bluuebunny/crossref_metadata_2025_split huggingface dataset:
An amphibian model to test the effects of xenobiotic chemicals on development of the hematopoietic system
Authors: Rollins-Smith Louise A , Hopkins B. Diane , Reiner Laura K 
Published: November 2004

Abstract
A number of manmade chemicals have deleterious effects on the developing immune system. Very few assay systems are available to study the effects of xenobiotics on hematopoietic stem cells. In rodent models, assays require exposure of pregnant females and analysis of the hematopoietic potential of stem cells from the offspring. These models are less relevant to lower vertebrates such as fish or amphibians where exposure of embryos is direct. To overcome this problem, an amphibian model was developed. Diploid (2N) embryos (16–20 h of age) of the South African clawed frog, Xenopus laevis, were exposed to 10 μg/ml diazinon or 10−6 M lead acetate for 2 h. After 2 h, the ventral blood island (VBI) was transplanted from a chemically treated or untreated control embryo to an untreated triploid (3N) host embryo. After 55 d, the contribution of the donor VBI-derived stem cells to populations in the blood, thymus, and spleen was assessed by flow cytometry. Diazinon, but not lead acetate, interfered with the ability of transplanted stem cells to contribute to hematopoiesis. Because amphibian embryos are very sensitive indicators of the toxic effects of chemicals, this VBI assay could be employed to test any toxic chemical that is suspected of having a negative effect on development of the hematopoietic system.
Influence of multiple water-quality characteristics on copper toxicity to fathead minnows (Pimephales promelas)
Authors: Sciera Katherine L , Isely J. Jeffery , Jr. Tomasso Joseph R , Klaine Stephen J 
Published: November 2004

Abstract
Water quality influences the bioavailability and toxicity of copper to aquatic organisms. Understanding the relationships between water-quality parameters and copper toxicity may facilitate the development of site-specific criteria for water quality and result in better protection of aquatic biota. Many studies have examined the influence of a single water-quality parameter on copper toxicity, but the interactions of several characteristics have not been well studied in low-hardness water. The goal of the present research was to examine the interactions among water-quality characteristics and their effects on copper toxicity to larval fathead minnows (Pimephales promelas). The effects of dissolved organic carbon (DOC) concentration, DOC source, pH, and hardness on acute copper toxicity were determined using a complete factorially designed experiment. Hardness, pH, DOC, and interaction of pH and DOC all significantly affected copper toxicity. A predictive model based on these data described 88% of the variability in copper toxicity. This model also explained 58% of the variability in copper toxicity for an independent dataset of South Carolina (USA) waters. The biotic ligand model underpredicted the acute copper toxicity to fathead minnows when compared with observed values.
Genotoxicity in native fish associated with agricultural runoff events
Authors: Whitehead Andrew , Kuivila Kathryn M , Orlando James L , Kotelevtsev Sergey , Anderson Susan L 
Published: November 2004

Abstract
The primary objective of the present study was to test whether agricultural chemical runoff was associated with instream genotoxicity in native fish. Using Sacramento sucker (Catostomus occidentalis), we combined field-caging experiments in an agriculturally dominated watershed with controlled laboratory exposures to field-collected water samples, and we coupled genotoxicity biomarker measurements in fish with bacterial mutagenicity analysis of water samples. We selected DNA strand breakage as a genotoxicity biomarker and Ames Salmonella mutagenicity tests as a second, supporting indicator of genotoxicity. Data from experiments conducted during rainfall runoff events following winter application of pesticides in 2000 and 2001 indicated that DNA strand breaks were significantly elevated in fish exposed to San Joaquin River (CA, USA) water (38.8, 28.4, and 53.6% DNA strand breakage in year 2000 field, year 2000 lab, and year 2001 field exposures, respectively) compared with a nearby reference site (15.4, 8.7, and 12.6% DNA strand breakage in year 2000 field, year 2000 lab, and year 2001 field exposures, respectively). Time-course measurements in field experiments supported a linkage between induction of DNA strand breakage and the timing of agricultural runoff. San Joaquin River water also caused significant reversion mutation in two Ames Salmonella tester strains. Salmonella mutagenicity corroborated in-stream effects, further strengthening a causal relationship between runoff events and genotoxicity. Potentially responsible agents are discussed in the context of timing of runoff events in the field, concordance between laboratory and field exposures, pesticide application patterns in the drainage, and analytical chemistry data.
Bacterial energetics, stoichiometry, and kinetic modeling of 2,4-Dinitrotoluene biodegradation in a batch respirometer
Authors: Zhang Chunlong , Hughes Joseph B 
Published: November 2004

