bluuebunny/crossref_metadata_2025 huggingface dataset:
What limits the altitudinal distribution of Craspedolepta species (Sternorrhyncha: Psylloidea) on fireweed?
Authors: Bird Jeremy M. , Hodkinson Ian D.
Published: September 2005

Abstract.  1. Craspedolepta nebulosa and C. subpunctata were studied on their shared host plant Epilobium angustifolium along an altitudinal transect in the Hardangervidda area of southern Norway.

2. The following was investigated: whether (a) the altitudinal distribution and abundance of each psyllid species was determined by summer heat budgets, acting directly on rates of insect development and/or through their host plant and (b) whether parasitism, predation, and interspecific competition played any role in restricting the distribution of the two species.

3. Craspedolepta nebulosa extended to higher elevations than C. subpunctata but within their ranges neither species showed a clear altitudinal trend in abundance per plant. However, the former species grew to a smaller size with increasing elevation.

4. There was little evidence for interspecific competitive effects and observed levels of parasitism and predation were negligible across the transect.

5. Development and distribution of both species mirrored significant differences in the phenology, size, leaf number, and reproductive output of E. angustifolium with increasing altitude.

6. Distributions were related to available heat budgets acting on psyllid/plant development rates, with C. nebulosa developing more efficiently at lower heat availability.

7. Population transplant experiments supported the overall conclusions, with neither psyllid species able to establish viable populations above their current upper altitudinal range limit, despite the presence of their host plant.
Mind or Virtue
Authors: Li Jin
Published: September 2005

Traditional research on human learning has neglected people's beliefs about learning, the role of culture in shaping those beliefs, and people's consequent learning behavior. Recent research provides evidence that cultural beliefs about learning are essential in influencing individuals' beliefs and their actual learning. This article reviews research on Western learning beliefs, which emphasize the mind, and Chinese learning beliefs, which emphasize personal virtue, as well as on the differences these beliefs produce in people's actual learning. Developmental evidence is also presented to show that the cultural influences begin early. Future research directions are discussed.
The Body Stripped Down
Authors: Goldenberg Jamie L.
Published: September 2005

According to terror management theory, cultural beliefs and standards provide protection from fears associated with mortality by convincing individuals that their existence matters more than that of any mere mortal animal. The body threatens the efficacy of such mechanisms by reminding us that we are animals nonetheless, and therefore fated to death. I present research demonstrating that existential concerns contribute to uneasiness with the body, especially regarding sex, and also to pervasive concerns with how the body measures up to cultural standards, most obviously regarding women's appearance. These findings show that in effort to defend against threats associated with the body's physicality, people may deny themselves pleasure and endanger their health.
‘Scirrhous’ type hepatocellular carcinomas: a special reference to expression of cytokeratin 7 and hepatocyte paraffin 1
Authors: Matsuura S , Aishima S , Taguchi K , Asayama Y , Terashi T , Honda H , Tsuneyoshi M
Published: September 2005

Aims : ‘Scirrhous’ hepatocellular carcinoma (scirrhous HCC) is extremely rare and its characteristics remain unclear. We investigated the clinicopathological and immunohistochemical features of scirrhous HCC, compared with those of ordinary hepatocellular carcinoma (ordinary HCC).

Methods and results : We compared the clinicopathological and immunohistochemical features of 20 resected cases of scirrhous HCC with those of 69 resected cases of ordinary HCC. Scirrhous HCC was characterized by its gross and histological findings, such as a higher proportion of contiguous multinodular type tumours, the absence of a complete fibrous capsule around the tumour, the absence of tumour necrosis and highly preserved portal tracts in the tumour. The immunohistochemical results revealed a significantly higher expression of cytokeratin 7 and a significantly lower expression of hepatocyte paraffin 1 in scirrhous HCC than in ordinary HCC (P < 0.0001, respectively). There were no significant differences in proliferative activity and survival curves between the patients with scirrhous HCC and those with ordinary HCC.

Conclusion : Scirrhous HCC has several particular gross, histological and immunohistochemical features. In particular, we would like to emphasize the greater immunohistochemical expression of cytokeratin 7 and lower expression of hepatocyte paraffin 1 in scirrhous HCC than in ordinary HCC.
T‐bet expression patterns in coeliac disease, cryptic and overt enteropathy‐type T‐cell lymphoma
Authors: Jöhrens K , Anagnostopoulos I , Stein H
Published: September 2005

Aims : To clarify the distribution and lineage allocation of T‐bet‐expressing cells in coeliac disease (CD) and in enteropathy‐type T‐cell lymphoma (ETTCL). The detection of elevated levels of interferon‐gamma, interleukin‐18 and the key regulator of Th1 helper immune response T‐bet in CD biopsies led to the view that CD is the result of a Th1 response to gluten. It remains unknown whether T‐bet is expressed in cryptic and overt ETTCL.

Methods : Specimens from 20 patients with CD, five patients with cryptic and 10 patients with overt ETTCL were analysed by immunohistology employing single and double labellings for T‐bet and CD4 or CD8 antigens.

Results : In CD specimens nearly all intraepithelial CD8 cells and many CD4 cells in the lamina propria expressed T‐bet. Cryptic ETTCL showed T‐bet expression in the intraepithelial neoplastic cells while T‐bet+ CD4 cells in the lamina propria were rare. Overt ETTCL showed T‐bet expression in cases with non‐anaplastic morphology. In addition, a proportion of bystander T cells expressed T‐bet.

