Determination of pore sizes and relative porosity in porous nanoshell architectures using dextran retention with single monomer resolution and proton permeation

Unilamellar phospholipid vesicles prepared using the polymerizable lipid bis-sorbylphosphatidylcholine (bis-SorbPC) yield three-dimensional nanoarchitectures that are highly permeable to small molecules. The resulting porous phospholipid nanoshells (PPNs) are potentially useful for a range of biomedical applications including nanosensors and nanodelivery vehicles for cellular assays and manipulations. The uniformity and size distribution of the pores, key properties for sensor design and utilization, have not previously been reported. Fluorophore-assisted carbohydrate electrophoresis (FACE) was utilized to assess the nominal molecular weight cutoff limit (NMCL) of the PPN via analysis of retained dextran with single monomer resolution. The NMCL of PPNs prepared from pure bis-SorbPC was equivalent to a 1800 Da linear dextran, corresponding to a maximum pore diameter of 2.6 nm. Further investigation of PPNs prepared using binary mixtures of bis-SorbPC and dioleoylphosphatidylcholine (DOPC) revealed a similar NMCL when the bis-SorbPC content exceeded 30 mol %, whereas different size-dependent permeation was observed below this composition. Below 30 mol % bis-SorbPC, dextran retention provided insufficient mass resolution (162 Da) to observe porosity on the experimental time scale; however, proton permeability showed a marked enhancement for bis-SorbPC ≥ 10 mol %. Combined, these data suggest that the NMCL for native pores in bis-SorbPC PPNs results from an inherent property within the lipid assembly that can be partially disrupted by dilution of bis-SorbPC below a critical value for domain formation. Additionally, the analytical method described herein should prove useful for the challenging task of elucidating porosity in a range of three-dimensional nanomaterials.

Synergistic degradation of methyl orange in an ultrasound intensified photocatalytic reactor

An original ultrasound (US) directly intensified photocatalytic reactor was designed to degrade azo dye pollutant methyl orange (MeO) using Degussa TiO(2) as the photocatalyst. The sonolytic, photocatalytic and sonophotocatalytic degradation of MeO in the new reactor and the synergistic effect between sonolysis and photocatalysis were investigated. Effects of operation parameters i.e., US power, TiO(2) dosage, liquid circulation velocity and air flow rate on degradation efficiency were investigated and optimized. The results showed that all parameters have optimal values for the sonophotocatalytic degradation of MeO, and the optimum conditions for the new process are US power 600 W, TiO(2) dosage 3g/L, liquid circulation velocity 4.05×10(-2) m/s and air flow rate 0.2 L/min. Under the optimum conditions, 91.52% MeO had been degraded within 1h, and the combination of sonolysis and TiO(2) photocatalysis exhibited an obvious synergetic effect.

Application of prospective ECG-triggered dual-source CT coronary angiography for infants and children with coronary artery aneurysms due to Kawasaki disease

OBJECTIVES

The aim of this study was to prospectively evaluate the initial application and value of prospective electrocardiogram (ECG)-triggered dual-source CT coronary angiography (DSCTCA) in the diagnosis of infants and children with coronary artery aneurysms due to Kawasaki disease.

METHODS

19 children [12 males; mean age 13.47 months, range 3 months to 5 years; mean heart rate 112 beats per minute (bpm), range 83-141 bpm] underwent prospective ECG-triggered DSCTCA with free breathing. Subjective image quality was assessed on a five-point scale (1, excellent; 5, non-diagnostic) by two blinded observers. The location, number and size of each aneurysm were observed and compared with those of transthoracic echocardiography (TTE) performed within 1 week. Interobserver agreement concerning the subjective image quality was evaluated with Cohen's κ-test. Bland-Altman analysis was used to evaluate the agreement on measurements (diameter and length of aneurysms) between DSCTCA and TTE. The average effective dose required for DSCTCA was calculated for all children.

