bluuebunny/crossref_metadata_2025_split huggingface dataset:
Age‐Related Increase in Resistance to Acute Trypanosoma cruzi Infection in Rats is Associated with an Appropriate Antibody Response
Authors: Pascutti M. F. , Bottasso O. A. , Hourquescos M. C. , Wietzerbin J. , Revelli S. 
Published: July 2003

AbstractInoculation at weaning with Trypanosoma cruzi in inbred ‘l’ rats resulted in a self‐resolving acute infection characterized by marked parasitaemias, whereas challenge to adult rats revealed a mild disease with extremely low parasitaemias. To explore the mechanisms underlying such age‐associated differences in disease outcome, we analysed the in vitro replication of T. cruzi, nitric oxide and tumour necrosis factor‐α (TNF‐α) production in peritoneal macrophages (PMs), the serum concentrations of the specific immunoglobulins (Igs) IgM and IgG, antibodies exhibiting lytic activity against bloodstream forms of T. cruzi and circulating levels of nitrate, TNF‐α and interferon‐γ (IFN‐γ). Macrophages from young rats were as effective as their adult counterparts for restraining intracellular parasite replication. When stimulated with IFN‐γ, culture supernatants from young PMs contained higher amounts of nitrite and TNF‐α. Serum samples from 4 and 7 days post infection revealed easily detectable amounts of nitrate, with values being further augmented by day 7 post infection and significantly higher in the young group. TNF‐α levels were only detected in the young group by day 7 post infection. Both groups had increased amounts of IFN‐γ in their sera, although in adult rats, this trend was followed by a significant drop at day 7, with young rats showing values still higher by the same time point evaluation. In contrast, young rats presented significantly lower levels of IgM and IgG antibodies during the first week of infection. Increased resistance in adult rats seems to be the result of a more appropriate antibody production.
Increased Production of Interferon‐γ by Leishmania Homologue of the Mammalian Receptor for Activated C Kinase‐Reactive CD4+ T cells among Human Blood Mononuclear Cells: An Early Marker of Exposure to Leishmania?
Authors: Bourreau E. , Pascalis H. , Prévot G. , Kariminia A. , Jolly N. , Milon G. , Buffet P. , Michel R. , Meynard J.‐B. , Boutin J.‐P. , Aschimoff D. , Launois P. 
Published: July 2003

AbstractA prospective study was undertaken to define early predictive immunological marker(s) of exposure to Leishmania in naïve subjects who have never been exposed to any Leishmania and who were also free of any cutaneous leishmaniasis lesions. These naïve subjects could have been exposed to Leishmania in a rain forest where Leishmania guyanensis and their natural vectors and mammalian host are cocirculating. The production of interferon (IFN)‐γ in response to the Leishmania homologue of the mammalian receptor for activated c kinase (LACK), a candidate for vaccine against leishmaniasis was analysed. At the end of their stay in the rain forest, LACK‐specific CD8+ T cells were detected in subjects whose peripheral blood mononuclear cell (PBMC) produced IFN‐γ in response to soluble Leishmania antigens (SLA) and in those whose PBMC remained unresponsive to SLA. However, LACK‐specific CD4+ T cells were detected only in PBMCs from individuals who became IFN‐γ responders to SLA. In subjects whose PBMC became positive to SLA, LACK‐reactive CD4+ T cells producing high level of IFN‐γ were detectable before the SLA‐reactive IFN‐γ producing CD4+ T cells, suggesting that the former readout assay could be used as an early predictive immunological marker of exposure to Leishmania in subjects who remained disease free.
Immobilized MICA Could Expand Human Vδ1 γδ T Cells In Vitro that Displayed Major Histocompatibility Complex Class I Chain‐Related A‐Dependent Cytotoxicity to Human Epithelial Carcinomas
Authors: Qi J. , Zhang J. , Zhang S. , Cui L. , He W. 
Published: July 2003