Abstract
A stoichiometric equation and kinetic model were developed and validated using experimental data from batch respirometer studies on the biodegradation of 2,4-dinitrotoluene (DNT). The stoichiometric equation integrates bacterial energetics and is revised from that in a previous study by including the mass balance of phosphorus (P) in the biomass. Stoichiometric results on O2 consumption, CO2 evolution, and nitrite evolution are in good agreement with respirometer data. However, the optimal P requirement is significantly higher than the stoichiometrically derived P, implying potentially limited bioavailability of P and the need for buffering capacity in the media to mitigate the adverse pH effect for optimal growth of DNT-degrading bacteria. An array of models was evaluated to fit the O2/CO2 data acquired experimentally and the DNT depletion data calculated from derived stoichiometric coefficients and cell yield. The deterministic, integrated Monod model provides the goodness of fit to the test data on DNT depletion, and the Monod model parameters (Ks, X0, μmax, and Y) were estimated by nonlinear regression. Further analyses with an equilibrium model (MINTEQ) indicate the interrelated nature of medium chemical compositions in controlling the rate and extent of DNT biodegradation. Results from the present batch respirometer study help to unravel some key factors in controlling DNT biodegradation in complex remediation systems, in particular the interactions between acidogenic DNT bacteria and various parameters, including pH and P, the latter of which could serve as a nutrient, a buffer, and a controlling factor on the bioavailable fractions of minerals (Ca, Fe, Zn, and Mo) in the medium.
Latino(a) students and Caucasian mentors in a rural after‐school program: Towards empowering adult–youth relationships
Authors: Diversi Marcelo , Mecham Connie 
Published: November 2004

AbstractHigh rates of immigration, especially from Latin America, have created a large population of immigrant youth, many of whom are having difficulty in American schools. The central goals of our project were to assist in empowering students to find academic success and to foster a more bicultural identity. According to three perspectives (youth, mentor, and coordinator), the adult–youth relationship central to our project has been successful in fostering academic engagement and cross‐cultural relations. Youth improved their grades and reported being more connected to school. Mentors and youth reported trust in their relationship and satisfaction in learning about each other's culture. We also discuss shortcomings in our program and offer suggestions for positive adult–youth practices. © 2005 Wiley Periodicals, Inc. J Comm Psychol 33: 31–40, 2005.
The adoption of innovation in youth organizations: Creating the conditions for youth–adult partnerships
Authors: Zeldin Shepherd , Camino Linda , Mook Carrie 
Published: November 2004

AbstractYouth–adult partnerships (Y‐APs) for organizational and community change represent an innovative practice in the United States. Innovations are typically a challenge to implement, so it is not surprising that youth organizations are seeking guidance on how to adopt and sustain Y‐APs. This article brings contemporary scholarship to bear on the issue. Through a synthesis of theory, research, and field‐based data, it identifies six managerial guidelines for adopting and beginning to implement the innovative practice of Y‐APs: (1) gain clarity and consensus on the purpose of Y‐AP, (2) mobilize and coordinate a diverse range of stakeholders, (3) create favorable narratives about Y‐AP, (4) construct theories and stories of organizational change, (5) affirmatively address issues of power, and (6) institutionalize new roles for youth. These guidelines depend on stakeholders having adequate time for shared organizational learning. Time for reflective dialogue, however, is a precious commodity in youth organizations, one that is rarely financed by public agencies or private foundations. A major challenge for the future, in terms of the wide‐scale adoption and implementation of innovation, specifically Y‐AP, may therefore lie in the creation of incentives and support for organizational reflection. © 2005 Wiley Periodicals, Inc. J Comm Psychol 33: 121–135, 2005.
Specificity in lipases: A computational study of transesterification of sucrose
Authors: Fuentes Gloria , Ballesteros Anthonio , Verma Chandra S. 
Published: November 2004

