, several degradation products were detected and their time-course changes were monitored using GC/MS. The DHP-degradation rate of cutinase was surprisingly high; i.e. almost 70% of the initial DHP (500 mg l(-1)) was decomposed within 4.5 h. Although the same amount of esterase was employed, more than 85% of the DHP remained after 3 days. Almost all the DHP was converted by cutinase into 1,3-isobenzofurandione (IBF), whereas hexyl methyl phthalate and IBF were abundantly produced by esterase. In addition, the toxicities of the DHP-degraded products by esterase were evaluated using various recombinant bioluminescent bacteria, which caused oxidative and protein damage, whereas the hydrolysis products from cutinase never caused any cellular damage in the methanol-containing reaction system. CONCLUSIONS: Cutinase starts to act as a DHP-degrader much earlier and faster than esterase, with high stability in ester-hydrolytic activity, therefore a plausible approach to the practical application of cutinase for DHP degradation in the DHP-contaminated environments may be possible. SIGNIFICANCE AND IMPACT OF THE STUDY: This study describes the enhanced degradation and detoxification of DHP using Fusarium oxysporum f. sp. pisi cutinase.

Alveolar macrophages suppress non-specific inflammation caused by inhalation challenge with trimellitic anhydride conjugated to albumin.

Occupational exposure to low molecular weight chemicals, like trimellitic anhydride (TMA), can result in occupational asthma. Alveolar macrophages (AMs) are among the first cells to encounter these inhaled compounds and were previously shown to affect TMA-induced asthma-like symptoms in the Brown Norway rat (Valstar et al., Toxicol. Appl. Pharmacology 211:20-29, 2006). TMA is a hapten that will bind to endogenous proteins upon entrance of the body. Therefore, in the present study we determined if TMA conjugated to albumin is able to induce asthma-like symptoms and if these are affected by AM depletion. Female Brown Norway rats were sensitized by dermal application of TMA or received vehicle alone on days 0 and 7. One day prior to the inhalation challenge the rats were treated intratracheally with either empty liposomes or liposomes containing clodronate (dichloromethylene diphosphonate) to specifically deplete the lungs of AMs. On day 21, all groups of rats were challenged by inhalation of TMA-BSA. Breathing frequency, tidal volume, and minute ventilation were measured before, during, within 1 h, and 24 h after challenge and the gross respiratory rate score was determined during challenge. Total and TMA-specific IgE levels were determined in serum and lung lavage fluid and parameters of inflammation and tissue damage were assessed in lung lavage fluid and/or lung tissue 24 h after challenge. Sensitization with TMA had no effect on the lung function before challenge, but TMA-BSA challenge resulted in an early asthmatic response as compared to the non-sensitized rats, irrespective of AM depletion. AM depletion had no effect on the sensitization-induced serum and lung lavage fluid IgE levels. TMA-BSA inhalation did not induce airway inflammation and tissue damage irrespective of sensitization, unless AM were depleted. Data indicate that AMs inhibit immunologically non-specific damage and inflammatory cell influx into the lungs as caused by TMA-BSA inhalation. Since effects of inhalation challenge with TMA-BSA are partly different from those of TMA, challenge with the latter is to be preferred for hazard identification.

Determination of hexahydrophthalic acid and methylhexahydrophthalic acid in plasma after derivatisation with pentafluorobenzyl bromide using gas chromatography and mass spectrometric detection.

A method for the simultaneous determination of hexahydrophthalic acid (HHP acid) and methylhexahydrophthalic acid (MHHP acid) in human plasma was developed. The procedure was a rapid, single step extractive derivatisation with pentafluorobenzyl bromide as the derivatisation agent. The formed pentafluorobenzyl esters were analysed by gas chromatography-mass spectrometry in negative ion chemical ionisation mode with ammonia as the moderating gas. Deuterium-labeled HHP acid and MHHP acid were used as internal standards. The detection limit was 0.4 ng/ml for HHP acid (m/z 153) and 0.3 ng/ml for MHHP acid (m/z 365). The within-day precision of the method was between 2 and 3% and the between-day precision was between 3 and 12%. The overall recovery was between 65 and 83%. A comparison between HHP acid determinations with a previous and this method showed that the methods gave similar results. The method was applicable for analysis of plasma from occupationally exposed workers.

