[The efficacy and safety of ticagrelor versus clopidogrel in elderly patients with acute coronary syndrome undergoing percutaneous coronary intervention]

Objective: To compare the efficacy and safety of ticagrelor and clopidogrel in elderly Chinese patients with acute coronary syndrome (ACS) underwent percutaneous coronary intervention (PCI) in the real world. Methods: This study is a post-hoc analysis of a single center, retrospective cohort study. Between March 2016 and March 2018, elderly (age≥65) ACS patients who underwent PCI in the General Hospital of Northern Theater Command were included in the study. The patients were grouped according to P2Y₁₂ receptor inhibitor. The primary endpoints of this study were ischemic events during the 2-year follow-up, which were defined as the composite of cardiac death, myocardial or stroke. The secondary efficiency endpoints included all-cause death and BARC 2, 3, 5 bleeding events. Results: A total of 4 022 elderly (mean age: (71.5±5.3) years) ACS patients were included in this study. Based on the choice of P2Y₁₂ receptor inhibitor, patients were divided into clopidogrel (n=3 201) and ticagrelor (n=821) groups. Incidences of ischemic events (3.2% (26/821) vs. 5.6% (179/3 201), P=0.005) at 2 years were significantly lower in ticagrelor group compared to clopidogrel group. BARC 2, 3, 5 bleeding events (1.7% (14/821) vs. 1.6% (52/3 201), P=0.818) were comparable between the two groups. The incidence of all-cause death (1.5% (12/821) vs. 4.1% (132/3 201), P=0.005) were also lower in the ticagrelor group compared to the clopidogrel group. Clinical outcomes were consistent after adjusting for confounding factors, the incidence of ischemic events (HR= 0.637, 95%CI 0.409-0.991, P=0.046) and all-cause mortality (HR=0.402, 95%CI 0.213-0.758, P=0.005) was significantly lower in the ticagrelor group compared with the clopidogrel group. Risk of BARC 2, 3, 5 bleeding events were similar between the two groups (HR=0.957, 95%CI 0.496-1.848, P=0.897). Conclusion: In real-world clinical practice, for elderly patients with ACS undergoing PCI, ticagrelor use might reduce the incidence of long-term ischemic events and all-cause death without increasing the risk of bleeding.

[Five-year clinical outcomes of the second generation biodegradable polymer sirolimus-eluting stent (EXCROSSAL) in treating patients with de novo coronary lesions]

Objective: To evaluate the five-year safety and efficacy of the second generation biodegradable polymer sirolimus-eluting stent (EXCROSSAL) in treating patients with de novo coronary artery diseases. Methods: Patients with coronary artery disease (CAD)who were implanted with EXTROSSAL stents in CREDIT Ⅱ and CREDIT Ⅲ study were included. CREDIT Ⅱ was a randomized trial, and CREDIT Ⅲ was a single-arm study. From November 2013 to December 2014, 833 CAD patients with de novo coronary lesions implanted with EXTROSSAL stents were selected from 33 centers in China. The primary outcome was 5-year target lesion failure (TLF), a composite of cardiac death, target vessel myocardial infarction and clinically indicated target lesion revascularization. Secondary endpoints was patient-oriented composite endpoint (PoCE), including all-cause death, all myocardial infarction, or any revascularization within 5 years post stenting and stent thrombosis according to Academic Research Consortium's (ARC) definition. Kaplan Meier method was used to calculate the incidence of TLF and PoCE within 5 years after operation. Univariate Cox regression analysis was used to analyze the impacts of diabetes, small vessel disease (vessel diameter ≤ 2.74 mm), lesion length ≥ 16.7 mm and multivessel disease on the incidence of TLF within 5 years after operation. Results: A total of 833 patients were included in this study including 579 males (69.5%), the age was (59.3±9.1) years. And 832 (99.9%) patients completed 5-year clinical follow-up. The incidence of TLF and PoCE in the 5-year follow-up were 10.6%(86/811) and 15.5%(126/811), respectively. Stent thrombosis occurred in 1.0%(8/811) of patients. Univariate Cox regression analysis showed that vessel diameter ≤ 2.74 mm (HR=3.20,95%CI 1.90-5.39,P<0.001), lesion length ≥ 16.7 mm (HR=1.88,95%CI 1.18-2.99,P=0.007) and multivessel disease (HR=2.44,95%CI 1.60-3.72,P<0.001) were related factors of TLF within 5 years after operation. Conclusion: EXCROSSAL stent is effective and safe in treating CAD patients with de novo coronary lesions, with low incidence of TLF and PoCE within 5 years after operation.