Conclusions : Morphological evidence proves that while T‐bet orchestrates a CD4‐ and CD8‐based Th1 reaction in CD, its expression shifts to the neoplastic intraepithelial compartment of cryptic ETTCL and becomes absent or lost in anaplastic overt ETTCL.
Aedes aegypti phosphohexomutases and uridine diphosphate‐hexose pyrophosphorylases: comparison of primary sequences, substrate specificities and temporal transcription
Authors: Kato N. , Mueller C. R. , Wessely V. , Lan Q. , Christensen B. M.
Published: September 2005

Phosphohexomutases reversibly catalyse the transfer of the phosphate group of a glycosyl phosphate between the C6 and C1 positions, and uridine diphosphate (UDP)‐hexose pyrophosphorylases catalyse the synthesis of UDP‐hexose from uridine triphosphate (UTP) and hexose‐1‐phosphate. Both enzyme families are essential for nucleoside diphosphate hexose biosynthesis and are therefore critical for various physiological functions in the midgut of mosquitoes after a blood meal. We cloned and sequenced three phosphohexomutase and two UDP‐hexose pyrophosphorylase cDNAs from Aedes aegypti. The products of the cDNAs were expressed and substrate specificities were examined. Herein we describe Ae. aegypti phosphoglucomutase 1, phosphoglucomutase 2, phosphoacetylglucosamine mutase, UDP‐glucose pyrophosphorylase, and UDP‐N‐acetylglucosamine pyrophosphorylase. Transcripts of the genes expressing the enzymes are constitutively present in all life stages and blood‐feeding does not seem to influence transcript abundance.
The behavioural phenotype of Angelman syndrome
Authors: Horsler K. , Oliver C.
Published: September 2005

Background  The purpose of this review is to examine the notion of a behavioural phenotype for Angelman syndrome and identify methodological and conceptual influences on the accepted presentation.

Methods  Studies examining the behavioural characteristics associated with Angelman syndrome are reviewed and methodology is described.

Results  Potential bias in the description of the phenotype emerges with the use of case and cohort studies with the absence of comparison groups. A trend in the literature from a direct gene effect to a socially mediated effect on laughter is evident.

Conclusion  Evidence for a behavioural phenotype of Angelman syndrome has begun to emerge. However, by adopting the concept of a ‘behavioural phenotype’, attention may become biased towards the underlying biological basis of the syndrome, with developmental and environmental factors being overlooked.
A language programme to increase the verbal production of a child dually diagnosed with Down syndrome and autism
Authors: Kroeger K. A. , Nelson W. M.
Published: September 2005

Background  The incidence of children dually diagnosed with Down syndrome and autism is estimated to be as high as 11%. There is a paucity of research investigating linguistic treatment interventions for such children. This single‐subject experiment examined a programme designed to increase the language production and verbal behaviour of a 9‐year‐old dually diagnosed boy who had been receiving a 15‐h/week home‐based applied behaviour analysis (ABA) programme.

Methods  Training principles were derived from previously empirically validated research in discrete trail learning and natural environment teaching, as well as modified incidental teaching procedures. The crux of the language programme involved withholding reinforcement until a spoken request was made.

Results  Language production noticeably increased for each target area after the introduction of the language programme and was maintained at a 9‐month follow‐up session.

Conclusions  A combined treatment approach incorporating direct instruction, natural environment teaching and incidental teaching can be effective in increasing and maintaining responsive and spontaneous speech in a child with Down syndrome diagnosed with autism. Replication studies are needed with such multiple dually diagnosed children to further evaluate the effectiveness and generalizability of this combined language programme.
Molecular Characterization of Major Histocompatibility Complex Class I (B‐F) mRNA Variants from Chickens Differing in Resistance to Marek's Disease
Authors: Dalgaard T. S. , Vitved L. , Skjødt K. , Thomsen B. , Labouriau R. , Jensen K. H. , Juul‐Madsen H. R.
Published: September 2005

In this study, the relative distributions of two alternatively polyadenylated chicken major histocompatibility complex (MHC) mRNA isoforms of approximately 1.5 and 1.9 kb were analysed in spleen cells from chickens homozygous for the MHC haplotypes B21 and B19v1 as well as in heterozygous B19v1/B21 birds. Both isoforms are likely to encode classical MHC class I (B‐F) alpha chains. The B19v1 and B21 MHC haplotypes confer different levels of protection against Marek's disease (MD), which is caused by infection with MD virus (MDV). In spleen cells, MD‐resistant B21 birds were shown to have the highest percentage of the 1.5 kb variant relative to the total MHC class I expression, MD‐susceptible B19v1 birds the lowest and B19v1/B21 birds an intermediate percentage. Infection of 4‐week‐old chickens with the GA strain of MDV was shown to cause a significant increase in the relative amount of 1.5 kb transcripts in B21 birds 32 days postinfection (dpi). Alternatively polyadenylated mRNA isoforms may encode identical proteins, but differences in the 3′ untranslated region (UTR) can influence polyadenylation, mRNA stability, intracellular localization and translation efficiency. It was shown that the increased 1.5 kb percentage in B21 birds 32 days postinfection may be a result of a change in the choice of poly(A) site rather than a locus‐specific upregulated transcription of the BF1 gene that preferentially expresses the 1.5 kb variant. Furthermore, the 3′ end of the 1.5 kb mRNA variants deriving from B19v1 and B21 chickens was characterized by Rapid Amplification of cDNA Ends (RACE) and sequencing. No potentially functional elements were identified in the 3′ UTR of the RACE products corresponding to this short isoform. However, variation in polyadenylation site was observed between the BF1 and BF2 mRNA transcripts and alternative splicing‐out of the sequence (exon 7) encoding the second segment of the cytoplasmic part of the mature BF2*19 molecules. This alternative exon 7 splice variant was also detected in other MD‐susceptible haplotypes, but not in the MD‐resistant B21 and B21‐like haplotypes, suggesting a potential role of exon 7 in MHC‐related MD resistance.
Development of Early PCLP1‐Expressing Haematopoietic Cells within the Avian Dorsal Aorta
Authors: Suonpää P. , Kohonen P. , Koskela K. , Koskiniemi H. , Salminen‐Mankonen H. , Lassila O.
Published: September 2005

