bluuebunny/crossref_metadata_2025 huggingface dataset:
Dietary Insulin Affects Leucine Aminopeptidase, Growth Hormone, Insulin-Like Growth Factor I and Insulin Receptors in the Intestinal Mucosa of Neonatal Pigs
Authors: Huo Yong Jiu , Wang Tian , Xu Ruo Jun , Macdonald Scot , Liu Gentao , Shi Fangxiong
Published: February 2006

Background: Recent studies suggest that milk-borne insulin may regulate the development of the gastrointestinal tract in neonatal mammals. Objectives: To explore the mechanism by which milk-borne insulin affects gastrointestinal tract development, we examined the effect of dietary insulin on the expression levels of leucine aminopeptidase (LAP) and insulin-like growth factor I (IGF-I), as well as its effect on growth hormone (GH), IGF-I and insulin receptors in the small intestinal mucosa of neonatal pigs. Methods: Five piglets were anesthetized and sampled within 2–4 h after birth. They were not allowed to suckle and were used as newborn controls (group N). Ten other piglets from 5 litters were randomly divided into group M (n = 5), which was fed cow’s milk, and group MI (n = 5), which was fed cow’s milk and insulin (2.5 mg/l). Piglets in groups M and MI were artificially fed for 3 days and then sampled. Total RNA in their intestinal mucosa was extracted with Tripure reagents (Roche, USA). Reverse transcription PCR (RT-PCR) was used to semi-quantify mRNA levels of target genes and 18S rRNA was used in an RT-PCR system as an internal control. PCR products were loaded onto a 9% nondenaturing polyacrylamide gel. The gel was stained by silver staining agents. Digital photos were taken and the strength of the band areas was quantified using software. Results: The results showed that the DNA contents and LAP activity in the small intestines of the piglets in group MI were higher (p < 0.05) than in the piglets in group N. Compared with group M, piglets in group MI exhibited significantly increased expression levels of both insulin and GH receptor in the ileum, and LAP in the jejunum (p < 0.05); IGF-I receptor expression levels in both the jejunum and ileum were significantly decreased (p < 0.01 and p < 0.05, respectively), while IGF-I expression was unchanged (p > 0.05). Conclusion: Collectively, dietary insulin increased mRNA levels of insulin and GH receptor, which could help explain the effect of dietary insulin on receptor-mediated postnatal development of the small intestine. Dietary insulin suppressed IGF-I receptor expression, which may be the result of negative feedback caused when insulin binds to IGF-I receptors.
Role of Latent Genital Tuberculosis in Repeated IVF Failure in the Indian Clinical Setting
Authors: Dam Purvita , Shirazee Hasibul Hasan , Goswami Sourendra Kanta , Ghosh Sanghamitra , Ganesh Ashalatha , Chaudhury Koel , Chakravarty Baidyanath
Published: February 2006

Genital tuberculosis is reported to be a major pelvic factor causing infertility in Indian women and often exists without any apparent signs and symptoms. The role of latent tuberculosis in repeated IVF failure in unexplained infertility is examined. 81 women with unexplained infertility having repeated IVF failure tested for Mycobacterium tuberculosis using PCR, ZN staining and BACTEC-460 culture were selected. Fresh IVF-ET or frozen embryo transfer (FET) was attempted on patients successfully treated with anti-tubercular drugs (ATD). ATD-treated fresh cycles (group A1) and frozen cycles (group B1) were compared to previously failed fresh cycles (group A2) and FET attempts (group B2), respectively. Main outcome measures were gonadotropin required, terminal E2, number of oocytes retrieved, fertilization rate, embryo quality, endometrial thickness and sub-endometrial blood flow (Vmax). Gonadotropin required in group A1 was significantly less as compared to group A2. Number of oocytes retrieved and grade I embryos, endometrial thickness and Vmax were significantly higher in group A1. Endometrial thickness and Vmax were significantly increased in group B1 as compared to B2. The study indicates that latent tuberculosis should be considered in young Indian patients presenting with unexplained infertility with apparently normal pelvic and non-endometrial tubal factors and repeated IVF failure.
Cognitive Profiles in Alzheimer’s Disease and in Mild Cognitive Impairment of Different Etiologies
Authors: Loewenstein David A. , Acevedo Amarilis , Agron Joscelyn , Issacson Richard , Strauman Silvia , Crocco Elizabeth , Barker Warren W. , Duara Ranjan
Published: February 2006

There has been increasing interest in determining whether amnestic, nonamnestic and multiple-domain subtypes of mild cognitive impairment (MCI) reflect different disease etiologies. In this study, we examined the extent to which cognitive profiles of nondemented patients with MCI diagnosed with prodromal Alzheimer’s disease (AD) differed from those MCI patients diagnosed with vascular disease. We also compared these diagnostic groups to mildly demented patients diagnosed with AD and normal elderly controls. Results indicate that a majority of both MCI-AD and MCI-vascular patients experienced amnestic features and that multiple-domain was the most common presentation. MCI-AD and MCI-vascular groups did not differ on neuropsychological measures tapping memory, language, visuospatial skills/praxis or executive function. Further both MCI groups could be distinguished from dementia patients with regards to performance on measures of memory but not on non-memory measures. Considerable variability was observed in the degree of memory impairment among MCI patients with scores as much as 6 standard deviations below expected mean values. MCI-AD and MCI-vascular patients frequently exhibit both common and overlapping amnestic and nonamnestic features. The implication of these findings for future clinical research is discussed.
Effect of Polyvinylpyrrolidone-Iodine Liposomal Hydrogel on Wound Microcirculation in SKH1-hr Hairless Mice
Authors: Langer S. , Botteck N.M. , Bosse B. , Reimer K. , Vogt P.M. , Steinau H.-U. , Mueller S.
Published: February 2006