Inflammatory marker and aryl hydrocarbon receptor-dependent responses in human macrophages exposed to emissions from biodiesel fuels

Biodiesel or renewable diesel fuels are alternative fuels produced from vegetable oil and animal tallow that are being considered to help reduce the use of petroleum-based fuels and emissions of air pollutants including greenhouse gases. Here, we analyzed the gene expression of inflammatory marker responses and the cytochrome P450 1A1 (CYP1A1) enzyme after exposure to diesel and biodiesel emission samples generated from an in-use heavy-duty diesel vehicle. Particulate emission samples from petroleum-based California Air Resource Board (CARB)-certified ultralow sulfur diesel (CARB ULSD), biodiesel, and renewable hydro-treated diesel all induced inflammatory markers such as cyclooxygenase-2 (COX)-2 and interleukin (IL)-8 in human U937-derived macrophages and the expression of the xenobiotic metabolizing enzyme CYP1A1. Furthermore, the results indicate that the particle emissions from CARB ULSD and the alternative diesel fuel blends activate the aryl hydrocarbon receptor (AhR) and induce CYP1A1 in a dose- and AhR-dependent manner which was supported by the AhR luciferase reporter assay and gel shift analysis. Based on a per mile emissions with the model year 2000 heavy duty vehicle tested, the effects of the alternative diesel fuel blends emissions on the expression on inflammatory markers like IL-8 and COX-2 tend to be lower than emission samples derived from CARB ULSD fuel. The results will help to assess the potential benefits and toxicity from biofuel use as alternative fuels in modern technology diesel engines.

Bone marrow-derived clonal mesenchymal stem cells inhibit ovalbumin-induced atopic dermatitis

Mesenchymal stem cells (MSCs) possess immunomodulatory activities, including suppression of T- and B-cell activation. However, their effects on atopic dermatitis (AD) have not yet been studied. Using an ovalbumin-induced AD mouse model, we investigated whether MSCs can be used as therapeutics in AD. We isolated both allogeneic and syngeneic clonal MSCs (cMSCs) from mouse bone marrow according to the subfractionation culturing method. Our cMSCs suppressed both T- and B-cell activation. T-cell proliferation and cytokine production, including interferon (IFN)-γ and interleukin (IL)-4, were suppressed by inhibition of transcription factors, such as T-bet, GATA-3, and c-Maf. Those transcription factors were nitric oxide dependent. Immunoglobulin E (IgE) suppression occurred through downregulation of AID and BLIMP-1, important regulators for isotype class switch and B-cell differentiation. The cMSCs were injected intravenously into ovalbumin-induced AD mouse model, and the therapeutic effects were analyzed. Injection of both allogeneic and syngeneic cMSCs in an AD mouse model inhibited cell infiltration in skin lesions and decreased the serum level of IgE. IL-4 expression was also suppressed by cMSCs in both the lymph node and skin. The cMSCs migrated to skin lesions and draining lymph nodes. Taken together, these data demonstrated that cMSCs, which suppressed T- and B-cell functions, can be used for the treatment of AD in mice.

Porcine feasibility and safety study of a new paclitaxel-eluting biliary stent with a Pluronic-containing membrane

BACKGROUND AND STUDY AIM

Metal stents for malignant biliary obstruction are susceptible to occlusion by tumor ingrowth or overgrowth. Therefore, we previously reported our use of a metal stent covered with a paclitaxel-incorporated membrane giving an antitumor effect to prevent occlusion from tumor ingrowth. We have also developed a new generation of paclitaxel-eluting biliary stent using a membrane containing Pluronic F-127 for effective drug delivery. The aim of this study was to investigate the safety and efficacy of drug delivery for this newly developed stent in the biliary tract.

