Biomedical subjects

Jian Yang

Publications and source records attributed to Jian Yang.

At least 37 records · Page 2Linked to original sources

PubMed2006

Impact of waterborne copper on the structure of gills and hepatopancreas and its impact on the content of metallothionein in juvenile giant freshwater prawn Macrobrachium rosenbergii (Crustacea: Decapoda).

This study aims to elucidate both the impact of copper on the structure of the gills and hepatopancreas and the induction of metallothionein (MT) during waterborne copper exposure in juvenile Macrobrachium rosenbergii. Structural observations were performed with light microscopy, and the MT titrations were performed with the cadmium saturation assay. The structural changes that occurred in the gills and hepatopancreas appeared to result from copper accumulation, and the degree of damage observed in both tissues was relevant to the elevated waterborne copper concentration. Exposure to copper concentrations ranging from 0.01 mg/L to 0.4 mg/L for 7 days resulted in profound structural changes including the accumulation of hemocytes in the hemocoelic space; swelling and fusion of the lamellae; abnormal gill tips; and hyperplastic, necrotic, and clavate-globate lamellae in the gills. Similarly, hemocytic infiltration in the interstitial sinuses, an increased number of hemocytes, thickening and ruptures of the basal laminae, and necrosis of the tubules were observed in the hepatopancreas. The MT measurements showed no significant differences in MT contents between the control group and the group treated with 0.01 mg/L waterborne copper. The maximum MT content was observed at the level of 0.4 mg/L waterborne copper.

Animals↗

PubMed2006

Photochemotherapeutic agent 8-methoxypsoralen induces cytochrome P450 3A4 and carboxylesterase HCE2: evidence on an involvement of the pregnane X receptor.

8-Methoxypsoralen (8-MOP) is a prototype photochemotherapeutic agent and used to treat various skin disorders such as psoriasis and cutaneous T-cell lymphoma. Animal studies demonstrate that repeated treatment with 8-MOP markedly increases the capacity of drug metabolism. In this study, we report that 8-MOP is a potent inducer of cytochrome P450 3A4 (CYP3A4) and carboxylesterase 2 (HCE2), two major human enzymes that catalyze oxidative and hydrolytic reactions, respectively. In human primary hepatocytes, 8-MOP markedly induced the expression of CYP3A4 (approximately sixfold) and HCE2 (approximately threefold) and the induction occurred in a concentration-dependent manner (0-50 microM). RNA interference of the expression of the pregnane X receptor (PXR) proportionally decreased the induction. In a reporter assay, 8-MOP stimulated both CYP3A4 and HCE2 promoters, and the stimulation was enhanced by cotransfection of PXR. Several natural variants of PXR differed markedly from the wild-type receptor in responding to 8-MOP. In addition to human PXR (hPXR), 8-MOP activated rat PXR, and the activation was comparable to that of hPXR (EC(50) = approximately 14 microM). PXR is recognized as a master regulator of the genes encoding drug-metabolizing enzymes and transporters. The involvement of PXR in 8-MOP induction suggests that this chemotherapeutic agent causes a broader range of drug-drug interactions, and the differential activation of certain PXR variants suggests that the magnitude of the interactions varies from person to person.

Adult↗

PubMed2006

A single amino acid mutation attenuates rundown of voltage-gated calcium channels.

The activity of voltage-gated calcium channels (VGCCs) decreases with time in whole-cell and inside-out patch-clamp recordings. In this study we found that substituting a single amino acid (I1520) at the intracellular end of IIIS6 in the alpha(1) subunit of P/Q-type Ca(2+) channels with histidine or aspartate greatly attenuated channel rundown in inside-out patch-clamp recordings. The homologous mutations also slowed rundown of N- and L-type Ca(2+) channels, albeit to a lesser degree. In P/Q-type channels, the attenuation of rundown is accompanied by an increased apparent affinity for phosphatidylinositol-4,5-bisphosphate, which has been shown to be critical for maintaining Ca(2+) channel activity [L. Wu, C.S. Bauer, X.-G. Zhen, C. Xie, J. Yang, Dual regulation of voltage-gated calcium channels by PtdIns(4,5)P2. Nature 419 (2002) 947-952]. Furthermore, the histidine mutation significantly stabilized the open state, making the channels easier to open, slower to close, harder to inactivate and faster to recover from inactivation. Our finding that mutation of a single amino acid can greatly attenuate rundown provides an easy and efficient way to slow the rundown of VGCCs, facilitating functional studies that require direct access to the cytoplasmic side of the channel.