AbstractHuman major histocompatibility complex class I chain‐related A (MICA) is a human leucocyte antigen‐related polymorphic molecule, which is expressed on many kinds of epithelial tumours and can be recognized by the Vδ1 subset of γδ T cells. In the present study, monoclonal antibodies (MoAbs) were produced in mice immunized with recombinant MICA (rMICA)*008. It was found that MICA was expressed on ovarian and colonic tumour tissues and could be detected by these anti‐MICA MoAbs. The immobilized rMICA could induce the proliferation of human ovarian epithelial carcinoma‐ or colonic carcinoma‐derived γδ T cells of the Vδ1 phenotype in vitro. These Vδ1 T cells displayed a strong, broad‐range cytolytic activity towards tumour cell lines positive for MICA. The efficiency of this cytolytic activity depended greatly on the level of MICA expressed on the cell surface and could be inhibited by anti‐MICA MoAbs. Therefore, MICA may play an important role in immune responses against epithelial tumours and function as a stimulating factor for the growth of Vδ1 γδ T cells, whereas MICA‐reactive Vδ1 γδ T cells might serve as a new candidate for adoptive cellular therapy of tumours.
Mucosal Vaccination Against Encapsulated Respiratory Bacteria – New Potentials for Conjugate Vaccines?
Authors: Jakobsen H. , Jonsdottir I. 
Published: July 2003

AbstractPolysaccharide (PS)‐encapsulated bacteria such as Haemophilus influenzae type b (Hib), Streptococcus pneumoniae (pneumococcus), Neisseria meningitides (meningococcus) and group B streptococcus (GBS), cause a major proportion of disease in early childhood. Native PS vaccines are immunogenic and provide protection against disease in healthy adults but do not induce immunological memory. PSs are T‐cell‐independent antigens and do not elicit antibodies in infants and young children, but by conjugating PS to proteins they become T‐cell dependent and immunogenic at an early age. Despite excellent efficacy of PS–protein conjugate vaccines against invasive disease, protection against mucosal infections such as pneumococcal otitis media has been less efficacious. Circulating PS‐specific antibodies may protect against infections at mucosal sites, but mucosal immunoglobulin A antibodies may also contribute significantly to protection against mucosal infections. Mucosal immunization of experimental animals with conjugate vaccines against Hib, pneumococcus, meningococcus and GBS induces systemic and mucosal immune responses, which provide protection against carriage, otitis media and invasive disease in a variety of challenge models, providing new means for protection against encapsulated bacteria. In addition, mucosal immunization of neonatal mice with a pneumococcal conjugate and the nontoxic adjuvant LT‐K63 has been superior to parenteral immunization in eliciting protective antibodies and PS‐specific memory, and thus circumventing the limitations of antibody responses to PS that are responsible for enhanced susceptibility of neonates and infants to infections caused by encapsulated bacteria. Through T‐cell dependent enhanced immunogenicity of PS–protein conjugate vaccines, mucosal immunization could be an attractive approach for early life immunization against encapsulated bacteria.
Positional Cloning of Ncf1– a Piece in the Puzzle of Arthritis Genetics
Authors: Olofsson P. , Holmdahl R. 
Published: July 2003

AbstractPositional cloning of susceptibility genes in complex diseases like rheumatoid arthritis in humans is hampered by aspects like genetic heterogeneity and environmental variations, while genetic studies in animal models contain several advantages. With animal models, the environment can be controlled, the genetic complexity of the disease is minimized and the disease onset can be predicted, which simplify diagnosis and characterization. We use pristane‐induced arthritis in rats to investigate the inheritance of arthritis. Until now, we have identified 15 loci that significantly predispose rats to the development of arthritis. One of these arthritis loci has been isolated and confirmed to be caused by a polymorphism in the Ncf1 gene. In this review, we outline the methods used to identify Ncf1 as one single susceptibility gene in a complex puzzle of inherited factors that render susceptibility to a complex autoimmune disorder like arthritis.
Regulation of Adhesion and Motility in B Lymphocytes
Authors: Severinson E. , Westerberg L. 
Published: July 2003

AbstractDuring the differentiation process of B lymphocytes, they go through changes in adhesion and motility. In order to investigate the molecular mechanism of such changes, in vitro culture systems are necessary. When B cells are activated by various stimuli, they form different types of homotypic aggregates. In addition, they might also spread and express microvilli and/or become polarized, the latter being a sign of motility. In this review, we summarize our own research in this area. We give evidence for involvement of different adhesion and signalling molecules, and by the end, we speculate on the in vivo significance of our findings.
A Human Leucocyte Antigen‐DR1 Transgene Confers Susceptibility to Experimental Allergic Encephalomyelitis Elicited by an Epitope of Myelin Basic Protein
Authors: Sireci G. , Dieli F. , Caccamo N. , Barera A. , Carta P. , Di Sano C. , Meraviglia S. , Bonanno C. T. , Salerno A. 
Published: July 2003