METHODS

Metal stents were coated with paclitaxel and various concentrations of Pluronic F-127 in phosphate-buffered saline solution. Stents containing varying concentrations were placed in the bile ducts of eight pigs divided as follows: group I, 0% Pluronic + 0% paclitaxel; group II, 0% Pluronic + 10% paclitaxel; group III, 10% Pluronic + 10% paclitaxel; group IV, 20% Pluronic + 10% paclitaxel. The histology of the porcine bile duct and the amount of paclitaxel in the porcine serum were examined. The amount of paclitaxel released was also measured in vitro.

RESULTS

Histologic changes in the porcine biliary epithelium were acceptable in terms of safety, based on inflammatory cell infiltration and fibrotic reaction. No significant differences in histology were observed between the groups. In the porcine serum analysis, released paclitaxel was detected for 28 days with the 10% Pluronic concentration (group III). However, released paclitaxel was observed for only 7 days in groups II and IV. In the in vitro experiments, long-lasting release of paclitaxel was also noted from the stent with 10% Pluronic.

CONCLUSIONS

The new paclitaxel-eluting stent with 10% Pluronic F-127 is safe and provides enhanced local drug delivery.

Wetting behavior and nanotribological properties of silicon nanopatterns combined with diamond-like carbon and perfluoropolyether films

A large number of silicon (Si) patterns consisting of nanopillars of varying diameter and pitch have been fabricated and further coated with diamond-like carbon (DLC) and perfluoropolyether (Z-DOL) films. The wetting behavior and nano-adhesion/friction of the patterns are investigated experimentally in relation to the nanostructures and the hydrophobicity of the materials. Measurements of water contact angle illustrate that the patterning-enhanced wettability of the Si flat surface, along with two distinct wettings which are in good agreement with the Wenzel and hemi-wicking states, depended on the value of the pitch-over-diameter ratio. In the case of the coated patterns, three wetting states are observed: the Cassie-Baxter, the Wenzel, and a transition from the Cassie-Baxter into the Wenzel, which varies with regard to the hydrophobic properties of the DLC and Z-DOL. In terms of tribological properties, it is demonstrated that a combination of the nanopatterns and the films is effective in reducing adhesive and frictional forces. In addition, the pitch and diameter of the patterns are found to significantly influence their adhesion/friction behaviors.

Fine organic particle, formaldehyde, acetaldehyde concentrations under and after the influence of fire activity in the atmosphere of Riverside, California

Concentrations of gas-phase organic carbons (formaldehyde (HCHO) and acetaldehyde (CH(3)CHO)) and fine particle-phase carbons (organic carbon (OC) and elemental carbon (EC)) were measured under and after the influence of fire activity in southern California. The measurement was conducted after the start of the wildfire activities from October 27 through November 6, 2003 at a site in Riverside, southern California. Under the influence of the fire activities, HCHO, CH(3)CHO and EC concentrations were found to be over two times as high as those after the fire activities ended. The total lifetime cancer risk estimated by HCHO and CH(3)CHO concentrations measured was significantly higher under the influence of the wildfire activities than that after the activities ended. OC showed a larger difference in concentrations between the two event periods as compared with gas-phase organic carbons and EC. OC/EC ratios ranged from 3.7 to 12.5 during the study period with the highest OC/EC ratio observed when the study area was under the influence of the fire activities. Correlation analysis and multiple linear regressions between OC/EC concentrations and visibility were performed. It was found that the visibility was even worse under the influence of fire activity as compared to the period after fire activity ended. EC was a stronger contributor to the visibility reduction compared to OC. The influence of air mass pathways on HCHO, CH(3)CHO, OC, and EC concentrations during the wildfire activities was addressed using a backward trajectory model developed by NOAA.

Secondary organic aerosol formation from m-xylene in the absence of NOx

Formation of secondary organic aerosol (SOA) from m-xylene photoxidation in the absence of NOx was investigated in a series of smog chamber experiments. Experiments were performed in dry air and in the absence of seed aerosol with H2O2 photolysis providing a stable hydroxyl radical (OH radical) source. SOA formation from this study is exceptionally higher than experiments with existence of NOx. The experiments with elevated HO2 levels indicate that organic hydroperoxide compounds should contribute to SOA formation. Nitrogen oxide (NO) is shown to reduce aerosol formation; the constant aerosol formation rate obtained before addition of NO and after consumption of NO strongly suggests that aerosol formation is mainlythrough reactions with OH and HO2 radicals. In addition, a density of 1.40 +/- 0.1 g cm(-3) for the SOA from the photooxidation of m-xylene in the absence of NOx has been measured, which is significantly higherthan the currently used unit density.

