bluuebunny/crossref_metadata_2025 huggingface dataset:
Nonfunctional Regulatory T Cells and Defective Control of Th2 Cytokine Production in Natural Scurfy Mutant Mice
Authors: Lahl Katharina , Mayer Christian T. , Bopp Tobias , Huehn Jochen , Loddenkemper Christoph , Eberl Gérard , Wirnsberger Gerald , Dornmair Klaus , Geffers Robert , Schmitt Edgar , Buer Jan , Sparwasser Tim
Published: October 2009

Foxp3+ regulatory T cells (Tregs) are crucial for preventing autoimmunity. We have demonstrated that depletion of Foxp3+ Tregs results in the development of a scurfy-like disease, indicating that Foxp3− effector T cells are sufficient to induce autoimmunity. It has been postulated that nonfunctional Tregs carrying potentially self-reactive T cell receptors may contribute to scurfy (sf) pathogenesis due to enhanced recognition of self. Those cells, however, could not be identified in sf mutants due to the lack of Foxp3 protein expression. To address this issue, we crossed the natural sf mouse mutant with bacterial artificial chromosome transgenic DEREG (depletion of regulatory T cells) mice. Since DEREG mice express GFP under the control of an additional Foxp3 promoter, those crossings allowed proving the existence of “would-be” Tregs, which are characterized by GFP expression in the absence of functional Foxp3. Sf Tregs lost their in vitro suppressive capacity. This correlated with a substantial reduction of intracellular cAMP levels, whereas surface expression of Treg markers was unaffected. Both GFP+ and GFP− sf cells produced high amounts of Th2-type cytokines, reflected also by enhanced Gata-3 expression, when tested in vitro. Nevertheless, sf Tregs could be induced in vitro, although with lower efficiency than DEREG Tregs. Transfer of GFP+ sf Tregs, in contrast to GFP− sf T cells, into RAG1-deficient animals did not cause the sf phenotype. Taken together, natural and induced Tregs develop in the absence of Foxp3 in sf mice, which lack both suppressive activity and autoreactive potential, but rather display a Th2-biased phenotype.
β1 Integrin-Dependent Engulfment of Yersinia enterocolitica by Macrophages Is Coupled to the Activation of Autophagy and Suppressed by Type III Protein Secretion
Authors: Deuretzbacher Anne , Czymmeck Nicole , Reimer Rudolph , Trülzsch Konrad , Gaus Kristin , Hohenberg Heinrich , Heesemann Jürgen , Aepfelbacher Martin , Ruckdeschel Klaus
Published: October 2009

Autophagy is a central lysosomal degradation process that is essential for the maintenance of cellular homeostasis. Autophagy has furthermore emerged as integral part of the host immune response. Autophagic processes promote the separation and degradation of intracellular microorganisms which contributes to the development of innate and adaptive immunity. Some pathogenic microbes have therefore evolved mechanisms to evade or impede autophagy. We analyzed the effects of the enteropathogenic bacterium Yersinia enterocolitica on autophagy in macrophages. Yersiniae use a number of defined adhesins and secreted proteins to manipulate host immune responses. Our results showed that Y. enterocolitica defective in type III protein secretion efficiently activated autophagy in macrophages. Autophagy was mediated by the Yersinia adhesins invasin and YadA and particularly depended on the engagement of β1 integrin receptors. Several autophagy-related events followed β1 integrin-mediated engulfment of the bacteria including the formation of autophagosomes, processing of the marker protein LC3, redistribution of GFP-LC3 to bacteria-containing vacuoles, and the segregation of intracellular bacteria by autophagosomal compartments. These results provide direct evidence for the linkage of β1 integrin-mediated phagocytosis and autophagy induction. Multiple microbes signal through integrin receptors, and our results suggest a general principle by which the sensing of an extracellular microbe triggers autophagy. Owing to the importance of autophagy as host defense response, wild-type Y. enterocolitica suppressed autophagy by mobilizing type III protein secretion. The subversion of autophagy may be part of the Y. enterocolitica virulence strategy that supports bacterial survival when β1 integrin-dependent internalization and autophagy activation by macrophages are deleterious for the pathogen.
CTL Clones Isolated from an HLA-Cw-Mismatched Bone Marrow Transplant Recipient with Acute Graft-Versus-Host Disease
Authors: Sugimoto Kyoko , Murata Makoto , Terakura Seitaro , Naoe Tomoki
Published: October 2009