The first haematopoietic stem cells (HSC) develop in the dorsal aorta as haematopoietic intra‐aortic clusters (HIAC). To evaluate the initial steps of definitive haematopoiesis, we have studied the emergence and the expression profile of podocalyxin‐like protein 1 (PCLP1)‐expressing cells in early chick embryos. Here we demonstrate that at embryonic day 2 (E2), the PCLP1+ cells are present in the splanchnic mesoderm and in the ventral lining of the paired dorsal aorta. Following aortic fusion at E3, the PCLP1‐expressing cells are exclusively found in the aortic floor and as the development proceeds, both the haematopoietic clusters and the aortic endothelial cells express PCLP1. In parallel with the early PCLP1 expression, bone morphogenetic protein 4 (BMP4) expression was detected in the splanchnopleura and thereafter in the densely packed mesenchymal cells beneath the HIAC. The microarray analyses of early E3 PCLP1+ cells revealed elevated expression of genes known to be involved in the stem cell function. These data suggest that splanchnopleura‐derived PCLP1‐expressing cells give rise to the earliest definitive haematopoietic progenitors.
Viewpoint: Are doctors responsible for the increase in allergic diseases?
Authors: Van Bever Hugo P. , Shek Lynette P.‐C. , Lim Dawn L. , Lee Bee Wah
Published: September 2005

There is no exact explanation for the increase in allergic diseases that occurred since the last two decades. An increased allergen exposure and/or a decreased bacterial load cannot explain the phenomenon completely. Other causal factors that rose at the beginning of the 1980s must be taken into consideration. Important changes at that time in our management of children were the worldwide switch from aspirin to paracetamol, the introduction of broad‐spectrum antibiotics such as cephalosporins and the advice to avoid dust and pets in newborns from allergic families. General application of these new approaches, in itself or in combination, might be responsible, at least in part, for the increase of allergic diseases in children.
The prevalence of peanut sensitization and the association to pollen sensitization in a cohort of unselected adolescents – The Odense Adolescence Cohort Study on Atopic Diseases and Dermatitis (TOACS)
Authors: Mortz Charlotte Gotthard , Andersen Klaus Ejner , Bindslev‐Jensen Carsten
Published: September 2005

In the last decade an increased occurrence of peanut hypersensitivity and severe anaphylactic reactions to peanut have been reported. However, few prevalence studies have been performed in unselected populations. This study evaluated the point prevalence of peanut hypersensitivity in Danish adolescents. The point prevalence of peanut allergy confirmed by oral challenge was estimated to 0.5%. The number of adolescents sensitized to peanut by specific immunoglobulin E (IgE) (CAP FEIA) and skin prick test (SPT) were higher (5.8% resp. 3.4%). In adolescents without clinically relevant peanut sensitization most cases were sensitized to grass pollen and the IgE class for grass was higher than for peanut. A correlation between peanut and pollen (grass) sensitization is therefore plausible. Before a positive SPT or specific IgE measurement to peanut is considered clinically relevant in a patient, the case history should be evaluated together with examination for pollen sensitization.
Immunological evaluation of allergic respiratory children with recurrent sinusitis
Authors: Costa Carvalho Beatriz T. , Nagao Aparecida Tiemi , Arslanian Cristina , Carneiro Sampaio Magda M. S. , Naspitz Charles K. , Sorensen Ricardo U. , Leiva Lily , Solé Dirceu
Published: September 2005

The objective of this study was to evaluate humoral immunity of allergic respiratory children with chronic/recurrent sinusitis. Twenty‐seven allergic respiratory (persistent mild/moderate asthma and persistent allergic rhinitis) children (7–15‐year old) with chronic or recurrent sinusitis were evaluated. Patients had symptoms and abnormal computer tomography scan even after two adequate treatments (long‐lasting antibiotics, decongestants, and short‐term oral corticosteroids). clinical examination, sweat test, total blood cell count, measurement of serum levels of: total and specific IgE, immunoglobulins (G, M, A), IgG subclasses, antibodies to Haemophilus influenza type b (IgG anti‐Ps Hib) and pneumococcal serotypes (IgG anti‐Ps 1, 3, 5, 6B, 9V, and 14) before and after active immunization (Act‐Hib® and Pneumo23®, Aventis Pasteur SA, Lyon, France), Rubella neutralizing antibody titers and human immunodeficiency virus antibodies. Specific IgE to inhalant allergens higher than class III were observed in 24/27 patients. One patient had IgA plus IgG2 deficiency and other an IgG3 deficiency. Eight and 12 of 27 patients had IgG2 and IgG3 serum levels below 2.5th percentile, respectively. Immunological responses to protein and polysaccharide antigens were normal in all patients. Although our patients have been appropriately treated of their allergic diseases, they persisted with chronic/recurrent sinusitis and 60% of them had a documented osteomeatal complex blockade. In spite of the diagnosis of IgA plus IgG2 deficiency and an isolated IgG3 deficiency, in all patients an adequate response to Ps antigens was observed. Primary and/or secondary humoral immunodeficiency seems not to be the main cause of chronic/recurrent sinusitis in patients with respiratory allergic disease.
Bronchial hyper‐responsiveness in selective IgA deficiency
Authors: Papadopoulou Athina , Mermiri Despina , Taousani Sofia , Triga Maria , Nicolaidou Polyxeni , Priftis Kostas N.
Published: September 2005