Secondary organic aerosol formation from the photooxidation of p- and o-xylene

The formation of secondary organic aerosol (SOA) from the photooxidation of xylene isomers (m-, p-, and o-xylenes) has been extensively investigated. The dependence of SOA aerosol formation on the structure of xylene isomers in the presence of NO was confirmed. Generally, SOA formation of p-xylene was less than that of m- and o-xylenes. This discrepancy varies significantly with initial NOx levels. In a NOx-free environment, the difference of aerosol formation between o- and p-xylenes becomes insignificant. Several chemical pathways for the SOA dependence on structure and NOx are explored, with the experimental findings indicating that organic peroxides may be a major key to explaining SOA formation from aromatic hydrocarbons.

Impact of propene on secondary organic aerosol formation from m-xylene

Propene is widely used in smog chamber experiments to increase the hydroxyl radical (OH) level based on the assumption that the formation of secondary organic aerosol (SOA) from parent hydrocarbon is unaffected. A series of m-xylene/NO(x) photooxidation experiments were conducted in the presence of propene in the University of California CE-CERT atmospheric chamber facility. The experimental data are compared with previous m-xylene/N0(x) photooxidation work performed in the same chamber facility in the absence of propene (Song et al. Environ. Sci. Technol. 2005, 39, 3143-3149). The result shows that, for similar initial conditions, experiments with propene have lower reaction rates of m-xylene than those without propene, which indicates that propene reduces OH in the system. Furthermore, experiments with propene showed more than 15% reduction in SOA yield compared to experiments in the absence of propene. Additional experiments of m-xylene/ NO(x) with CO showed similar trends of suppressing OH and SOA formation. These results indicate that SOA from m-xylene/NO(x) photooxidation is strongly dependent on the OH level present, which provides evidence for the critical role of OH in SOA formation from aromatic hydrocarbons.

Effect of ammonia on secondary organic aerosol formation from alpha-pinene ozonolysis in dry and humid conditions

This study examines the influence of ammonia (NH3) on secondary organic aerosol (SOA) formation from the alpha-pinene/ozone oxidation system for dry and humid conditions. Aerosol yield differed depending on which OH scavenger was used, with the highest yield noted for CO, followed by cyclohexane and 2-butanol. Number and volume concentrations were quickly increased within the reactor by 15 and 8%, respectively, when NH3 was added after the reaction ceased. The increase in number concentration indicated the formation of new particles resulting from gas-to-particle conversion. Moreover, average particle size increased from 242 to 248 nm. The resulting aerosol growth was attributed to ammonium salts formed by the reaction between organic acids and NH3. When NH3 was added to aerosolized cis-pinonic acid in the environmental reactor, a dramatic increase in both number and volume concentrations of cis-pinonic acid was observed. This provides further evidence that NH3 can interact with gas-phase organic acids forming condensable salts and thereby enhancing SOA formation. Initially present NH3 significantly enhanced aerosol yield in alpha-pinene-ozone reactions, regardless of the presence of water vapor. The role of NH3 on SOA formation in the dry and humid conditions is discussed in terms of a theoretical modeling study.

JP-8 Jet Fuel Can Promote Auditory Impairment Resulting From Subsequent Noise Exposure in Rats