HLA-Cw disparity in a donor increases the risk of acute graft-vs-host disease (GVHD) after bone marrow transplantation. Acute GVHD is mediated by donor CTLs. However, mismatched HLA-Cw-specific CTLs generated in posttransplant recipients who developed acute GVHD have not been characterized in detail. In this study, CTL clones isolated from a recipient at the onset of acute GVHD who was transplanted from an HLA-A, -B, and -DRB1-matched, HLA-Cw-mismatched (recipient, Cw*0303/Cw*0702; donor, Cw*0801/Cw*0702), unrelated donor were characterized. The seven isolated CTLs, including CD4+, CD8+, and CD4+CD8+ T lymphocytes, lysed recipient cells, HLA-Cw*0303-transfected 721.211 cells, and HLA-Cw*0303-transfected donor cells, but not untransfected 721.211 cells or donor cells. Thus, all CTLs recognized the mismatched Cw*0303 molecule as an alloantigen. The sequences of Cw*0303 and Cw*0801 differ by 16 aas. Stimulation of CTLs by COS cells transfected with Cw*0303 cDNA constructs demonstrated that Cw*0303 mutants in which individual amino acids constituting peptide-binding pockets were substituted with the corresponding Cw*0801 amino acids significantly decreased IFN-γ production by all CTLs, whereas Cw*0303 mutants bearing Cw*0801 amino acids outside the positions constituting peptide-binding pockets stimulated all CTLs to the same degree as the wild-type Cw*0303 construct. These data suggest that all CTLs recognized the Cw molecule in a peptide-dependent manner. ELISPOT revealed that Cw*0303-reactive T cells accounted for one-half of the total of alloreactive T cells in the blood during GVHD. Taken together, non-self Cw-specific CTL clones with a variety of phenotypes and peptide specificities can be generated in posttransplant recipients with acute GVHD.
Genetically Attenuated Parasite Vaccines Induce Contact-Dependent CD8+ T Cell Killing of Plasmodium yoelii Liver Stage-Infected Hepatocytes
Authors: Trimnell Adama , Takagi Akihide , Gupta Megha , Richie Thomas L. , Kappe Stefan H. , Wang Ruobing
Published: October 2009

The production of IFN-γ by CD8+ T cells is an important hallmark of protective immunity induced by irradiation-attenuated sporozoites against malaria. Here, we demonstrate that protracted sterile protection conferred by a Plasmodium yoelii genetically attenuated parasite (PyGAP) vaccine was completely dependent on CD8+ T lymphocytes but only partially dependent on IFN-γ. We used live cell imaging to document that CD8+ CTL from PyGAP-immunized mice directly killed hepatocyte infected with a liver stage parasite. Immunization studies with perforin and IFN-γ knockout mice also indicated that the protection was largely dependent on perforin-mediated effector mechanisms rather than on IFN-γ. This was further supported by our observation that both liver and spleen CD8+ T cells from PyGAP-immunized mice induced massive apoptosis of liver stage-infected hepatocytes in vitro without the release of detectable IFN-γ and TNF-α. Conversely, CD8+ T cells isolated from naive mice that had survived wild-type P. yoelii sporozoite infection targeted mainly sporozoite-traversed and uninfected hepatocytes, revealing an immune evasion strategy that might be used by wild-type parasites to subvert host immune responses during natural infection. However, CTLs from wild-type sporozoite-challenged mice could recognize and kill infected hepatocytes that were pulsed with circumsporozoite protein. Additionally, protection in PyGAP-immunized mice directly correlated with the magnitude of effector memory CD8+ T cells. Our findings implicate CTLs as key immune effectors in a highly protective PyGAP vaccine for malaria and emphasize the critical need to define surrogate markers for correlates of protection, apart from IFN-γ.
Activation of the Nlrp3 Inflammasome by Streptococcus pyogenes Requires Streptolysin O and NF-κB Activation but Proceeds Independently of TLR Signaling and P2X7 Receptor
Authors: Harder Jürgen , Franchi Luigi , Muñoz-Planillo Raúl , Park Jong-Hwan , Reimer Thornik , Núñez Gabriel
Published: October 2009

Macrophages play a crucial role in the innate immune response against the human pathogen Streptococcus pyogenes, yet the innate immune response against the bacterium is poorly characterized. In the present study, we show that caspase-1 activation and IL-1β secretion were induced by live, but not killed, S. pyogenes, and required expression of the pore-forming toxin streptolysin O. Using macrophages deficient in inflammasome components, we found that both NLR family pyrin domain-containing 3 (Nlrp3) and apoptosis-associated speck-like protein (Asc) were crucial for caspase-1 activation and IL-1β secretion, but dispensable for pro-IL-1β induction, in response to S. pyogenes infection. Conversely, macrophages deficient in the essential TLR adaptors Myd88 and Trif showed normal activation of caspase-1, but impaired induction of pro-IL-1β and secretion of IL-1β. Notably, activation of caspase-1 by TLR2 and TLR4 ligands in the presence of streptolysin O required Myd88/Trif, whereas that induced by S. pyogenes was blocked by inhibition of NF-κB. Unlike activation of the Nlrp3 inflammasome by TLR ligands, the induction of caspase-1 activation by S. pyogenes did not require exogenous ATP or the P2X7R. In vivo experiments revealed that Nlrp3 was critical for the production of IL-1β but was not important for survival in a mouse model of S. pyogenes peritoneal infection. These results indicate that caspase-1 activation in response to S. pyogenes infection requires NF-κB and the virulence factor streptolysin O, but proceeds independently of P2X7R and TLR signaling.
Helminth Antigens Modulate Immune Responses in Cells from Multiple Sclerosis Patients through TLR2-Dependent Mechanisms
Authors: Correale Jorge , Farez Mauricio
Published: October 2009

