bluuebunny/crossref_metadata_2025 huggingface dataset:
Preparation of porous poly(3‐hexylthiophene) by freeze‐dry method and its application to organic photovoltaics
Authors: Huang Ping‐Tsung , Chang Yao‐Sheng , Chou Cheng‐Wei
Published: April 2011

Poly(3‐hexylthiophene)(P3HT) with a microporous network structure was prepared from a 1% p‐xylene solution by freeze‐dry method. Scanning electron microscopy (SEM) showed P3HT molecules formed swollen gel‐like structures with different extent of compactness depending on the length of the aggregation period. Absorption spectrum of this P3HT film showed a characteristic peak at 620 nm, which indicated a high degree of order between polymer chains. Photoluminescence (PL) of this highly ordered P3HT film appeared at 712 nm revealing large extent of π–π stacking between P3HT molecules in the freeze‐dry film. Both absorption and photoluminescence results indicated that the original aggregated states of P3HT molecules in gel form had been preserved throughout the freeze‐dry operation. X‐ray diffraction of the annealed samples showed a strong characteristic peak for the side chain aggregation at 2θ = 5.1°, which proved that the freeze‐dry film was with highly order structure. The interconnected and highly ordered P3HT film is used in the study of organic photovoltaics (OPV) after applying an n‐type semiconductor to the surface of the dry porous fibers. A prototype OPV device with power conversion efficiency of 1.47% was prepared by this method. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011.
Mechanism of seeded dispersion polymerization of methyl methacrylate using submicron polystyrene seed particles
Authors: Song Zhipeng , Daniels Eric S. , David Sudol E. , El‐Aasser Mohamed S. , Klein Andrew
Published: April 2011

Submicron polystyrene (PS) latex particles were used as seed in seeded dispersion polymerization of methyl methacrylate (MMA) to investigate the particle nucleation and aggregation behavior in this type of polymerization. The PS seed particles were located and tracked during the reaction using a refractive index matching technique. The number of PS seed particles present in the poly(methyl methacrylate) (PMMA) particles was investigated in detail throughout the reaction. The change in the distribution of PMMA particle populations containing different numbers of seed particles indicated that intensive nucleation and aggregation occurred during the early stage of the reaction until a transition point of 8.7% conversion was attained under the reaction conditions studied. The size of the large particles at this point was around 1 μm. These particles were regarded as mature particles that did not aggregate with other mature particles. Meanwhile, immature particle were still generated continuously from the continuous phase. These immature particles could not survive the aggregation process to grow to become mature particle, but instead, were captured by the mature particles. Therefore, the total number of the mature particles remained constant from this point until the end of the reaction. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Thermal and mechanical properties of stretched recyclable polyimide film
Authors: Wang Han‐Yi , Liu Ta‐Jo , Liu Shur‐Fen , Jeng Jhy‐Long , Guan Chi‐En
Published: April 2011

An operating window, which is bounded by two temperatures and draw ratios, defines the stable and defect‐free stretching region of a polymer film. Physical properties including the coefficient of thermal expansion (CTE), birefringence, and Young's modulus of a recyclable polyimide (PIR) film were measured under stretching conditions. While values of birefringence and Young's modulus increased with increasing stretching stress in the machine direction, the CTE was found to decrease. A semiempirical model for the prediction of birefringence and Young's modulus under stretching conditions was developed, from which the CTE could be estimated from the Young's modulus data. Theoretically evaluated physical properties were found to be in qualitative agreement with the experimental data. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Modification of nylon 66 by electron beam irradiation for improved properties and superior performances
Authors: Pramanik N. K. , Haldar R. S. , Bhardwaj Y. K. , Sabharwal S. , Niyogi U. K. , Khandal R. K.
Published: April 2011

Nylon 66 has been transformed into a material with significantly improved properties like hardness, tensile strength, and flexural modulus by processing it under the optimized dose rate of electron beam in the presence of suitable crosslinkers. Furthermore, percent water absorption of nylon 66 was reduced substantially on irradiation. Thermogravimetric analysis revealed that thermal stability of nylon 66 improved with increasing dose of radiation. Improvement of mechanical and thermal properties and reduction of water absorption of nylon 66 were due to the crosslinking of polyamide molecules made possible by the high energy radiation. Increase of crosslinking with increasing radiation dose was verified by the increase of gel content at higher doses. Differential scanning calorimetry showed that both melting and crystallization temperatures along with percent crystallinity of nylon 66 were decreased with the increasing dose of radiation leading to the development of more amorphous character in this semicrystalline polymer. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011.
Association of endogenous anti–interferon‐α autoantibodies with decreased interferon‐pathway and disease activity in patients with systemic lupus erythematosus
Authors: Morimoto Alyssa M. , Flesher Donna Thibault , Yang Jihong , Wolslegel Kristen , Wang Xiangdan , Brady Ann , Abbas Alexander R. , Quarmby Valerie , Wakshull Eric , Richardson Bruce , Townsend Michael J. , Behrens Timothy W.
Published: April 2011

Objective

Numerous observations implicate interferon‐α (IFNα) in the pathophysiology of systemic lupus erythematosus (SLE); however, the potential impact of endogenous anti‐IFNα autoantibodies (AIAAs) on IFN‐pathway and disease activity is unclear. The aim of this study was to characterize IFN‐pathway activity and the serologic and clinical profiles of AIAA‐positive patients with SLE.