Secretory IgA in mucosal secretions has a broad protective function. The insufficient protection provided by the respiratory mucosa in children with selective IgA deficiency (sIgAD) might facilitate the development of bronchial hyper‐responsiveness (BHR) and consequently asthma symptoms. This study was conducted to clarify the prevalence of BHR in sIgAD children and the relationship with atopic status. A cohort of 20 children (group A) aged 6.4–20.1 yr (median: 12.6) with sIgAD (serum IgA <6 mg/dl) were evaluated for BHR using inhaled hypertonic saline test as well as for atopy by skin prick testing (SPT) to eight common aero‐allergens. Seventy other children with normal levels of serum IgA, but sensitized to aero‐allergens (group B) and 102 with normal IgA and negative SPTs (group C) were also evaluated. Baseline spirometry demonstrated that forced vital capacity (FVC) values in group A were significantly lower than in C. Forced expiratory volume in 1 s values were similar in all groups, but impairment of the forced expiratory flow over the middle half of the FVC was detected in group B. The prevalence of BHR was similar among group A (30.0%) and group B (35.7%) (p = 0.79) but they differed from group C (5.9%) (p = 0.005). An association between BHR and reported current (p = 0.001) but not lifetime asthma symptoms among group A was also observed. There was no association between atopy and BHR in group A but only to mites’ sensitization (p = 0.03). In conclusion, these results indicate that sIgAD constitutes a risk factor for development of BHR but it appears to be related to sensitization to mites.
Comparison of Tc‐99 measurement of glomerular filtration rate vs. calculated creatinine clearance to assess renal function pretransplant in pediatric patients undergoing hematopoietic stem cell transplantation
Authors: Kletzel M. , Pirich L. , Haut P. , Cohn R. A.
Published: September 2005

Abstract:  We compared the results of Tc‐99 evaluation of glomerular filtration rate (GFR) vs. the calculation of the creatinine clearance (CCrC) as a predictor for the development of renal insufficiency in pediatric patients following hematopoietic stem cell transplantation (HSCT). We reviewed 95 consecutive patients receiving autologous (n = 37) or allogeneic (n = 58) HSCT at Children's Memorial Hospital between January, 1995 and February, 1998. Diagnoses included leukemia (n = 43), solid tumor (n = 27), bone marrow failure syndrome (n = 12), non‐malignant disease (n = 8), CNS tumors (n = 5) and immunodeficiency (n = 3). Tc‐99 GFR was compared with a calculated creatinine clearance derived from the Schwartz formula (CCrC) prior to HSCT. These measures of renal function were compared with the patient's subsequent clinical course to determine if patients who developed renal insufficiency of sufficient magnitude as to require continuous veno‐venous hemofiltration (CVVH) or dialysis, could have been identified. Overall comparison of the two methods of evaluation of renal function showed low correlation with values obtained by CCrC, which were consistently higher in most patients (r‐value 0.01 in the regression analysis and a p = 0.08 95% CI −24.15 to 1.48). When stratified for age, correlation between the two methods was excellent only in children younger than 5 yr of age p = 0.02 95%, CI 0.032–0.49). Eleven patients required therapy with CVVH or dialysis but neither CCrC nor Tc‐99 GFR prior to transplant predicted this event. Patients who received TBI were statistically more prone to develop renal insufficiency than those without TBI (p < 0.0001, 95% CI 0.25–0.008). Neither the Tc‐99 GFR nor the CCrC was predictive of the development of renal insufficiency in HSCT patients as the majority of patients who required dialysis had normal Tc‐99 GFR prior to transplant. The characteristics found in the patients who developed renal insufficiency and required dialysis include: the use of total body irradiation as part of the transplant‐conditioning regimen (p < 0.0001) and the use of continuous infusion CSA (p = 0.04).
Long‐term glomerular filtration rate following pediatric liver transplantion
Authors: Wiesmayr Silke , Jungraithmayr Therese C. , Ellemunter Helmut , Stelzmüller Ingrid , Bonatti Hugo , Margreiter Raimund , Zimmerhackl Lothar Bernd
Published: September 2005

Abstract: In adult patients a significant proportion of chronic renal failure after liver transplantation (LTX) has been described. This was attributed mainly to nephrotoxicity caused by Calcineurin inhibitors (CNI). If these results are transferable to pediatric patients was the aim of this study.

Forty‐five pediatric patients with a LTX performed between 1988 and 2003 were evaluated. Glomerular filtration rate was calculated using the Schwartz formula (calculated GFR (cGFR) (mL/min/1.73 m2) = k× height (cm)/serum creatinine (mg/dL)).

Median age at LTX was 4 yr (range 0.3–18.1). Pretransplant median cGFR was significantly elevated with 157.5 mL/min/1.73 m2. Within the first 3 months after LTX median cGFR normalized to a median value of 102.7 (p < 0.05 vs. pretransplant cGFR). During long‐term follow‐up median cGFR remained stable with calculated values of 108.0 two years and 112.6 five years after transplantation. Using a linear and an exponential one compartment mathematical modeling of renal function the calculated GFR was stable even for very long observation times (n > 10 yr).

Liver insufficiency prior to transplantation was associated with glomerular hyperfiltration. After successful liver transplantation cGFR normalized within the first 3 month and, in contrast to the reported GFR impairment in adult liver transplant recipients, remained stable, even in long‐term follow‐up.
Ocular penetration of oral doxycycline in the horse
Authors: Gilmour Margi A. , Clarke Cyril R. , MacAllister Charles G. , Dedeo Jacqueline M. , Caudell David L. , Morton Rebecca J. , Pugh Martin
Published: September 2005

Objective To investigate intraocular penetration of orally administered doxycycline in the normal equine eye and to compare intraocular and serum doxycycline concentrations.