Aim: Polyvinylpyrrolidone-iodine liposomal hydrogel (PVP-ILH) is a hydrogel formulation based on polyvinylpyrrolidone-iodine (PVP-I) and liposomes. The beneficial effects of PVP-ILH on wound healing have been previously shown. The aim of this study was to investigate the effects of topically applied PVP-ILH on wound microcirculation. Materials and Methods: Experiments were performed on wounds in male SKH1-hr hairless mice (n = 48). Mice were randomized into five treatment groups: mice treated with polyacrylic acid (PAA) and PAA 1:10 as well as PVP-ILH and PVP-ILH 1:10. Mice treated with sodium chloride served as control. Immediately as well as 3, 7, and 14 days after wounding, intravital fluorescent microscopy (IFM) was performed to determine wound surface area and standard microcirculatory parameters. Results: Topically administered PVP-ILH reduced wound size significantly faster compared to controls. Standard microcirculatory parameters, e.g. functional capillary density (FCD) and plasma leakage, showed no differences. FCD increases in all groups after wound creation. Using PVP-ILH, a trend towards higher FCD was observed. Conclusion: The wound model in hairless mice in combination with IFM is suitable to qualitatively assess wound microcirculation over a period of 2 weeks even after topical application of pigmented ointments. PVP-ILH showed a positive effect on dermal wound healing and wound microcirculation.
Apolipoproteins as Predictors of Ischaemic Stroke in Patients with a Previous Transient Ischaemic Attack
Authors: Bhatia M. , Howard S.C. , Clark T.G. , Neale R. , Qizilbash N. , Murphy M.F.G. , Rothwell P.M.
Published: February 2006

Background: Weak associations between total and LDL cholesterol and ischaemic stroke compared with coronary heart disease (CHD) are at odds with the similar effectiveness of statin drugs in preventing ischaemic stroke and CHD, suggesting that other lipid sub-fractions that are affected by statins might be better predictors of ischaemic stroke. Apolipoprotein B levels are reduced by statins and are a stronger predictor of CHD than total and LDL cholesterol in patients both on and off statins. However, there are very few published data on apolipoproteins and stroke risk and no studies in patients with previous transient ischaemic attack (TIA). Methods: We performed a prospective cohort study of the associations of baseline total cholesterol, LDL, HDL, apolipoproteins A1 and B (apo A1; apo B) and risk of ischaemic stroke in 261 patients with previous TIA. Cox proportional hazards models were used to determine crude and multivariate-adjusted hazard ratios (HR) above versus below median values at 10-years follow-up. Results: The apo B/apo A1 ratio was the strongest independent predictor of ischaemic stroke (HR = 2.94, 95% CI 1.43–5.88, p = 0.003) followed by apo B (HR = 2.26, 95% CI 1.16–4.38, p = 0.02). The associations between total cholesterol, LDL, HDL, LDL/HDL ratio and apo A1 and ischaemic stroke risk did not reach statistical significance. Conclusions: Apo B and the apo B/apo A1 ratio are predictive of ischaemic stroke in patients with previous TIA. Further studies are required to determine whether the prognostic value of apolipoprotein levels is maintained in patients on statins.
Meiji Japan as a Model for Africa's Economic Development
Authors: Nafziger E. Wayne
Published: February 2006

This paper examines the major ways in which the economic development model of Meiji Japan, 1868-1912, applies to contemporary Africa. The focus is on capital formation and technology policies that contributed to Meiji Japan's rapid industrial capitalist growth: self-directed strategies, technological borrowing, taking advantage of shifts in comparative advantage from the product cycle, educational policy, business assistance, financial institutions, transfer of agricultural savings to industry, low wages policy, industrial dualistic complementarity, and foreign-exchange rate policies conducive to export expansion. For each of these policies, the author analyzes the extent to which African countries can emulate Meiji Japan's approaches or whether changing circumstances require modification of the Japanese model.
Education and Modernization: An Examination of the Experiences of Japan and Ethiopia
Authors: Felleke Getachew
Published: February 2006

Japan has cultivated an immensely positive image among countries in the Sub-Saharan Region of Africa. Its industrial prowess, its post-war image as champion of peace, and its generous contributions of aid through its ODA lie behind this image. Beyond this, it also has long been regarded as a model of how a non-western and non-European country can successfully undertake a fast paced process of modernization. It is especially appealing as a model for African states to emulate in that the country managed to achieve its modernization without having to bear an undue cost of erosion of sovereignty and cultural integrity. This paper is a comparative examination of the early and divergent approaches to modernization that were adopted by Japan and Ethiopia.
Development and the Changing Dynamics of Global Production: Global Value Chains and Local Clusters in Apparel Manufacturing
Authors: Cammett Melani
Published: February 2006

Focusing on the apparel industry, this article contends that the global manufacturing context increasingly obliges developing countries to construct or promote regionalised production sites aiming to capitalise on local institutional assets. The dissemination of standardised business practices and procedures by leading multinational firms to their main suppliers has played a critical role in driving this trend. Changes in recent decades in global apparel production as well as new, high-tech systems of supply-chain management are compelling retailers to source from local ‘clusters’ of interrelated firms and institutions. At the same time, this trend may contradict the key contentions of the locally-oriented cluster approach because the adoption of similar apparel contracting, assembly and delivery procedures in diverse developing regions can undercut the logic of emphasising local institutional assets. The rising importance of inter-linked clusters in the global apparel industry supports theoretical conceptualisations that integrate the global value chain and cluster perspectives and delineates how the spread of similar logistics and supply chain management practices by multinational retailers and buyers shape development strategy and, therefore, development prospects.
Flexible Specialisation 20 Years On: How the ‘Good’ Industrial Districts in Italy Have Lost Their Momentum
Authors: Marangoni Giandemetrio , Solari Stefano
Published: February 2006