AbstractMuch evidence now indicates that human leucocyte antigen (HLA) class I and class II transgenic (Tg) mice can be of value in analysing HLA‐restricted presentation of T‐cell epitopes relevant to experimental models of autoimmune diseases. One area where this has been applied is the characterization of myelin epitopes presented by HLA class II molecules in experimental model of multiple sclerosis (experimental allergic encephalomyelitis (EAE)). As a first step towards humanized disease models in HLA Tg mice, we have analysed immune response of lymph node cells of HLA‐DR1 Tg mice immunized with the human myelin basic protein (MBP) peptides 13–33, 87–106 and 139–154 bound by HLA‐DR1. We report here that HLA‐DR1 Tg mice display a hierarchy of response in vivo and in vitro to MBP epitopes depending on the binding affinity to DRB*0101 molecule. In fact, the 13–33 epitope induced a strong T helper 1 (Th1) response accompanied by high T‐cell precursor frequency and caused mild EAE, while the two other epitopes gave poor (139–154) or no disease (87–106), and these data correlate with in vitro Th1 response. These data could prove a useful tool in understanding the role played by different MBP epitopes in EAE.
Transforming Growth Factor‐β as a Regulator of Site‐Specific T‐Cell Inflammatory Response
Authors: Lúðvíksson B. R. , Gunnlaugsdóttir B. 
Published: July 2003

AbstractA common immunopathological hallmark of many autoimmune inflammatory diseases is a T‐cell invasion and accumulation at the inflamed tissue. Although the exact molecular and microenvironmental mechanisms governing such cellular invasion and tissue retention are not known, some key immunological principles must be at work. Transforming growth factor‐β (TGF‐β) is known to modulate some of these processes including homing, cellular adhesion, chemotaxis and finally T‐cell activation, differentiation and apoptosis. The chronicity of such T‐cell‐driven inflammation probably involves an innate immunological response leading to a T‐1 (Th/Tc), T‐2 or T‐3 (Th/Tr) T‐cell adaptive immune response. Several studies suggest that the key to T‐cell final destination resides on its and the antigen‐presenting cell's phenotype as well as the coreceptor expression pattern and their signalling intensity. Recent observations suggest other equally important regulatory elements of T‐cell inflammatory response that are sensitive to TGF‐β modulation. These include: (i) the stage of T‐cell activation/differentiation; (ii) the chemotactic/adhesion molecule expression pattern; and (iii) the conditioning at the immunological synapse determining their sensitivity to known regulators such as TGF‐β. In this article, we focus on how the phenotype of the responding T cell and the T‐cell receptor (TCR)‐signalling intensity could drive the given inflammatory response. In particular, we discuss how TGF‐β can influence the process of T‐cell migration and activation during such site‐specific inflammation.
Fractalkine is Not a Major Chemoattractant for the Migration of Neutrophils Across Microvascular Endothelium
Authors: Beck G. Ch. , Ludwig F. , Schulte J. , Van Ackern K. , Van Der Woude F. J. , Yard B. A. 
Published: July 2003

AbstractInflammatory responses during sepsis are determined by leucocyte recruitment into inflamed tissues. Both chemokines and adhesion molecules are believed to be involved in this process. As fractalkine exists as transmembrane protein with cell adhesion properties and as soluble chemotactic factor, the present study was conducted to study the role of fractalkine, produced by microvascular and macrovascular endothelial cells, in neutrophil recruitment. Lung microvascular endothelial cells (LMVECs) stimulated with lipopolysaccharide, tumour necrosis factor‐α or interleukin‐1 (IL‐1) produced much more fractalkine compared with the macrovascular human umbilical vein endothelial cells (HUVECs). No differences were found between microvascular endothelial cells of different organs. Chemotactic activity in supernatants was significantly stronger in stimulated LMVEC when compared with HUVEC. Although recombinant fractalkine induced migration of neutrophils, IL‐8 and monocyte chemoattractant protein‐1 were found to be more strictly required. In vivo fractalkine was strongly upregulated in septic lung and kidney. Our data suggest that fractalkine production per se does not explain the preference for inflammation in the lung of septic patients.
Remembrance of Antigens Past: New Insights into Memory T Cells
Authors: Farber D. L. 
Published: July 2003