RESULTS

All interobserver agreement for subjective image quality assessment was excellent (κ=0.87). The mean ± standard deviation (SD) aneurysm diameter with DSCTCA was 0.76 ± 0.36 cm and with TTE was 0.76 ± 0.39 cm. The mean ± SD aneurysm length with DSCTCA was 2.06 ± 1.35 cm and with TTE was 2.00 ± 1.22 cm. The Bland-Altman plot for agreement between DSCTCA and TTE measurements showed good agreement. The mean effective dose was 0.36 ± 0.06 mSv.

CONCLUSION

As an alternative diagnostic modality, prospective ECG-triggered DSCTCA with excellent image quality and low radiation exposure has been proved useful for diagnosing infants and children with coronary artery aneurysms due to Kawasaki disease.

ADVANCES IN KNOWLEDGE

Prospective ECG-triggered DSCTCA for infants and children allows rapid, accurate assessment of coronary aneurysms due to Kawasaki diseases, compared with TTE.

Influence of oxytetracycline on carprofen pharmacodynamics and pharmacokinetics in calves

A tissue cage model of inflammation in calves was used to determine the pharmacokinetic and pharmacodynamic properties of individual carprofen enantiomers, following the administration of the racemate. RS(±) carprofen was administered subcutaneously both alone and in combination with intramuscularly administered oxytetracycline in a four-period crossover study. Oxytetracycline did not influence the pharmacokinetics of R(-) and S(+) carprofen enantiomers, except for a lower maximum concentration (Cmax ) of S(+) carprofen in serum after co-administration with oxytetracycline. S(+) enantiomer means for area under the serum concentration-time curve (AUC0-96 h were 136.9 and 128.3 μg·h/mL and means for the terminal half-life (T(1/2) k10 ) were = 12.9 and 17.3 h for carprofen alone and in combination with oxytetracycline, respectively. S(+) carprofen AUC0-96 h in both carprofen treatments and T(1/2) k10 for carprofen alone were lower (P < 0.05) than R(-) carprofen values, indicating a small degree of enantioselectivity in the disposition of the enantiomers. Carprofen inhibition of serum thromboxane B2 ex vivo was small and significant only at a few sampling times, whereas in vivo exudate prostaglandin (PG)E2 synthesis inhibition was greater and achieved overall significance between 36 and 72 h (P < 0.05). Inhibition of PGE2 correlated with mean time to achieve maximum concentrations in exudate of 54 and 42 h for both carprofen treatments for R(-) and S(+) enantiomers, respectively. Carprofen reduction of zymosan-induced intradermal swelling was not statistically significant. These data provide a basis for the rational use of carprofen with oxytetracycline in calves and indicate that no alteration to carprofen dosage is required when the drugs are co-administered.

Simultaneous quantification of tumor uptake for targeted and nontargeted liposomes and their encapsulated contents by ICPMS

Liposomes are intensively being developed for biomedical applications including drug and gene delivery. However, targeted liposomal delivery in cancer treatment is a very complicated multistep process. Unfavorable liposome biodistribution upon intravenous administration and membrane destabilization in blood circulation could result in only a very small fraction of cargo reaching the tumors. It would therefore be desirable to develop new quantitative strategies to track liposomal delivery systems to improve the therapeutic index and decrease systemic toxicity. Here, we developed a simple and nonradiative method to quantify the tumor uptake of targeted and nontargeted control liposomes as well as their encapsulated contents simultaneously. Specifically, four different chelated lanthanide metals were encapsulated or surface-conjugated onto tumor-targeted and nontargeted liposomes, respectively. The two liposome formulations were then injected into tumor-bearing mice simultaneously, and their tumor delivery was determined quantitatively via inductively coupled plasma mass spectroscopy (ICPMS), allowing for direct comparisons. Tumor uptake of the liposomes themselves and their encapsulated contents was consistent with targeted and nontargeted liposome formulations that were injected individually.

