bluuebunny/crossref_metadata_2025_split huggingface dataset:
Rotavirus-specific T cell responses and cytokine mRNA expression in children with diabetes-associated autoantibodies and type 1 diabetes
Authors: Mäkelä M , Öling V , Marttila J , Waris M , Knip M , Simell O , Ilonen J 
Published: June 2006

SummaryRotavirus infections have been implicated as a possible trigger of type 1 diabetes. We elucidated this connection by comparing peripheral blood T cell responses to rotavirus between children with newly diagnosed type 1 diabetes (n = 43), healthy children with multiple diabetes-associated autoantibodies (n = 36) and control children carrying human leukocyte antigen (HLA)-conferred susceptibility to type 1 diabetes but without autoantibodies (n = 104). Lymphocyte proliferation assays based on stimulation with an antigen were performed using freshly isolated peripheral blood mononuclear cells (PBMC) and IgG and IgA class rotavirus antibodies were measured using plasma samples collected from the children. The expression of interferon (IFN)-γ, interleukin (IL)-4, IL-10 and transforming growth factor (TGF)-β in PBMC was studied with real-time polymerase chain reaction (PCR) in a subgroup of 38 children. No differences were observed in the strength or frequency of positive T cell responses to rotavirus between children with overt diabetes, children with multiple autoantibodies and control children. Children with diabetes-associated autoantibodies had, instead, stronger T cell responses to purified coxsackie B4 virus than control children. Rotavirus-stimulated lymphocytes from autoantibody-positive children produced more IL-4 and phytohaemagglutinin (PHA)-stimulated lymphocytes more IL-4 and IFN-γ than lymphocytes from control children. PHA-stimulated lymphocytes from children with diabetes also produced more IL-4 and purified protein derivative (PPD)-stimulated lymphocytes less TGF-β than lymphocytes from autoantibody-negative control children. In conclusion, our lymphocyte proliferation studies did not provide evidence supporting an association between rotavirus infections and the development of type 1 diabetes or diabetes-associated autoantibodies in young children.
Pneumococcal surface protein A (PspA) is effective at eliciting T cell-mediated responses during invasive pneumococcal disease in adults
Authors: Baril L , Dietemann J , Essevaz-Roulet M , Béniguel L , Coan P , Briles D E , Guy B , Cozon G 
Published: June 2006

SummaryHumoral immune response is essential for protection against invasive pneumococcal disease and this property is the basis of the polysaccharide-based anti-pneumococcal vaccines. Pneumococcal surface protein A (PspA), a cell-wall-associated surface protein, is a promising component for the next generation of pneumococcal vaccines. This PspA antigen has been shown to stimulate an antibody-based immunity. In the present study, we evaluated the capacity of PspA to stimulate CD4+ T cells which are needed for the correct development of a B cell based immune response in humans. Cellular immunity to PspA was evaluated by whole-blood culture with different pneumococcal antigens, followed by flow cytometric detection of activated CD4+CD25+ T cells. T cell-mediated immune responses to recombinant PspA proteins were assessed in acute-phase and convalescent blood from adults with invasive pneumococcal disease and in blood from healthy subjects. All cases had detectable antibodies against PspA on admission. We found that invasive pneumococcal disease induced transient T cell depletion but adaptive immune responses strengthened markedly during convalescence. The increased production of both interleukin (IL)-10 and interferon (IFN)-γ during convalescence suggests that these cytokines may be involved in modulating antibody-based immunity to pneumococcal disease. We demonstrated that PspA is efficient at eliciting T cell immune responses and antibodies to PspA. This study broadens the applicability of recombinant PspA as potent pneumococcal antigen for vaccination against S. pneumoniae.
Anti-oxidant enzyme activities and expression and oxidative damage in patients with non-immediate reactions to drugs
Authors: Cornejo-Garcia J A , Mayorga C , Torres M J , Fernandez T D , R-Pena R , Bravo I , Mates J M , Blanca M 
Published: June 2006