AbstractMemory immune responses against foreign antigens protect the host from pathogens previously encountered via illness or vaccination, yet can also contribute to the pathology of autoimmune disease when generated against self‐antigens. Memory immune responses are classically attributed to the reactivation of long‐lived, antigen‐specific T lymphocytes that arise directly from differentiated effector T cells and persist in a uniformly quiescent state. Recent findings in both humans and mice, using new biochemical, molecular and cellular approaches, have identified novel features of memory T cells providing new insight into models for memory cell development and differentiation. Biochemical and molecular studies on memory T cells have identified novel markers for memory T cells that may play integral roles in their generation and maintenance. Recent cellular immunological studies have uncovered remarkable heterogeneity amongst antigen‐specific memory T cells. Memory cell heterogeneity in the expression of homing and chemokine receptor delineates functional subsets of memory T cells that differ in their proliferative capacity, differentiation potential, homing properties and protective abilities. These findings suggest that memory T cells with diverse properties residing in both lymphoid and nonlymphoid tissues may be necessary to elicit a rapid and effective protective recall immune response involving both cellular and humoral immunity.
Agronomic evaluation of precise mechanical hoeing and chemical weed control in sugar beet
Authors: Wiltshire J J J , Tillett N D , Hague T 
Published: July 2003

SummaryMost herbicide applications to sugar beet (Beta vulgarisL.) are made to the whole crop area, but there is the opportunity to restrict applications to the crop row, decreasing the usage of herbicide by up to 70%. However, this would require greater use of mechanical weed control between rows. Experiments were performed in two seasons to evaluate the weed control performance of a novel, vision‐guided, inter‐row hoe in sugar beet crops grown on a peat fen soil. Hoe lateral placement was within ±30 mm. A precise hoeing and band spraying treatment was compared with overall herbicide use, and with treatments in which the herbicide applications were replaced by hand weeding to minimize competition between crop and weeds. Two hoe passes were made in each season, at crop growth stages of two and 10–12 true leaves in the first season and four and eight true leaves in the second season. Plant population density was not affected by treatment, indicating that none of the treatments caused crop plant loss. Use of the guided hoe controlled weeds better than overall spraying. Crop yields were not significantly different between treatments, indicating that weed control prevented competition with the crop in all treatments.
Effect of air temperature, rain and drought on hot water weed control
Authors: Hansson D , Mattsson J E 
Published: July 2003

SummaryThe influence of rain and drought before, and air temperature during, weed control with hot water was studied in laboratory experiments on the test weedSinapis alba(white mustard). The plants were grown in a greenhouse and treated outdoors. There was no difference in weed control effect whenS. albaplants at the four‐leaf stage were treated at the air temperatures 7°C and 18∘C. The effective energy dose for a 90% fresh weight reduction was 465 kJ m−2for both air temperatures. Weed control ofS. albaat the four‐ to six‐leaf stage in rainfall above the rainwater run‐off level increased the required effective energy dose by 20% (i.e. 120 kJ m−2) compared with dry plants. A short period of drought just before treatment onS. albaat the two‐ to four‐leaf stage increased the plant fresh weight reduction, which was 22% at low energy dose (190 kJ m−2) and 44% at high energy dose (360 kJ m−2). Hot water weed control should thus be carried out when the plants are drought stressed and avoided when the plants are wet. The air temperature seems to be of little importance in the range 7–18∘C.
Towards multifunctional agriculture – weeds as ecological goods?
Authors: Gerowitt B , Bertke E , Hespelt S‐K , Tute C 
Published: July 2003

SummaryAgricultural land use has production, ecological, aesthetic and social functions. Certainly, in Europe, the concept of agricultural land use as being multifunctional seems to be increasingly accepted. Ecological goods and services can be rewarded as results or as actions – the differences between these ways are described and an outcome‐based rewarding system is elucidated for the creation of incentives for innovation and taking responsibility. The principle requirements for ecological goods are summarized. The contribution of agricultural land use to plant biodiversity is the most appropriated factor for an outcome‐based rewarding system. The various types of vegetation connected with agricultural land use can be used as recognizable ecological goods. The reasoning behind defining specific arable goods is shown. Information about creating the supply is available from the research performed on weed control in different arable systems. As the majority of ecological goods are public goods, mechanisms adapted from market situations for private goods must be stimulated and organized. The decision as to which ecological goods should be stimulated could be transferred to a decentralized and region‐specific public committee in which the relevant stakeholders are represented. Implementation exercises undertaken in a region of the German Federal State of Lower Saxony are introduced.
Retention and degradation of metribuzin in sandy loam and clay soils of Lebanon
Authors: Khoury R , Geahchan A , Coste C M , Cooper J‐F , Bobe A 
Published: July 2003