To better understand the link between parasite infections and the course of multiple sclerosis (MS), we studied the role of TLRs in helminth product recognition by dendritic cells (DCs) and B cells. Baseline expression of TLR2 was significantly higher in infected-MS patients compared with uninfected MS subjects or healthy controls. Moreover, cells exposed to TLR2 agonists or to soluble egg Ag (SEA) from Schistosoma mansoni resulted in significant TLR2 up-regulation. SEA suppressed the LPS-induced DCs production of IL-1β, IL-6, IL-12, and TNF-α and enhanced TGF-β as well as IL-10 production. Similarly, after exposure to SEA, anti-CD40-activated B cells increased IL-10 production. Both processes were MyD88 dependent. In addition, SEA down-regulated the expression of LPS-induced costimulatory molecules on DCs in a MyD88-independent manner. DCs stimulation by SEA and TLR2 agonists induced increasing phosphorylation of the MAPK ERK1/2. Neither stimulus showed an effect on p38 and JNK1/2 phosphorylation, however. Addition of the ERK1/2 inhibitor U0126 was associated with dose-dependent inhibition of IL-10 and reciprocal enhancement of IL-12. Finally, cytokine effects and changes observed in DCs costimulatory molecule expression after SEA exposure were lost when TLR2 expression was silenced. Overall, these findings indicate that helminth molecules exert potent regulatory effects on both DCs and B cells through TLR2 regulation conducted via different signaling pathways. This knowledge could prove critical in developing novel therapeutic approaches for the treatment of autoimmune diseases such as MS.
Reducing Epitope Spread during Affinity Maturation of an Anti-Ganglioside GD2 Antibody
Authors: Hu Jian , Huang Xiaodong , Ling Chang-Chun , Bundle David R. , Cheung Nai-Kong V.
Published: October 2009

Ab affinity maturation in vivo is always accompanied by negative selection to maintain Ag specificity. In contrast, in vitro affinity maturation can lead to epitope spread, resulting in loss of specificity. Anti-ganglioside-GD2 mAbs are clinically effective against neuroblastoma; pain and neuropathy are major side effects. We used structural relatives of GD2 to define epitope spread during in vitro affinity maturation of an anti-GD2 single-chain variable fragment (scFv) called 5F11-scFv. Clonal dominance identified by polyclonal sequencing was confirmed by analyzing individual clones. Affinity-matured mutations were introduced into scFv-streptavidin for functional studies. Without a negative selector, 19-fold affinity improvement (clone Q, where Q is the symbol for glutamine) was associated with strong cross-reactivity with GM2 and GD1b and moderate cross-reactivity with GD3, resulting in positive immunohistochemical staining of all 13 non-neural normal human tissues, in contrast to none of 13 tissues with parental clone P. With GM2 as a negative selector, clone Y (where Y is the symbol for tyrosine) was generated with only weak cross-reactivity with GD1b, adrenal and thyroid glands, and no staining of other non-neural normal tissues. Even though there was only a 3-fold affinity improvement, clone Y showed significantly higher tumor uptake over parental clone P (134%, p = 0.04), whereas clone Q was inferior (54% of clone P; p = 0.05) as confirmed by tumor-to-normal tissue ratios across 16 organs (41% of clone P; p < 0.0001). Using the less efficient negative selector GD3, a clone mixture (Q, V, and Y, where V is the symbol for valine) emerged. We conclude that epitope spread during affinity maturation can be reduced by negative selection. Furthermore, efficiency of the negative selector depends on its cross-reactive affinity with the matured scFv.
IL-17/Th17 Promotes Type 1 T Cell Immunity against Pulmonary Intracellular Bacterial Infection through Modulating Dendritic Cell Function
Authors: Bai Hong , Cheng Jianjun , Gao Xiaoling , Joyee Antony George , Fan Yijun , Wang Shuhe , Jiao Lei , Yao Zhi , Yang Xi
Published: October 2009

Although their contribution to host defense against extracellular infections has been well defined, IL-17 and Th17 are generally thought to have limited impact on intracellular infections. In this study, we investigated the role and mechanisms of IL-17/Th17 in host defense against Chlamydia muridarum, an obligate intracellular bacterium, lung infection. Our data showed rapid increase in IL-17 production and expansion of Th17 cells following C. muridarum infection and significant detrimental impact of in vivo IL-17 neutralization by anti-IL-17 mAb on disease course, immune response, and dendritic cell (DC) function. Specifically, IL-17-neutralized mice exhibited significantly greater body weight loss, higher organism growth, and much more severe pathological changes in the lung compared with sham-treated control mice. Immunological analysis showed that IL-17 neutralization significantly reduced Chlamydia-specific Th1 responses, but increased Th2 responses. Interestingly, the DC isolated from IL-17-neutralized mice showed lower CD40 and MHC II expression and IL-12 production, but higher IL-10 production compared with those from sham-treated mice. In two DC-T cell coculture systems, DC isolated from IL-17-neutralized mice induced higher IL-4, but lower IFN-γ production by Ag-specific T cells than those from sham-treated mice in cell priming and reaction settings. Adoptive transfer of DC isolated from IL-17-neutralized mice, unlike those from sham-treated mice, failed to protect the recipients against challenge infection. These findings provide in vivo evidence that IL-17/Th17 plays an important role in host defense against intracellular bacterial infection, and suggest that IL-17/Th17 can promote type 1 T cell immunity through modulating DC function.
Cognitive assessment of children with acute lymphoblastic leukemia: Preliminary findings
Authors: Abraham Anna , Appaji L
Published: October 2009

Aim:The objective of this study was to assess the cognitive functions of Indian children with acute lymphoblastic leukemia (ALL), periodically after initiation of treatment since prospective longitudinal research in this area on the Indian population has not been adequately documented. Unlike many western studies that have targeted survivors of ALL, we aimed to bring out the cognitive outcome after initiation of treatment.Materials and Methods:The cognitive functions of 19 patients diagnosed to have ALL were assessed using standardized tests after induction chemotherapy, and periodically thereafter following the second course of treatment comprising central nervous system-directed radiotherapy, and chemotherapy using intrathecal methotrexate.Results:The study found a statistically significant decline in the intelligence quotient and a deficit in the cognitive function of analytical reasoning.Conclusion:This preliminary study supports findings of an earlier Indian study and many studies conducted in the west. Since the life expectancy of these children has increased and most of them have long-term survival, and even cure, we suggest that identifying and managing children with cognitive difficulties are important in the rehabilitation of these children.
Primary pancreatic lymphoma: Report of three cases with review of literature
Authors: Haji Altaf Gauhar , Sharma Shekhar , Majeed K Abdul , Vijaykumar D K , Pavithran K , Dinesh M
Published: October 2009