SummaryAdverse drug reactions with an immunological basis (ADRIB) may involve activation of other concomitant, non-specific mechanisms, amplifying the specific response and contributing to the severity and duration. One concomitant mechanism could be the generation of reactive oxygen species (ROS) and/or their detoxification by anti-oxidants, including anti-oxidant enzymes. We analysed the activity of the anti-oxidant enzymes Cu/Zn-superoxide dismutase (SOD), catalase (CAT) and cellular glutathione peroxidase (GPX), as well as certain markers of oxidative damage (thiobarbituric acid reactive substances (TBARS) and carbonyl content) in peripheral blood mononuclear cells from patients with non-immediate ADRIB using spectrophotometric methods and the anti-oxidant enzymes expression by quantitative real-time reverse transcription–polymerase chain reaction. SOD activity and expression were increased in all types of non-immediate reactions (urticaria, maculopapular exanthema and toxic epidermal necrolysis). Regarding oxidative damage, TBARS were increased in urticaria and maculopapular exanthema, and carbonyl groups in all types of reactions. Our observations indicate that oxidative damage occurs in non-immediate reactions. Carbonyl stress and the inadequacy of the anti-oxidant defences are probable causes.
Metabolic effects of caffeine ingestion and physical work in 75‐year old citizens. A randomized, double‐blind, placebo‐controlled, cross‐over study
Authors: Norager C. B. , Jensen M. B. , Weimann A. , Madsen M. R. 
Published: June 2006

SummaryObjective  Whereas caffeine has been demonstrated to impact substantially on the metabolic response to exercise in healthy young subjects, this issue remains to be addressed in healthy elderly subjects.Design and participants  The metabolic response to caffeine ingestion (6 mg/kg) and exercise in healthy elderly citizens at 70 years was examined in a randomized, double‐blind, placebo‐controlled, cross‐over study. We included 30 subjects attending for driver license renewal at their general practitioner. Participants abstained from caffeinated drinks and food for 48 h and were randomized to receive placebo‐caffeine or caffeine‐placebo with 1 week between sessions.Measurements  A cycling endurance test at 65% of the expected maximal heart rate was performed 1 h after intervention. Blood samples were taken before intervention, before cycling, after 5 min of cycling, and at exhaustion. Analysis was by intention‐to‐treat and P < 0·05 was regarded as significant.Results  Caffeine significantly increased the concentration of plasma epinephrine (by 42%, 39%, and 49%), serum‐free fatty acids (by 53%, 44%, and 50%), and plasma lactate (by 46%, 36%, and 48%), and insulin resistance (homeostasis model assessment‐IR) (by 21%, 26%, and 23%) during rest, after 5 min of cycling, and at exhaustion. At exhaustion, the concentration plasma norepinephrine was elevated by 29%. A decrease was seen with caffeine treatment in blood potassium after 5 min of cycling and at exhaustion (by 3% and 2%, respectively).Conclusions  Caffeine treatment increased epinephrine, fatty acids, lactate and norepinephrine at different times during test session and led to insulin‐resistance.Hence, caffeine ingestion elicits a similar metabolic response in elderly participants at 70 years old to that seen in younger subjects.
Non‐invasive biomarkers of liver fibrosis in haemophilia patients with hepatitis C: can you avoid liver biopsy?
Authors: MAOR Y. , BASHARI D. , KENET G. , LUBETSKY A. , LUBOSHITZ J. , SCHAPIRO J. M. , PÉNARANDA G. , BAR‐MEIR S. , MARTINOWITZ U. , HALFON P. 
Published: June 2006

