bluuebunny/crossref_metadata_2025_split huggingface dataset:
Surviving the paradoxes of virtual teamwork
Authors: Dubé Line , Robey Daniel 
Published: July 2008

AbstractDespite the potential benefits of virtual teams, current literature suggests that virtual teamwork is rife with complex challenges. We frame some of these challenges as paradoxes inherent in the concept of virtual teamwork. Based on interviews with 42 leaders and members of virtual teams, we identify five paradoxes: (1) virtual teams require physical presence; (2) flexibility of virtual teamwork is aided by structure; (3) interdependent work in virtual teams is accomplished by members' independent contributions; (4) task‐oriented virtual teamwork succeeds through social interactions; and (5) mistrust is instrumental to establishing trust among virtual team members. In addition, we identify strategies that respondents used to cope with, or ‘survive’ the paradoxes of virtual teamwork.
An easy method using glutaraldehyde‐introduced fluorescence for the microscopic analysis of plant biotrophic interactions
Authors: FESTER T. , BERG R.H. , TAYLOR C.G. 
Published: July 2008

SummaryThe method introduced in this article makes use of the glutaraldehyde‐induced auto‐fluorescence of proteins after cross‐linking with glutaraldehyde for the analysis of cellular and sub‐cellular structures. Because the interface of biotrophic interactions is rich in proteins, the method presented is particularly suitable for the analysis of such interactions; we have exemplified its usefulness by analyzing (1) the root feeding sites induced in roots fromArabidopsis thalianaby the root‐knot nematodeMeloidogyne incognita; (2) leaves fromCucurbita pepoinfected by powdery mildew and (3) roots fromNicotiana tabacumcolonized by the arbuscular mycorrhizal fungusGlomus intraradices. The use of confocal and multi‐photon laser scanning microscopy allows three‐dimensional reconstructions from optical sections of complex biotrophic interactions. In the case of root‐knot nematode feeding sites, our method enabled us to simultaneously study the development of the plant xylem elements (using lignin auto‐fluorescence), the nematode feeding site and the nematode itself.
Hydrodynamic flow in the cytoplasm of plant cells
Authors: ESSELING‐OZDOBA A. , HOUTMAN D. , VAN LAMMEREN A.A.M. , EISER E. , EMONS A.M.C. 
Published: July 2008

SummaryPlant cells show myosin‐driven organelle movement, called cytoplasmic streaming. Soluble molecules, such as metabolites do not move with motor proteins but by diffusion. However, is all of this streaming active motor‐driven organelle transport? Our recent simulation study (Houtman et al., 2007) shows that active transport of organelles gives rise to a drag in the cytosol, setting up a hydrodynamic flow, which contributes to a fast distribution of proteins and nutrients in plant cells. Here, we show experimentally that actively transported organelles produce hydrodynamic flow that significantly contributes to the movement of the molecules in the cytosol. We have used fluorescence recovery after photobleaching and show that in tobacco Bright Yellow 2 (BY‐2) suspension cells constitutively expressing cytoplasmic green fluorescent protein (GFP), free GFP molecules move faster in cells with active transport of organelles than in cells where this transport has been inhibited with the general myosin inhibitor BDM (2,3‐butanedione monoxime). Furthermore, we show that the direction of the GFP movement in the cells with active transport is the same as that of the organelle movement and that the speed of the GFP in the cytosol is proportional to the speed of the organelle movement. In large BY‐2 cells with fast cytoplasmic streaming, a GFP molecule reaches the other side of the cell approximately in the similar time frame (about 16 s) as in small BY‐2 cells that have slow cytoplasmic streaming. With this, we suggest that hydrodynamic flow is important for efficient transport of cytosolic molecules in large cells. Hydrodynamic flow might also contribute to the movement of larger structures than molecules in the cytoplasm. We show that synthetic lipid (DOPG) vesicles and ‘stealth’ vesicles with PEG phospholipids moved in the cytoplasm.
Pectin‐like carbohydrates in the green algaMicrasteriascharacterized by cytochemical analysis and energy filtering TEM
Authors: EDER M. , LÜTZ‐MEINDL U. 
Published: July 2008