Amino Acid Sequence↗

PubMed2006

Rational synthesis, self-assembly, and optical properties of PbS-Au heterogeneous nanostructures via preferential deposition.

High-quality, monodisperse PbS-Au(1), PbS-Au(4), and PbS-Au(n) nanostructures have been synthesized via a facile and convenient solution chemistry approach. HRTEM images of these nanostructures showed good selectivity of gold deposition on the semiconductor in several spatially correlated directions. The formation of these regular nanostructures can be explained by the difference in polarity of crystal facets that led to the selective growth of metal on the semiconductor surface. Owing to their narrow size distribution and intrinsic high-symmetry, the resulting PbS-Au(4) and PbS-Au(n) heterogeneous nanostructures could spontaneously self-assemble into ordered arrays with different symmetries. From the results of the pump-probe measurements, the presence of Au in PbS-Au(4) nanostructures has substantially altered the nonlinear optical response of PbS nanocrystals.

Gold↗

PubMed2006

Recombinant M. smegmatis vaccine targeted delivering IL-12/GLS into macrophages can induce specific cellular immunity against M. tuberculosis in BALB/c mice.

In the present study, we constructed a viable therapeutic vaccine of recombinant M. smegmatis mediated IL-12/GLS (granulysin) gene transfer into murine macrophages to exert the immunotherapy effects on the Mycobacterium tuberculosis infection. We tested this recombinant therapeutic vaccine in an in vivo study to determine its capability of stimulating host specific immune responses against M. tuberculosis. BALB/c mice intranasally immunized with the therapeutic vaccine developed an efficient Th1 protective immune response against M. tuberculosis which was equal to that of the BCG strain. Inoculation intranasally with this viable vaccine induced high level of serum IFN-gamma, IL-12 and IgG2a. The viable vaccine was capable of inducing purified protein derivative (PPD) antigen-specific splenocytes proliferation and IFN-gamma production from T cells in spleens of the immunized mice. In addition, intranasally inoculation with the viable vaccine can induce PPD antigen-specific sIgA production in the broncho-alveolar lavage fluid (BALF) of the immunized mice. No change of IL-4 level was found in all groups. The therapeutic mechanism of this viable vaccine against M. tuberculosis infection observed here appeared to be a result of the specific Th1 immune response activated by mycobacterium antigen from M. smegmatis and the expression of sIL-12/GLS in alveolar macrophages via the M. smegmatis-mediated gene transfer method. This research demonstrates that the therapeutic gene can be introduced into a host by viable mycobacteria works to induce the host specific immune response against M. tuberculosis infection in vivo. Since this therapeutic vaccine can strongly induce specific Th1 responses against M. tuberculosis in BALB/c mice and has no obviously harmfulness to the host simultaneously, the recombinant vaccine might be a potential candidate therapeutic vaccine against tuberculosis.

Animals↗

PubMed2006

Anti-influenza prodrug oseltamivir is activated by carboxylesterase human carboxylesterase 1, and the activation is inhibited by antiplatelet agent clopidogrel.

Oseltamivir is the main medicine recommended by the World Health Organization in anticipation of next influenza pandemic. This anti-influenza viral agent is an ester prodrug, and the antiviral activity is achieved by its hydrolytic metabolite: oseltamivir carboxylate. In this study, we report that the hydrolytic activation is catalyzed by carboxylesterase human carboxylesterase (HCE) 1. Liver microsomes rapidly hydrolyzed oseltamivir, but no hydrolysis was detected with intestinal microsomes or plasma. The overall rate of the hydrolysis varied among individual liver samples and was correlated well with the level of HCE1. Recombinant HCE1 but not HCE2 hydrolyzed this prodrug and produced similar kinetic parameters as the liver microsomes. Several HCE1 natural variants differed from the wild-type enzyme on the hydrolysis of oseltamivir. In the presence of antiplatelet agent clopidogrel, the hydrolysis of oseltamivir was inhibited by as much as 90% when the equal concentration was assayed. Given the fact that hydrolysis of oseltamivir is required for its therapeutic activity, concurrent use of both drugs would inhibit the activation of oseltamivir, thus making this antiviral agent therapeutically inactive. This is epidemiologically of significance because people who receive oseltamivir and clopidogrel simultaneously may maintain susceptibility to influenza infection or a source of spreading influenza virus if already infected.