Background:Primary pancreatic lymphoma (PPL) is an extremely rare neoplasm, which may be confused with pancreatic adenocarcinoma. So far only about 150 cases of PPL have been reported.Materials and Methods:We present our experience of 3 cases of PPL over a 4-year period.Results:All the patients presented with vague abdominal pain of duration ranging from 1½ months to 3 months. Two patients had diagnosis confirmed histologically by CT-guided core biopsy or Fine needle aspiration procedure. We were able to avoid unnecessary laparotomy in 2 patients using preoperative guided Fine needle aspiration Cytology, although the third patient did undergo a Whipple′s procedure as the diagnosis of PPL was not considered during the initial workup.Conclusions:There is no significant difference noted with regard to patient′s age or duration of symptoms between patients with either pancreatic adenocarcinoma or PPL. The differential diagnosis of PPL includes pancreatic adenocarcinoma and secondary involvement of pancreas from extra-nodal lymphoma. Combination of two things is suggestive of Pancreatic lymphoma: (1) Bulky localized tumor in pancreatic head (2) Absence of significant dilatation of main pancreatic duct strengthens a diagnosis of pancreatic lymphoma over adenocarcinoma. Majority of patients can be managed with chemotherapy with much better prognosis compared to patients with pancreatic adenocarcinoma. Larger series of patients are needed to evaluate whether chemotherapy, eventually followed by involved-field radiation therapy, is the treatment of choice for PPL.
Primary mammary small-cell carcinoma: A case report and review of the literature
Authors: Haji Altaf Gauhar , Sharma Shekhar , Vijaykumar D K , Mukherjee Poulome , Babu R , Chitrathara K
Published: October 2009

Only a few cases of primary small-cell carcinoma of the breast have been documented in the current medical literature. A confident diagnosis can only be made if a nonmammary site is excluded or if an in-situ component can be demonstrated histologically. These criteria have been met only in a very few of the published cases, including this case report. We describe a case of a 68-year-old lady with left breast lump, which was diagnosed as breast cancer on fine-needle aspiration and core biopsy. Metastatic workup was negative for disease elsewhere, and she received 3 cycles of neoadjuvant chemotherapy followed by surgery (modified radical mastectomy). However, the disease behaved very aggressively in the postoperative period. There is a lack of consensus regarding the management of the primary tumor. Present surgical treatment options are similar to those in cases of invasive ductal breast cancer, as appropriate for the size and stage of the lesion. A review of current literature on his rare entity is also presented.
Carcinoma in situ of true vocal cord in a nonsmoker adolescent female
Authors: Mondal Dodul , Kundu Sayan , Chattopadhyay Subrata , De Sumitava , Dastidar A Ghosh , Roy Amitabha
Published: October 2009

Carcinoma in situ (precancerous lesion) of true vocal cord in a nonsmoker adolescent female without any history of prior neck irradiation is rare. A 16-year-old female patient without any of the known risk factors presented with history of gradual-onset hoarseness of voice unrelieved by symptomatic treatments for 1 year. Contrast-enhanced CT scan of neck and laryngoscopy and histopathology of the tissue from irregular lesions along the medial margin of the left vocal cord diagnosed it as a case of carcinoma in situ of vocal cord. Absence of known risk factors and very young age of the patient made this case a rarity and hence the case is being reported.
Spontaneous Current Oscillations during Hard Anodization of Aluminum under Potentiostatic Conditions
Authors: Lee Woo , Kim Jae‐Cheon , Gösele Ulrich
Published: October 2009

Nanoporous anodic aluminum oxide is prepared by hard anodization of aluminum under potentiostatic conditions using 0.3 M H2C2O4. Under unstirred electrolyte condition, spontaneous current oscillations are observed. The amplitude and period of these current oscillations are observed to increase with anodization time. As a consequence of the oscillatory behavior, the resulting anodic alumina exhibits modulated pore structures, in which the diameter contrast and the length of pore modulation increase with the amplitude and the period of current oscillations, respectively, and the current peak profile determines the internal geometry of oxide nanopores. The mechanism responsible for the oscillatory behavior is suggested to be a diffusion‐controlled anodic oxidation of aluminum.
Customized Electronic Coupling in Self‐Assembled Donor–Acceptor Nanostructures
Authors: de Oteyza Dimas G. , García‐Lastra Juan M. , Corso Martina , Doyle Bryan P. , Floreano Luca , Morgante Alberto , Wakayama Yutaka , Rubio Angel , Ortega J. Enrique
Published: October 2009