Twenty-two years ago, Piore and Sabel (1984) identified a ‘second industrial divide’. The aim of this paper is to propose some reflections, starting from that work, on the interaction between industrial organisation and institutional configurations as it has evolved in Italy in the form of ‘industrial districts’ or ‘regional clusters’. Given that Piore and Sabel proposed a necessary change in institutions, our concern is whether the flexible specialisation model, characterising industrial districts and regional clusters, really requires institutions to have less of a stabilising effect. Contrary to Piore and Sabel, we suggest that such systems do not benefit from a general deregulation and from a substantial rise in uncertainty due to the demise of stabilising institutions.
Entrainment Defects
Authors: Campbell J.
Published: February 2006

Most metals start their lives in the liquid state, and are subjected to various transfers involving pouring or other types of surface turbulence. These actions entrain (fold in) the surface film to create entrainment defects. These are principally (a) bubbles that in turn create bubble trails; (b) bifilms; doubled over surface films, that act as cracklike defects; and (c) sundry entrained debris, collectively known as exogenous inclusions. The bifilm is the subject of this perspective. It appears to be a common, but serious and almost overlooked metallurgical defect. Analysis of bifilms provides a simple, powerful and elegant concept based on an enduring legacy from turbulence during the pouring of liquid metals. Usually large populations of bifilms are introduced into metals at an early stage of their production. In general their presence has been unsuspected because although they can have large area, they can often be only nanometres thick and not easily detected by conventional non-destructive techniques. The populations of cracks in suspension in liquid metal explains many otherwise inexplicable features of cast products such as porosity, hot tearing, the morphologies of second phases, and impaired reliability of mechanical properties. The fundamental difference between such entrained defects (associated with a macroscopic unbonded interface) and defects and inclusions grown in the melt is seen to be of central significance for the failures of metals by mechanical or corrosion type mechanisms. For wrought products the continued presence of bifilms, now usually extended and elongated and mainly occupying grain boundaries, appears to offer explanations for many metallurgical phenomena. Bifilms are likely to influence the development of texture, and are the most likely source for many types of failure in the solid state. Thus the limitations to superplastic forming, cavitation in tertiary creep, pitting corrosion of various types and stress corrosion cracking are likely to be profoundly affected by bifilms. Although the effects of bifilms can be reduced by expensive post-casting operations such as hipping or working, the major future potential lies in techniques for their avoidance. Some casting operations are already taking some first steps in new technology for their avoidance, and benefiting technically and commercially.
Transformation of austenite remaining after intercritical rolling to ferrite
Authors: Khlestov V. M. , Konopleva E. V. , McQueen H. J.
Published: February 2006

The impact of austenite deformation in the intercritical range on the rate of transformation in continuous cooling to ferrite, pearlite, bainite or martensite has been studied. The austenite associated with the rolled ferrite is much higher in carbon content, which does not influence the pearlite transformation but retards bainite and martensite. Furthermore, in comparison with rolling of stable austenite the increased strain hardening of the intercritically cooled austenite accelerates the formation of ferrite and pearlite (+ 10–30°C) and refines them but retards the bainite and martensite transformations (−20–40°C). At the intermediate cooling rate near 16 K s−1, these several influences combined with near doubling of the ferrite production give rise to the suppression of bainite formation and to maximum increased delay of martensite start.
Process model for strength of age hardenable aluminium alloy welds
Authors: Robson J. D. , Sullivan A.
Published: February 2006

An existing process model for hardness prediction in age hardenable aluminium alloy welds is presented and analysed. One of the key criticisms of this model is that its derivation assumes softening is due to precipitate dissolution alone. The influence of precipitate coarsening has been determined by developing an equivalent model for softening owing to coarsening. It is shown that the experimentally derived master curves that form the basis of the model are capable of representing softening by a mixture of precipitate coarsening and dissolution. Methods to predict post-weld natural aging are discussed, and a new method is presented based on direct prediction of the Guinier–Preston zone fraction. The model has been applied to friction stir welding. Model predictions agree well with measured hardness profiles, and the sensitivity of the predictions to temperature is discussed.
Effects of fibre surface silanisation on silica fibre/phenolics composites produced by resin transfer moulding process
Authors: Wang B. C. , Huang Y. D. , Liu L.
Published: February 2006

The effects of fibre surface silanisation on silica fibre/phenolics composites produced by the resin transfer moulding (RTM) solution impregnation route were investigated. Diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy and micro-Wilhelmy method were used to evaluate the surface properties of silanised silica fibre. The interlaminar shear strength (ILSS) measurements and morphological observations of the silica fibre/phenolics composites were also performed. The interactions occurring between silica fibre and the components of phenolic resin solution affect the dynamic adsorption behaviour of phenolic resin onto fibre reinforcement. The competitive adsorption of ethanol as solvent onto silica fibre suppresses that of phenolic resin. Fibre surface silanisation by γ-aminopropyl-triethoxysilane ( γ-APS), γ-glycidoxypropyl-trimethoxysilane ( γ-GPS) and γ-methacryloxypropyl-trimethoxysilane ( γ-MPS) leads to the improvement of mechanical interfacial properties of silica fibre/phenolics composites on one hand and decreases the inhomogeneities of resin distribution and mechanical interfacial properties at different regions of the RTM product on the other hand.
Clonal restriction of the expansion of antigen-specific CD8+ memory T cells by transforming growth factor-β
Authors: Cheng Mei-Lien , Chen Hsin-Wei , Tsai Jy-Ping , Lee Yi-Ping , Shih Yan-Chung , Chang Chung-Ming , Ting Chou-Chik
Published: February 2006