We report on the transient and persistent effects of JP-8 jet fuel exposure on auditory function in rats. JP-8 has become the standard jet fuel utilized in the United States and North Atlantic Treaty Organization countries for military use and it is closely related to Jet A fuel, which is used in U.S. domestic aviation. Rats received JP-8 fuel (1000 mg/m(3)) by nose-only inhalation for 4 h and half of them were immediately subjected to an octave band of noise ranging between 97 and 105 dB in different experiments. The noise by itself produces a small, but permanent auditory impairment. The current permissible exposure level for JP-8 is 350 mg/m(3). Additionally, a positive control group received only noise exposure, and a fourth group consisted of untreated control subjects. Exposures occurred either on 1 day or repeatedly on 5 successive days. Impairments in auditory function were assessed using distortion product otoacoustic emissions and compound action potential testing. In other rats, tissues were harvested following JP-8 exposure for assessment of hydrocarbon levels or glutathione (GSH) levels. A single JP-8 exposure by itself at 1000 mg/m(3) did not disrupt auditory function. However, exposure to JP-8 and noise produced an additive disruption in outer hair cell function. Repeated 5-day JP-8 exposure at 1000 mg/m(3) for 4 h produced impairment of outer hair cell function that was most evident at the first postexposure assessment time. Partial though not complete recovery was observed over a 4-week postexposure period. The adverse effects of repeated JP-8 exposures on auditory function were inconsistent, but combined treatment with JP-8 + noise yielded greater impairment of auditory function, and hair cell loss than did noise by itself. Qualitative comparison of outer hair cell loss suggests an increase in outer hair cell death among rats treated with JP-8 + noise for 5 days as compared to noise alone. In most instances, hydrocarbon constituents of the fuel were largely eliminated in all tissues by 1-h postexposure with the exception of fat. Finally, JP-8 exposure did result in a significant depletion of total GSH that was observable in liver with a nonsignificant trend toward depletion in the brain and lung raising the possibility that the promotion of noise-induced hearing loss by JP-8 might have resulted from oxidative stress.

Promotion of Noise-Induced Cochlear Injury by Toluene and Ethylbenzene in the Rat

Ethylbenzene + toluene are known individually to have ototoxic potential at high exposure levels and with prolonged exposure times generally of 4-16 weeks. Both ethylbenzene + toluene are minor constituents of JP-8 jet fuel; this fuel has recently been determined to promote susceptibility to noise-induced hearing loss. Therefore, the current study evaluates the ototoxic potential of combined exposure to ethylbenzene + toluene exposure in a ratio calculated from the average found in three laboratories. Rats received ethylbenzene + toluene by inhalation and half of them were subjected simultaneously to an octave band of noise (OBN) of 93-95 dB. Another group received only the noise exposure which was designed to produce a small, but permanent auditory impairment while an unexposed control group was also included. In two separate experiments, exposures occurred either repeatedly on 5 successive days for 1 week or for 5 days on 2 successive weeks to 4000 mg/m(3) total hydrocarbons for 6 h based upon initial pilot studies. The concentration of toluene was 400 ppm and the concentration of ethylbenzene was 660 ppm. Impairments in auditory function were assessed using distortion product otoacoustic emissions and compound action potential testing. Following completion of these tests, the organs of Corti were dissected to permit evaluation of hair cell loss. The uptake and elimination of the solvents was assessed by harvesting key organs at two time points following ethylbenzene + toluene exposure from additional rats not used for auditory testing. Similarly, glutathione (GSH) levels were measured in light of suggestions that oxidative stress might result from solvent-noise exposures. Ethylbenzene + toluene exposure by itself at 4000 mg/m(3) for 6 h did not impair cochlear function or yield a loss of hair cells. However, when combined with a 93-dB OBN exposure combined solvent + noise did yield a loss in auditory function and a clear potentiation of outer hair cell death that exceeded the loss produced by noise alone. No evidence was found for a loss in total GSH in lung, liver, or brain as a consequence of ethylbenzene + toluene exposure.

Determination of VOC source signature of vehicle exhaust in a traffic tunnel

This study describes the methodology used to obtain the volatile organic compound (VOC) source signature of vehicle exhaust. To accomplish this, C(2)-C(9) VOCs were measured in a traffic tunnel located in Seoul, South Korea. The effect of VOC concentrations from the outside ambient air was considered in the determination of the source signature. To examine the effects of ambient air on VOC concentrations inside the tunnel, the ratio of propane to the total VOC concentrations was compared between the entrance and middle sites in the tunnel. Propane was used as a standard not only because of its insignificant contribution to vehicle exhaust gas, but also the fact that propane is the most abundant VOC in the atmosphere of Seoul. The ratio of propane to the total VOC concentrations was higher at the entrance site than at the middle location by, on average, 60%. This suggests that ambient air affects the inside tunnel air to a greater extent at the entrance site as compared to the middle site. The contribution of ambient air to the air inside the tunnel at the entrance location varied from 30% to 67%, with an average of 55%. This is 1.5 times higher than the value measured at the middle location, which ranged from 20% to 48%, with an average of 36%. This shows that ambient air substantially affects the inside air of the tunnel. Excluding the effects of ambient air on the air inside the tunnel can provide an improved chemical composition for vehicle exhaust using tunnel measurements. We believe that the concentration difference between the two sites within the tunnel provides a more accurate chemical composition of vehicle exhaust as compared to that obtained from a measurement taken at only one point inside the tunnel.