SummaryPectins are the major matrix polysaccharides of plant cell walls and are important for controlling growth, wall porosity and regulation of the ionic environment in plant cells. Pectic epitopes recognized by the monoclonal antibodies JIM5, JIM7 and 2F4 could be localized in the primary wall during development of the green algaMicrasterias. As the degree of pectin esterification determines the calcium‐binding capacity and thus the physical properties of the cell wall, chemical and enzymaticin situde‐esterification was performed. This resulted in displacement of epitopes recognized by JIM5, JIM7 and 2F4, respectively, in changes in the intensity of the antibody labelling as visualized in CLSM. In addition, calcium‐binding capacities of cell walls and components of the secretory apparatus were determined in transmission electron microscopy by electron energy loss spectroscopy and electron spectroscopic imaging. These analyses revealed that pectic polysaccharides are transported to the cell wall in a de‐esterified form. At the primary wall, pectins get methyl‐esterified at the inner side, thus allowing flexibility of the wall. At the outer side of the wall they become again de‐esterified and bind high amounts of calcium which leads to cell wall stiffening. Mucilage vesicles posses the highest calcium‐binding capacity of all structures observed inMicrasterias, indicating that the pectic polysaccharides of mucilage are secreted in a de‐esterified, compact form. When mucilage is excreted through the cell wall, it loses its ability to bind calcium. The esterification of pectins involved is obviously required for swelling of mucilage by water uptake, which generates the motive force for orientation of this unicellular organism in respect to light. Incubation ofMicrasteriasin pectin methylesterase (PME), which de‐esterifies pectic polymers in higher plants, resulted in growth inhibition, cell shape malformation and primary wall thickening. A PME‐like enzyme could be found inMicrasteriasby PME activity assays.
The role of the plant cytoskeleton in the interaction between legumes and rhizobia
Authors: TIMMERS A. C. J. 
Published: July 2008

SummaryThe study of the symbiotic interaction between rhizobia and legumes represents a major theme in plant biology. This interaction results in the formation of nodules, root organs in which the bacteria reduce atmospheric nitrogen into ammonia, which can subsequently be utilized by the plant. The execution of the different developmental stages observed during nodule ontogenesis involves many cellular processes with significant roles for the plant cytoskeleton. A challenging question in cell biology is how the cytoskeleton organizes itself into the dynamic arrays required for cell differentiation and functioning. Nodulation is, particularly, well qualified as an experimental system for cytoskeleton research because an early essential step of the plant/microbe interaction takes place in surface‐exposed root hairs, well suited for cell biological in vivo experimentation. Moreover, the changes in the organization of the cytoskeleton can be elicited by a well‐defined molecule, the Nod factor, or by bacterial inoculation, thus providing the researcher with the possibility of controlling the cytoskeletal changes in target cells. In addition, the well‐known cytology of the symbiotic interaction facilitates the correlation between the changes in the organization of the plant cytoskeleton with both histological and cellular changes. In this review, the current knowledge on the role of the plant cytoskeleton during nodulation is summarized, with emphasis on the interaction between Medicago truncatula and Sinorhizobium meliloti.
Olive pollen profilin (Ole e 2 allergen) co‐localizes with highly active areas of the actin cytoskeleton and is released to the culture medium during in vitro pollen germination
Authors: MORALES S. , JIMÉNEZ‐LÓPEZ J.C. , CASTRO A.J. , RODRÍGUEZ‐GARCÍA M.I. , ALCHÉ J.D. 
Published: July 2008

SummaryPollen allergens offer a dual perspective of study: some of them are considered key proteins for pollen physiology, but they are also able to trigger allergy symptoms in susceptible humans after coming in contact with their tissues. Profilin (Ole e 2 allergen) has been characterized, to some extent, as one of the major allergens from Olea europaea L. pollen, a highly allergenic species in the Mediterranean countries. In order to obtain clues regarding the biological role of this protein, we have analyzed both its cellular localization and the organization of actin throughout pollen hydration and early pollen tube germination. The localization of the cited proteins was visualized by confocal laser scanning microscopy immunofluorescence using different antibodies. Upon pollen hydration and pollen germination, a massive presence of profilin was detected close to the site of pollen tube emergence, forming a ring‐like structure around the ‘effective’ apertural region. Profilin was also detected in the pollen exine of the germinating pollen grains and in the germination medium. After using a permeabilization‐enhanced protocol for immunolocalization, profilin was also localized in the cytoplasm of the pollen tube, particularly at both the proximal and apical ends. Noticeable accumulations of actin were observed in the cytoplasm of the pollen tube; particularly, in both the apical region and the area immediately close to the aperture. Actin filaments were not observed, probably due to the need of further enhanced fixation procedures. The ultrastructural localization of profilin showed the presence of the protein in the cytoplasm of both the mature pollen grain and the pollen tube.The results shown here could be interpreted as signs of a massive dissociation of the actin–profilin complexes, mobilization of actin monomers, and therefore, an intense activity of the actin cytoskeleton. The extensive release of allergenic proteins from the pollen grain into the surrounding aqueous media, as described here for profilin, may help us to understand the mechanisms by which these allergens might come in contact with the human mucosa, therefore triggering the symptoms of allergy.
Overbank sedimentation rates in former channel lakes: characterization and control factors
Authors: CITTERIO ANNE , PIÉGAY HERVE 
Published: July 2008