Recent evidence showed that transforming growth factor-β (TGF-β) regulates the global expansion of CD8+ T cells, which are CD44hi, a marker for memory cells. However, it is not clear whether this regulatory mechanism also applies to the antigen-specific CD8+ memory cells. By using a murine mixed lymphocyte culture (MLC) model, we examined the effect of TGF-β on antigen-specific CD8+ memory cells [cytotoxic T lymphocyte (CTL)]. We found that the secondary CTL response in CD8+ memory cells from untreated MLC was not affected by TGF-β but augmented by interleukin (IL)-2, whereas the CD8+ memory cells from TGF-β-pretreated MLC (MLC-TGF-β) failed to mount a significant, secondary CTL response, even when IL-2 was added. In exploring this dichotomy, in combination with flow cytometry analysis, we found that prolonged exposure to TGF-β reduces the CTL activity in CD8+ memory cells. The increase by IL-2 and the reduction by TGF-β of the CTL responses were clonal-specific. TGF-β did not affect the CTL response to a third-party antigen or polyclonal T cell activation. Experiments performed with transgenic 2C cells gave similar results. Cell-cycle study performed with adoptive transfer of the cell tracker-labeled MLC cells revealed that the in vivo expansion of CD8+ memory cells from MLC-TGF-β was restricted severely, and the restriction was clonal-specific, thus offering direct evidence to show that TGF-β induces clonal restriction of CD8+ memory cell expansion.
Ethanol affects the generation, cosignaling molecule expression, and function of plasmacytoid and myeloid dendritic cell subsets in vitro and in vivo
Authors: Lau Audrey H , Abe Masanori , Thomson Angus W
Published: February 2006

The influence of ethanol (EtOH) on multiple dendritic cell (DC) subsets, in the steady state or following their mobilization in vivo, has not been characterized. Herein, generation of mouse bone marrow-derived DC (BMDC) in response to fms-like tyrosine kinase 3 ligand was inhibited by physiologically relevant concentrations of EtOH with selective suppression of plasmacytoid (p)DC. EtOH reduced surface expression of costimulatory molecules (CD40, CD80, CD86) but not that of coinhibitory CD274 (B7-H1) on resting or CpG-stimulated DC subsets. Interleukin (IL)-12p70 production by activated DC was impaired. Consistent with these findings, EtOH-exposed BMDC exhibited a reduced capacity to induce naïve, allogeneic T cell proliferation and impaired ability to prime T cells in vivo. DC subsets freshly isolated from EtOH-fed mice were also examined. Liver DC, inherently immature and resistant to maturation, exhibited little change in their low surface cosignaling molecule expression, whereas splenic DC showed reduced expression of surface costimulatory molecules in response to CpG stimulation in vivo. These splenic DC elicited reduced naïve, allogeneic T cell proliferation in vitro, and the stimulatory capacity of resting but not CpG-activated liver DC was reduced by chronic EtOH administration. T cells from animals primed with EtOH-exposed DC produced elevated levels of IL-10 following ex vivo challenge with donor alloantigen. Thus, EtOH impairs cytokine-driven differentiation and function of myeloid DC and pDC in vitro. Hepatic DC from chronic EtOH-fed mice are less affected than splenic DC, which exhibit impaired functional maturation following CpG stimulation. These results indicate a potential mechanism by which alcohol consumption is associated with immunosuppression.
Matrix metalloproteinase-9 modulates intestinal injury in rats with transmural colitis
Authors: Medina Carlos , Santana Alfredo , Paz Maria Cristina , Díaz-Gonzalez Federico , Farre Esther , Salas Antonio , Radomski Marek W , Quintero Enriquie
Published: February 2006

Proteolysis and degradation of extracellular matrix by metalloproteinases (MMPs) may contribute to intestinal injury in inflammatory bowel disease. In the present study, we investigated the pathogenic role of gelatinases (MMP-9 and MMP-2) on transmural colonic injury in a rat model of chronic colitis, which was induced by intracolonic instillation of trinitrobenzene sulfonic acid (TNBS). The activity and expression of MMP-2 and MMP-9 were measured in colonic tissue and peripheral neutrophils by fluorescence, zymography, Western blot, or immunohistochemistry at different time-points. Furthermore, myeloperoxidase content in colonic homogenates was analyzed to evaluate inflammation. Finally, morphological changes were assessed following early or delayed administration of CGS-27023-A, a synthetic inhibitor of MMPs. We found that the induction of colitis led to a significant up-regulation in tissue gelatinase concentration, whereas no changes in collagenase activity were observed. In addition, up-regulation of pro-MMP-9, but not of pro-MMP-2, was found on Days 7 and 10 following the induction of colitis. Furthermore, transmural MMP-9 was detected by immunofluorescent staining in the inflamed tissue. Consistent with tissue samples, neutrophils from colitic rats showed a significantly increased activity of pro-MMP-9. Finally, early but not delayed treatment with CGS-27023-A attenuated colonic mucosal injury in rats with TNBS-induced colitis. In conclusion, up-regulation of MMP-9 in peripheral and colonic neutrophils modulates transmural colonic injury in rats with TNBS-induced colitis.
Tissue-specific expression of estrogen receptors and their role in the regulation of neutrophil infiltration in various organs following trauma-hemorrhage
Authors: Yu Huang-Ping , Shimizu Tomoharu , Hsieh Ya-Ching , Suzuki Takao , Choudhry Mashkoor A , Schwacha Martin G , Chaudry Irshad H
Published: February 2006