Charge transfer processes between donor–acceptor complexes and metallic electrodes are at the heart of novel organic optoelectronic devices such as solar cells. Here, a combined approach of surface‐sensitive microscopy, synchrotron radiation spectroscopy, and state‐of‐the‐art ab initio calculations is used to demonstrate the delicate balance that exists between intermolecular and molecule–substrate interactions, hybridization, and charge transfer in model donor–acceptor assemblies at metal‐organic interfaces. It is shown that charge transfer and chemical properties of interfaces based on single component layers cannot be naively extrapolated to binary donor–acceptor assemblies. In particular, studying the self‐assembly of supramolecular nanostructures on Cu(111), composed of fluorinated copper‐phthalocyanines (F16CuPc) and diindenoperylene (DIP), it is found that, in reference to the associated single component layers, the donor (DIP) decouples electronically from the metal surface, while the acceptor (F16CuPc) suffers strong hybridization with the substrate.
Novel microfibrous‐structured silver catalyst for high efficiency gas‐phase oxidation of alcohols
Authors: Mao Jiping , Deng Miaomiao , Chen Li , Liu Ye , Lu Yong
Published: October 2009

Novel microfibrous‐structured silver catalysts were developed for gas‐phase selective oxidation of mono‐/aromatic‐/di‐alcohols. Sinter‐locked three‐dimensional microfibrous networks consisting of 5 vol % 8‐μm‐Ni (or 12‐μm‐SS‐316L) fibers and 95 vol % void volume were built up by the papermaking/sintering processes. Silver was then deposited onto the surface of the sinter‐locked fibers by incipient wetness impregnation method. At relatively low temperatures (e.g., 380°C), the microfibrous‐structured silver catalysts provided quite higher activity/selectivity compared to the electrolytic silver. The microfibrous Ag/Ni‐fiber offered much better low‐temperature activity than the Ag/SS‐fiber. The interaction at Ag particles and Ni‐fiber interface not only visibly increased the active/selective sites of Ag+ ions and Agnδ+ clusters but also significantly promoted their low‐temperature reducibility and ability for O2 activation. In addition, the microfibrous structure provided a unique combination of large void volume, entirely open structure, high thermal conductivity and high permeability. © 2009 American Institute of Chemical Engineers AIChE J, 2010
Proinflammatory phenotype with imbalance of KLF2 and RelA: Risk of childhood stroke with sickle cell anemia
Authors: Enenstein Judy , Milbauer Liming , Domingo Evidio , Wells Alexandra , Roney Mark , Kiley Jim , Wei Peng , Hebbel Robert P.
Published: October 2009

Altered inflammation signaling within the cerebral vasculature may be an important risk factor for stroke in children with sickle cell anemia (SCA). This study examines how differential expression of NFκB/p65 (RelA), KLF2, and other transcription factors may act as switches in inflammation signaling leading to observed differences between non‐SCA (NS) African Americans and African Americans with SCA who are either at risk (AR) or not at risk (NAR) of childhood stroke based on occurrence of Circle of Willis disease. Clover/Transfac analysis was used to identify overrepresented transcription factor binding motifs on genes associated with inflammation. Transcription factor binding motifs for the NFκB family and RFX1 were overrepresented on inflammation signaling gene set analysis. Variations in protein expression were determined by flow cytometry of blood outgrowth endothelial cells (BOECs) from NS, AR, and NAR donors and Western blots of protein extracts from both unstimulated and TNFα/IL1β‐stimulated BOECs. BOECs from patients with SCA had more cytoplasmic‐derived RelA compared with NS BOECs. Sickle BOECs also had heightened responses to inflammatory stimuli compared with NS BOECs, as shown by increased nuclear RelA, and intracellular adhesion molecule (ICAM) response to TNFα/IL1β stimulation. Multiple control points in RelA signaling were associated with risk of childhood stroke. The ratio of proinflammatory factor RelA to anti‐inflammatory factor KLF2 was greater in BOECs from AR donors than NS donors. Group risk of childhood stroke with SCA was greatest among individuals who exhibited increased expression of proinflammatory transcription factors and decreased expression of transcription factors that suppress inflammation. Am. J. Hematol. 2010. © 2009 Wiley‐Liss, Inc.
Workers are people too: Societal aspects of occupational health disparities—an ecosocial perspective
Authors: Krieger Nancy
Published: October 2009

Workers are people too. What else is new? This seemingly self‐evident proposition, however, takes on new meaning when considering the challenging and deeply important issue of occupational health disparities—the topic that is the focus of 12 articles in this special issue of theAmerican Journal of Industrial Medicine. In this commentary, I highlight some of the myriad ways that societal determinants of health intertwine with each and every aspect of occupation‐related health inequities, as analyzed from an ecosocial perspective. The engagement extends from basic surveillance to etiologic research, from conceptualization and measurement of variables to analysis and interpretation of data, from causal inference to preventive action, and from the political economy of work to the political economy of health. A basic point is that who is employed (or not) in what kinds of jobs, with what kinds of exposures, what kinds of treatment, and what kinds of job stability, benefits, and pay—as well as what evidence exists about these conditions and what action is taken to address them—depends on societal context. At issue are diverse aspects of people's social location within their societies, in relation to their jointly experienced—and embodied—realities of socioeconomic position, race/ethnicity, nationality, nativity, immigration and citizen status, age, gender, and sexuality, among others. Reviewing the papers' findings, I discuss the scientific and real‐world action challenges they pose. Recommendations include better conceptualization and measurement of socioeconomic position and race/ethnicity and also use of the health and human rights framework to further the public health mission of ensuring the conditions that enable people—including workers—to live healthy and dignified lives. Am. J. Ind. Med. 53:104–115 2010. © 2009 Wiley‐Liss, Inc.
New route to synthesis of PVP‐stabilized palladium(0) nanoclusters and their enhanced catalytic activity in Heck and Suzuki cross‐coupling reactions
Authors: Durap Feyyaz , Metin Önder , Aydemir Murat , Özkar Saim
Published: October 2009