Method for the biological monitoring of hexahydrophthalic anhydride by the determination of hexahydrophthalic acid in urine using gas chromatography and selected-ion monitoring.

A method for the determination of hexahydrophthalic acid, a metabolite of hexahydrophthalic anhydride, in human urine has been developed. The urine was worked-up by liquid-solid extraction, esterified with boron trifluoride-methanol, and analysed by capillary gas chromatography and selected-ion monitoring. Hexadeuterium-labelled hexahydrophthalic acid was used as the internal standard. The precision was 4% at 0.7 microgram/ml and 5% at 0.07 microgram/ml. The recovery of the acid for the overall method was 101% at 0.07 micrograms/ml of urine (with a coefficient of variation of 4%) and 95% at 0.7 microgram/ml (coefficient of variation 2%). The limit of detection was 20 ng/ml urine.

Synthesis and application of chemically reactive proteins by the reversible modification of protein amino groups with exo-cis-3,6-endo-epoxy-4,5-cis-epoxyhexahydrophthalic anhydride.

The reversible reaction of exo-cis-3,6-endo-epoxy-4,5-cis-epoxyhexahydrophthalic anhydride (EEHPA) with free protein amino groups is described. The free protein amino groups of lysozyme can be completely blocked through the reaction of the anhydride EEHPA. The chemically less reactive epoxy groups in EEHPA-modified lysozyme remain intact during modification of the protein and can be used for many subsequent chemical reactions. Hydrolysis of the modified inactive lysozyme at pH 2.5 results in deblocking and almost complete recovery of the enzymic activity of the protein. The epoxy groups in EEHPA-modified proteins have a great many potential uses: disaggregation of supramolecular structures, conversion of hydrophobic membrane proteins or tryptic peptides into water-soluble coloured proteins or peptides, inhibition of tryptic cleavage at lysine residues, synthesis of chemically reactive proteins or enzymes for affinity chromatography or immobilized-enzyme technology, two-dimensional separation techniques for complex protein mixtures, detection of specific protein-binding sites for organic substrates or tumour diagnostics, synthesis of defined artificial glycoproteins for biophysical and cytochemical studies and chemical synthesis of radioactively labelled proteins.

Mass spectrometric characterization of human hemoglobin adducts formed in vitro by hexahydrophthalic anhydride.

Primary structural information of anhydride binding to endogenous proteins is of interest in order to determine the mechanism causing the type-I allergy seen in many anhydride-exposed workers. In addition, studies on specific protein adducts may generate new methods for biological monitoring. In this study, the binding of hexahydrophthalic anhydride (HHPA) to human hemoglobin (Hb) in vitro was investigated. The in vitro synthesized conjugates were analyzed using a hybrid quadrupole-time-of-flight mass spectrometer (Q-TOF) with electrospray ionization (ESI) to determine the number of HHPA adducts per Hb molecule. Structural information on the locations of the adducts was obtained through nanospray Q-TOF, liquid chromatography-ESI mass spectrometric analysis, and gas chromatography/mass spectrometric analysis of Pronase E and tryptic digests. Up to six adducts were found on the alpha-chain and five on the beta-chain. The HHPA-adducts were localized to the N-terminal valine of the alpha- and beta-chains of Hb and to lysine residues at positions 7, 11, 16, and 40 of the alpha-chain and 8, 17, 59, 66, and 144 of the beta-chain. These results will constitute a basis for studies on structure-activity relationships as well as for development of methods for biological monitoring of acid anhydrides.

Lysine adducts between methyltetrahydrophthalic anhydride and collagen in guinea pig lung.