AbstractOverbank sedimentation rates were studied in former channels of three rivers in south‐eastern France. Depth and spatial distribution of sediment, as well as geometry, hydrological connectivity and age of 39 lakes, were both measured and calculated. The mean sedimentation rate of lakes varied between 0 and 2·57 cm year−1. Sedimentation rates are linked to water depth and often undergo a decreasing gradient from the downstream outlet to the inner part of the lake. Multiple regression modelling demonstrates that sediment depth is essentially a function of overbank flow frequency. The greater the difference between upstream and downstream overbank flow frequency, the faster the sedimentation rate. These differences in sedimentation rates also correspond to different former channel geometry: the rates are slower in narrow and straight channels (former braided, and point‐bar backwater channels), and faster in large and sinuous channels (exhibiting meanders, anastomosing channels and coves). The suspended sediment flux is variable from one reach to another, the middle reach of the Rhône conveying more sediment than the upper reaches, the Doubs or the Ain reaches. The suspended sediment flux does not explain a statistical difference in lake sedimentation rates between the reaches, which also provide clear evidence of the importance of local connectivity controls. Sedimentation patterns were also complicated by temporal changes in lake connectivity associated with geomorphological or anthropogenic changes operating within the main channel.
Gallstones and Clonorchis sinensis infection: A hospital‐based case–control study in Korea
Authors: Choi Dongil , Lim Jae Hoon , Lee Kyu Taek , Lee Jong Kyun , Choi Seong Ho , Heo Jin Seok , Choi Dong Wook , Jang Kee‐Taek , Lee Nam Yong , Kim Seonwoo , Hong Sung‐Tae 
Published: July 2008

AbstractBackground and Aim:  A high prevalence of intrahepatic stones in some areas of East Asia has been believed to be related with Clonorchis sinensis infection. The authors conducted a hospital‐based case–control study to evaluate the role of Clonorchis sinensis infection as a risk factor for the development of gallstones in Korea.Methods:  The cases of 138 patients with gallstones (intrahepatic 44, gallbladder 67, and extrahepatic 27) and matched controls underwent microscopy for C. sinensis, serological tests for C. sinensis using enzyme‐linked immunosorbent assay, radiological examinations, and interviews concerning the history of eating raw freshwater fish. We assessed a relationship of three types of gallstones and variables regarding C. sinensis by using univariate and multivariate statistical analyses.Results:  Univariate statistical analyses showed that radiological evidence of C. sinensis and recent history of eating raw freshwater fish were related to an increased risk of intrahepatic stones (P = 0.0002 and 0.0039, respectively). According to multivariate statistical analyses, radiological evidence of C. sinensis was the only risk factor for intrahepatic stones (odds ratio = 7.835; 95% confidence interval = 1.671–36.724). Any evidence regarding C. sinensis was not related to an increased risk of either gallbladder or extrahepatic stones.Conclusion:  Radiological evidence of C. sinensis was significantly associated with intrahepatic stones.
Expression of Toll‐like receptor 4 in various organs in rats with d‐galactosamine‐induced acute hepatic failure
Authors: Kitazawa Toshiyuki , Tsujimoto Tatsuhiro , Kawaratani Hideto , Fujimoto Masao , Fukui Hiroshi 
Published: July 2008

AbstractBackground and Aims:  Activation of the pro‐inflammatory cytokine cascade, including tumor necrosis factor alpha (TNF‐α) is considered to play an important role in the pathophysiology and clinical outcome of severe liver injury. Kupffer cells, resident macrophages of the liver, have a transmembrane protein Toll‐like receptor 4 (TLR4), which recognizes endotoxin (lipopolysaccharide; LPS) or LPS‐CD14 complex and mediates macrophage activation and pro‐inflammatory cytokine release. d‐Galactosamine (GalN), a hepatocyte‐specific inhibitor of RNA synthesis, is known to sensitize animals to the lethal effects of LPS and TNF‐α. In the present study we seek to address TLR4‐signaling in the development of GalN‐induced acute hepatic failure (AHF) and explore the expression of TLR4 mRNA as compared to TNF‐α mRNA and CD14 mRNA in the liver, spleen and lung of rats with GalN‐induced hepatitis.Methods:  AHF was induced in male Wistar rats by the intraperitoneal injection of 1 g/kg bodyweight GalN. Expression levels of TNF‐α, TLR4 and CD14 mRNA in the whole liver, spleen and lung of rats were detected by reverse transcription–polymerase chain reaction analysis.Results:  Expression level of TLR4 mRNA in the liver of rats with GalN‐induced AHF was increased parallel with that of TNF‐α and CD14 mRNA as compared to the control rats. However, expression levels of TNF‐α, TLR4 and CD14 mRNA in the whole spleen and lung were not different between rats with AHF and control.Conclusions:  There may be a difference of stimulatory effects of endotoxin on the innate immunity between the liver and other organs of rats with GalN‐induced AHF.
Brush border enzyme activities in relation to histological lesion in pediatric celiac disease
Authors: Prasad Kaushal K , Thapa Babu R , Nain Chander K , Sharma Arun K , Singh Kartar 
Published: July 2008