Methods

Sera obtained from patients with SLE (n = 49), patients with rheumatoid arthritis (n = 25), and healthy control subjects (n = 25) were examined for the presence of AIAAs, using a biosensor immunoassay. Serum type I IFN bioactivity and the ability of AIAA‐positive sera to neutralize IFNα activity were determined using U937 cells. Levels of IFN‐regulated gene expression in peripheral blood were determined by microarray, and serum levels of BAFF, IFN‐inducible chemokines, and other autoantibodies were measured using immunoassays.

Results

AIAAs were detected in 27% of the serum samples from patients with SLE, using a biosensor immunoassay. Unsupervised hierarchical clustering analysis identified 2 subgroups of patients, IFNlow and IFNhigh, that differed in the levels of serum type I IFN bioactivity, IFN‐regulated gene expression, BAFF, anti–ribosomal P, and anti‐chromatin autoantibodies, and in AIAA status. The majority of AIAA‐positive patients had significantly lower levels of serum type I IFN bioactivity, reduced downstream IFN‐pathway activity, and lower disease activity compared with the IFNhigh patients. AIAA‐positive sera were able to effectively neutralize type I IFN activity in vitro.

Conclusion

Patients with SLE commonly harbor AIAAs. AIAA‐positive patients have lower levels of serum type I IFN bioactivity and evidence for reduced downstream IFN‐pathway and disease activity. AIAAs may influence the clinical course in SLE by blunting the effects produced by IFNα.
The associations between finger length pattern, osteoarthritis, and knee injury: Data from the Framingham community cohort
Authors: Haugen Ida K. , Niu Jingbo , Aliabadi Piran , Felson David T. , Englund Martin
Published: April 2011

Objective

To investigate the associations of index finger–to–ring finger (2D:4D) length ratio with radiographic knee and hand osteoarthritis (OA), previous knee injury, and meniscal lesions in the general population.

Methods

We measured the length of the right second and fourth phalangeal and metacarpal bones on hand radiographs from 1,020 randomly recruited subjects (ages 51–92 years). Knee radiography and magnetic resonance imaging (MRI) were performed on subjects. Women and men were divided into tertiles according to their 2D:4D phalangeal and metacarpal ratios. We assessed the odds ratios (ORs) and 95% confidence intervals (95% CIs) for radiographic knee OA, severe symptomatic knee OA, radiographic hand OA, previous knee injury, and MRI‐defined meniscal lesion, using logistic regression with adjustment for age and body mass index. Because hand OA may affect the 2D:4D phalangeal ratio, we performed sensitivity analyses in subjects without joint space narrowing in the second and fourth interphalangeal joints.

Results

We found no significant associations between 2D:4D length ratio and radiographic knee OA, severe symptomatic knee OA, or meniscal lesions. Low 2D:4D phalangeal ratio was associated with hand OA in women (OR 1.80, 95% CI 1.11–2.93), but in the sensitivity analysis, the association was attenuated (OR 1.35, 95% CI 0.79–2.32). Low 2D:4D phalangeal ratios were associated with knee injury in men (OR 1.78, 95% CI 1.02–3.10). We found no significant associations for 2D:4D metacarpal ratios.

Conclusion

Low 2D:4D phalangeal ratios in men are associated with knee injury, but we did not find any significant association with knee OA. Low 2D:4D length ratio may be a consequence, rather than a cause, of hand OA in women.
Differential antiinflammatory and antinociceptive effects of the somatostatin analogs octreotide and pasireotide in a mouse model of immune‐mediated arthritis
Authors: Imhof Anne‐Katja , Glück Laura , Gajda Mieczyslaw , Lupp Amelie , Bräuer Rolf , Schaible Hans‐Georg , Schulz Stefan
Published: April 2011

Objective

Clinical and preclinical evidence suggests that somatostatin exhibits potent antiinflammatory and antinociceptive properties. However, it is not known which of the 5 somatostatin receptor subtypes (SSTRs 1–5) is involved in these actions. The purpose of this study was to assess the effects of the stable somatostatin analogs octreotide and pasireotide (SOM230) in a mouse model of antigen‐induced arthritis (AIA).

Methods

Studies were performed in SSTR2‐deficient mice (SSTR2–/–) and their wild‐type littermates (SSTR2+/+). The expression of SSTR1, SSTR2A, SSTR3, and SSTR5 in dorsal root ganglia was examined by immunohistochemistry.

Results

Untreated SSTR2–/– mice with AIA displayed joint swelling and mechanical hyperalgesia similar to that seen in SSTR2+/+ mice. In wild‐type mice, both octreotide and pasireotide significantly attenuated knee joint swelling and histopathologic manifestations of arthritis to an extent comparable to that of dexamethasone. In SSTR2–/– mice, the antiinflammatory effects of both octreotide and pasireotide were completely abrogated. Prolonged administration of pasireotide also inhibited joint swelling and protected against joint destruction during AIA flare reactions. In addition, both octreotide and pasireotide reduced inflammatory hyperalgesia. The antinociceptive actions of octreotide were abolished in SSTR2–/– mice, but those of pasireotide were retained. In dorsal root ganglia of naive wild‐type mice, only SSTR1 and SSTR2A, but not SSTR3 or SSTR5, were detected in a subset of small‐ and medium‐diameter neurons.

Conclusion

Our findings indicate that the antinociceptive and antiinflammatory actions of octreotide and pasireotide are largely mediated via the SSTR2 receptor. In addition, we identified the SSTR1 receptor as a novel pharmacologic target for somatostatin‐mediated peripheral analgesia in inflammatory pain.
Biomarkers of incident radiographic knee osteoarthritis: Do they vary by chronic knee symptoms?
Authors: Golightly Yvonne M. , Marshall Stephen W. , Kraus Virginia B. , Renner Jordan B. , Villaveces Andrés , Casteel Carri , Jordan Joanne M.
Published: April 2011

Objective

To explore the ability of osteoarthritis (OA)–related biomarkers to predict incident radiographic knee OA in a large sample of African American and Caucasian men and women.