Impact of the hydrocarbon to NOx ratio on secondary organic aerosol formation

A series of m-xylene/NOx experiments were conducted in the new Bourns College of Engineering-Center for Environmental Research and Technology dual 90 m3 indoor smog chamber to elucidate the role of NOx on the secondary organic aerosol (SOA) formation potential of m-xylene. The results presented herein demonstrate a clear dependence of m-xylene SOA formation potential on NOx, particularly at atmospherically relevant organic aerosol concentration. Experiments with lower NOx levels generated considerably more organic aerosol mass than did experiments with higher NOx levels when reacted m-xylene was held constant. For example, SOA formation from approximately 150 microg m(-3) reacted m-xylene produced 0.6-9.3 microg m(-3) aerosol mass for NOx concentrations ranging from 286 to 10 ppb. The increase in SOA formation was not attributable to changes in ozone and nitrate concentration. A general discussion about possible influences of NOx on SOA formation for this system is included.

Chemical composition of major VOC emission sources in the Seoul atmosphere

This paper describes a chemical analysis of volatile organic compounds (VOCs) for five emission sources in Seoul. The source categories included motor vehicle exhaust, gasoline evaporation, paint solvents, natural gas and liquefied petroleum gas (LPG). These sources were selected because they have been known to emit significant quantities of VOCs in the Seoul area (more than 5% of the total emission inventory). Chemical compositions of the five emission sources are presented for a group of 45 C2-C9 VOCs. Motor vehicle exhaust profiles were developed by conducting an urban tunnel study. These emissions profiles were distinguished from the other emission profiles by a high weight percentage of butanes over seasons and propane in the wintertime. It was found that this is due to the wide use of butane-fueled vehicles. To obtain gasoline vapor profiles, gasoline samples from five major brands for each season were selected. The brands were blended on the basis of the marketshare of these brands in Seoul area. Raoult's law was used to calculate gasoline evaporative compositions based on the liquid gasoline compositions. The measured and estimated gasoline vapor compositions were found to be in good agreement. Vehicle and gasoline evaporation profiles were made over seasons because of the seasonal change in their compositions. Paint solvent emissions profiles were produced based on a product-use survey and sales figures. These profiles are a composite of four major oil-based paints and thinning solvent. The source profile of natural gas was made on a methane-free basis. It was found that Ethane and propane were the most abundant compounds accounting for 95% of the natural gas composition. LPG was largely composed of propane and ethane and the remaining components were minor contributors.

Cytokine balance in kidney tissue from lupus nephritis patients

OBJECTIVE

To identify the balance of Th1/Th2 cytokine expression in the kidney and evaluate the difference in cytokine balance between patients with lupus nephritis WHO classes IV and V.

METHODS

The expression of the CD40 molecule on cultured human mesangial cells was assessed by flow cytometry after stimulation with interferon gamma (IFN-gamma) or other cytokines. Frozen sections of kidney tissue from 10 patients with lupus nephritis and two non-SLE patients (with minimal-change disease) were stained with monoclonal antibodies for interleukin (IL)-4, IL-10, IL-12, IFN-gamma, CD4, CD8, CD40, CD68 and CD40L.

RESULTS

CD40 expression of cultured mesangial cells was up-regulated by IFN-gamma, but was not down-regulated in the presence of the Th2 cytokines IL-4 and IL-10. In the glomeruli, CD40 expression and the ratios of IFN-gamma-/IL-10-, IL-12-/IL-4- and (IFN-gamma+IL-12)/(IL-4+IL-10)-positive cells were significantly higher in class IV than in class V lupus nephritis (P < 0.05). Also CD40, IFN-gamma and the activity index derived from the renal biopsy were closely correlated.