Herein we report a new method for the synthesis and characterization of PVP‐stabilized palladium(0) nanoclusters and their enhanced catalytic activity in Suzuki coupling and Heck reactions of aryl bromides with phenylboronic acid and styrene, respectively, under mild conditions. The PVP‐stabilized palladium(0) nanoclusters with a particle size of 4.5 ± 1.1 nm were prepared using a new method: refluxing a mixture of potassium tetrachloropalladate(II) and PVP in methanol at 80 °C for 1 h followed by reduction with sodium borohydride. Palladium(0) nanoclusters prepared in this way were stable in solution for weeks, could be isolated as solid materials and were characterized by TEM, XPS, UV–vis, and XRD techniques. The PVP‐stabilized palladium(0) nanoclusters were active catalysts in Heck and Suzuki coupling reactions of arylbromides with styrene and phenylboronic acid affording stilbenes and biphenyls, respectively, in high yield. Recycling experiments showed that PVP‐stabilized palladium(0) nanoclusters could be used five times with essentially no loss in activity in the Heck and Suzuki coupling reactions. Copyright © 2009 John Wiley & Sons, Ltd.
Access to scientific literature in India
Authors: Gaulé Patrick
Published: October 2009

This article uses an evidence‐based approach to assess the difficulties faced by developing country scientists in accessing scientific literature. I compare the backward citation patterns of Swiss and Indian scientists in a database of 43,150 scientific papers published by scientists from either country in 2007. Controlling for fields and quality with citing journal fixed effects, I find that Indian scientists have shorter reference lists (−6%) and are more likely to cite articles from open access journals (+50%). Moreover, the difference in the length of the reference list is more pronounced in biology and medicine, where circulation of (free) preprints and conference proceedings is non‐existent. Informal file‐sharing practices among scientists mitigate the effects of access restrictions.
A delimiter‐based general approach for Chinese term extraction
Authors: Yang Yuhang , Lu Qin , Zhao Tiejun
Published: October 2009

This article addresses a two‐step approach for term extraction. In the first step on term candidate extraction, a new delimiter‐based approach is proposed to identify features of the delimiters of term candidates rather than those of the term candidates themselves. This delimiter‐based method is much more stable and domain independent than the previous approaches. In the second step on term verification, an algorithm using link analysis is applied to calculate the relevance between term candidates and the sentences from which the terms are extracted. All information is obtained from the working domain corpus without the need for prior domain knowledge. The approach is not targeted at any specific domain and there is no need for extensive training when applying it to new domains. In other words, the method is not domain dependent and it is especially useful for resource‐limited domains. Evaluations of Chinese text in two different domains show quite significant improvements over existing techniques and also verify its efficiency and its relatively domain‐independent nature. The proposed method is also very effective for extracting new terms so that it can serve as an efficient tool for updating domain knowledge, especially for expanding lexicons.
The impact factor's Matthew Effect: A natural experiment in bibliometrics
Authors: Larivière Vincent , Gingras Yves
Published: October 2009

Since the publication of Robert K. Merton's theory of cumulative advantage in science (Matthew Effect), several empirical studies have tried to measure its presence at the level of papers, individual researchers, institutions, or countries. However, these studies seldom control for the intrinsic “quality” of papers or of researchers—“better” (however defined) papers or researchers could receive higher citation rates because they are indeed of better quality. Using an original method for controlling the intrinsic value of papers—identical duplicate papers published in different journals with different impact factors—this paper shows that the journal in which papers are published have a strong influence on their citation rates, as duplicate papers published in high‐impact journals obtain, on average, twice as many citations as their identical counterparts published in journals with lower impact factors. The intrinsic value of a paper is thus not the only reason a given paper gets cited or not, there is a specific Matthew Effect attached to journals and this gives to papers published there an added value over and above their intrinsic quality.
Document categorization in legal electronic discovery: computer classification vs. manual review
Authors: Roitblat Herbert L. , Kershaw Anne , Oot Patrick
Published: October 2009

In litigation in the US, the parties are obligated to produce to one another, when requested, those documents that are potentially relevant to issues and facts of the litigation (called “discovery”). As the volume of electronic documents continues to grow, the expense of dealing with this obligation threatens to surpass the amounts at issue and the time to identify these relevant documents can delay a case for months or years. The same holds true for government investigations and third‐parties served with subpoenas. As a result, litigants are looking for ways to reduce the time and expense of discovery. One approach is to supplant or reduce the traditional means of having people, usually attorneys, read each document, with automated procedures that use information retrieval and machine categorization to identify the relevant documents. This study compared an original categorization, obtained as part of a response to a Department of Justice Request and produced by having one or more of 225 attorneys review each document with automated categorization systems provided by two legal service providers. The goal was to determine whether the automated systems could categorize documents at least as well as human reviewers could, thereby saving time and expense. The results support the idea that machine categorization is no less accurate at identifying relevant/responsive documents than employing a team of reviewers. Based on these results, it would appear that using machine categorization can be a reasonable substitute for human review.
Genome‐scale analysis of library sorting (GALibSo): Isolation of secretion enhancing factors for recombinant protein production in Pichia pastoris
Authors: Stadlmayr Gerhard , Benakovitsch Katrin , Gasser Brigitte , Mattanovich Diethard , Sauer Michael
Published: October 2009