Summary.  Introduction:  Liver biopsy remains the gold standard for the evaluation of fibrosis despite its risks and limitations, especially in haemophilia patients. Recently, non‐invasive biomarkers have been used to assess histological features. The most thoroughly evaluated biomarker is the FibroTest (FT) (AUROC 0.80 for fibrosis stages F2F3F4 vs. F0F1).Aim:  To estimate liver fibrosis in haemophilia patients infected with hepatitis C (HCV) using non‐invasive biomarkers without liver biopsy.Methods:  One hundred and thirty‐two haemophilia patients (124 male, mean age 38 ± 14 years) with anti‐HCV antibodies were evaluated. These patients were stratified into several groups: patients with features of advanced liver disease – seven, persistently HCV RNA‐negative – 21, persistently normal liver function tests (LFTs)– 24, HCV/HIV co‐infected – 27. The following biomarkers of fibrosis were used: FT, AST‐to‐platelet ratio index (APRI), Forns index, age‐platelet index and hyaluronic acid. The obtained scores were correlated with the clinical features of the patients.Results:  Estimated by the FT, the distribution of the stage of fibrosis in the 132 patients was F0F1 = 65% (86/132), F2 = 5% (7/132), F3 = 13% (17/132) and F4 = 17% (22/132). Using FT, all patients with clinical suspicion of advanced liver disease were classified as F3F4, whereas patients with persistently HCV RNA‐negative were all classified as F0F1. Twenty‐one per cent (5/24) of the patients with persistently normal LFTs had fibrosis stage F3F4. The proportion of F3F4 among HCV/HIV co‐infected patients was significantly higher than among HCV mono‐infected (52% vs. 33%; P = 0.05). Concordance of three or more biomarkers was present in 43% (57/132) of the patients. Liver biopsy could be avoided in 70% (92/132) using a practical assumption that if FT is in concordance with APRI and/or Forns, then we may confidently rely on the biomarker. Concordance rate for patients with presumably advanced or minimal liver disease was excellent (100% and 95% respectively).Conclusions:  In our HCV‐infected haemophilia patients, FT correctly identified clinically advanced or minimal liver disease. Discordance among the various biomarkers of fibrosis was considerate; nevertheless, practical combination of FT, APRI, and Forns may predict stage of fibrosis with accuracy, potentially avoiding liver biopsy in the majority of the patients.
A variable number of tandem repeats polymorphism influences the transcriptional activity of the neonatal Fc receptor α‐chain promoter
Authors: Sachs Ulrich J. H. , Socher Ines , Braeunlich Christian G. , Kroll Hartmut , Bein Gregor , Santoso Sentot 
Published: June 2006

SummaryThe neonatal Fc receptor, FcRn, plays a central role in immunoglobulin G (IgG) transport across placental barriers. Genetic variations of FcRn‐dependent transport across the placenta may influence antibody‐mediated pathologies of the fetus and the newborn. Sequencing analysis of 20 unrelated individuals demonstrated no missense mutation within the five exons of the FcRn gene. However, a variable number of tandem repeats (VNTR) region within the FcRn promoter was observed, consisting of five different alleles (VNTR1–VNTR5). Alleles with two (VNTR2) and three (VNTR3) repeats were found to be most common in Caucasians (7·5 and 92·0%, respectively). Real‐time polymerase chain reaction revealed that monocytes from VNTR3 homozygous individuals express 1·66‐fold more FcRn transcript than do monocytes from VNTR2/VNTR3 heterozygous individuals (P = 0·002). In reporter plasmid assays, the VNTR3 allele supported the transcription of a reporter gene twice as effectively as did the VNTR2 allele (P = 0·003). Finally, under acidic conditions, monocytes from VNTR3 homozygous individuals showed an increased binding to polyvalent human IgG when compared with monocytes from VNTR2/VNTR3 heterozygous individuals (P = 0·021). These data indicate that a VNTR promoter polymorphism influences the expression of the FcRn receptor, leading to different IgG‐binding capacities.
CD43‐independent augmentation of mouse T‐cell function by glycoprotein cleaving enzymes
Authors: Berger Scott B. , Sadighi Akha Amir A. , Miller Richard A. , Garcia Gonzalo G. 
Published: June 2006

SummaryPrevious work has shown that the function of mouse CD4+ T cells can be augmented by an enzyme, O‐sialoglycoprotein endopeptidase (OSGE), which cleaves surface CD43, suggesting the idea that the high levels of glycosylated CD43 found on T cells from aged mice may contribute to immune senescence. New results now show that OSGE improves T‐cell function even in mice lacking CD43, showing that other glycoproteins must contribute to the OSGE effect on function. Evaluation of other enzymes found two whose ability to stimulate CD4 activation was higher in aged than in young T cells. One of these, PNGase F, is a glycosidase specific for N‐linked glycans, and the other, ST‐Siase(2,3) from Salmonella typhimurium, is specific for α2,3‐linked terminal sialic acid residues. Parallel lectin‐binding experiments showed that removal of α2,3‐linked sialic acid residues vulnerable to PNGase F and ST‐Siase(2,3) was also greater in old than in young T cells. The preferential ability of PNGase F and ST‐Siase(2,3) to improve the function of T cells from aged mice may involve cleavage of glycoproteins containing α2,3‐linked sialic acid residues on N‐linked or O‐linked glycans or both.
Determination of antibacterial effects and total phenolic contents of grape (Vitis vinifera L.) seed extracts
Authors: Baydar Nilgun Gokturk , Sagdic Osman , Ozkan Gulcan , Cetin Sema 
Published: June 2006