Bioequivalence in dogs of a meloxicam formulation administered as a transmucosal oral mist with an orally administered pioneer suspension product

A mucosal mist formulation of meloxicam, administered as a spray into the mouth (test article), was compared for bioequivalence to a pioneer meloxicam suspension for oral administration (reference article). Pharmacokinetic profiles and average bioequivalence were investigated in 20 dogs. The study design comprised a two-period, two-sequence, two-treatment cross-over design, with maximum concentration (C(max)) and area under plasma concentration-time curve to last sampling time (AUC(last)) used as pivotal bioequivalence variables. Bioequivalence of the products was confirmed, based on relative ratios of geometric mean concentrations (and 90% confidence intervals within the range 0.80-1.25) for C(max) of 101.9 (97.99-106.0) and for AUC(last) of 97.24 (94.44-100.1). The initial absorption of meloxicam was more rapid for the test article, despite virtually identical C(max) values for the two products. Mean elimination half-lives were 29.6 h (test article) and 30.0 h (reference article). The meloxicam plasma concentration-time profiles were considered in relation to published data on the inhibition of the cyclooxygenase-1 (COX-1) and COX-2 isoenzymes by meloxicam.

Pathogenic role of mast cells in the development of diabetic nephropathy: a study of patients at different stages of the disease

AIMS/HYPOTHESIS

Increased renal mast cells have been detected in diabetic nephropathy. However, only a few patients have been examined. Evidence of the involvement of mast cells in diabetic nephropathy is still scarce, and no observation of mast cells during the development of diabetic nephropathy has yet been reported in humans. Here, we examined changes in renal mast cells in patients at different stages of diabetic nephropathy and related these to the development of the disease.

METHODS

Eighty patients at different clinical stages of diabetic nephropathy and 16 normal kidney donors were recruited. Immunohistochemical staining for tryptase, chymase, TGF-β1, renin and TNF-α was done on renal sections from patients and control participants. Changes in mast cell number, degranulation, subtype and phenotype were examined. Correlation between mast cells and patients' clinical and pathological indices was analysed.

RESULTS

With progression of diabetic nephropathy, the number and degranulation level of mast cells increased. Increase in mast cell number and degranulation level correlated significantly with tubular interstitial injury. Almost all renal mast cells in patients with diabetic nephropathy were found to produce chymase, renin, TGF-β1 and TNF-α. The level of TNF-α in mast cells increased with progression of diabetic nephropathy.

CONCLUSIONS/INTERPRETATION

This study suggests that mast cells are involved in development of diabetic nephropathy. Through release of bioactive substances, such as tryptase, chymase, TGF-β1, renin and TNF-α, into the tubular interstitium by degranulation, mast cells could promote renal inflammation and fibrosis, and thus contribute to diabetic nephropathy.

Reproductive performance and survival of Chinese Holstein dairy cows in central China

Fertility and longevity, major factors affecting the economic performance of dairy herds, are influenced by management and genetics. This study determined the reproductive performance and survival of Chinese Holstein cows in a large, modern dairy farm in central China using two complementary datasets. In Dataset 1, fertility and culling records were obtained from 1430 cows calving in 2008; in Dataset 2, all calving episodes during 2005 and 2006 were recorded (n = 1540) and the subsequent survival and reasons for death or culling of all female calves born during this period were monitored. In Dataset 1, the mean ages at first breeding and first calving for heifers were 18.7 ± 2.6 and 29.3 ± 3.6 months, respectively. Cows (lactations 1–10) were first inseminated at 110 ± 49 days after calving (mean ± s.d.), conceived at 185 ± 103 days and required 2.3 ± 1.6 services per conception with a first service conception rate of 34%. Reproduction performance was lower in the first lactation, with the best fertility in autumn-calving cows. In Dataset 2, 601 live-born heifers were monitored from birth until first calving. Of these, 521 (87%) were inseminated at least once and 502 (84%) calved once, but only 68% of the starting population calved successfully for a second time. The main reasons for culling in both datasets were poor fertility, disease and lameness. Improved management strategies to avoid calving cows in the spring and so offset the adverse effects of summer heat stress together with increased emphasis on selection for good fertility and conformation traits would increase future profitability.