CONCLUSION

IFN-gamma may contribute to the pathogenesis of proliferative glomerulonephritis by the up-regulation of CD40 and the activation of the cellular immune response in human lupus.

Incorporation of sulfonylurea into N-isopropylacrylamide as an extracellular matrix for an artificial pancreas

High-molecular-weight N-isopropylacrylamide copolymers with small amounts of sulfonylurea (SU, typically 2-4 mol% in the feed) were synthesized by free radical polymerization in benzene. SU-incorporated polymer solutions (5, 6, 8, and 10% w/v) in a culture medium (pH 7.4, 0.15 M ionic strength) with islet cells were mixed and poured into Millicells which supported gel formation. In order to increase the gelation temperature, the SU-incorporated copolymer gel, p(NiPAAm-co-SU), was blended with the p(NiPAAm-co-AAc) polymer at a ratio of 4 to 96. Interaction between the islet cells and the synthetic matrix of SU-incorporated copolymer gel resulted in effective cell viability and such cell functions as insulin secretion. To verify the specific interaction between the SU (K+ channel closer)-incorporated copolymer and islet cells, the cells were pretreated with diazoxide, an agonist of the ATP-sensitive K+ channel (K+ channel opener), before interaction between the polymer and islet cells. This treatment suppressed the action of SU on the islet cells. The results from this study provide evidence that the SU-incorporated copolymer stimulated insulin secretion by specific interaction between SU moieties in the polymer and the islet cells.

Conjugation of Arg-Gly-Asp (RGD) sequence in copolymer bearing sugar moiety for insulinoma cell line (MIN6) culture

Copolymers composed of an Arg-Gly-Asp (RGD) sequence for the adhesion molecule and sugar moieties were synthesized for an insulinoma cell (MIN6) culture. MIN6 cells attached on the poly(N-p-vinylbenzyl-D-maltonamide-co-6-(p-vinylbenzamido)-hexanoic acid-g-GRGDS) (p(VMA-co-VBGRGDS))-coated dishes were in a more aggregated form than other polymer-coated surfaces. P(VMA-co-VBGRGDS) also shows faster proliferation of MIN6 cells (about 18% higher) than with p(VLA-co-VBGRGDS). By interaction between cell and matrix, about 80% greater insulin secretion from MIN6 cells was produced with the p(VMA-co-VBGRGDS), and about 50% greater insulin secretion was produced with the poly(N-p-vinylbenzyl-D-lactonamide-co-6-(p-vinylbenzamido)-hexanoic acid-g-GRGDS) (p(VLA-co-VBGRGDS) as compared with unstimulated cells. Moreover, attachment of MIN6 cells treated with RGD monomer was suppressed approximately 50% for the p(VMA-co-VBGRGDS) surface. This result supported the idea that conjugation of adhesion molecules of RGD peptide in p(VMA-co-VBGRGDS) copolymer specifically interact with integrin families on MIN6 cell membrane.

Self-assembled hydrogel nanoparticles from curdlan derivatives: characterization, anti-cancer drug release and interaction with a hepatoma cell line (HepG2)

Self-assembled hydrogel nanoparticles were synthesized from carboxymethylated (CM)-curdlan, substituted with a sulfonylurea (SU) as a hydrophobic moiety for self-assembly. The degree of SU substitution was 2.4, 5.6, or 7.2 SU groups per hundred anhydroglucose units of curdlan. The physicochemical properties of the self-assembled hydrogel nanoparticles (DS 2.4, DS 5.6, and DS 7.2) in aqueous media were characterized by dynamic light scattering, transmission electron microscopy, and fluorescence spectroscopy. The mean diameter of all samples was less than 300 nm with a unimodal size distribution. The critical aggregation concentrations (CAC) of self-assembled hydrogel nanoparticles in distilled water were 4.2 x 10(-2), 3.1 x 10(-2) and 1.9 x 10(-2) mg/ml for DS 2.4, 5.6 and 7.2, respectively. The loading and release of all-trans retinoic acid (ATRA) was studied. The ATRA loading efficiencies and loading contents of CM-curdlan/SU nanoparticles increased as the degree of SU substitution increased. The ATRA release rate was controlled by the degree of substitution and drug-loading. For specific interaction with a hepatic carcinoma cell line (HepG2), CM-curdlan was additionally conjugated with lactobionic acid (LBA; galactose moiety) (5.5 LBA molecules per hundred glucose units). HepG2 was strongly luminated by ligand-receptor interactions with fluorescence-labeled LBA/CM-curdlan/SU hydrogel nanoparticles. The luminescence was not observed for other control cases. It is concluded that LBA/CM-curdlan/SU hydrogel nanoparticles are a useful drug carrier for the treatment of liver cancer, because of the potential immunological enhancement activities of CM-curdlan in the body, the ligand-receptor mediated specific interactions, and the controlled release of the anti-cancer drug.