AbstractComputational conformational searches of putative transition states of the reaction of sucrose with vinyl laurate catalyzed by lipases fromCandida antarctica BandThermomyces lanuginosushave been carried out. The dielectric of the media have been varied to understand the role of protein plasticity in modulating the observed regioselective transesterification. The binding pocket of lipase fromCandidaadapts to the conformational variability of the various substates of the substrates by small, local adjustments within the binding pocket. In contrast, the more constrained pocket of the lipase fromThermomycesadapts by adjusting through concerted global motions between subdomains. This leads to the identification of one large pocket inCandidathat accommodates both the sucrose and the lauroyl moieties of the transition state, whereas inThermomycesthe binding pocket is smaller, leading to the localization of the two moieties in two distinct pockets; this partly rationalizes the broader specificity of the former relative to the latter. Mutations have been suggested to exploit the differences towards changing the observed selectivities.
Expression and purification of recombinant proteins from Escherichia coli: Comparison of an elastin‐like polypeptide fusion with an oligohistidine fusion
Authors: Trabbic‐Carlson Kimberly , Liu Li , Kim Bumjoon , Chilkoti Ashutosh 
Published: November 2004

AbstractThermally responsive elastin like polypeptides (ELPs) can be used to purify proteins from Escherichia coli culture when proteins are expressed as a fusion with an ELP. Nonchromatographic purification of ELP fusion proteins, termed inverse transition cycling (ITC), exploits the reversible soluble–insoluble phase transition behavior imparted by the ELP tag. Here, we quantitatively compare the expression and purification of ELP and oligohistidine fusions of chloramphenicol acetyltransferase (CAT), blue fluorescent protein (BFP), thioredoxin (Trx), and calmodulin (CalM) from both a 4‐h culture with chemical induction of the plasmid‐borne fusion protein gene and a 24‐h culture without chemical induction. The total protein content and functional activity were quantified at each ITC purification step. For CAT, BFP, and Trx, the 24‐h noninduction culture of ELP fusion proteins results in a sevenfold increase in the yield of each fusion protein compared to that obtained by the 4‐h–induced culture, and the calculated target protein yield is similar to that of their equivalent oligohistidine fusion. For these proteins, ITC purification of fusion proteins also results in ∼75% recovery of active fusion protein, similar to affinity chromatography. Compared to chromatographic purification, however, ITC is inexpensive, requires no specialized equipment or reagents, and because ITC is a batch purification process, it is easily scaled up to accommodate larger culture volumes or scaled down and multiplexed for high‐throughput, microscale purification; thus, potentially impacting both high‐throughput protein expression and purification for proteomics and large scale, cost‐effective industrial bioprocessing of pharmaceutically relevant proteins.
Studies on recombinant single chain Jacalin lectin reveal reduced affinity for saccharides despite normal folding like native Jacalin
Authors: Sahasrabuddhe Anagh A. , Gaikwad Sushama M. , Krishnasastry M.V. , Khan M. Islam 
Published: November 2004

AbstractSugar binding studies, inactivation, unfolding, and refolding of native Jacalin (nJacalin) from Artocarpus integrifolia and recombinant single‐chain Jacalin (rJacalin) expressed in Escherichia coli were studied by intrinsic fluorescence and thermal and chemical denaturation approaches. Interestingly, rJacalin does not undergo any proteolytic processing in an E. coli environment. It has 100fold less affinity for methyl‐α‐galactose (Ka: 2.48 × 102) in comparison to nJacalin (Ka: 1.58 × 104), and it also binds Thomsen‐Friedenreich (TF) disaccharide (Galβ1–3GalNAc) with less affinity. Overall sugar binding characteristics of rJacalin are qualitatively similar to that of nJacalin (Gal<MeαGal<MeαTFdisaccharide). Circular dichroism studies at near‐ and far‐UV, thermal, and chemical denaturation studies reveal that the rJacalin behaves like nJacalin. Guanidine hydrochloride‐induced denaturation, followed by renaturation, yielded total recovery of sugar binding activity of rJacalin in comparison to partial recovery for nJacalin. This signifies the minor changes in the refolding pathways between native and recombinant lectins. The stability of rJacalin is dramatically reduced in the extreme pH range unlike nJacalin. Both lectins do not bind 1‐anilino‐8‐naphthalene sulfonic acid (ANS) in the pH range of 5 to 12 but they do in the pH range of 1–3. Solute quenching studies of the lectin using acrylamide, KI, and CsCl indicated that the tryptophan residues have full accessibility to the neutral quencher and poor accessibility to ionic quenchers. In summary, biophysical and biochemical studies on the native versus recombinant Jacalin suggest that post‐translational modification, i.e., the processing of Jacalin into two chains is probably not a prerequisite for sugar binding but may be required for higher affinity.
Structural and functional analysis of the gpsA gene product of Archaeoglobus fulgidus: A glycerol‐3‐phosphate dehydrogenase with an unusual NADP+ preference
Authors: Sakasegawa Shin‐Ichi , Hagemeier Christoph H. , Thauer Rudolf K. , Essen Lars‐O. , Shima Seigo 
Published: November 2004