Photocatalytic degradation of bisphenol A using an integrated system of a new gas-liquid-solid circulating fluidized bed reactor and micrometer Gd-doped TiO2 particles

A new gas-liquid-solid circulating fluidized bed photocatalytic reactor (GLSCFBPR) with internally placed multi-layered UV lamps was developed. Micrometer Gd-TiO2 particles and commercial nanometer P25-TiO2 were chosen as the photocatalysts, and the hazardous substance bisphenol A (BPA) was chosen as the model pollutant to investigate the performance of this new photocatalytic system. The results showed that the photocatalytic degradation efficiency of the micrometer Gd-TiO2 particles was similar to that of the nanometer P-25 particles at their respective optimum dosage but the former could be easily separated out by gravity. After investigating the effects of process parameters on the photocatalytic BPA degradation, the response surface method (RSM) was further used for process optimization. The interactions among process parameters, i.e., TiO2 concentration, superficial gas velocity and superficial liquid velocity were discovered and a related analysis was carried out to explore the underlying mechanism. A quadratic mathematic model was established and performed satisfactorily when used for prediction. The optimum conditions for this new process were as follows: TiO2 concentration 4.5 g/L, superficial gas velocity 7.83 x 10(-3) m/sec and superficial liquid velocity 8.65 x 10(-3) m/sec.

ICP-MS analysis of lanthanide-doped nanoparticles as a non-radiative, multiplex approach to quantify biodistribution and blood clearance

Recent advances in material science and chemistry have led to the development of nanoparticles with diverse physicochemical properties, e.g. size, charge, shape, and surface chemistry. Evaluating which physicochemical properties are best for imaging and therapeutic studies is challenging not only because of the multitude of samples to evaluate, but also because of the large experimental variability associated with in vivo studies (e.g. differences in tumor size, injected dose, subject weight, etc.). To address this issue, we have developed a lanthanide-doped nanoparticle system and analytical method that allows for the quantitative comparison of multiple nanoparticle compositions simultaneously. Specifically, superparamagnetic iron oxide (SPIO) with a range of different sizes and charges were synthesized, each with a unique lanthanide dopant. Following the simultaneous injection of the various SPIO compositions into tumor-bearing mice, inductively coupled plasma mass spectroscopy (ICP-MS) was used to quantitatively and orthogonally assess the concentration of each SPIO composition in serial blood samples and the resected tumor and organs. The method proved generalizable to other nanoparticle platforms, including dendrimers, liposomes, and polymersomes. This approach provides a simple, cost-effective, and non-radiative method to quantitatively compare tumor localization, biodistribution, and blood clearance of more than 10 nanoparticle compositions simultaneously, removing subject-to-subject variability.

Trepanation and curettage treatment for acute implant periapical lesions

Six dental implants in six patients with periapical lesions were inserted and underwent trepanation and thorough curettage. During surgery, the lesion area was irrigated with copious natural saline and chlorhexidine and the bone defects were treated with tetracycline paste. The six implants were stable and asymptomatic postoperatively. The implants were loaded after 3 months. Radiologically, the radiolucency in the apical part disappeared gradually. These prostheses have functioned satisfactorily with no further complication during the follow-up period. For cases in which small lesions initially appear soon after implant placement, trepanation and curettage of the periapical lesion without resection of the apical part of the implant or bone substitute material and/or autogenous bone grafting is an effective management option. A rapid and exact diagnosis is important for treating implant periapical lesions.