Methods

Baseline levels of serum cartilage oligomeric matrix protein (COMP), hyaluronan (HA), high‐sensitivity C‐reactive protein (hsCRP), and keratan sulfate (KS) and baseline and followup radiographs were available for 353 knees without baseline osteophyte formation and for 446 knees without baseline joint space narrowing (JSN). Cox models estimated the hazard ratio (HR) and 95% confidence interval (95% CI) for incident knee OA for a 1‐unit increase in the ln of each biomarker, with adjustment for age, race, sex, body mass index, and knee OA of the contralateral limb. Report of chronic knee symptoms was explored as a modifier of the association.

Results

The hazard of incident knee osteophytes (HR 2.16 [95% CI 1.39–3.37]) and incident JSN (HR 1.82 [95% CI 1.15–2.89]) increased with higher baseline ln(COMP) levels. The hazard of incident knee JSN increased with higher ln(HA) levels (HR 1.46 [95% CI 1.14–1.87]). Baseline ln(hsCRP) and ln(KS) did not predict incident knee outcomes. HRs per unit increase in ln(COMP), ln(HA), and ln(KS) were higher among knees with chronic symptoms than among those without symptoms.

Conclusion

Higher baseline ln(COMP) and ln(HA) levels were associated with incident knee OA over an average followup period of 6.3 years. These results represent detection of a molecular stage of OA prior to radiographic manifestations. Further exploration is needed to determine how chronic knee symptoms modify the biomarker–incident knee OA association.
Characterization of the anticollagen antibody response in a new model of chronic polyarthritis
Authors: Conigliaro Paola , Benson Robert A. , Patakas Agapitos , Kelly Sharon M. , Valesini Guido , Holmdahl Rikard , Brewer James M. , McInnes Iain B. , Paul Garside
Published: April 2011

Objective

Type II collagen (CII)–specific B cell responses have been recognized in human rheumatoid arthritis (RA) and in collagen‐induced arthritis (CIA). An important limitation of the CIA model is that the CII response and the disease are stimulated by exogenously injected collagen. A model of experimental ovalbumin (OVA)–mediated acute arthritis has been established in which autoimmunity is spontaneous and elicited by antigen‐specific T cells. This study was undertaken to create a new model of chronic autoimmune polyarthritis and characterize the associated CII‐specific B cell response.

Methods

Secondary challenge with OVA or CII in adjuvant was used to elicit chronic disease. CII‐specific B cell responses against the epitopes U1, J1, C1, and citrullinated C1, together with the antibody affinity, were investigated in OVA‐mediated arthritis.

Results

Chronic autoimmune polyarthritis was induced and was dependent on the antigen used in the secondary challenge. U1 was the major CII epitope recognized, and antibodies showed the same affinity as those in CIA.

Conclusion

Our findings indicate that the development and severity of chronic disease is dependent on the antigen and is associated with an increased autoreactive B cell response directed against a specific CII epitope (U1). OVA‐mediated chronic arthritis exhibits anti‐CII antibodies (against U1), resembling human RA and murine CIA.
A Facile One‐Pot Synthesis and Enhanced Formic Acid Oxidation of Monodisperse Pd–Cu Nanocatalysts
Authors: Park Kyu‐Hwan , Lee Young Wook , Kang Shin Wook , Han Sang Woo
Published: April 2011

Highly monodisperse spherical 3 nm Pd–Cu alloy nanoparticles (NPs) were synthesized in high yield through the coreduction of [Pd(acac)2] (acac=acetylacetonate) and [Cu(acac)2] in nonhydrolytic solutions by using trioctylamine and oleic acid. The relative compositions of Pd and Cu could be tuned by controlling the molar ratios between the metal precursors in the raw solutions. The carbon‐supported Pd–Cu NPs (Pd–Cu/C) were chemically dealloyed by acetic acid washing, which resulted in the formation of porous structures. The prepared Pd–Cu/C catalysts exhibited at least threefold enhancement of Pd mass activities compared with a commercial Pd/C catalyst toward formic acid oxidation in an acidic medium, and also showed outstanding electrocatalytic stabilities. The improved electrocatalytic properties of the Pd–Cu NPs are attributed to the presence of a large number of active sites on their surfaces owing to their small particle sizes and chemically dealloyed porous structures.
Effects of oral curcumin on the pharmacokinetics of intravenous and oral etoposide in rats: possible role of intestinal CYP3A and P‐gp inhibition by curcumin
Authors: Lee Chong‐Ki , Ki Sung‐Hwan , Choi Jun‐Shik
Published: April 2011

This study aimed to investigate the effects of oral curcumin on the pharmacokinetics of intravenous and oral etoposide in rats. Intravenous (6 mg/kg) or oral (2 mg/kg) etoposide was administered to rats in the absence and the presence of oral curcumin (0.4, 2 or 8 mg/kg). The effects of curcumin on the P‐glycoprotein (P‐gp) and CYP3A4 activity was also evaluated. Curcumin inhibited CYP3A4 enzyme activity with a 50% inhibition concentration (IC50) of 2.7 µM. In addition, curcumin (10 µm) significantly enhanced the cellular accumulation of rhodamine‐123 in MCF‐7/ADR cells overexpressing P‐gp. Compared with the control group (given etoposide alone), curcumin (2 or 8 mg/kg) increased significantly the oral bioavailability (AUC and Cmax) of etoposide. Consequently, the extent of absolute oral bioavailability (F) of etoposide with curcumin was significantly enhanced compared with that in the control group. In contrast, curcumin did not affect the pharmacokinetics of etoposide after intravenous administration. Therefore, the enhanced oral bioavailability of etoposide in the presence of curcumin might be due mainly to inhibition of the P‐gp efflux pump in the small intestine and possibly by reduced first‐pass metabolism of etoposide in the small intestine by inhibition of CYP3A activity in rats. The combined use of curcumin may be helpful to improve the F of etoposide in chemotherapeutic applications. Copyright © 2011 John Wiley & Sons, Ltd.
Signatures of co‐translational folding
Authors: Saunders Rhodri , Mann Martin , Deane Charlotte M.
Published: April 2011