Antiviral Agents↗

PubMed2006

Antiplatelet agents aspirin and clopidogrel are hydrolyzed by distinct carboxylesterases, and clopidogrel is transesterificated in the presence of ethyl alcohol.

Aspirin (acetylsalicylic acid) and clopidogrel are two major antithrombogenic agents that are widely used for the treatment and prevention of cerebro- and cardiovascular conditions such as stroke. Combined use produces enhanced therapeutic effect. Aspirin and clopidogrel both are esters, and hydrolysis leads to decreased or inactivated therapeutic activity. The aim of the study was to determine whether aspirin and clopidogrel are hydrolyzed by the same enzyme(s), thus reciprocally prolonging the antithrombogenic activity. To test this possibility, microsomes from the liver and intestine were assayed for the hydrolysis of aspirin and clopidogrel. In contrary to the hypothesis, aspirin and clopidogrel were hydrolyzed in a tissue-differential manner. Liver microsomes hydrolyzed both drugs, whereas intestinal microsomes hydrolyzed aspirin only. Consistent with the tissue distribution of two carboxylesterases human carboxylesterase (HCE) 1 and HCE2, recombinant HCE1 hydrolyzed clopidogrel, whereas recombinant HCE2 hydrolyzed aspirin. In addition, hydrolysis of clopidogrel among liver samples was correlated well with the level of HCE1, and hydrolysis of aspirin with HCE2. Certain natural variants differed from the wild-type enzymes on the hydrolysis of aspirin or clopidogrel. In the presence of ethyl alcohol, clopidogrel is converted to ethyl clopidogrel. Carboxylesterases are important pharmacological determinants for drugs containing ester linkages and exhibit a large interindividual variation. The isoform-specific hydrolysis of aspirin and clopidogrel suggests that these two antithrombogenic agents may have pharmacokinetic interactions with different sets of ester drugs, and the altered hydrolysis by polymorphic mutants provides a molecular explanation to the interindividual variation.

Animals↗

PubMed2006

The use of comparative genomic hybridization to characterize genome dynamics and diversity among the serotypes of Shigella.

BACKGROUND: Compelling evidence indicates that Shigella species, the etiologic agents of bacillary dysentery, as well as enteroinvasive Escherichia coli, are derived from multiple origins of Escherichia coli and form a single pathovar. To further understand the genome diversity and virulence evolution of Shigella, comparative genomic hybridization microarray analysis was employed to compare the gene content of E. coli K-12 with those of 43 Shigella strains from all lineages. RESULTS: For the 43 strains subjected to CGH microarray analyses, the common backbone of the Shigella genome was estimated to contain more than 1,900 open reading frames (ORFs), with a mean number of 726 undetectable ORFs. The mosaic distribution of absent regions indicated that insertions and/or deletions have led to the highly diversified genomes of pathogenic strains. CONCLUSION: These results support the hypothesis that by gain and loss of functions, Shigella species became successful human pathogens through convergent evolution from diverse genomic backgrounds. Moreover, we also found many specific differences between different lineages, providing a window into understanding bacterial speciation and taxonomic relationships.

DNA, Bacterial↗

PubMed2006

A citric acid-based hydroxyapatite composite for orthopedic implants.

We describe a novel approach to process bioceramic microparticles and poly(diol citrates) into bioceramic-elastomer composites for potential use in orthopedic surgery. The composite consists of the biodegradable elastomer poly(1,8-octanediol-citrate) (POC) and the bioceramic hydroxyapatite (HA). The objective of this work was to characterize POC-HA composites and assess the feasibility of fabricating tissue fixation devices using machining and molding techniques. The mechanical properties of POC-HA composites with HA (40, 50, 60, 65wt.%) were within the range of values reported for tissue fixation devices (for POC-HA 65wt.%, S(b)=41.4+/-3.1, E(b)=501.7+/-40.3, S(c)=74.6+/-9.0, E(c)=448.8+/-27.0, S(t)=9.7+/-2.3, E(t)=334.8+/-73.5, S(s)=27.7+/-2.4, T(s)=27.3+/-4.9, all values in MPa). At 20 weeks, the weight loss of POC-HA composites ranged between 8 and 12wt.%, with 65wt.% HA composites degrading the slowest. Exposure of POC-HA to simulated body fluid resulted in extensive mineralization in the form of calcium phosphate with Ca/P of 1.5-1.7 similar to bone. POC-HA supported osteoblast adhesion in vitro and histology results from POC-HA samples that were implanted in rabbit knees for 6 weeks suggest that the composite is biocompatible. Synthesis of POC-HA is easy and inexpensive, does not involve harsh solvents or initiators, and the mechanical properties of POC-HA with 65wt.% HA are suitable for the fabrication of potentially osteoconductive bone screws.