A method combining fluorescence activated cell sorting (FACS) and DNA microarray assisted clone identification was developed and termed Genome‐Scale Analysis of Library Sorting (GALibSo). Genes enhancing the production of secreted heterologous proteins in Pichia pastoris were identified out of a cDNA library by cell surface display and FACS. The trends of gene enrichment during consecutive FACS rounds were monitored by DNA microarrays. In a case study a P. pastoris cDNA library was co‐expressed in a strain secreting the Fab fragment of a monoclonal antibody against human immunodeficiency virus type 1 as a model protein. Three genes were identified, increasing the relative expression level of the surface‐displayed model protein up to 45%. While one of these genes had a positive effect on three out of four tested proteins, the product specific effect of the other two suggested that the effects of the co‐expressed secretion enhancing factors are partly dependent on the protein to be produced. The microarray based monitoring of the enrichment of genes causing enhanced protein secretory capacity led to novel insights into the limitation of protein secretion. Biotechnol. Bioeng. 2010; 105: 543–555. © 2009 Wiley Periodicals, Inc.
PEGDA hydrogels with patterned elasticity: Novel tools for the study of cell response to substrate rigidity
Authors: Nemir Stephanie , Hayenga Heather N. , West Jennifer L.
Published: October 2009

The ability of cells to migrate in response to mechanical gradients (durotaxis) and differential cell behavior in adhesion, spreading, and proliferation in response to substrate rigidity are key factors both in tissue engineering, in which materials must be selected to provide the appropriate mechanical signals, and in studies of mechanisms of diseases such as cancer and atherosclerosis, in which changes in tissue stiffness may inform cell behavior. Using poly(ethylene glycol) diacrylate hydrogels with varying polymer chain length and photolithographic patterning techniques, we are able to provide substrates with spatially patterned, tunable mechanical properties in both gradients and distinct patterns. The hydrogels can be patterned to produce anisotropic structures and exhibit patterned strain under mechanical loading. These hydrogels may be used to study cell response to substrate rigidity in both two and three dimensions and can also be used as a scaffold in tissue‐engineering applications. Biotechnol. Bioeng. 2010; 105: 636–644. © 2009 Wiley Periodicals, Inc.
Considerations for the design and construction of a synthetic platform cell for biotechnological applications
Authors: Foley P.L. , Shuler M.L.
Published: October 2009

The design and construction of an artificial bacterial cell could revolutionize biotechnological processes and technologies. A functional platform cell that can be easily customized for a pre‐defined task would be useful for applications from producing therapeutics to decontaminating waste streams. The platform cell must be robust and highly efficient. A biotechnological platform cell is related to the concept of a minimal cell, but several factors beyond those necessary for a minimal cell must be considered for a synthetic organism designed for biotechnological applications. Namely, a platform cell must exhibit robust cell reproduction, decreased genetic drift, a physically robust cell envelope, efficient and simplified transcription and translation controls, and predictable metabolic interactions. Achieving a biotechnological platform cell will benefit from insights acquired from a minimal cell, but an approach of minimizing an existing organism's genome may be a more practical experimental approach. Escherichia coli possess many of the desired characteristics of a platform cell and could serve as a useful model organism for the design and construction of a synthetic platform organism. In this article we review briefly the current state of research in this field and outline specific characteristics that will be important for a biotechnologically relevant synthetic cell that has a minimized genome and efficient regulatory structure. Biotechnol. Bioeng. 2010; 105: 26–36. © 2009 Wiley Periodicals, Inc.
IgG‐single chain Fv fusion protein therapeutic for alzheimer's disease: Expression in CHO cells and pharmacokinetics and brain delivery in the rhesus monkey
Authors: Boado Ruben J. , Lu Jeff Zhiqiang , Hui Eric Ka‐Wai , Pardridge William M.
Published: October 2009

Monoclonal antibodies (MAb) directed against the Abeta amyloid peptide of Alzheimer's disease (AD) are potential new therapies for AD, since these antibodies disaggregate brain amyloid plaque. However, the MAb is not transported across the blood–brain barrier (BBB). To enable BBB transport, a single chain Fv (ScFv) antibody against the Abeta peptide of AD was re‐engineered as a fusion protein with the MAb against the human insulin receptor (HIR). The HIRMAb acts as a molecular Trojan horse to ferry the ScFv therapeutic antibody across the BBB. Chinese hamster ovary (CHO) cells were stably transfected with a tandem vector encoding the heavy and light chains of the HIRMAb–ScFv fusion protein. A high secreting line was isolated following methotrexate amplification and dilutional cloning. The HIRMAb–ScFv fusion protein in conditioned serum‐free medium was purified by protein A affinity chromatography. The fusion protein was stable as a liquid formulation, and retained high‐affinity binding of both the HIR and the Abeta amyloid peptide. The HIRMAb–ScFv fusion protein was radiolabeled with the 125I‐Bolton–Hunter reagent, followed by measurement of the pharmacokinetics of plasma clearance and brain uptake in the adult Rhesus monkey. The HIRMAb–ScFv fusion protein was rapidly cleared from plasma and was transported across the primate BBB in vivo. In conclusion, the HIRMAb–ScFv fusion protein is a new class of antibody‐based therapeutic for AD that has been specifically engineered to cross the human BBB. Biotechnol. Bioeng. 2010; 105: 627–635. © 2009 Wiley Periodicals, Inc.
Behavior of Marinobacter hydrocarbonoclasticus SP17 cells during initiation of biofilm formation at the alkane–water interface
Authors: Klein Benjamin , Bouriat Patrick , Goulas Philippe , Grimaud Régis
Published: October 2009