Procedures Six mares were administered doxycycline at 10 mg/kg every 12 h by nasogastric tube for 5 days. Blood, aqueous, and vitreous samples were collected on days 1 and 5. All samples were assayed for doxycycline concentrations. Aqueous and vitreous samples were also assayed for protein quantitation.

Results Doxycycline was rapidly absorbed after the first dose (Tmaxvalue of 1.42 ± 1.28 h); and elimination of doxycycline occurred slowly (mediant1/2 = 10.88 h). Doxycycline could not be detected in the aqueous on days 1 and 5, nor could it be detected in the vitreous on day 1. On day 5, the mean vitreous doxycycline concentration was 0.17 ± 0.04 µg/mL at 2 h after drug administration.

Conclusions Repeated oral administration of doxycycline in the horse resulted in steady state serum concentrations of < 1 µg/mL; however, it did not result in appreciable concentrations of drug in the aqueous and vitreous in normal eyes.
Demonstration of P2Y4 purinergic receptors in the HT‐29 human colon cancer cell line
Authors: Delbro D. S. , Nylund G. , Nordgren S.
Published: September 2005

1  The aim of the current study was to investigate the existence of P2Y4 purinergic receptors in the HT‐29 human colon cancer cell line.

2  We utilized Western blots and immunocytochemistry for the analysis.

3  Western blotting demonstrated two bands that could not be found after the antibody had been preabsorbed with the control peptide, suggesting that both bands are related to the P2Y4 purinergic receptor.

4  Immunocytochemistry showed immunoreactivity for the P2Y4 purinergic receptor localized in the cytoplasm of the HT‐29 cells.

5  This is the first demonstration of the protein expression of P2Y4 purinergic receptors in a human colon cancer cell line.
Tourism: A Facilitator of Social Awareness in an Indigenous Mexican Community?
Authors: Greathouse‐Amador Louisa M.
Published: September 2005

As Latin American economies and cultures become increasingly tied to a global political, economic, and social order, indigenous and other marginalized people find themselves at a crossroads where their cultural survival is challenged. Tourism is one important aspect of this new economic order and it is often one of the few resources remaining in countries such as Mexico whose economy has been tied more directly to interests of dominating leaders contributing to this new world order. And while many observers note that tourism often has an exploitative impact on indigenous and marginalized people, this article examines the contradictions in tourism, identifying those economic spaces where the indigenous people have been successful in renegotiating their position with the dominant mestizo group in their community. This article offers provocative insights about the impact of tourism on indigenous people in a community in the northern mountains (Sierra Norte) in Puebla, México. It examines the potential contradictions in tourism under the economic conditions of neoliberalism.
PO2 Dependence of the Diffuse‐Phase Transition in Base Metal Capacitor Dielectrics
Authors: McCauley Daniel E. , Chu Mike S. H. , Megherhi Mohammed H.
Published: September 2005

The diffuse‐phase transition in BaTiO3‐based dielectrics for capacitor applications has been studied with respect to its dependence on oxygen partial pressure during sintering. Understanding the mobility of this transition is critical in developing next generation dielectrics for ultra thin (≤1 μm) applications while maintaining the appropriate temperature stability and insulation resistance. Historically, a heterogeneous core/shell microstructure was developed to maintain temperature stability. However, in fired grains of ≤250 nm (required for layers ≤1 μm) a well‐defined core/shell structure is very difficult to establish. The results from this study demonstrate that careful control of the diffuse‐phase transition addresses some of these problems.
Effects of Silica on the Combustion Synthesis and Glass Formation of TiB2‐Containing Calcium Aluminate Matrix Composites
Authors: Yi Hu Chun , Guigné Jacques Y. , Robinson Lisa A. , Manerbino Anthony R. , Moore John J.
Published: September 2005

Combustion synthesis has been used to study the combustion characteristics and microstructure in the TiB2–CaO–Al2O3–SiO2 system. Both the combustion temperature and wave velocity decreased with an increase in the amount of silica. The reacted product consisted of solid crystalline TiB2 phase and CaO–Al2O3–SiO2 matrix. No significant reaction between the TiB2 and the matrix was observed. It was found that the binary calcium aluminate matrix (Ca12Al7O33 and CaAl2O4 compounds) could form amorphous phase (glass) at a high cooling rate. Under a normal cooling rate, significant formation of glass in the matrix was found possible only by adding another glass‐former, e.g., silica (SiO2). The addition of SiO2 led to the formation of Gehelenite, to the reduction of the other crystal phases and to an increase in the glass phase in the matrix. A pure glass matrix was obtained for all compositions in the composition range from Ca12Al7O33 to CaAl2O4 compounds provided that an adequate amount of SiO2 was added. The resulting glass matrix can be expressed by the formula Ca2(SixAl1−x)3O, where x=0.32–0.58, depending on the composition. Effects of the TiB2 phase on the combustion synthesis process and on the microstructure are also discussed. TiB2 increased the reactivity and led to the formation of the molten matrix which was critical for glass formation. However, its effects on the vitrification of the matrix was considered to be minimum. The mechanism of glass formation in the matrix is discussed using the Zachariasen–Warren network theory.
Preparation of Grain‐Oriented Sr0.5Ba0.5Nb2O6 Ferroelectric Ceramics by Magnetic Alignment
Authors: Chen Weiwu , Kinemuchi Yoshiaki , Watari Koji , Tamura Takuya , Miwa Kenji
Published: September 2005