Animals↗

PubMed2006

Long-period grating refractive index sensor with a modified cladding structure for large operational range and high sensitivity.

What is believed to be a novel long-period grating (LPG) refractive index sensor with a modified cladding structure is proposed and studied. In the proposed structure, the cladding of the fiber has a two-layer structure, i.e., a cladding layer of low refractive index with a reduced radius and an overlay of high refractive index. The sensitivity of the structure-modified LPG sensor to the ambient refractive index change as a function of the cladding layer and overlay parameters is investigated by way of modeling. It is found that an increase of the ambient refractive index causes a field redistribution of the cladding mode into the overlay when the parameters of the overlay are properly selected. It is shown that by reducing the radius of the cladding layer, the operational range of the LPG refractive index sensor can be as large as 0.195 (from 1.244 to 1.440) with a minimum sensitivity of 660 nm/refractive index, which represents a 31% increase of operational range in comparison with the operational range obtained from the reported structure. The design guidelines for achieving this large operation range and high sensitivity are explained by investigating the dependence of the cladding modes on the radius of the cladding layer.

Journal Article↗

PubMed2006

Development of small-molecule cyclin D1-ablative agents.

Previously, we demonstrated that the peroxisome proliferator-activated receptor gamma (PPARgamma) agonist troglitazone mediated the repression of cyclin D1 in MCF-7 breast cancer cells by facilitating proteasome-facilitated proteolysis. This PPARgamma-independent mechanism provided a molecular basis for using troglitazone as scaffold to develop a novel class of cyclin D1-ablative agents. The proof of principle of this premise is provided by Delta2TG, in which the introduction of a double bond adjacent to the thiazolidinedione ring abrogated the PPARgamma activity while retaining the activity in cyclin D1 repression. Structural optimization of Delta2TG led to STG28 [(S)-5-(4-{[6-(allyloxy)-2,5,7,8-tetramethylchroman-2-yl]methoxy}-3-methoxybenzylidene)thiazolidine-2,4-dione], which exhibited low micromolar potency in ablating cyclin D1 and inhibiting MCF-7 cell proliferation. It is noteworthy that STG28 mediated the proteasomal degradation of cyclin D1 with a high degree of specificity. Exposure to STG28 did not cause any appreciable change in the expression levels of a series of other cyclins and CDK-dependent kinases. In light of the pivotal role of cyclin D1 in promoting tumorigenesis and drug resistance, this novel cyclin D1-ablating agent may have therapeutic relevance in cancer therapy.

Antineoplastic Agents↗

PubMed2006

Novel model of inflammatory neointima formation reveals a potential role of myeloperoxidase in neointimal hyperplasia.

Atherosclerosis, which is characterized by neointima formation, is an inflammatory disease. However, there is no inflammatory product-elicited neointimal model to support the causal role of inflammation in atherogenesis. We reported previously that leukocyte-derived MPO induces vascular injury responses such as endothelial dysfunction. We now test the role of MPO in inflammatory neointima formation. We infused temporarily isolated rat common carotid arteries with MPO (200 nM) and incubated for 1 h. We found that although MPO itself did not induce any neointima formation 2 wk after treatment, in the presence of its substrate, hydrogen peroxide, MPO was able to elicit neointimal hyperplasia. We further confirmed that MPO-induced neointimal hyperplasia is mediated by its product, hypochlorous acid (HOCl). HOCl elicited apoptosis both in intima and media followed by vascular proliferative response and resulted in neointima formation with a heterogeneous cell population. Both histological and functional features of HOCl-treated vessels are similar to those in atherosclerotic lesions. To our knowledge, this is the first direct in vivo demonstration of neointimal formation induced by a product of the inflammatory cascade. The results suggest that MPO may be a mediator for pathological neointima growth. This novel neointimal model could be useful for studying inflammation and atherosclerosis.

Animals↗

PubMed2006

Complete genome sequence of Shigella flexneri 5b and comparison with Shigella flexneri 2a.