SummaryIn the study, antibacterial activities of the seed extracts of three different grapes were examined against fifteen bacteria, and total phenolic contents of the extracts were additionally determined. The contents of total phenolic compounds of the grape seed extracts were 589.09 (Hasandede), 506.60 (Emir) and 549.54 (Kalecik Karasi) mg gallic acid equivalent (GAE) per gram with acetone:water:acetic acid (90:9.5:0.5). These extracts at 1%, 2.5%, 5% and 10% concentrations were tested for their antibacterial effects by using the agar diffusion method against some pathogenic and spoilage bacteria including Aeromonas hydrophila, Bacillus cereus, Enterobacter aerogenes, Enterococcus faecalis, Escherichia coli, E. coli O157:H7, Klebsiella pneumoniae, Mycobacterium smegmatis, Proteus vulgaris, Pseudomonas aeruginosa, Pseudomonas fluorescens, Salmonella enteritidis, Salmonella typhimurium, Staphylococcus aureus and Yersinia enterocolitica. All tested bacteria were inhibited by the grape seed extracts using agar well diffusion method. The most sensitive of the bacteria was A. hydrophila while Hasandede grape seed extract was the most inhibitive extract on test bacteria. Hasandede seed extract at 10% concentration gave the largest inhibition zone diameter (30.67 mm) against A. hydrophila. According to serial dilution method, while all the grape seed extracts at 0.5% and 1% concentrations had generally bacteriostatic activities against E. coli O157:H7, the same extracts appeared to have bactericidal effects at concentrations above 2.5%. In addition, the extracts at all concentrations had bactericidal activities against S. aureus at the end of 48 h. and A. hydrophila at the end of 1 h.
Experimental and model analyses of the effects of competition on individual size variation in wood frog (Rana sylvatica) tadpoles
Authors: PEACOR SCOTT D. , PFISTER CATHERINE A. 
Published: June 2006

Summary

Size variation is a ubiquitous feature of animal populations and is predicted to strongly influence species abundance and dynamics; however, the factors that determine size variation are not well understood.
In a mesocosm experiment, we found that the relationship between mean and variation in wood frog (Rana sylvatica) tadpole size is qualitatively different at different levels of competition created by manipulating resource supply rates or tadpole density. At low competition, relative size variation (as measured by the coefficient of variation) decreased as a function of mean size, while at high competition, relative size variation increased. Therefore, increased competition magnified differences in individual performance as measured by growth rate.
A model was developed to estimate the contribution of size‐dependent factors (i.e. based on size alone) and size‐independent factors (i.e. resulting from persistent inherent phenotypic differences other than size that affect growth) on the empirical patterns.
Model analysis of the low competition treatment indicated that size‐dependent factors alone can describe the relationship between mean size and size variation. To fit the data, the size scaling exponent that describes the dependence of growth rate on size was determined. The estimated value, 0·83, is in the range of that derived from physiological studies.
At high competition, the model analysis indicated that individual differences in foraging ability, either size‐based or due to inherent phenotypic differences (size‐independent factors), were much more pronounced than at low competition. The model was used to quantify the changes in size‐dependent or size‐independent factors that underlie the effect of competition on size‐variation. In contrast to results at low competition, parameters derived from physiological studies could not be used to describe the observed relationships.
Our experimental and model results elucidate the role of size‐dependent and size‐independent factors in the development of size variation, and highlight and quantify the context dependence of individual (intrapopulation) differences in competitive abilities.
Sensitivity analysis of Markov models for communities of competing sessile organisms
Authors: SPENCER MATTHEW 
Published: June 2006