AbstractBackground and Aim:  In celiac disease (CD), abnormalities of brush border enzyme activities have been detected in the course of the disease activity. There are conflicting results on intestinal mucosal enzyme activities and its correlation to mucosal injury in CD. The aim of the present study was to evaluate the brush border enzyme activities (disaccharidases and alkaline phosphatase) in the duodenal mucosa of North Indian children with CD and to examine their correlation to duodenal mucosal morphological alterations.Methods:  This prospective study included 71 children with CD and 29 controls (patients with gastroesophageal reflux disease) in whom upper gastrointestinal endoscopy was performed and distal duodenal biopsies were taken for histological assessment, and estimation of disaccharidases and alkaline phosphatase activities. Each biopsy sample was classified according to the modified Oberhuber classification. Lactase, sucrase, maltase and alkaline phosphatase activities were estimated in duodenal biopsy homogenates from patients with CD and from controls. The association between enzyme activities and duodenal morphology was examined.Results:  The mean age of the 71 patients with CD (M:F, 43:28) was 6.0 ± 0.3 years and mean age of onset of symptoms was 2.7 ± 0.4 years. Sixty‐four of 71 (90.1%) CD patients showed type 3 (destructive) lesion, whereas it was grade 0 in all patients with gastroesophageal reflux disease. In CD and patients with gastroesophageal reflux disease, the mean level (IU/g protein) of lactase was 12.1 ± 0.9 versus 24.4 ± 1.0 (P < 0.001), mean level of sucrase was 25.9 ± 1.9 versus 42.5 ± 1.9 (P < 0.001), mean level of maltase was 56.6 ± 3.5 versus 76.1 ± 13.0 (NS), and mean level of alkaline phosphatase was 602.8 ± 56.2 versus 1359.3 ± 51.2 (P < 0.001), respectively. The mean disaccharidases and alkaline phosphatase levels were not significantly different in patients with milder lesions (type 2 and type 3a) compared with those of control. However, mean lactase, sucrase and alkaline phosphatase levels were significantly lower (P < 0.001) in CD patients with moderate (type 3b) and severe (type 3c) lesions compared with control.Conclusions:  A generalized decrease of disaccharidases and alkaline phosphatase activity was seen in the duodenal mucosa of children with CD. The depressed activities of lactase, sucrase and alkaline phosphatase were well correlated with the histological grade of duodenal mucosal lesions in children with CD.
Prognostic models in cirrhotics admitted to intensive care units better predict outcome when assessed at 48 h after admission
Authors: Cholongitas Evangelos , Betrosian Alex , Senzolo Marco , Shaw Steve , Patch David , Manousou Pinelopi , O'Beirne James , Burroughs Andrew K 
Published: July 2008