Hexadecane assimilation by Marinobacter hydrocarbonoclasticus SP17 occurs through the formation of a biofilm at the alkane–water interface. In this study we focused on the interactions of cells with the alkane–water interface occurring during initiation of biofilm development. The behavior of cells at the interface was apprehended by investigating alterations of the mechanical properties of the interface during cell adsorption, using dynamic drop tensiometry measurements. It was found that after having reached the hexadecane–water interface, by a purely thermal diffusion process, cells released surface‐active compounds (SACs) resulting in the formation of an interfacial visco‐elastic film. Release of SACs was an active process requiring protein synthesis. This initial interaction occurred on metabolizable as well as non‐metabolizable alkanes, indicating that at this stage cells are not affected by the nature of the alkane forming the interface. In contrast, at a later stage, the nature of the interface turned out to exert control over the behavior of the cells. The availability of a metabolizable alkane at the interface influenced cell activity, as revealed by cell cluster formation and differences in the interfacial elasticity. Biotechnol. Bioeng. 2010; 105: 461–468. © 2009 Wiley Periodicals, Inc.
Hydrodynamic modulation of embryonic stem cell differentiation by rotary orbital suspension culture
Authors: Sargent Carolyn Y. , Berguig Geoffrey Y. , Kinney Melissa A. , Hiatt Luke A. , Carpenedo Richard L. , Berson R. Eric , McDevitt Todd C.
Published: October 2009

Embryonic stem cells (ESCs) can differentiate into all somatic cell types, but the development of effective strategies to direct ESC fate is dependent upon defining environmental parameters capable of influencing cell phenotype. ESCs are commonly differentiated via cell aggregates referred to as embryoid bodies (EBs), but current culture methods, such as hanging drop and static suspension, yield relatively few or heterogeneous populations of EBs. Alternatively, rotary orbital suspension culture enhances EB formation efficiency, cell yield, and homogeneity without adversely affecting differentiation. Thus, the objective of this study was to systematically examine the effects of hydrodynamic conditions created by rotary orbital shaking on EB formation, structure, and differentiation. Mouse ESCs introduced to suspension culture at a range of rotary orbital speeds (20–60 rpm) exhibited variable EB formation sizes and yields due to differences in the kinetics of cell aggregation. Computational fluid dynamic analyses indicated that rotary orbital shaking generated relatively uniform and mild shear stresses (≤2.5 dyn/cm2) within the regions EBs occupied in culture dishes, at each of the orbital speeds examined. The hydrodynamic conditions modulated EB structure, indicated by differences in the cellular organization and morphology of the spheroids. Compared to static culture, exposure to hydrodynamic conditions significantly altered the gene expression profile of EBs. Moreover, varying rotary orbital speeds differentially modulated the kinetic profile of gene expression and relative percentages of differentiated cell types. Overall, this study demonstrates that manipulation of hydrodynamic environments modulates ESC differentiation, thus providing a novel, scalable approach to integrate into the development of directed stem cell differentiation strategies. Biotechnol. Bioeng. 2010; 105: 611–626. © 2009 Wiley Periodicals, Inc.
Stability‐indicating HPTLC method for quantitative estimation of silybin in bulk drug and pharmaceutical dosage form
Authors: Parveen Rabea , Ahmad Sayeed , Baboota Sanjula , Ali Javed , Alka Ahuja
Published: October 2009

In the present study a novel stability‐indicating high‐performance thin‐layer chromatography (HPTLC) method for quantitative determination of silybin in bulk drug and nanoemulsion formulation has been developed and validated on silica using solvent chloroform–acetone–formic acid (9 : 2 : 1 v/v/v) (Rf of silybin 0.46 ± 0.05) in the absorbance mode at 296 nm. The method showed a good linear relationship (r2 ± 0.999) in the concentration range 25–1500 ng per spot. It was found to be linear, accurate, precise, specific, robust and stability‐indicating and can be applied for quality control and standardization of several multi‐component hepatoprotective formulations as well as for stability testing of different dosage forms. The method proposed was also used to investigate the kinetics of acidic and alkaline degradation processes by quantification of drug at different temperature to calculate the activation energy and half‐life for silymarin degradation. Copyright © 2009 John Wiley & Sons, Ltd
Carbon Dioxide Desorption from Saturated Organic Solvents
Authors: Kierzkowska‐Pawlak H. , Chacuk A.
Published: October 2009

Carbon dioxide removal from various gaseous streams and its subsequent recovery are of considerable industrial importance. The absorption technologies represent the most important operation to separate CO2. In this work, the mass transfer rates during CO2 absorption and desorption from propylene carbonate dimethyl ether of polyethylene glycol, and N‐methyl‐2‐pyrrolidone solutions were measured over the temperature range of 293.15–323.15 K in a baffled agitated reactor with a flat gas‐liquid interface operated in a batchwise manner. Two distinct mechanisms of desorption were observed: bubbling and diffusive desorption. The volumetric gas‐liquid mass transfer coefficients for the bubbling desorption were determined from the measured overall and diffusive desorption rates, and were correlated by the semi‐empirical equation. The proposed correlation is a power relationship of supersaturation, Reynolds and Weber numbers, and was found to quantitatively explain the observed phenomena with satisfactory agreement.