Improved tumor targeting of polymer-based nanovesicles using polymer-lipid blends

Block copolymer-based vesicles have recently garnered a great deal of interest as nanoplatforms for drug delivery and molecular imaging applications due to their unique structural properties. These nanovesicles have been shown to direct their cargo to disease sites either through enhanced permeability and retention or even more efficiently via active targeting. Here, we show that the efficacy of nanovesicle targeting can be significantly improved when prepared from polymer-lipid blends compared with block copolymer alone. Polymer-lipid hybrid nanovesicles were produced from the aqueous coassembly of the diblock copolymer, poly(ethylene oxide)-block-polybutadiene (PEO-PBD), and the phospholipid, hydrogenated soy phosphatidylcholine (HSPC). The PEG-based vesicles, 117 nm in diameter, were functionalized with either folic acid or anti-HER2/neu affibodies as targeting ligands to confer specificity for cancer cells. Our results revealed that nanovesicles prepared from polymer-lipid blends led to significant improvement in cell binding compared to nanovesicles prepared from block copolymer alone in both in vitro cell studies and murine tumor models. Therefore, it is envisioned that nanovesicles composed of polymer-lipid blends may constitute a preferred embodiment for targeted drug delivery and molecular imaging applications.

Effects of n-6 polyunsaturated fatty acids on prostaglandin production in ovine fetal chorion cells in vitro in late gestation ewes

OBJECTIVE

To use an in vitro model of the ovine placenta to determine effects of n-6 polyunsaturated fatty acid (PUFA) supplementation on prostaglandin (PG) production. PGs are key regulators of fetal maturation and parturition.

STUDY DESIGN

Fetal allantochorion tissue (FC) was collected in late pregnancy (day 135). FC cells were isolated and cultured with 0-100 μM of linoleic acid (LA), γ-linolenic acid (GLA) or arachidonic acid (AA) in serum free medium and challenged with control medium, lipopolysaccharide (LPS, 0.1 μg/ml), dexamethasone (DEX, 5 μM) or a combination of LPS (0.1 μg/ml) with DEX (5 μM). Spent medium was harvested at 2 h and 24 h post challenge for measuring PGs.

MAIN OUTCOME MEASURES

To assess the effects of treatment on placental 1- and 2-series PGE production.

RESULTS

LA supplementation inhibited both PGE(1) and PGE(2) production. GLA predominantly stimulated PGE(1) generation, although it also increased PGE(2) production. AA supplementation predominantly increased PGE(2) production, but also stimulated PGE(1). DEX treatment with or without LPS inhibited PG production. Supplementation with n-6 PUFAs attenuated or neutralised the stimulatory effect of LPS challenge on FC cells for both PGE(1) and PGE(2) production.

CONCLUSION

These data show that supplementation with n-6 PUFAs alters placental PG production, but their precise effects depend on their position in the biosynthetic pathway for PG synthesis. This study supports the possibility that GLA containing oils, widely promoted as dietary supplements, might reduce the risk of pre-term labour by inhibiting the responsiveness of PGE(2) production to LPS challenge in the placenta.

Tangeretin and its metabolite 4'-hydroxytetramethoxyflavone attenuate EGF-stimulated cell cycle progression in hepatocytes; role of inhibition at the level of mTOR/p70S6K

BACKGROUND AND PURPOSE

The mechanisms by which the dietary compound tangeretin has anticancer effects may include acting as a prodrug, forming an antiproliferative product in cancer cells. Here we show that tangeretin also inhibits cell cycle progression in hepatocytes and investigate the role of its primary metabolite 4'-hydroxy-5,6,7,8-tetramethoxyflavone (4'-OH-TMF) in this effect.

EXPERIMENTAL APPROACH

We used epidermal growth factor (EGF)-stimulated rat hepatocytes, with [(3)H]-thymidine incorporation into DNA as an index of progression to S-phase of the cell cycle, and Western blots for phospho-proteins involved in the cell signalling cascade.