BACKGROUND: Shigella bacteria cause dysentery, which remains a significant threat to public health. Shigella flexneri is the most common species in both developing and developed countries. Five Shigella genomes have been sequenced, revealing dynamic and diverse features. To investigate the intra-species diversity of S. flexneri genomes further, we have sequenced the complete genome of S. flexneri 5b strain 8401 (abbreviated Sf8401) and compared it with S. flexneri 2a (Sf301). RESULTS: The Sf8401 chromosome is 4.5-Mb in size, a little smaller than that of Sf301, mainly because the former lacks the SHI-1 pathogenicity island (PAI). Compared with Sf301, there are 6 inversions and one translocation in Sf8401, which are probably mediated by insertion sequences (IS). There are clear differences in the known PAIs between these two genomes. The bacteriophage SfV segment remaining in SHI-O of Sf8401 is clearly larger than the remnants of bacteriophage SfII in Sf301. SHI-1 is absent from Sf8401 but a specific related protein is found next to the pheV locus. SHI-2 is involved in one intra-replichore inversion near the origin of replication, which may change the expression of iut/iuc genes. Moreover, genes related to the glycine-betaine biosynthesis pathway are present only in Sf8401 among the known Shigella genomes. CONCLUSION: Our data show that the two S. flexneri genomes are very similar, which suggests a high level of structural and functional conservation between the two serotypes. The differences reflect different selection pressures during evolution. The ancestor of S. flexneri probably acquired SHI-1 and SHI-2 before SHI-O was integrated and the serotypes diverged. SHI-1 was subsequently deleted from the S. flexneri 5b genome by recombination, but stabilized in the S. flexneri 2a genome. These events may have contributed to the differences in pathogenicity and epidemicity between the two serotypes of S. flexneri.

Chromosome Aberrations↗

PubMed2006

Energy migration study of random immobile anthracene derivatives by time-resolved fluorescence anisotropy decays.

We describe time-resolved fluorescence anisotropy measurements for a simple 2-substituted anthracene derivative (2-An-M) as a function of concentration in poly(methyl methacrylate) (PMMA) films. The anisotropy decays via energy migration among 2-An-M molecules in the matrix. The data were interpreted in terms of the survival probability of the initially excited chromophores and are in good agreement with the plot predicted using R0 = 1.8 nm, the value of the Förster radius determined independently by the spectral overlap method. For all concentrations, we found r0 = 0.20 +/- 0.01 for the initial anisotropy at time zero, whereas the residual anisotropy, r(infinity), was concentration-dependent and higher in magnitude than the theoretically predicted value, 4% of r0. The higher residual anisotropy values may originate from the possibility that not all of the anthracene molecules are involved in the energy migration process. Similar anthracene anisotropy experiments were performed on anthracene-labeled poly(isoprene-b-methyl methacrylate) (PI-PMMA). The results show an increased depolarization rate for samples containing a higher fraction of polymers labeled at the junction with anthracene chromophores.

Journal Article↗

PubMed2006

L-arginine chlorination results in the formation of a nonselective nitric-oxide synthase inhibitor.

Reduced nitric oxide (NO) bioavailability and impaired vascular function are the key pathological characteristics of inflammatory diseases such as atherosclerosis. We have recently found that leukocyte-derived hypochlorous acid is able to react with the nitric-oxide synthase (NOS) substrate L-arginine to produce chlorinated L-arginine (cl-L-Arg). Interestingly, cl-L-Arg potently inhibits the formation of NO metabolites in cultured endothelial cells. It is unknown whether cl-L-Arg has a direct inhibitory effect on endothelial NOS (eNOS). In addition, the effect of cl-L-Arg on the other NOS isoforms, neuronal NOS (nNOS) and inducible NOS (iNOS), is also unknown. Therefore, we designed the current study to test the effects of cl-L-Arg on eNOS, nNOS, and iNOS. Using recombinant NOS, we found that cl-L-Arg had a direct inhibitory effect on the activity of NOS. The effect of cl-L-Arg on NOS activity is nonselective, as all three NOS isoforms were inhibited with a similar IC(50). We further determined the effect of cl-L-Arg on the three NOS isoforms at the tissue level. The results demonstrated that cl-L-Arg potently inhibited all three NOS isoform-mediated vessel reactivities, as well as the NOS signaling molecule cGMP. Cl-L-Arg might serve as a novel endogenous NOS inhibitor and an important mediator for vascular dysfunction under inflammatory conditions such as atherosclerosis. Blocking cl-L-Arg formation may be a new therapeutic approach to cardiovascular diseases.