SummaryThe retention and degradation of metribuzin herbicide were studied under two environmental conditions. Field studies were carried out on two soils, a sandy loam soil (soil A) and a clay soil (soil B). Metribuzin was applied with a jet sprayer at 1060 g a.i. ha−1 and 1960 g a.i. ha−1 on soils A and B respectively. Reconstituted soil columns were used to study the herbicide movement and metabolism in the two soils. Analyses of metribuzin and its metabolites were carried out using standardized methods. The results indicated a very weak capacity of adsorption of metribuzin in the two soils, and the weak adsorbed fraction is easily desorbed. Degradation and mobility of metribuzin in the field and laboratory soil columns were very intense and rapid. Soil A favoured reductive deamination whereas soil B favoured oxidative desulphuration and the respective metabolites deaminometribuzin and diketometribuzin yield the same product deaminodiketometribuzin. Both leaching by rainfall and degradation were important in the disappearance of metribuzin from the soils.
Predispersal seed predation of Amaranthus retroflexus and Chenopodium album growing in soyabean fields
Authors: Nurse R E , Booth B D , Swanton C J 
Published: July 2003

SummaryField experiments were made in 1998 and 1999 to determine the influence of tillage and soyabean (Glycine max) row width on predispersal weed seed predation in Amaranthus retroflexus L. (redroot pigweed) and Chenopodium album L. (common lambsquarters). Soyabean was planted in wide (76 cm) and narrow (19 cm) rows with conventional or conservation tillage. Additional control plots without soyabean were also established. The two objectives were to determine (1) whether predispersal seed predation occurs in A. retroflexus or C. album, and (2) whether disturbance (soil tillage) or microclimate (planting pattern) influence predation level. Mean rates of seed predation were 26% and 4% in A. retroflexus and C. album, respectively. Although these levels were low at the population level, individual plants of both species had predation levels ranging from 0% to 80%, however, very few individuals of C. album had levels of predation above 10%. Differences among tillage and row width treatments occurred for A. retroflexus, but not for C. album. Amaranthus retroflexus and C. album growing within the soyabean crop received less light than those in the no‐crop plots, and produced less above‐ground biomass, smaller terminal inflorescences, and fewer seeds per inflorescence. Plant height, terminal inflorescence weight, and total seeds were correlated with predation in both weed species.
Survival, germinability and fungal colonization of dimorphic achenes of the annual weedGalinsoga parvifloraburied in the soil
Authors: Espinosa‐García F J , Vázquez‐Bravo R , Martínez‐Ramos M 
Published: July 2003

SummaryGalinsoga parviflora(Asteraceae) is a widespread annual weed that produces capitula containing both disc achenes with pappus and ray achenes without pappus. The latter are dispersed within a winged structure formed by capitulum bracts. We buried both achene types in an agricultural soil to be exhumed regularly to investigate whether they differed in survival, germinability and fungal colonization in the soil seedbank. Ray achenes remained viable longer than disc achenes, with different loss rates for the achene types. In both cases, loss rate was very high for the first 10 months, and then loss rates for the achene types tended to level off and even converge by the end of the observation period. The percentage of remaining viable disc achenes was alwaysc.10–15% lower than that of the ray achenes, except on the first and last sampling dates. Germination percentages for viable ray and disc achenes before burial and after exhumation were not statistically different during most of the observation period, except for that between 100 and 200 days of burial (mid‐autumn–winter). There, germination of disc achenes reached 26.4% after 126 days of burial, whereas germination of ray achenes was close to zero. In addition, after 779 days, the germinability of ray achenes was 21.3%, whereas it was 0% for disc achenes. Surface‐disinfected viable disc and ray achenes had low infection rates (0–15%) for both fungi and bacteria during the observation period. The fungal and bacterial infection peaks for both achene types were asynchronous. In general, the expected difference (lower infection rate for ray achenes) was not observed for fungal or bacterial infection.