The formation of adducts between methyltetrahydrophthalic anhydride (MTHPA), an important industrial chemical and potent allergen, and collagen from guinea pig lung tissue was investigated. Collagen peptides were obtained from the lung tissue by homogenization, defatting, washing, and digestion with collagenase. In experiments in vitro, lung tissue was exposed to 8.4 mumol (50 microCi) of 14C MTHPA. The amount of adducts was 97 nmol MTHPA/g of wet tissue as determined from the bound radioactivity. In a study in vivo, four guinea pigs were injected intratracheally with 8.4 mumol of 14C MTHPA each. The amount of adducts was 0-1.2 nmol MTHPA/g of wet tissue (determined by bound radioactivity). N epsilon-methyltetrahydrophthaloyl-L-lysine (MTHPL) was synthesized and characterized by NMR, UV, and mass spectrometry (MS). A method to analyze MTHPL, after derivatization with methanol and pentafluorobenzoyl chloride, using gas chromatography-MS was developed. Analysis of Pronase-digested MTHPA-exposed lung tissue showed a concentration of 19 nmol MTHPL/g wet lung in vitro and between 0 and 0.15 nmol MTHPL/g wet lung in vivo. Thus, 20% in vitro and 12-15% in vivo of the bound radioactivity was found as adducts with lysine. These results are a first step toward studies of allergenic epitopes in proteins and methods for biological monitoring of exposure to acid anhydrides.

Poly(2-alkylacrylic acid) polymers deliver molecules to the cytosol by pH-sensitive disruption of endosomal vesicles.

The permeability barrier posed by cell membranes represents a challenge for the delivery of hydrophilic molecules into cells. We previously proposed that poly(2-alkylacrylic acid)s are endocytosed by cells into acidified vesicles and are there triggered by low pH to disrupt membranes and release the contents of endosomes/lysosomes to the cytosol. If this hypothesis is correct, these polymers could be valuable in drug-delivery applications. The present paper reports functional comparisons of a family of three poly(2-alkylacrylic acid)s. Poly(2-propylacrylic acid) (PPAA), poly(2-ethylacrylic acid) (PEAA) and poly(2-methylacrylic acid) (PMAA) were compared in red-blood-cell haemolysis assays and in a lipoplex (liposome-DNA complex) assay. We also directly examined the ability of these polymers to disrupt endosomes and lysosomes in cultured human cells. Our results show that: (i) unlike membrane-disruptive peptides, the endosomal-disruptive ability of poly(2-alkylacrylic acid)s cannot necessarily be predicted from their haemolytic activity at low pH, (ii) PPAA (but not PEAA or PMAA) potently facilitates gene transfection by cationic lipoplexes and (iii) endocytosed poly(2-alkylacrylic acid)s are triggered by luminal acidification to selectively disrupt endosomes (not lysosomes) and release their contents to the cytosol. These results will facilitate the rational design of future endosomal-disrupting polymers for drug delivery.

Gas transfer and blood compatibility of fluorinated polyimide membranes.

Fluorinated polyimide derived from 2,2'-bis(3,4-dicarboxyphenyl) hexafluoropropane dianhydride (6FDA) and bis[4-(4-aminophenoxy) phenyl]sulfone (APPS) was synthesized to develop a novel membrane oxygenator combining excellent gas transfer and blood compatibility. The asymmetric gas exchange membranes of 6FDA-APPS made by a dry/wet process consisted of an ultrathin and defect-free skin layer supported by a porous substructure. O2 transfer through the 6FDA-APPS membrane was extremely augmented as compared with that of the presently available membrane, poly(dimethylsiloxane), and the previously reported 6FDA-DDS membrane. Since CO2 transfer through the 6FDA-APPS membrane increased with a decrease in CO2 pressure according to dual-mode transport theory, CO2 from the membrane was selectively removed at low CO2 pressure. For the evaluation of in vitro blood compatibility, the platelet adhesion and the plasma protein adsorption on the surface of the 6FDA-APPS membrane were observed by using scanning electron microscopy and the amounts of platelet and plasma protein were determined by an amino acid analyzer. The results indicated that the fluorinated polyimide membranes showed excellent blood compatibility.