The properties of polycrystalline ceramics are strongly influenced by their crystallographic texture. In this study, highly grain‐oriented tungsten bronze structure ferroelectric ceramics, Sr0.5Ba0.5Nb2O6, were successfully fabricated by magnetic alignment and gelcasting techniques using only the conventional solid‐state‐synthesized starting powder. Spherical Sr0.5Ba0.5Nb2O6 particles were aligned according to their anisotropic magnetic property in 40 vol% slurry in a 10 T magnetic field, and then in situ locked by polymerization via a gelcasting technique for 30 min. A 〈00l〉‐axis orientation perpendicular to the magnetic field direction (B) was obviously observed in the green compact and sintered sample. The sintered Sr0.5Ba0.5Nb2O6 sample contained equiaxial grains and reached 98% theoretical density. Compared with the sample with randomly oriented grains, the magnetically aligned sample showed an enhanced with dielectric constant in the ⊥B direction (1100 versus 750 at room temperature and 4300 versus 2800 at Curie temperature). This new method is readily applicable to other ceramics with tungsten bronze structure, and is expected to facilitate mass preparation of large and dense grain‐oriented ceramic materials.
Transcriptional Profiling of Target of RNAIII-Activating Protein, a Master Regulator of Staphylococcal Virulence
Authors: Korem Moshe , Gov Yael , Kiran Madanahally D. , Balaban Naomi
Published: September 2005

Staphylococcus aureus
is a gram-positive bacterium that is part of the normal healthy flora but that can become virulent and cause infections by producing biofilms and toxins. The production of virulence factors is regulated by cell-cell communication (quorum sensing) through the histidine phosphorylation of target of RNAIII-activating protein (TRAP), which is a 21-kDa protein that is highly conserved among staphylococci. Using microarray analysis, we show here that the expression and phosphorylation of TRAP upregulate the expression of most, if not all, toxins known to date, as well as their global regulator
agr
. In addition, we show here that the expression and phosphorylation of TRAP are also necessary for the expression of genes known to be necessary for the survival of the bacteria in a biofilm, like
arc
,
pyr
, and
ure
. TRAP is thus demonstrated to be a master regulator of staphylococcal pathogenesis.
Inhibition of Cell Surface Export of Group A Streptococcal Anchorless Surface Dehydrogenase Affects Bacterial Adherence and Antiphagocytic Properties
Authors: Boël Grégory , Jin Hong , Pancholi Vijay
Published: September 2005

Surface dehydrogenase (SDH) is an anchorless, multifunctional protein displayed on the surfaces of group A
Streptococcus
(GAS) organisms. SDH is encoded by a single gene,
sdh
(
gap
or
plr
) that is essential for bacterial survival. Hence, the resulting nonfeasibility of creating a knockout mutant is a major limiting factor in studying its role in GAS pathogenesis. An insertion mutagenesis strategy was devised in which a nucleotide sequence encoding a hydrophobic tail of 12 amino acids (
337
IVLVGLVMLLLS
348
) was added at the 3′ end of the
sdh
gene, successfully creating a viable mutant strain (M1-SDH
HBtail
). In this mutant strain, the SDH
HBtail
protein was not secreted in the medium but was retained in the cytoplasm and to some extent trapped within the cell wall. Hence, SDH
HBtail
was not displayed on the GAS surface. The mutant strain, M1-SDH
HBtail
, grew at the same rate as the wild-type strain. The SDH
HBtail
protein displayed the same GAPDH activity as the wild-type SDH protein. Although the whole-cell extracts of the wild-type and mutant strains showed similar GAPDH activities, cell wall extracts of the mutant strain showed 5.5-fold less GAPDH activity than the wild-type strain. The mutant strain, M1-SDH
HBtail
, bound significantly less human plasminogen, adhered poorly to human pharyngeal cells, and lost its innate antiphagocytic activity. These results indicate that the prevention of the cell surface export of SDH affects the virulence properties of GAS. The anchorless SDH protein, thus, is an important virulence factor.
Enteropathogenic
Escherichia coli
Type III Effectors EspG and EspG2 Alter Epithelial Paracellular Permeability
Authors: Matsuzawa Takeshi , Kuwae Asaomi , Abe Akio
Published: September 2005

Enteropathogenic
Escherichia coli
(EPEC) delivers a subset of effectors into host cells via a type III secretion system. Here we show that the type III effector EspG and its homologue EspG2 alter epithelial paracellular permeability. When MDCK cells were infected with wild-type (WT) EPEC, RhoA was activated, and this event was dependent on the delivery of either EspG or EspG2 into host cells. In contrast, a loss of transepithelial electrical resistance and ZO-1 disruption were induced by infection with an
espG/espG2
double-knockout mutant, as was the case with the WT EPEC, indicating that EspG/EspG2 is not involved in the disruption of tight junctions during EPEC infection. Although EspG- and EspG2-expressing MDCK cells exhibited normal overall morphology and maintained fully assembled tight junctions, the paracellular permeability to 4-kDa dextran, but not the paracellular permeability to 500-kDa dextran, was greatly increased. This report reveals for the first time that a pathogen can regulate the size-selective paracellular permeability of epithelial cells in order to elicit a disease process.
Th1 Cytokines Are Essential for Placental Immunity toListeria monocytogenes
Authors: Barber Ellen M. , Fazzari Melissa , Pollard Jeffrey W.
Published: September 2005