AbstractBackground and Aim:  The accuracy of prognostic models in critically ill cirrhotics at admission to intensive care units (ICU) may be unreliable. Predictive accuracy could be improved by evaluating changes over time, but this has not been published. The aim of the present study was to assess the performance of prognostic models in cirrhotics at admission (baseline) and at 48 h to predict mortality in the ICU or within 6 weeks after discharge from the ICU.Methods:  One hundred and twenty‐eight cirrhotics (77 males, mean age 49 ± 11.3 years) were consecutively admitted and alive 48 h after admission with 89% on mechanical ventilation, 76% on inotrope support, and 42% with renal failure. Prognostic models used were Child‐Turcotte‐Pugh (CTP), Model for End‐stage Liver Disease (MELD), Acute Physiology and Chronic Health Evaluation (APACHE) II, Sequential Organ Failure Assessment (SOFA), failing organ systems (FOS) at baseline and at 48 h, Δscore (difference between baseline and at 48 h) and the mean score (MN − score admission + 48 h/2) which were compared by area under the receiver operating characteristic curves (AUC).Results:  Mortality was 54.7% (n = 70) due to multiple organ failure in 55%. CTP, MELD, APACHE II, SOFA and FOS performed better at 48 h (AUC: 0.78, 0.86, 0.78, 0.88 and 0.85, respectively) than at baseline (AUC: 0.75, 0.78, 0.75, 0.81 and 0.79, respectively). The mean score had better discrimination than the baseline score; the Δscore had poor predictive ability (AUC < 0.70). SOFA score (48 h: 0.88, mean: 0.88) and FOS (mean: 0.88) had the best accuracy, with a SOFA and MN‐SOFA ≥ 10 predicting mortality in 93% and 91%, respectively, and MN‐FOS ≥ 1.5 in 98%.Conclusions:  In cirrhotics, prognostic scores in the ICU at 48 h had better discrimination than baseline scores for short‐term mortality. SOFA and FOS models had the best performance.
Bone marrow findings in patients with autoimmune liver diseases
Authors: Tsikrikoni Aikaterini , Rigopoulou Eirini I , Zachou Kalliopi , Liaskos Christos , Kyriakou Despina , Dalekos George N 
Published: July 2008

AbstractBackground and Aims:  We have recently reported quantitative and qualitative differences of the bone marrow (BM) hematopoietic progenitor cells in autoimmune hepatitis type‐1 (AIH‐1) and primary biliary cirrhosis (PBC). In order to better investigate the possible involvement of BM in these diseases, we studied the morphological abnormalities of BM aspirates in the same patients with AIH‐1 and PBC.Methods:  BM smears from 13 AIH‐1 and 13 PBC patients were investigated. BM from 12 patients with cirrhosis of non‐autoimmune etiology and eight healthy individuals served as pathological (PC) and healthy controls (HC).Results:  Erythroid, granulocyte and platelet precursors were variably altered. Polychromatic normoblasts and immature megakayocytes were higher in AIH‐1 (11.9 ± 2.9 and 16.2 ± 16.9, respectively) and PBC (10.2 ± 3.6 and 17.3 ± 20.2, respectively) compared to PC (7 ± 2 and 2.3 ± 6.0, respectively) and HC (7.9 ± 1.6 and 0 ± 0, respectively) (P = 0.0001 and P = 0.006). In AIH‐1, immature megakaryocytes were significantly higher in patients receiving immunosuppression (25.71 ± 17.66 vs 5.00 ± 5.48; P < 0.02) and were associated negatively with laboratory markers of disease activity. BM plasmacytosis was observed more frequently in AIH‐1 compared to PBC and PC. BM monocytosis was found in all patients with AIH‐1, PBC and PC whereas approximately half of the patients with autoimmune liver diseases and all PC had BM lymphocytosis.Conclusions:  BM monocytosis and lymphocytosis are commonly found in AIH‐1 and PBC patients irrespective of the presence of cirrhosis or the use of immunosuppression. BM plasmacytosis appears to be a distinct finding in some AIH‐1 patients, as similar findings were observed in only one PBC and one PC, whereas BM immature megakaryocytes characterize both AIH‐1 and PBC. Whether BM is a target organ in AIH‐1 and PBC needs further investigation.
Tumor and liver determinants of prognosis in unresectable hepatocellular carcinoma: A case cohort study
Authors: Carr Brian I , Buch Shama C , Kondragunta Venkateswarlu , Pancoska Petr , Branch Robert A 
Published: July 2008

AbstractBackground and Aims:  A total of 967 patients with unresectable and untransplantable, biopsy‐proven hepatocellular carcinoma (HCC) were prospectively evaluated at baseline and followed up till death.Methods:  Survival was the end‐point for all analyses.Results:  We found in our overall analysis, that male gender, ascites, cirrhosis, portal vein thrombosis (PVT), elevated alpha‐fetoprotein (AFP) or bilirubin or alkaline phosphatases were each statistically significant adverse prognostic factors. Patients with normal AFP survived longer than those with elevated AFP, in the presence of PVT, large or bilobar tumors or cirrhosis. We used a bivariate analysis to separate patient subgroups based on poor liver function and aggressive tumor characteristics. In subgroup analysis based on these subsets, there was clear discrimination in survival between subsets; in addition both cirrhosis and presence of PVT were significant, independent but modest risk factors. The results of this large dataset show that amongst nonsurgical HCC patients, there are clear subsets with longer survival than other subsets.Conclusions:  This data also supports the concept of heterogeneity of HCC.