AbstractNAD+‐dependent glycerol‐3‐phosphate dehydrogenase (G3PDH) is generally absent in archaea, because archaea, unlike eukaryotes and eubacteria, utilize glycerol‐1‐phosphate instead of glycerol‐3‐phosphate for the biosynthesis of membrane lipids. Surprisingly, the genome of the hyperthermophilic archaeon Archaeoglobus fulgidus comprises a G3PDH ortholog, gpsA, most likely due to horizontal gene transfer from a eubacterial organism. Biochemical characterization proved G3PDH‐like activity of the recombinant gpsA gene product. However, unlike other G3PDHs, the up to 85°C thermostable A. fulgidus G3PDH exerted a 15‐fold preference for NADPH over NADH. The A. fulgidus G3PDH bears the hallmarks of adaptation to halotolerance and thermophilicity, because its 1.7‐Å crystal structure showed a high surface density for negative charges and 10 additional intramolecular salt bridges compared to a mesophilic G3PDH structure. Whereas all amino acid residues required for dihydroxyacetone phosphate binding and reductive catalysis are highly conserved, the binding site for the adenine moiety of the NAD(P) cosubstrate shows a structural variation that reflects the observed NADPH preference, for example, by a putative salt bridge between R49 and the 2′‐phosphate.
Forging Mandalic Space: Bhaktapur, Nepal's Cow Procession and the Improvisation of Tradition
Authors: Price Grieve Gregory 
Published: November 2004

AbstractIn 1995, as part of Bhaktapur, Nepal's Cow Procession, the new suburban neighborhood of Suryavinayak celebrated a "forged" goat sacrifice. Forged religious practices seem enigmatic if one assumes that traditional practice consists only of the blind imitation of timeless structure. Yet, the sacrifice was not mechanical repetition; it could not be, because it was the first and only time it was celebrated. Rather, the religious performance was a conscious manipulation of available "traditional" cultural logics that were strategically utilized during the Cow Procession's loose carnivalesque atmosphere to solve a contemporary problem — what can one do when one lives beyond the borders of religiously organized cities such as Bhaktapur? This paper argues that the "forged" sacrifice was a means for this new neighborhood to operate together and improvise new man. d. alic space beyond the city's traditional cultic territory.
Supportive Care
Authors: Wingard John R. , Nichols W. Garrett , McDonald George B. 
Published: November 2004

Abstract
To optimize treatment outcomes for hematologic malignancies, minimizing the consequences of treatment complications requires as much skill as the choice of the treatment itself. Myelosuppression and immunosuppression are frequent complications and have potentially serious infectious consequences. Invasive fungal infections and infections from respiratory viruses are increasing in frequency and have life-threatening potential. Damage to vital organs, especially the liver, is another important concern. In this chapter, the scope of invasive fungal and respiratory viral infections, recent insights into the pathogenesis of hepatic sinusoidal injury, and recent developments that impact prevention and treatment approaches for these complications are described.
In Section I, Dr. John Wingard describes the advantages and disadvantages of various treatment options for invasive infections by the two chief fungal pathogens, Candida and Aspergillus. Adjunctive therapies and practical considerations that clinicians should weigh in choosing one or another of the various agents are discussed. The studies that have evaluated antifungal prophylaxis and empirical treatment strategies are reviewed. Finally, new approaches such as combination therapy, new diagnostics, and efforts to bolster host immunity are considered.
In Section II, Dr. W. Garrett Nichols describes the epidemiology of community-acquired respiratory viruses (CRV) in patients with hematologic malignancies. Risk factors, clinical syndromes, and possible indirect effects of CRV infections are discussed. Treatment and prevention options are reviewed.
In Section III, Dr. George McDonald describes sinusoidal obstruction syndrome (once known as hepatic veno-occlusive disease). Recent insights into pathogenesis are described. Diagnostic criteria and the advantages and disadvantages of various diagnostic methods are reviewed and prognosis is considered. Prevention and treatment options are discussed.
Congenital and Acquired Neutropenia
Authors: Berliner Nancy , Horwitz Marshall , Loughran Thomas P. 
Published: November 2004