The fetal allograft poses an immunological challenge: how is it protected while immunity to pathogens, particularly those that replicate in the placenta, is maintained? Several theories have been proposed to explain this fetal protection, including a pregnancy-based bias towards a Th2 rather than Th1 cytokine profile in order to avoid generating cytotoxic T cells that could threaten the fetus.Listeria monocytogenespreferentially replicates in the placenta and systemically requires a Th1 response for sterile eradication. In the placenta, the Th1 cytokines tumor necrosis factor alpha (TNF-α) and gamma interferon (IFN-γ) are also synthesized in response to this pathogen, without fetal loss. Here we show, by using mice homozygous for null mutations in either the cytokine or cytokine receptor genes, a requirement for both TNF-α and IFN-γ signaling for an effective placental immune response toL. monocytogenes. However, T cells were not recruited to the placenta. Genetic studies in which the fetal component of the placenta was genetically different from the mother indicated that both the production of and response to these cytokines were maternal. Despite the requirement for these cytokines, the early recruitment of neutrophils to the placenta was normal. Consequently, the bacterium appeared to be delayed in its colonization of this organ and did not fully gain hold until 72 h postinfection. These data show a requirement for Th1 cytokines during pregnancy for effective immunity and indicate that a bias away from Th1 cytokine synthesis is not a necessary prerequisite of pregnancy.
Massive Destruction of Malaria-Parasitized Red Blood Cells despite Spleen Closure
Authors: Krücken Jürgen , Mehnert Liv I. , Dkhil Mohamed A. , El-Khadragy Manal , Benten W. Peter M. , Mossmann Horst , Wunderlich Frank
Published: September 2005

It is currently accepted that malaria-parasitized red blood cells (pRBC) are eliminated, like senescent erythrocytes, phagocytically by macrophages in the red pulp of the spleen. Here, however, we show that self-healing
Plasmodium chabaudi
malaria activates spleen closure in C57BL/6 mice. Confocal laser scanning microscopy revealed that spleen closing was manifested by elimination of entry into the red pulp of 3-μm polystyrol particles, pRBC, and nonparasitized red blood cells but not of bovine serum albumin. This spleen closure did not reflect a reduction in the number of phagocytic cells, as shown by flow cytometry, whereas marginal zone macrophages (MZM) were lost and red pulp macrophages entered the white pulp. Splenic trapping of pBRC was strongly reduced in the absence of MZM and marginal metallophilic macrophages (MMM), as it is in noninfected mice with a disrupted lymphotoxin β receptor (LTβR
−/−
), and it was still significantly reduced when the number of MZM and MMM was diminished, as in tumor necrosis factor alpha-deficient (TNF-α
−/−
) mice. Moreover, mice deficient in TNF-α, tumor necrosis factor receptor I (TNFRI
−/−
), and LTβR exhibited progressive impairment in malaria-induced spleen closing. Treatment of C57BL/6 mice with TNF-α induced loss of MZM and spleen closing by about 20%. Our data indicate that TNF/TNFRI signaling is involved in regulating malaria-induced spleen closure, which is maximal during crisis, when parasitemia declines more than 100-fold. Consequently, the vast majority of pRBC cannot be destroyed by the spleen during crisis, suggesting that the known sophisticated sequestration system of
Plasmodium
parasites did not evolve to avoid splenic clearance.
The Surface-Associated Protein of
Staphylococcus saprophyticus
Is a Lipase
Authors: Sakinc Türkan , Woznowski Magdalena , Ebsen Michael , Gatermann Sören G.
Published: September 2005

Staphylococcus saprophyticus
surface-associated protein (Ssp) was the first surface protein described for this organism. Ssp-positive strains display a fuzzy layer of surface-associated material in electron micrographs, whereas Ssp-negative strains appear to be smooth. The physiologic function of Ssp, however, has remained elusive. To clone the associated gene, we determined the N-terminal sequence, as well as an internal amino acid sequence, of the purified protein. We derived two degenerate primers from these peptide sequences, which we used to identify the
ssp
gene from genomic DNA of
S. saprophyticus
7108. The gene was cloned by PCR techniques and was found to be homologous to genes encoding staphylococcal lipases. In keeping with this finding, strains 7108 and 9325, which are Ssp positive, showed lipase activity on tributyrylglycerol agar plates, whereas the Ssp-negative strain CCM883 did not. Association of enzyme activity with the cloned DNA was proven by introducing the gene into
Staphylococcus carnosus
TM300. When wild-type strain 7108 and an isogenic mutant were analyzed by transmission electron microscopy, strain 7108 exhibited the fuzzy surface layer, whereas the mutant appeared to be smooth. Lipase activity and the surface appendages could be restored by reintroduction of the cloned gene into the mutant. Experiments using immobilized collagen type I did not provide evidence for the involvement of Ssp in adherence to this matrix protein. Our experiments thus provided evidence that Ssp is a surface-associated lipase of
S. saprophyticus
.
THP-1 Monocytes Up-Regulate Intercellular Adhesion Molecule 1 in Response to Pneumolysin fromStreptococcus pneumoniae
Authors: Thornton Justin , McDaniel Larry S.
Published: September 2005

Pneumolysin (PLY) is a major virulence factor ofStreptococcus pneumoniaethat elicits a variety of proinflammatory responses from cells of the host immune system. Intercellular adhesion molecule 1 (ICAM-1) is a cell adhesion molecule involved in leukocyte trafficking toward inflammatory stimuli in extravascular sites. In this study, we evaluated the effect of PLY on expression of ICAM-1 in THP-1 monocytic cells exposed toS. pneumoniae. Exposure of cells to PLY-expressingS. pneumoniaestrain WU2 for 6 h led to significantly higher levels of ICAM-1 message than those in cells exposed to either medium alone or ΔPLY1, a PLY-negative isogenic mutant of WU2. Cells exposed to purified recombinant PLY also showed a dose-dependent increase in ICAM-1 mRNA compared to cells exposed to medium alone. Exposure to recombinant PLY containing a single amino acid substitution (Trp433→Phe) that decreases cytolytic activity did not increase ICAM-1 mRNA to levels seen with wild-type PLY. In addition, THP-1 cells exposed to wild-type strain WU2 or D39 had increased ICAM-1 on their surface compared to cells exposed to medium alone or their PLY-negative isogenic mutants ΔPLY1 and ΔPLY2, respectively. These data indicate that PLY induces transcription and production of a cell adhesion molecule involved in the inflammatory response that may play a role in pneumococcal infection.
Activation and Mitogen-Activated Protein Kinase Regulation of Transcription Factors Ets and NF-κB in Mycobacterium-Infected Macrophages and Role of These Factors in Tumor Necrosis Factor Alpha and Nitric Oxide Synthase 2 Promoter Function
Authors: Lee Seong-Beom , Schorey Jeffrey S.
Published: September 2005