Although 17β-estradiol (E2) administration after trauma-hemorrhage (T-H) reduces tissue neutrophil sequestration in male rodents, it remains unknown which of the estrogen receptor (ER) subtypes mediates this effect and whether the same ER subtype is involved in all the tissues. We hypothesized that the salutary effects of E2 on attenuation of neutrophil accumulation following T-H are tissue and receptor subtype-specific. Male Sprague-Dawley rats underwent sham operation or T-H (mean blood pressure, 40 mmHg for 90 min and then resuscitation). E2 (50 μg/kg), ER-α agonist propyl pyrazole triol (PPT; 5 μg/kg), ER-β agonist diarylpropiolnitrile (DPN; 5 μg/kg), or vehicle (10% dimethyl sulfoxide) was administered subcutaneously during resuscitation. Twenty-four hours thereafter, tissue myeloperoxidase (MPO) activity (a marker of neutrophil sequestration), cytokine-induced neutrophil chemoattractant (CINC)-1, CINC-3, and intercellular adhesion molecule (ICAM)-1 levels in the liver, intestine, and lung were measured (n=6 rats/group). ER-α and ER-β mRNA levels in sham-operated rats were also determined. T-H increased MPO activity, CINC-1, CINC-3, and ICAM-1 levels in the liver, intestine, and lung. These parameters were improved significantly in rats receiving E2 after T-H. Administration of the ER-α agonist PPT but not the ER-β agonist DPN improved the measured parameters in the liver. In contrast, DPN but not PPT significantly improved these parameters in the lung. In the intestine, ER subtype specificity was not observed. ER-α mRNA expression was highest in the liver, whereas ER-β mRNA expression was greatest in the lung. Thus, the salutary effects of E2 administration on tissue neutrophil sequestration following T-H are receptor subtype and tissue-specific.
Rickettsia felis, from Culture to Genome Sequencing
Authors: OGATA H , ROBERT C , AUDIC S , ROBINEAU S , BLANC G , FOURNIER P E , RENESTO P , CLAVERIE J M , RAOULT D
Published: February 2006

Abstract: Rickettsia felis has been recently cultured in XTC2 cells. This allows production of enough bacteria to create a genomic bank and to sequence it. The chromosome of R. felis is longer than that of previously sequenced rickettsiae and it possess 2 plasmids. Microscopically, this bacterium exhibits two forms of pili: one resembles a conjugative pilus and another forms hair‐like projections that may play a role in pathogenicity. R. felis also exhibits several copies of ankyrin‐repeat genes and tetratricopeptide encoding gene that are specifically linked to pathogenic host‐associated bacteria. It also contains toxin‐antitoxin system encoding genes that are extremely rare in intracellular bacteria and may be linked to plasmid maintenance.
Rickettsia conorii and R. prowazekii Proteome Analysis by 2DE‐MS: A Step toward Functional Analysis of Rickettsial Genomes
Authors: RENESTO PATRICIA , AZZA SAÏD , DOLLA ALAIN , FOURQUET PATRICK , VESTRIS GUY , GORVEL JEAN‐PIERRE , RAOULT DIDIER
Published: February 2006

Abstract: In this work, we present a comparative two‐dimensional (2D) PAGE analysis of Rickettsia conorii and Rickettsia prowazekii. This analysis reveals protein spots that were either unique to or common to both strains, some of them being identified by matrix‐assisted laser desorption ionization‐time of flight mass spectrometry.
Phylogenetic Study of Rickettsia Species Using Sequences of the Autotransporter Protein‐Encoding Gene sca2
Authors: NGWAMIDIBA MAXIME , BLANC GUILLAUME , OGATA HIROYUKI , RAOULT DIDIER , FOURNIER PIERRE‐EDOUARD
Published: February 2006

Abstract: The analyses of genome sequences from Rickettsia conorii and R. prowazekii have allowed the identification of five genes encoding autotransporter proteins, including ompA and four genes annotated in the R. prowazekii genome as “surface cell antigen” (sca) genes. Of these, ompA and sca5 (ompB) are known to encode membrane‐exposed antigenic proteins playing a major role in the host's immune response, and sca4 encodes a truncated autotransporter protein. In order to study further the phylogeny of the genus Rickettsia, we attempted amplification and sequencing of the sca2 genes from the 20 currently validated Rickettsia species. Sixteen species exhibited a complete sca2 gene, ranging from 2,727 bp in R. bellii to 5,580 bp in R. rhipicephali. R. helvetica and R. canadensis had a split gene, and R. prowazekii and R. typhi had remnant fragments of sca2. We also identified in R. akari, R. prowazekii, and R. typhi a duplication of the sca2 gene. The phylogenetic trees inferred from both the nucleotide and protein sequences of sca2 showed four clusters of rickettsiae, that is, the R. rickettsii, R. massiliae, R. akari, and typhus groups, which were supported by significant bootstrap values.
Protective Immunity against Q Fever Induced with a Recombinant P1 Antigen Fused with HspB of Coxiella burnetii
Authors: LI QINGFENG , NIU DONGSHENG , WEN BOHAI , CHEN MEILING , QIU LING , ZHANG JINGBO
Published: February 2006