Global and co‐translational protein folding may both occur in vivo, and understanding the relationship between these folding mechanisms is pivotal to our understanding of protein‐structure formation. Within this study, over 1.5 million hydrophobic–polar sequences were classified based on their ability to attain a unique, but not necessarily minimal energy conformation through co‐translational folding. The sequence and structure properties of the sets were then compared to elucidate signatures of co‐translational folding. The strongest signature of co‐translational folding is a reduced number of possible favorable contacts in the amino terminus. There is no evidence of fewer contacts, more local contacts, or less‐compact structures. Co‐translational folding produces a more compact amino‐ than carboxy‐terminal region and an amino‐terminal‐biased set of core residues. In real proteins these signatures are also observed and found most strongly in proteins of the alpha/beta structural class of proteins (SCOP) where 71 % have an amino‐terminal set of core residues. The prominence of co‐translational features in experimentally determined protein structures suggests that the importance of co‐translational folding is currently underestimated.
Amide‐linkage formed between ammonia plasma treated poly(D,L‐lactide acid) scaffolds and bio‐peptides: Enhancement of cell adhesion and osteogenic differentiation in vitro
Authors: Xu Zi‐Xing , Li Tao , Zhong Zhao‐Ming , Zha Ding‐Sheng , Wu Song‐Hui , Liu Fu‐Qiang , Xiao Wen‐De , Jiang Xiao‐Rui , Zhang Xin‐Xin , Chen Jian‐Ting
Published: April 2011

The surface characteristics of scaffolds for bone tissue engineering must support cell adhesion, migration, proliferation, and osteogenic differentiation. In the study, poly(D,L‐lactide acid) (PDLLA) scaffolds were modified by combing ammonia (NH3) plasma pretreatment with Gly‐Arg‐Gly‐Asp‐Ser (GRGDS)‐peptides coupling technologies. The x‐ray photoelectron spectroscopy (XPS) survey spectra showed the peak of N1s at the surface of NH3 plasma pretreated PDLLA, which was further raised after GRGDS conjugation. Furthermore, N1s and C1s in the high‐resolution XPS spectra revealed the presence of CN (imine), CNH (amine), and CONH (amide) groups. The GRGDS conjugation increased amide groups and decreased amine groups in the plasma‐treated PDLLA. Confocal microscope and high performance liquid chromatography verified the anchored peptides after the conjugation process. Bone marrow mesenchymal stem cells were co‐cultured with scaffolds. Fluorescent microscope and scanning electron microscope photographs revealed the best cell adhesion in NH3 plasma pretreated and GRGDS conjugated scaffolds, and the least attachment in unmodified scaffolds. Real‐time PCR demonstrated that expression of osteogenesis‐related genes, such as osteocalcin, alkaline phosphatase, type I collagen, bone morphogenetic protein‐2 and osteopontin, was upregulated in the single NH3 plasma treated and NH3 plasma pretreated scaffolds following GRGDS conjugation. The results show that NH3 plasma treatment promotes the conjugation of GRGDS peptides to the PDLLA scaffolds via the formation of amide linkage, and combination of NH3 plasma treatment and peptides conjugation may enhance the cell adhesion and osteogenic differentiation in the PDLLA scaffolds. © 2011 Wiley Periodicals, Inc. Biopolymers 95: 682–694, 2011.
Influence of amino acid specificities on the molecular and supramolecular organization of glycine‐rich elastin‐like polypeptides in water
Authors: Salvi Anna M. , Moscarelli Pasquale , Satriano Giuseppina , Bochicchio Brigida , Castle James E.
Published: April 2011

Elastin‐like polypeptides adopt complex supramolecular structures, showing either a hydrophobic or a hydrophilic surface, depending on their surrounding environment and the supporting substrate. The preferred organization is important in many situations ranging from biocompatibility to bio‐function. Here we compare the n‐repeat pentamer LeuGlyGlyValGly (n = 7) with the analogue ValGlyGlyValGly (n = 5), as water suspensions and as deposits on silicon substrates. These sequences contain the repeat XxxGlyGlyZzzGly (Xxx, Zzz = Val, Leu) motif belonging to the hydrophobic glycine‐rich domain of elastin and represent a simplified model from which to obtain information on molecular interactions functional to elastin itself. The compounds studied differ only by the presence of the CH2 spacer in the Leu moiety and thus the work was aimed at revealing the influence of this spacer element on self assembly. Both polypeptides were studied under identical conditions, using combined techniques, to identify differences in their conformational states both at molecular (CD, FTIR) and supramolecular (XPS, AFM) levels. By these means, together with a Congo Red spectroscopic assay of β‐sheet formation in water, a clear correlation between amino acid sequences (sequence specificity) and their kinetics and ordering of aggregation has emerged. The novel outcomes of this work are from the supplementary measurements, made to augment the AFM and XPS studies, showing that the significant step in the self assembly of both polypeptides takes place in the liquid phase and from the finding that the substitution of Val by Leu in the first position of the pentapeptide effectively inhibits the formation of amyloidal fibers. © 2011 Wiley Periodicals, Inc. Biopolymers 95: 702–721, 2011.
Characterizing flexible and intrinsically unstructured biological macromolecules by SAS using the Porod‐Debye law
Authors: Rambo Robert P. , Tainer John A.
Published: April 2011