Previous studies have shown that primary murine macrophages infected withMycobacterium aviumproduced lower levels of tumor necrosis factor alpha (TNF-α) and inducible nitric oxide synthase 2 (NOS2) compared to cells infected with nonpathogenicMycobacterium smegmatis. TNF-α and NOS2 levels correlated with and were dependent on the activation of mitogen-activated protein kinases (MAPKs) p38 and extracellular signal-regulated kinase 1/2 (ERK1/2). To define the macrophage transcriptional responses dependent on ERK1/2 activation following a mycobacterial infection, we used RAW 264.7 cells transfected with a TNF-α or NOS2 promoter vector. We determined that macrophages infected withM. aviumcompared toM. smegmatisshowed diminished TNF-α and NOS2 promoter activity. A more pronounced difference in promoter activity was observed when only the consensus ETS and NF-κB binding sites were used as promoters. Mutational analysis of the ETS and NF-κB binding sites present on the TNF-α and NOS2 promoters, respectively, showed that these sites were essential for a functional promoter. Moreover, the Ets/Elk but not the NF-κB transcriptional response was dependent on ERK1/2. This correlated with the requirement for ERK1/2 in TNF-α but not NOS2 promoter activity. Our data indicate that the increased Ets/Elk and NF-κB promoter activities associated withM. smegmatis-infected macrophages are responsible, at least in part, for the increased TNF-α and NOS2 production observed in these infected cells and that ERK1/2 is required for Ets/Elk activity and full TNF-α production.
Evaluation of Three
Pichia pastoris
-Expressed
Plasmodium falciparum
Merozoite Proteins as a Combination Vaccine against Infection with Blood-Stage Parasites
Authors: Zhang Dongmei , Pan Weiqing
Published: September 2005

Because invasion of erythrocytes by
Plasmodium falciparum
merozoites involves multiple receptor-ligand interactions, it may be necessary to develop a multivalent malaria vaccine that is comprised of distinct parasite ligands. PfAMA-1, PfMSP1, and PfEBA-175 are merozoite proteins that play important roles in invasion. We have constructed a PfCP-2.9 chimeric protein consisting of PfAMA-1 and PfMSP1 and tested it for immunogenicity in animal models and humans. The F2 subdomain of PfEBA-175 (PfEBA-175II F2) was identified as the binding domain for glycophorin A on erythrocytes. In this study, we used the codon frequencies of the yeast
Pichia pastoris
to redesign and synthesize a gene encoding the F2 domain. We found that the codon-optimized gene was expressed at a high level in
P. pastoris
as a soluble protein with a yield of about 300 mg/liter. The expressed protein was able to bind normal erythrocytes but not those treated with neuraminidase or trypsin. Moreover, the protein was recognized by the sera of malaria patients and was highly immunogenic in mice, rabbits, and rhesus monkeys. Immunoglobulin G isolated from both immunized rabbits and monkeys inhibited in vitro parasite growth. Immunization of animals with a combination of PfEBA-175II F2 and PfCP-2.9 did not result in antigen (Ag) competition in animals. Moreover, antibodies to both PfEBA-175II F2 and PfCP-2.9, isolated from rabbits immunized with both constructs, inhibited parasite growth in vitro. The combination of high yield, functional folding, antibody inhibition, and lack of Ag competition provides support for inclusion of these merozoite proteins in a combination vaccine against infection with blood-stage parasites.
An Anthrax Lethal Factor-Neutralizing Monoclonal Antibody Protects Rats before and after Challenge with Anthrax Toxin
Authors: Lim Nam-Kyu , Kim Jung-Hwan , Oh Mee Sook , Lee Sangyoon , Kim Se-Yeon , Kim Keun-Soo , Kang Hyun-jung , Hong Hyo Jeong , Inn Kyung-Soo
Published: September 2005

Lethal factor (LF) is a component of anthrax lethal toxin (LeTx). We generated anti-LF murine monoclonal antibodies (MAbs) that show LeTx-neutralizing activity in vitro and in vivo. Anti-LF MAbs were generated by immunization with recombinant LF, and the MAbs showing LeTx-neutralizing activity in vitro were selected. Two MAbs with the highest affinities, 5B13B1 (dissociation constant [

K
d

], 2.62 nM) and 3C16C3 (

K
d

, 8.18 nM), were shown to recognize the same or closely overlapping epitopes on domain III of LF. The 50% inhibitory concentration of 5B13B1 (0.21 μg/ml) was approximately one-third that of 3C16C3 (0.63 μg/ml) in the in vitro LeTx-neutralization assay. The 5B13B1 antibody, which had the highest neutralizing activity, provided perfect protection against LeTx challenge in an in vivo LeTx neutralization assay using Fisher 344 rats. In addition, the antibody showed pre- and postexposure prophylactic effects in the animal experiments. This is the first report that an MAb binding to domain III of LF has neutralizing activity against LeTx. The 5B13B1 antibody may be useful in prophylaxis against anthrax poisoning.