Abstract: The gene fragments encoding outer membrane protein 1 (P1) and heat‐shock protein B (HspB) amplified from genomic DNA of Coxiella burnetii Xinqiao by PCR were inserted into prokaryotic expression vector pQE30 to construct recombinant expression plasmids pQE30/p1 and pQE30/hspB, respectively. The p1 fragment from pQE30/p1 was ligated with hspB of pQE30/hspB to construct pQE30/p1‐hspB. Recombinant proteins, P1, HspB, and P1‐HspB, were expressed in Escherichia coli cells transformed with pQE30/p1, pQE30/hspB, and pQE30/p1‐hspB, respectively. The purified recombinant proteins and whole‐cell antigen (WCA) of C. burnetii were used to immunize BALB/c mice. The antibody detection, T‐cell proliferation assay, and cytokine detection demonstrated that the animals immunized with P1‐HspB or WCA exhibited stronger humoral and cellular immune responses compared with animals immunized with P1 or HspB individually. Seven days after challenge of 10‐fold 50% infection dose of C. burnetii, mice were euthanized and their spleens were collected. The splenic weights of mice immunized with P1‐HspB or WCA were significantly lighter than that of mice immunized with P1 or HspB. By real‐time PCR assay, the coxiella loads of spleens of mice immunized with P1‐HspB or WCA were also significantly lower than that of mice immunized with P1 or HspB. The data from this study indicate that fusion antigen P1‐HspB is a good immunogen for eliciting immunoresponses against C. burnetii, and it may be a more suitable candidate for preparing subunit vaccine against Q fever.
Structural and Functional Characterization of the Glycan Antigens Involved in Immunobiology of Q Fever
Authors: VADOVIC PAVOL , SLABA KATARINA , FODOROVA MARCELA , SKULTETY LUDOVIT , TOMAN RUDOLF
Published: February 2006

Abstract: Coxiella burnetii is the causative agent of Q fever. The bacterium is extremely infectious and is classified as a category biological weapon. A lipopolysaccharide I (LPS I) belongs to the main components of the C. burnetii outer membrane and its structure‐function relationship studies are of potential interest. Size‐exclusion chromatography revealed noticeable differences in distribution and chemical composition of the O‐polysaccharide chains in LPS I. It is likely that C. burnetii is capable of synthesizing chemically distinct subclasses of O‐specific polysaccharide molecules differing in their antigenic reactivities. Methylation‐linkage analysis indicated the presence of terminal virenose (Vir), dihydrohydroxystreptose (Strep), and mannose (Man), 4‐substituted Vir, and 4‐substituted Man in the O‐specific chain. Serological data indicate that Vir and Strep might be involved in the immunobiology of Q fever.
Lack of Dendritic Cell Maturation Following Infection by Coxiella burnetii Synthesizing Different Lipopolysaccharide Chemotypes
Authors: SHANNON JEFFREY G. , HOWE DALE , HEINZEN ROBERT A.
Published: February 2006

Abstract: Coxiella burnetii is an obligate intracellular bacterium and the etiologic agent of the zoonotic disease Q fever. Symptomatic infection is normally characterized by flu‐like symptoms; however, in some cases, a persistent infection can ensue that may reactivate months or years after initial exposure to cause chronic disease. The mechanisms by which this obligate parasite evades clearance by the host immune response during persistent infection are unknown. We have previously demonstrated that lipopolysaccharide (LPS) length is critical in determining the response of human dendritic cells (DC) to C. burnetii. Here, we investigated whether LPS chemotype affects DC maturation or activation. Immature human DC were infected with three virulent strains of C. burnetii (Nine Mile phase I, S, or Priscilla) that produce chemically distinct LPS molecules. None of these strains stimulated significant upregulation of cell surface markers of DC maturation. Moreover, these strains were equally deficient in inducing DC IL‐12p70 production or p38 mitogen‐activated protein kinase phosphorylation. Infection of DC by virulent C. burnetii without stimulating significant maturation or inflammatory cytokine production may be a mechanism of immune evasion that results in persistent infection of an otherwise immunocompetent host. Our data indicate that LPS chemotype is not a determinant of DC maturation or cytokine production in response to C. burnetii.
TLR2 Is Necessary to Inflammatory Response in Coxiella burnetii Infection
Authors: MEGHARI SORAYA , HONSTETTRE AMÉLIE , LEPIDI HUBERT , RYFFEL BERNARDT , RAOULT DIDIER , MEGE JEAN‐LOUIS
Published: February 2006

Abstract: The resolution of Q fever, a zoonosis caused by Coxiella burnetii, depends on efficient innate and adaptive immune responses. Such responses are influenced by Toll‐like receptors (TLRs). TLR4 is involved only in part in immune responses against C. burnetii, suggesting a role for TLR2. We investigated C. burnetii infection in wild‐type and TLR2−/− mice. C. burnetii organisms were similarly eliminated by wild‐type and TLR2−/− mice. In contrast, the formation of granulomas, a marker for efficient cell‐mediated immunity, was markedly impaired. These results show that TLR2 is required for inflammatory and immune response to C. burnetii, but is dispensable for bacterial clearance.
Rickettsial Infections
Authors: OLANO JUAN P.
Published: February 2006