Unstructured proteins, RNA or DNA components provide functionally important flexibility that is key to many macromolecular assemblies throughout cell biology. As objective, quantitative experimental measures of flexibility and disorder in solution are limited, small angle scattering (SAS), and in particular small angle X‐ray scattering (SAXS), provides a critical technology to assess macromolecular flexibility as well as shape and assembly. Here, we consider the Porod‐Debye law as a powerful tool for detecting biopolymer flexibility in SAS experiments. We show that the Porod‐Debye region fundamentally describes the nature of the scattering intensity decay by capturing the information needed for distinguishing between folded and flexible particles. Particularly for comparative SAS experiments, application of the law, as described here, can distinguish between discrete conformational changes and localized flexibility relevant to molecular recognition and interaction networks. This approach aids insightful analyses of fully and partly flexible macromolecules that is more robust and conclusive than traditional Kratky analyses. Furthermore, we demonstrate for prototypic SAXS data that the ability to calculate particle density by the Porod‐Debye criteria, as shown here, provides an objective quality assurance parameter that may prove of general use for SAXS modeling and validation. © 2011 Wiley Periodicals, Inc. Biopolymers 95: 559–571, 2011.
Imaging of parastomal hernia using three-dimensional intrastomal ultrasonography
Authors: Gurmu A , Gunnarsson U , Strigård K
Published: April 2011

Background

Parastomal hernia is common in patients with a permanent stoma. At present there is no standard method for imaging a parastomal hernia. The aim of this study was to investigate the value of three-dimensional intrastomal ultrasonography in differentiating between a parastomal hernia and a bulge.

Methods

Twenty patients were divided into four groups according to ultrasonography setting and probe cover. All patients were tested using three different ultrasound probe frequencies (9, 13 and 16 MHz). The intrastomal examination was performed during provocation in both the supine and upright positions, with a protector or water-containing balloon surrounding the probe.

Results

The sharpest images were obtained using the rectal setting with a water-containing balloon surrounding the probe at 9 MHz in supine and erect positions, for evaluation of both fascia and muscle; in some instances even implanted mesh was detectable. When switched to render mode, the pictures improved in sharpness and it was easier to identify anatomical landmarks.

Conclusion

Intrastomal ultrasonography using the rectal setting and a frequency of 9 MHz is a feasible method for imaging a parastomal hernia and differentiating it from an abdominal bulge. The image quality improves when render mode is used.
Safety of hepatic resection in overweight and obese patients with cirrhosis
Authors: Cucchetti A , Cescon M , Ercolani G , Di Gioia P , Peri E , Pinna A D
Published: April 2011

Background

The simultaneous incremental increase in incidence of both obesity and hepatocellular carcinoma (HCC) will soon lead to more overweight and obese patients with cirrhosis needing surgery. At present, little is known about postoperative mortality and morbidity in such patients. This study investigated outcomes after hepatectomy in relation to obesity in a homogeneous cohort of patients with cirrhosis.

Methods

Perioperative data from 235 patients with cirrhosis who had hepatectomy for HCC were related to the presence of normal bodyweight (body mass index (BMI) 18·5–24·9 kg/m2), overweight (BMI 25·0–29·9 kg/m2) and obesity (BMI at least 30 kg/m2). Complications after surgery were graded according to the expanded Accordion Severity Classification of Postoperative Complications (T92).

Results

One hundred and one patients (43·0 per cent) were of normal bodyweight, 88 (37·4 per cent) were overweight and 46 (19·6 per cent) were obese; none was underweight. Overweight and obese groups showed a male preponderance (P = 0·024), and metabolic disorders were frequently the cause of cirrhosis in these patients (P < 0·001 and P = 0·014 for non-B non-C hepatitis and alcoholic cirrhosis respectively). Liver function tests, tumour stage and extent of hepatectomy did not significantly differ between BMI groups. The intraoperative course and postoperative mortality were unaffected by BMI. Overweight and obese patients had significantly more mild respiratory complications (P = 0·044). Severe complications and organ system (including liver) failure were not significantly affected by BMI.

Conclusion

Hepatic resection can be performed safely in overweight and obese patients with cirrhosis, although morbidity is increased in these patients.
Partitioning of amino acids in the aqueous biphasic system containing the water‐miscible ionic liquid 1‐butyl‐3‐methylimidazolium bromide and the water‐structuring salt potassium citrate
Authors: Zafarani‐Moattar Mohammed Taghi , Hamzehzadeh Sholeh
Published: April 2011