KEY RESULTS

Incubation of tangeretin with microsomes expressing CYP1A, or with hepatocytes, generated a primary product we identified as 4'-OH-TMF. Low micromolar concentrations of tangeretin or 4'-OH-TMF gave a concentration-dependent inhibition of EGF-stimulated progression to S-phase while having little effect on cell viability. To determine whether time for conversion of tangeretin to an active metabolite would enhance the inhibitory effect we used long pre-incubations; this reduced the inhibitory effect, in parallel with a reduction in the concentration of tangeretin. The EGF-stimulation of hepatocyte cell cycle progression requires signalling through Akt/mTOR/p70S6K kinase cascades. The tangeretin metabolite 4'-OH-TMF selectively inhibited S6K phosphorylation in the absence of significant inhibition of upstream Akt activity, suggesting an effect at the level of mTOR.

CONCLUSIONS AND IMPLICATIONS

Tangeretin and 4'-OH-TMF both inhibit cell cycle progression in primary hepatocytes. The inhibition of p70S6K phosphorylation by 4'-OH-TMF raises the possibility that inhibition of the mTOR pathway may contribute to the anticancer influence of a flavonoid-rich diet.

Characterization of 236 novel alleles at the HLA-A, -B, -C, -DRB1, -DQB1 and -DPB1 loci from China Marrow Donor Program

Two hundred and thirty-six novel human leukocyte antigen (HLA) alleles are described from volunteer donors of the China Marrow Donor Program: 71 HLA-A alleles, 79 HLA-B alleles, 43 HLA-C, 16 HLA-DRB1 alleles, 26 HLA-DQB1 and 1 HLA-DPB1. Two hundred and thirteen (90.3%) of the 236 novel alleles are single nucleotide substitution variants when compared with their most homologous allele. Seventy-eight of these single nucleotide variants are silent substitutions. The remaining novel alleles differ from their most similar allele by two to four nucleotide substitutions. Some of the novel alleles encode amino acid changes at positions not previously reported to be polymorphic, such as codons 57, 62, 67, 41 and 52 in HLA-A alleles; codons 133, 156, 201 and 215 in HLA-B alleles; codons 74, 208 and 225 in HLA-C; codons 25, 32 and 72 in HLA-DRB1; codons 20, 39 and 77 in HLA-DQB1.

Carbon nanodots as peroxidase mimetics and their applications to glucose detection

Carbon nanodots (C-Dots) were found to possess intrinsic peroxidase-like activity, and could catalytically oxidize 3,3',5,5'-tetramethylbenzidine (TMB) by H(2)O(2) to produce a colour reaction. This offers a simple, sensitive and selective colorimetric method for glucose determination in serum.

Dextran sulphate sodium increases splenic Gr1(+)CD11b(+) cells which accelerate recovery from colitis following intravenous transplantation

While Gr1(+)CD11b(+) cells are known to regulate immune responses and accumulate in most cancer tissues, the function of Gr1(+)CD11b(+) cells in inflammation is poorly understood. We investigated the role of Gr1(+)CD11b(+) cells in a dextran sulphate sodium (DSS)-treated mouse model of ulcerative colitis (UC). C57BL/6 mice were treated with 2% DSS in drinking water for 5 days. Disease progression and recovery were assessed by body weight, disease activity index score (DAI) score and colon length. Splenic Gr1(+)CD11b(+) cell number was greatly increased during the recovery phase of DSS-induced colitis. DSS-derived splenic Gr1(+)CD11b(+) cells were administered intravenously to recipient (C57BL/6) mice during the early phase of DSS treatment. The transplanted splenic DSS-induced Gr1(+)CD11b(+) cells improved DSS-induced colitis and promoted efficient colonic mucosal healing. We found that the CD11b(+) single positive cells increased in the course of DSS-induced colitis in lamina propria. The transplantation of splenic Gr1(+)CD11b(+) cells induced feedback suppression of myeloid-lineage cell development. Namely, the transplantation of splenic Gr1(+)CD11b(+) cells greatly suppressed the migration of CD11b(+) single positive cells to the lamina propria. Further, transplantation of Gr-1(+)CD11b(+) cells greatly suppressed the increase of the same population, especially during the late phase of DSS colitis both in spleen and bone marrow.