Abstract:Rickettsiaeare obligate intracellular α‐proteobacteria that primarily target the microvascular endothelium. In the last two decades, new rickettsial pathogens have been associated with human illness around the world. Clinically, the common denominator in all rickettsioses is the development of increased microvascular permeability, leading to cerebral and non‐cardiogenic pulmonary edema. With the development of powerful research tools, advances in the understanding of rickettsial pathogenesis have been dramatic. Entry into the host cell is followed by rapid escape into the cytoplasm to avoid phagolysosomal fusion. Spotted fever group rickettsiae induce actin polymerization via a group of proteins called RickA, which promote nucleation of actin monomers via the Arp2/3 complex at one rickettsial pole, propelling the bacteria across the cytoplasm and into neighboring cells. Damage to the host cell is most likely multifactorial. The most extensively studied mechanism is the generation of reactive oxygen species (ROS) and downregulation of enzymes involved in protection against oxidative injury. The significance of ROS‐mediated cellular damagein vivois beginning to be elucidated. The main pathogenic mechanism is increased microvascular permeability leading to profound metabolic disturbances in the extravascular compartment. The underlying factors responsible for those changes are beginning to be elucidatedin vitroand include direct effects of intracellular rickettsiae, cytokines, and possibly activated coagulation factors—all of which most likely modify interendothelial junctions. Our knowledge on rickettsial pathogenesis will continue to expand in the near future as new research tools become available.
Potential Roles for Regulatory Oxygenases in Rickettsial Pathogenesis
Authors: SAHNI SANJEEV K. , RYDKINA ELENA , SAHNI ABHA , JOSHI SURESH G. , SILVERMAN DAVID J.
Published: February 2006

Abstract: Clinical and experimental evidence suggests an important role for oxidative stress and associated cellular defense mechanisms in the pathogenesis of vasculopathic rickettsioses. Our laboratory has reported that R. rickettsii infection of endothelial cells in vitro induces the expression of HO‐1, the inducible isoform of the antioxidant defense enzyme heme oxygenase. HO‐1 plays a critical role in maintaining the integrity of the vasculature and controls the functioning of the cyclooxygenase (COX) system. This study was undertaken to investigate the expression of COX and HO isozymes during in vitro infection of EC with two major representatives of spotted fever group Rickettsia species. The mRNA expression of COX‐2 was significantly increased in endothelial cells infected with R. rickettsii and R. conorii, while that of COX‐1 remained unaffected. Western blot analysis using total protein lysates from infected endothelial cells and corresponding uninfected controls further confirmed specific induction of COX‐2 in response to infection. ELISA measurements on culture supernatants also suggested enhanced secretion of 6‐keto PGF1α (stable hydrolysis product of PGI2 and PGE2. As a functional consequence of HO‐1 upregulation, increased expression of the iron storage protein ferritin following R. rickettsii and R. conorii infection was also evident. Since products of HO‐1 and COX‐2 reactions govern a variety of physiologically important functions in the vasculature, further studies to define their regulation in the host cell should provide useful insights into the pathogenesis of rickettsial diseases.
Cloning and Sequence Analysis of the 22‐kDa Antigen Genes of Orientia tsutsugamushi Strains Kato, TA763, AFSC 7, 18–032460, TH1814, and MAK 119
Authors: GE HONG , TONG MIN , LI ANDREW , MEHTA RAJAN , CHING WEI‐MEI
Published: February 2006

Abstract: The 22‐kDa protein antigen is one of several antigens recognized by sera from scrub typhus patients infected with Orientia tsutsugamushi. The 22‐kDa protein genes from six O. tsutsugamushi strains (Kato, TA763, AFSC 7, 18–032460, TH1814, MAK119) were cloned and their sequences were determined and compared to each other and to the Karp strain sequence listed in GenBank. The sequence alignment revealed that the promoter regions of these seven strains were highly conserved. However, the ORFs exhibited some variation. The phylogenetic analysis of the DNA sequences indicated that among the seven strains assessed, Kato and TA763 were the most closely related, while Karp and TH1814 were the most distantly related. The information gained from this analysis will facilitate our selection of O. tsutsugamushi strains from which antigens should be derived to be included in a multivalent vaccine candidate for scrub typhus.
Effect of Antibiotic Treatment in Patients with DEBONEL/TIBOLA
Authors: IBARRA V , BLANCO J R , PORTILLO A , SANTIBÁÑEZ S , METOLA L , OTEO J A
Published: February 2006

Abstract: DEBONEL/TIBOLA is a tick‐borne acute/sub‐acute infection transmitted in our environment by Dermacentor marginatus and mainly caused by Rickettsia slovaca. The aim of our study was to know the effect of starting early treatment in the course of the DEBONEL/TIBOLA.
Bartonellae as Elegant Hemotropic Parasites
Authors: BIRTLES RICHARD J.
Published: February 2006

Abstract: Bartonella species are hemotropic bacterial parasites of a wide range of mammals that occasionally cause disease in humans. The low prevalence of clinical manifestations compared to the high prevalence of infection underlines the elegance of these parasites that carefully exploit their hosts in a manner that optimizes their transmission. Recent research efforts have begun to determine the strategies involved in this exploitation, and significant progress has been made in unraveling an unusually complex natural cycle. Studies aimed at determining bacterial attributes involved in parasitism characterized several “virulence” factors and explored their modes of action. These efforts have provided an intriguing foundation on which future efforts aimed at comprehending these sophisticated parasites can be soundly based.
Prophylactic Use of Sustained‐Release Doxycycline Blocks Tick‐Transmitted Infection by Anaplasma phagocytophilum in a Murine Model
Authors: MASSUNG ROBERT F. , ZEIDNER NORDIN S. , DOLAN MARC C. , ROELLIG DAWN , GABITZSCH ELIZABETH , TROUGHTON DANIELLE R. , LEVIN MICHAEL L.
Published: February 2006