In biotechnology, extraction by means of aqueous biphasic systems (ABS) is known as a promising tool for the recovery and purification of bio‐molecules. Over the past decade, the increasing emphasis on cleaner and environmentally benign extraction procedures has led to enhanced interest in the ABS containing ionic liquids (ILs)—a new class of non‐volatile alternative solvents. ABS composed of the hydrophilic IL {1‐butyl‐3‐methylimidazolium bromide ([C4mim]Br)} and potassium citrate—which is easily degraded—represents a clean media to green separation of bio‐molecules. In this regard, here, the extraction capability of this ABS was evaluated through its application to the extraction of some amino acids. To gain an insight into the driving forces of amino acid partitioning in the studied IL‐based ABS, the distribution of five model amino acids (L‐tryptophan, L‐phenylalanine, L‐tyrosine, L‐leucine, and L‐valine) at different aqueous medium pH values and different phase compositions was investigated. The studies indicated that hydrophobic interactions were the main driving force, although electrostatic interactions and salting‐out effects were also important for the transfer of the amino acids. Moreover, based on the statistical analysis of the driving forces of amino acid partitioning in the studied IL‐based ABS, a model was established to describe the partition coefficient of three model amino acids, L‐tryptophan, L‐phenylalanine, and L‐valine, and employed to predict the partition coefficient of two other model amino acids, L‐tyrosine and L‐leucine. © 2011 American Institute of Chemical Engineers Biotechnol. Prog., 2011
Dual perfluorocarbon method to noninvasively monitor dissolved oxygen concentration in tissue engineered constructs in vitro and in vivo
Authors: Goh Fernie , Long Robert , Simpson Nicholas , Sambanis Athanassios
Published: April 2011

Noninvasive in vivo monitoring of tissue implants provides important correlations between construct function and the observed physiologic effects. As oxygen is a key parameter affecting cell and tissue function, we established a monitoring method that utilizes 19F nuclear magnetic resonance (NMR) spectroscopy, with perfluorocarbons (PFCs) as oxygen concentration markers, to noninvasively monitor dissolved oxygen concentration (DO) in tissue engineered implants. Specifically, we developed a dual PFC method capable of simultaneously measuring DO within a tissue construct and its surrounding environment, as the latter varies among animals and with physiologic conditions. In vitro studies using an NMR‐compatible bioreactor demonstrated the feasibility of this method to monitor the DO within alginate beads containing metabolically active murine insulinoma βTC‐tet cells, relative to the DO in the culture medium, under perfusion and static conditions. The DO profiles obtained under static conditions were supported by mathematical simulations of the system. In vivo, the dual PFC method was successful in tracking the oxygenation state of entrapped βTC‐tet cells and the surrounding peritoneal DO over 16 days in normal mice. DO measurements correlated well with the extent of cell growth and host cell attachment examined postexplantation. The peritoneal oxygen environment was found to be variable and hypoxic, and significantly lower in the presence of metabolically active cells. The significance of the dual PFC system in providing critical DO measurements for entrapped cells and other tissue constructs, in vitro and in vivo, is discussed. © 2011 American Institute of Chemical Engineers Biotechnol. Prog., 2011
The effect of astrocytes on the induction of barrier properties in aortic endothelial cells
Authors: Shayan Gilda , Shuler Michael L. , Lee Kelvin H.
Published: April 2011

Construction of in vitro models of the blood‐brain barrier (BBB) using primary brain microvascular endothelial cells (BMEC) is time intensive and not high throughput, in part due to a lack of culture purity, low yields, and cellular dedifferentiation after the first passage. This problem has created interest in the substitution of BMEC with immortalized brain endothelial cells (EC), or peripheral EC such as bovine aortic EC (BAEC). Many BBB models have focused on further inducing the brain and peripheral ECs by incorporating astrocyte back‐to‐back or nonback‐to‐back cocultures. However, previous studies demonstrating induction effects of astrocytes on BAEC in back‐to‐back cocultures failed to recognize the extensive barrier properties of astrocytes alone, which can have a significant effect on interpreting the results. This manuscript reports the establishment of back‐to‐back and nonback‐to‐back cocultures between astrocytes and BAEC or BMEC (as a control) with primary focus on the properties of astrocytes alone and with a linear contrast statistical methodology to interpret the results. Transendothelial electrical resistance and permeability studies revealed that astrocytes can significantly increase the barrier tightening of BMEC by 167%, while having no effect on BAEC. Immunocytochemical studies also revealed the reorganization of BMEC occludin junctions in the presence of astrocytes, while indicating the absence of this junctional protein in BAEC. In contrast to a previous report, here the linear contrast statistical analysis revealed that observed decreases in permeability of BAEC in back‐to‐back cocultures is due to the addition of astrocytes' properties in series and not due to induction. © 2011 American Institute of Chemical Engineers Biotechnol. Prog., 2011
Crystallization and liquid‐liquid phase separation of monoclonal antibodies and fc‐fusion proteins: Screening results
Authors: Trilisky Egor , Gillespie Ronald , Osslund Timothy D. , Vunnum Suresh
Published: April 2011

Crystallization holds the potential to be used for protein purification and low‐viscosity drug substance and drug product formulations. Twenty‐two different proteins (20 monoclonal antibodies and two Fc‐fusions) were examined to determine the breadth of applicability of crystallization to these therapeutic proteins. Vapor diffusion technique and an evaporative screening method were used to identify crystallization conditions using around a 100 initial conditions based on reagents that are generally regarded as safe (GRAS). Of 16 IgG2s examined, at least four formed diffraction‐quality crystals and four others formed crystal‐like particles. At least three of the IgG2s that crystallized well were also crystallized under the same set of operating conditions using inexpensive GRAS reagents. The crystals were formed to high‐yields in a few hours and were dissolved quickly without impacting product quality. Although only a fraction of the proteins examined crystallized, all exhibited liquid‐liquid phase separation (LLPS), which could be used for their concentration or possibly purification. One of the Fc‐fusions, for example, was concentrated by LLPS to a self‐buffering solution at 150 g/L. Crystallization and LLPS in the salting‐in region were shown to be feasible. © 2011 American Institute of Chemical Engineers Biotechnol. Prog., 2011
Gas‐permeable membranes and co‐culture with fibroblasts enable high‐density hepatocyte culture as multilayered liver tissues
Authors: Evenou Fanny , Hamon Morgan , Fujii Teruo , Takeuchi Shoji , Sakai Yasuyuki
Published: April 2011