Characterization of PCB-degrading bacteria immobilized in polyurethane foam

This study is carried out to investigate (1) conditions for the synthesis of polyurethane foam to be used for immobilizing microorganisms, (2) the viability of microorganisms immobilized simultaneously into the pores of a polyurethane foam when the foam is synthesized, and (3) the difference in the ability to degrade PCBs between the immobilized and suspended microorganisms. The results of this study show that polyurethane foam is suitable for synthesizing 10% NCO-prepolymer, water and surfactant in the ratio of 100:2.6:1.2 (w/w), respectively, and the viability of microorganisms (input microbes) immobilized in the foam is high. The input microbes, designated as strain SY5, are isolated from a municipal sewage treatment plant. In addition, immobilized strain SY5 degrades 5-40% more PCB of a PCB mixture (Aroclor 1242) than the suspended strain SY5.

Self-assembling nanospheres of hydrophobized pullulans in water

In this report, we have prepared self-assembling nanospheres of hydrophobized pullulans. Pullulan acetate as a hydrophobized pullulan was synthesized by acetylation of pullulan and characterized by Fourier transform infrared (FTIR) measurement. From the results of photon correlation spectroscopy (PCS), hydrophobized pullulans could be self-assembled in water as nanospherical aggregates, and their number-average particle size was 74.3 +/- 38.2 nm with a unimodal distribution. Also, morphological studies observed by transmission electron microscopy (TEM) showed that self-assembly of hydrophobized pullulans results in nice spherical shapes with a size range of about 50-100 nm, which was in accordance with PCS measurements. Their size and morphology have acceptable properties for intravenous injectable drug-targeting carriers. The fluorescence probe technique was used for self-association of hydrophobized pullulans in water using pyrene as a hydrophobic probe. From the fluorescence measurement, the fluorescence intensity of pyrene increased with increasing concentration of hydrophobized pullulans, which indicates self-assembly formation of hydrophobized pullulans in water. Also, in the fluorescence excitation spectrum, a red shift was observed with increasing concentration of hydrophobized pullulans. These results also revealed that hydrophobized pullulans could be self-assembled in water, and from the plot of I337/I334 versus log c of hydrophobized pullulans, the critical association concentration was 0.0022 g/l, which was considerably lower than that of low molecular weight surfactants or poloxamer. A drug loading study was performed using clonazepam (CNZ) as a hydrophobic model drug. We observed that the higher the feeding amount of drug was, the more the drug loading contents were, the lower the drug loading efficiency was, and the larger the particle size was. CNZ was released from nanospheres via pseudo-zero-order kinetics, and the increased drug loading contents led to slower release of the drug.

pH-sensitive release of indomethacin using lactan-acetate microspheres

Hydrophobic lactan acetate was prepared from hydrophilic lactan gum by chemical modification and it was used for a pH-sensitive drug delivery system. Lactan acetate microspheres were prepared by the solvent evaporation method. The size of the microspheres prepared from lactan acetate was below 5 microns. The drug loading efficiencies of microspheres were approximately 70 and 80% at the initial amount of drug 40 and 80 mg, respectively. The microsphere showed pH-sensitive swelling behavior. The swelling capacity of microspheres at pH 7.4 was much greater than that at pH 1.2. The pH of the medium significantly influenced the in vitro release rate; the rate at pH 7.2 was approximately 10 times faster than that at pH 1.2. A pH-sensitive drug release pattern was due to the escape of drug from the microsphere that disintegrated after swelling.