Animals↗

PubMed2006

Three-dimensional surface model analysis in the gastrointestinal tract.

The biomechanical changes during functional loading and unloading of the human gastrointestinal (GI) tract are not fully understood. GI function is usually studied by introducing probes in the GI lumen. Computer modeling offers a promising alternative approach in this regard, with the additional ability to predict regional stresses and strains in inaccessible locations. The tension and stress distributions in the GI tract are related to distensibility (tension-strain relationship) and smooth muscle tone. More knowledge on the tension and stress on the GI tract are needed to improve diagnosis of patients with gastrointestinal disorders. A modeling framework that can be used to integrate the physiological, anatomical and medical knowledge of the GI system has recently been developed. The 3-D anatomical model was constructed from digital images using ultrasonography, computer tomography (CT) or magnetic resonance imaging (MRI). Different mathematical algorithms were developed for surface analysis based on thin-walled structure and the finite element method was applied for the mucosa-folded three layered esophageal model analysis. The tools may be useful for studying the geometry and biomechanical properties of these organs in health and disease. These studies will serve to test the structure-function hypothesis of geometrically complex organs.

Algorithms↗

PubMed2006

The -822G/A polymorphism in the promoter region of the MAP4K5 gene is associated with reduced risk of type 2 diabetes in Chinese Hans from Shanghai.

MAP4K5 (mitogen-activated protein kinase kinase kinase kinase 5), an early component of MAP kinase signal cascades was shown to activate Jun kinase in mammalian cells. The association between SNPs of MAP4K5 and type 2 diabetes (T2DM) was investigated due to the known relationship of the JNK pathway with T2DM. A total of 1,399 cases were included in the study. Oral glucose tolerance test (OGTT) and insulin release test (IRT) were performed, and blood DNA samples were extracted and genotyped on the MAP4K5 -822G/A site. These cases were subdivided into central-obesity and nonobesity groups, based upon their individual waist circumference. Allele-specific real-time PCR was employed for genotyping. No difference was found between the two groups in the distribution of three genotypes on MAP4K5 -822G/A. In the central-obesity group, fewer diabetic patients (38.9%) were present in the AA genotype group than the GG/GA group (58.5%, P=0.024). Glucose levels after 30 and 60 min of 75 g glucose tolerance, area under the curve for glucose, and insulin secretion indexes were lower (P<0.05) in AA than those in GG/GA genotype group in the central-obesity cases. Other variables did not show significant differences between the two groups. In the Han population from Shanghai, the AA genotype of MAP4K5 -822G/A in central-obesity cases appears less likely to develop diabetes compared with the other genotypes. Therefore, the G allele may be a factor that does not protect central-obesity cases from developing into diabetes.

Adult↗

PubMed2006

Hemocompatibility evaluation of poly(glycerol-sebacate) in vitro for vascular tissue engineering.

Poly(glycerol-sebacate) (PGS) is an elastomeric biodegradable polyester that could potentially be used to engineer blood vessels in vivo. However, its blood-material interactions are unknown. The objectives of this study were to: (a) fabricate PGS-based biphasic tubular scaffolds and (b) assess the blood compatibility of PGS in vitro in order to get some insight into its potential use in vivo. PGS was incorporated into biphasic scaffolds by dip-coating glass rods with PGS pre-polymer. The thrombogenicity (platelet adhesion and aggregation) and inflammatory potential (IL-1beta and TNFalpha expression) of PGS were evaluated using fresh human blood and a human monocyte cell line (THP-1). The activation of the clotting system was assessed via measurement of tissue factor expression on THP-1 cells, plasma recalcification times, and whole blood clotting times. Glass, tissue culture plastic (TCP), poly(l-lactide-co-glycolide) (PLGA), and expanded polytetrafluorethylene (ePTFE) were used as reference materials. Biphasic scaffolds with PGS as the blood-contacting surface were successfully fabricated. Relative to glass (100%), platelet attachment on ePTFE, PLGA and PGS was 61%, 100%, and 28%, respectively. PGS elicited a significantly lower release of IL-1beta and TNFalpha from THP-1 cells than ePTFE and PLGA. Similarly, relative to all reference materials, tissue factor expression by THP-1 cells was decreased when exposed to PGS. Plasma recalcification and whole blood clotting profiles of PGS were comparable to or better than those of the reference polymers tested.

Biocompatible Materials↗