To engineer reliable in vitro liver tissue equivalents expressing differentiated hepatic functions at a high level and over a long period of time, it appears necessary to have liver cells organized into a three‐dimensional (3D) multicellular structure closely resembling in vivo liver cytoarchitecture and promoting both homotypic and heterotypic cell–cell contacts. In addition, such high density 3D hepatocyte cultures should be adequately supplied with nutrients and particularly with oxygen since it is one of the most limiting nutrients in hepatocyte cultures. Here we propose a novel but simple hepatocyte culture system in a microplate‐based format, enabling high density hepatocyte culture as a stable 3D‐multilayer. Multilayered co‐cultures of hepatocytes and 3T3 fibroblasts were engineered on collagen‐conjugated thin polydimethylsiloxane (PDMS) membranes which were assembled on bottomless frames to enable oxygen diffusion through the membrane. To achieve high density multilayered co‐cultures, primary rat hepatocytes were seeded in large excess what was rendered possible due to the removal of oxygen shortage generally encountered in microplate‐based hepatocyte cultures. Hepatocyte/3T3 fibroblasts multilayered co‐cultures were maintained for at least 1 week; the so‐cultured cells were normoxic and sustained differentiated metabolic functions like albumin and urea synthesis at higher levels than hepatocytes monocultures. Such a microplate‐based cell culture system appears suitable for engineering in vitro miniature liver tissues for implantation, bioartificial liver (BAL) development, or chemical/drug screening. © 2011 American Institute of Chemical Engineers Biotechnol. Prog., 2011.
Visualization of human immunodeficiency virus protease inhibition using a novel Förster resonance energy transfer molecular probe
Authors: Jin Sha , Ellis Erika , Veetil Jithesh V. , Yao Huantong , Ye Kaiming
Published: April 2011

The in vivo high‐throughput screening (HTS) of human immunodeficiency virus (HIV) protease inhibitors is a significant challenge because of the lack of reliable assays that allow the visualization of HIV targets within living cells. In this study, we developed a new molecular probe that utilizes the principles of Förster resonance energy transfer (FRET) to visualize HIV‐1 protease inhibition within living cells. The probe is constructed by linking two fluorescent proteins: AcGFP1 (a mutant green fluorescent protein) and mCherry (a red fluorescent protein) with an HIV‐1 protease cleavable p2/p7 peptide. The cleavage of the linker peptide by HIV‐1 protease leads to separation of AcGFP1 from mCherry, quenching FRET between AcGFP1 and mCherry. Conversely, the addition of a protease inhibitor prevents the cleavage of the linker peptide by the protease, allowing FRET from AcGFP1 to mCherry. Thus, HIV‐1 protease inhibition can be determined by measuring the FRET signal's change generated from the probe. Both in vitro and in vivo studies demonstrated the feasibility of applying the probe for quantitative analyses of HIV‐1 protease inhibition. By cotransfecting HIV‐1 protease and the probe expression plasmids into 293T cells, we showed that the inhibition of HIV‐1 protease by inhibitors can be visualized or quantitatively determined within living cells through ratiometric FRET microscopy imaging measurement. It is expected that this new probe will allow high‐content screening (HCS) of new anti‐HIV drugs. © 2011 American Institute of Chemical Engineers Biotechnol. Prog., 2011
Process development and cGMP manufacturing of a recombinant ricin vaccine: An effective and stable recombinant ricin a‐chain vaccine—RVEc™
Authors: Meagher Michael M. , Seravalli Javier G. , Swanson S. Todd , Ladd Roger G. , Khasa Yogender P. , Inan Mehmet , Harner Jay C. , Johnson Scott K. , Van Cott Kevin , Lindsey Changhong , Wannemacher Robert , Smith Leonard A.
Published: April 2011

Ricin is a potent toxin and a potential bioterrorism weapon with no specific countermeasures or vaccines available. The holotoxin is composed of two polypeptide chains linked by a single disulfide bond: the A‐chain (RTA), which is an N‐glycosidase enzyme, and the B‐chain (RTB), a lectin polypeptide that binds galactosyl moieties on the surface of the mammalian target cells. Previously (McHugh et al.), a recombinant truncated form of RTA (rRTA1‐33/44‐198 protein, herein denoted RVEa™) expressed in Escherichia coli using a codon‐optimized gene was shown to be non‐toxic, stable, and protective against a ricin challenge in mice. Here, we describe the process development and scale‐up at the 12 L fermentation scale, and the current Good Manufacturing Practice (cGMP)‐compliant production of RVEc™ at the 40 L scale. The average yield of the final purified bulk RVEc™ is approximately 16 g/kg of wet cell weight or 1.2 g/L of fermentation broth. The RVEc™ was >99% pure by three HPLC methods and SDS‐PAGE. The intact mass and peptide mapping analysis of RVEc™ confirmed the identity of the product and is consistent with the absence of posttranslational modifications. Potency assays demonstrated that RVEc™ was immunoprotective against lethal ricin challenge and elicited neutralizing anti‐ricin antibodies in 95–100% of the vaccinated mice. Published 2011 American Institute of Chemical Engineers Biotechnol. Prog., 2011.
Isolation and characterization of a subset of erythropoietin glycoforms with cytoprotective but minimal erythropoietic activity
Authors: Mattio Mónica , Ceaglio Natalia , Oggero Marcos , Perotti Norma , Amadeo Ignacio , Orozco Gustavo , Forno Guillermina , Kratje Ricardo , Etcheverrigaray Marina
Published: April 2011