Summary

Communities of competing sessile organisms are often modelled using Markov chains. Sensitivity analysis of the stationary distribution of these models tells us how we expect the abundance of each organism to respond to changes in interactions between species. This is important for conservation and management.
Markov models for such communities have usually been formulated in discrete time. Each column of the discrete‐time transition matrix must sum to 1 (column stochasticity). Sensitivity analysis therefore involves defining a pattern of compensation that maintains column stochasticity as a single transition probability changes. There is little biological theory about the appropriate compensation pattern, but the usual choices involve changing only the elements of a single column of the transition matrix.
I argue that if the underlying dynamics occur in continuous time, each transition probability is the net outcome of direct and many indirect interactions.
Determining the consequences of changing a single direct interaction will often be of interest. I show how this can be achieved using a continuous‐time model. The resulting discrete‐time compensation pattern is quite different from those that have been considered elsewhere, with changes occurring in many columns.
I also show how to determine which direct interactions are being changed under any discrete‐time compensation pattern.
Predicting the ecological consequences of environmental change: a review of the methods*
Authors: SUTHERLAND WILLIAM J. 
Published: June 2006

SummaryThere is a clear need to increase our ability to predict the consequences of environmental change. The seven main approaches that are currently used are: extrapolation, experiments, phenomenological models, game‐theory population models, expert opinion, outcome‐driven modelling and scenarios. Each approach has different strengths and weaknesses. In practice, several approaches are often combined.Adaptive management aimed at testing hypotheses is excellent in principle and widely advocated. In reality, however, it is almost never carried out because the changes in management usually have to be severe in order to bring about detectable changes in a reasonable time, and the political risks of such management are usually considered too high.Game‐theory population models are used to determine population‐level phenomena based upon the decisions individuals make in response to resource depletion, interference, territoriality or rank. This allows predictions to be made regarding responses to novel conditions. The main drawback is that for some models considerable information is required.Much of conservation practice is not based upon evidence. Evidence‐based conservation is the practice of accumulating, reviewing and disseminating evidence with the aim of formulating appropriate management strategies. Evidence‐based medicine revolutionized medical practice and similar opportunities exist to improve conservation practice.Synthesis and applications. The conventional approach of making assumptions and deriving models to make predictions about the consequences of environmental change is often unsatisfactory for complex problems, with considerable uncertainty. Tackling such problems is likely to require greater exploration of techniques such as expert opinion, output‐driven modelling and scenarios.
Can management compensate for atmospheric nutrient deposition in heathland ecosystems?
Authors: HÄRDTLE WERNER , NIEMEYER MARION , NIEMEYER THOMAS , ASSMANN THORSTEN , FOTTNER SILKE 
Published: June 2006

SummaryAtmospheric nutrient deposition has contributed to widespread changes in heathlands throughout Europe. As a consequence, management is now being considered as a potential tool with which to compensate for increased nutrient loads. Currently, only limited information is available on the extent to which management measures could compensate for atmospheric nutrient deposition. We hypothesized that low‐intensity management measures are not sufficient to counterbalance current nutrient inputs, particularly of nitrogen (N).In order to improve heathland management schemes, we evaluated the effectiveness of different management measures in reducing the impact of ongoing atmospheric nutrient loads. We compared the effects of mowing, prescribed burning (low‐intensity management) and sod‐cutting (high‐intensity management) on heathland nutrient budgets [N, calcium (Ca), potassium (K), magnesium (Mg) and phosphorus (P)] in the Lueneburg Heath nature reserve (north‐west Germany). Nutrient balances were calculated by analysing the present‐day input, the output as a result of the removal of biomass/humus horizons, and changes in leaching rates.Nutrient losses by increased leaching following management measures were negligible compared with nutrient losses caused by the removal of above‐ground biomass or humus horizons. The total quantities of nutrients removed by sod‐cutting were equivalent to between 37 and 176 years of atmospheric input (for N, 89 years).In contrast, the quantities of N removed by mowing and prescribed burning were equivalent to only 5 years of atmospheric input. Thus, heathlands subjected to such treatments will accumulate N in the long term. In addition, output–input ratios for phosphorus (P) exceeded those for N in the mowing and sod‐cutting experiments. It is therefore likely that heathlands currently (co‐) limited by N will shift to being more P‐limited in the long term. This will promote species that are well adapted to P‐limited sites (e.g.Molinia caerulea).Synthesis and applications. This study shows that low‐intensity management cannot compensate for atmospheric N loads in the long term. Consequently, high‐intensity management measures are an indispensable tool in preserving a long‐term balanced N budget in heathlands. In order to maintain a diverse structure, managers need to combine low‐ and high‐intensity management measures. Prescribed burning proved to be the best means of avoiding an increasing P shortage, because this measure causes very low P outputs.