AbstractOur understanding of the pathogenesis of congenital and acquired neutropenia is rapidly evolving. New ground-breaking observations have identified the genes responsible for many of the congenital neutropenia syndromes and are also providing new insights into normal neutrophil commitment and differentiation. Acquired neutropenia remains a poorly understood syndrome, although new insights into its pathogenesis are also emerging, especially with regard to subsets of immune neutropenia.In Section I, Dr. Marshall Horwitz reviews the current understanding of the genetic basis, molecular pathology, and approaches to treatment of congenital neutropenia and cyclic hematopoiesis. Mutations in the ELA2 gene, which encodes for neutrophil elastase, cause cyclic hematopoiesis. ELA2 mutations are also the most common cause of congenital neutropenia, where their presence may equate with a more severe clinical course and higher frequency of leukemic progression. Emerging evidence indicates interrelatedness with Hermansky Pudlak syndrome and other disorders of neutrophil and platelet granules.In Section II, Dr. Nancy Berliner presents an overview of the clinical approach to the evaluation and treatment of acquired neutropenia. This includes a review of the pathogenesis of primary and secondary immune neutropenia, drug-induced neutropenia, and non-immune chronic idiopathic neutropenia of adults. Studies used to evaluate patients for potential immune neutropenia are reviewed. Management issues, especially the use of granulocyte colony-stimulating factor (G-CSF), are discussed.In Section III, Dr. Thomas Loughran, Jr., reviews the pathogenesis and clinical manifestations of large granular lymphocyte (LGL) leukemia. Possible mechanisms of neutropenia are discussed. In particular, discussion focuses on the relationship between LGL leukemia, rheumatoid disease, and Felty’s syndrome, and the complex interplay of defects in neutrophil production, distribution, destruction, and apoptosis that underly the development of neutropenia in those syndromes.
Symptomatic hypogammaglobulinemia in infancy and childhood – clinical outcome and in vitro immune responses
Authors: Kidon Mona Iancovici , Handzel Zeev T , Schwartz Rivka , Altboum Irit , Stein Michael , Zan-Bar Israel 
Published: November 2004

Abstract
Background
Symptomatic hypogammaglobulinemia in infancy and childhood (SHIC), may be an early manifestation of a primary immunodeficiency or a maturational delay in the normal production of immunoglobulins (Ig). We aimed to evaluate the natural course of SHIC and correlate in vitro lymphoproliferative and secretory responses with recovery of immunoglobulin values and clinical resolution.

Methods
Children, older than 1 year of age, referred to our specialist clinic because of recurrent infections and serum immunoglobulin (Ig) levels 2 SD below the mean for age, were followed for a period of 8 years. Patient with any known familial, clinical or laboratory evidence of cellular immunodeficiency or other immunodeficiency syndromes were excluded from this cohort. Evaluation at 6- to 12-months intervals continued up to 1 year after resolution of symptoms. In a subgroup of patients, in vitro lymphocyte proliferation and Ig secretion in response to mitogens was performed.

Results
32 children, 24 (75%) males, 8 (25%) females, mean age 3.4 years fulfilled the inclusion criteria. Clinical presentation: ENT infections 69%, respiratory 81%, diarrhea 12.5%. During follow-up, 17 (53%) normalized serum Ig levels and were diagnosed as transient hypogammaglobulinemia of infancy (THGI). THGI patients did not differ clinically or demographically from non-transient patients, both having a benign clinical outcome. In vitro Ig secretory responses, were lower in hypogammaglobulinemic, compared to normal children and did not normalize concomitantly with serum Ig's in THGI patients.

Conclusions
The majority of children with SHIC in the first decade of life have THGI. Resolution of symptoms as well as normalization of Ig values may be delayed, but overall the clinical outcome is good and the clinical course benign.