Although historically used for the treatment of anemia, erythropoietin (EPO) has emerged as a neurotrophic and neuroprotective agent in different conditions of neuronal damage (traumatic brain injury, ischemia, spinal cord compression, peripheral neuropathy, retinal damage, epilepsy, Parkinson's Disease, among others). Nonetheless, EPO's therapeutic application is limited due to its hematological side‐effects. With the aim of obtaining EPO derivatives resembling the hormone isolated from cells and tissues of neural origin, a novel combination of less acidic EPO glycoforms ‐designated as neuroepoetin (rhNEPO)‐ was purified to homogeneity from the supernatant of a CHO‐producing cell line by a four‐step chromatographic procedure. This simple and single process allowed us to prepare two EPO derivatives with distinct therapeutic expectations: the hematopoietic version and a minimally hematopoietic, but mainly in vitro cytoprotective, alternative. Further biological characterization showed that the in vivo erythropoietic activity of rhNEPO was 25‐times lower than that of rhEPO. Interestingly, using different in vitro cytoprotective assays we found that this molecule exerts cytoprotection equivalent to, or better than, that of rhEPO in cells of neural phenotype. Furthermore, despite its shorter plasma half‐life, rhNEPO was rapidly absorbed and promptly detected in the cerebrospinal fluid after intravenous administration in rats (5 min postinjection, in comparison with 30 min for rhEPO). Therefore, our results support the study of neuroepoetin as a potential drug for the treatment of neurological diseases, combining high cytoprotective activity with reduced hematological side‐effects. © 2011 American Institute of Chemical Engineers Biotechnol. Prog., 2011
CFD‐aided cell settler design optimization and scale‐up: Effect of geometric design and operational variables on separation performance
Authors: Shen Yuyi , Yanagimachi Kurt
Published: April 2011

The inclined multiplate (lamella) gravity settler has proven to be an effective cell retention device in industrial perfusion cell culture applications. Investigations on the effects of geometric design and operational variables of the cell settler are crucial to understanding how to best improve the settler performance. Maximizing the harvest/perfusion flow rate while minimizing viable cell loss out of the harvest is the primary challenge for optimization of the settler design. This study demonstrated that computational fluid dynamics (CFD) can be utilized to accurately model and evaluate the settler separation performance for near‐monodisperse suspensions and therefore aid in the design optimization of the settler under these baseline conditions. With the preferred geometric features that were identified from CFD modeling results, we proposed design guidelines for the scale‐up of these multiplate settler systems. With these guidelines and performance verification using the CFD model, a new large‐scale settler was designed and fabricated for a perfusion cell culture process using a minimally aggregating production cell line. Perfusion cell culture runs with this particular cell line were performed with this settler, and the CFD model was able to predict the initial ramp‐up performance, proving it to be a valuable scale‐up design tool for this production process. © 2011 American Institute of Chemical Engineers Biotechnol. Prog., 2011
Microvascular endothelial cells play potential immunoregulatory roles in the immune response to foot‐and‐mouth disease vaccines
Authors: Zhang Tao , Tian Lifang , Hu Ge , Teng Kedao , Mu Xiang
Published: April 2011

Microvascular endothelial cells (MVECs) have been documented to have important immunoregulatory effects. Exploring their roles in the immune response to foot‐and‐mouth disease (FMD) vaccines would help to improve their efficacy. In this study, the effects of FMD vaccine 146s antigens on gene expression profiles of rat intestinal mucosal and myocardial MVECs were analysed using microarray, and their effects on transendothelial migration (TEM) of peripheral blood mononuclear cells (PBMC) were investigated by the Transwell migration assay. Both kinds of MVECs displayed significant responses to 146s antigens, and 252 and 67 genes were differentially expressed in rat intestinal mucosal and myocardial MVECs, respectively. Despite different altered gene expression patterns, many immune‐associated genes were involved in both kinds of MVECs. The gene expression changes by microarray were confirmed by real‐time reverse transcription‐polymerase chain reaction. Transwell migration analysis indicated that the TEM of PBMC was increased by 146s antigens, which could be partially inhibited by blocking vascular cell adhesion molecule 1 in MVECs. This study suggests that MVECs play potential immunoregulatory roles in the immune response to FMD vaccines, one of which is influencing the TEM of immune cells. Copyright © 2011 John Wiley & Sons, Ltd.
Phenoxazine Dyes for Dye‐Sensitized Solar Cells: Relationship Between Molecular Structure and Electron Lifetime
Authors: Karlsson Karl Martin , Jiang Xiao , Eriksson Susanna K , Gabrielsson Erik , Rensmo Håkan , Hagfeldt Anders , Sun Licheng
Published: April 2011

A series of metal‐free organic dyes with a core phenoxazine chromophore have been synthesized and tested as sensitizers in dye‐sensitized solar cells. Overall conversion efficiencies of 6.03–7.40 % were reached under standard AM 1.5G illumination at a light intensity of 100 mW cm−2. A clear trend in electron lifetime could be seen; a dye with a furan‐conjugated linker showed a shorter lifetime relative to dyes with the acceptor group directly attached to the phenoxazine. The addition of an extra donor unit, which bore insulating alkoxyl chains, in the 7‐position of the phenoxazine could increase the lifetime even further and, together with additives in the electrolyte to raise the conduction band, an open circuit voltage of 800 mV could be achieved. From photoelectron spectroscopy and X‐ray absorption spectroscopy of the dyes adsorbed on TiO2 particles, it can be concluded that the excitation is mainly of cyano character (i.e., on average, the dye molecules are standing on, and pointing out, from the surface of TiO2 particles).