Abstract: A sustained‐release formulation of doxycycline hyclate was tested for its ability to block Anaplasma phagocytophilum infection in mice. Mice treated with sustained‐release doxycycline showed no splenomegaly and their blood samples were negative by PCR on days 7, 14, and 21. Control mice treated with either oral doxycycline or water had significant splenomegaly and were PCR positive at multiple time points. The sustained‐release doxycycline formulation was shown to be efficacious for preventing tick‐transmitted A. phagocytophilum infection in a mouse model.
The Interactions of Anaplasma phagocytophilum, Endothelial Cells, and Human Neutrophils
Authors: HERRON MICHAEL J. , ERICSON MARNA E. , KURTTI TIMOTHY J. , MUNDERLOH ULRIKE G.
Published: February 2006

Abstract: Ixodes scapularis ticks transmit Anaplasma phagocytophilum (Ap), agent of human granulocytic anaplasmosis (HGA). Invasion of neutrophil granulocytes (PMN) by Ap is the hallmark of the disease, but these short‐lived phagocytes are not likely the sole cell type required for productive infection. We analyzed infection of microvascular endothelial cells during pathogenesis of anaplasmosis in vivo and in vitro. Organs from Ap‐infected mice were processed for confocal microscopy 41 days p.i. Fluorescent labeling of heart and liver sections using anti‐factor VIII and anti‐MSP2 antibodies allowed colocalization of Ap and vascular endothelium, indicating infection. Ap rapidly invaded and grew within HMEC‐1 human microvascular endothelial cells and readily transferred to PMN. Over 50% of PMN became infected within two hours of coincubation with HMEC‐1. PMN adhered to, polarized, and migrated upon infected endothelial monolayers. The Ap receptor on human PMN is PSGL‐1, and infected endothelial cells upregulate ICAM‐1 (CD54), but the mechanisms of transfer of Ap remain unknown. To elucidate the cellular determinants involved, we tested relevant antibodies and lectins. Anti‐PSGL‐1 reduced infection of PMN, but did not inhibit adherence of PMN to Ap infected HMEC‐1 cells while anti‐CD18 did. Sialidase pretreatment increased, and EDTA and fucoidan decreased binding of Ap to HMEC‐1, whereas several other lectins had no effect. An endothelial reservoir of Ap offers opportunities for ongoing, direct cell‐to‐cell infection of PMN, avoidance of host immune effectors, and completion of the Ap life cycle by infection of circulating leukocytes available for transfer to blood‐feeding ticks.
Isolation and Cultivation of Human Testicular Peritubular Cells: A New Model for the Investigation of Fibrotic Processes in the Human Testis and Male Infertility
Authors: Albrecht Martin , Rämsch Romi , Köhn Frank M. , Schwarzer J. Ullrich , Mayerhofer Artur
Published: February 2006

Context: Fibrotic remodeling, especially of the tubule wall, in testes of infertile men is common, but reasons or consequences of these striking changes are not known. Based on cell culture and ex vivo studies, we previously suggested that mast cells via their products tryptase and histamine are involved in the development of fibrosis. However, studies in a relevant human testicular model are required to further test this hypothesis and the mechanisms of testicular fibrosis in general.

Objective: The objective of the study was the isolation, culture, and characterization of adult human testicular peritubular cells.

Patients and Interventions: Peritubular cells were obtained from biopsies of men suffering from obstructive azoospermia (n = 8) and varicocele (n = 2) but displaying normal spermatogenesis.

Results: Explant cultures were obtained from all biopsies. Immunostaining of the cultured cells and corresponding paraffin-embedded tissues with antibodies against markers of fibroblasts (CD90/Thy-1) and smooth muscle cells (α-smooth muscle actin) clearly proved their origin from the peritubular region. These cells displayed morphological features of myofibroblasts, and gene array analyses as well as immunohistochemistry revealed the predominant expression of extracellular matrix genes and genes coding for basement membrane components. The cultured cells retain receptors for the major mast cell products histamine and tryptase. The addition of histamine (100 μm) and the tryptase agonist peptide SLIGKV (10 μm) resulted in a transient increase in intracellular calcium levels, confirming the functionality of the receptors.

Conclusions: We conclude that human peritubular cells are a novel model for the investigation of paracrine, including mast cell initiated, interactions in the human testis, which will allow the study of fibrotic processes underlying male idiopathic infertility.
APC inhibits ERK pathway activation and cellular proliferation induced by RAS
Authors: Park Ki-Sook , Jeon Soung Hoo , Kim Sung-Eun , Bahk Young-Yil , Holmen Sheri L. , Williams Bart O. , Chung Kwang-Chul , Surh Young-Joon , Choi Kang-Yell
Published: February 2006

Inactivating mutations in the adenomatous polyposis coli gene (APC), and activating mutations in RAS, occur in a majority of colorectal carcinomas. However, the relationship between these changes and tumorigenesis is poorly understood. RAS-induced activation of the ERK pathway was reduced by overexpressing APC in DLD-1 colorectal cancer cells. ERK activity was increased by Cre-virus-induced Apc knockout in primary Apcflox/flox mouse embryonic fibroblasts, indicating that APC inhibits ERK activity. ERK activity was increased by overexpression and decreased by knock down of β-catenin. The activation of Raf1, MEK and ERK kinases by β-catenin was reduced by co-expression of APC. These results indicate that APC inhibits the ERK pathway by an action on β-catenin. RAS-induced activation of the ERK pathway was reduced by the dominant negative form of TCF4, indicating that the ERK pathway regulation by APC/β-catenin signaling is, at least, partly caused by effects on β-catenin/TCF4-mediated gene expression. The GTP loading and the protein level of mutated RAS were decreased in cells with reduced ERK activity as a result of APC overexpression, indicating that APC regulates RAS-induced ERK activation at least partly by reduction of the RAS protein level. APC regulates cellular proliferation and transformation induced by activation of both RAS and β-catenin signaling.