bluuebunny/crossref_metadata_2025_split huggingface dataset:
Inflammatory reaction to the human bot‐fly, Dermatobia hominis, in infested and reinfested mice
Authors: Lello E. , DE Rosis A. M. B. 
Published: December 2004

Abstract.Two groups of mice were infested with first stage larvae of the human bot‐fly, Dermatobia hominis (Linnaeus Jr) (Diptera: Oestridae). In the first group, skin biopsies were carried out 1, 3, 5, 7, 10 and 18 days after infestation. The second group was also infested but had all the larvae removed 5 days after infestation. The mice in the latter group were reinfested 4 weeks later and skin biopsies were carried out 1, 3, 5, 7, 10 and 18 days after reinfestation. In the first group, an inflammatory reaction began slowly, the neutrophils being the main inflammatory cells, eosinophils being scarce. The reaction progressed with time, developing a necrotic halo around the larvae containing inflammatory cells surrounded by fibroblasts. The inflammation invaded the adjacent tissue. In the second group, the inflammatory reaction was intense on the day immediately after reinfestation, the pattern being changed by the presence of a large number of eosinophils. Activated fibroblasts surrounding the necrotic area around the larvae appeared 3 days after reinfestation in the second group and 7 days after infestation in the first group. The results demonstrated that the previous contact with the antigens elicited the early arrival of eosinophils, probably through the chemotactic factors liberated by mast cells in the anaphylactic reaction.
Association between leg length and offspring birthweight: partial explanation for the trans‐generational association between birthweight and cardiovascular disease: findings from the British Women's Heart and Health Study
Authors: Lawlor Debbie A. , Davey Smith George , Ebrahim Shah 
Published: December 2004

SummaryLow birthweight individuals not only have increased risk of cardiovascular disease themselves, but cardiovascular disease risk is also increased in their parents. The mechanisms underlying these trans‐generational associations are not fully understood. We hypothesise that, in part, they reflect the trans‐generational effects of poor maternal environmental circumstances in early childhood. Adverse environmental factors acting early in the mother's life will not only influence her own predisposition to cardiovascular disease but will also result in adverse consequences – low birthweight and increased cardiovascular disease risk in later life – for her offspring. Adult leg length is a valid indicator of early life environmental circumstances, in particular of infant nutrition. If our hypothesis is correct, then adult leg length should be positively associated with offspring birthweight. In this study of 4286 randomly selected women aged 60–79 years from 23 towns across England, Scotland and Wales, the magnitude of the association between leg length and offspring birthweight was greater than the association between trunk length and offspring birthweight. After control for potential confounding factors, offspring birthweight increased by 89.8 g [95% confidence interval 66.1, 113.5 g] for each standard deviation increase in maternal leg length, and by 55.2 g [32.2, 78.1 g] for each standard deviation increase in maternal trunk length. The association between leg length and offspring birthweight was unaffected by adjustment for maternal birthweight, but the association between trunk length and offspring birthweight was attenuated to 38.0 g [1.0, 74.9 g]. These findings support the hypothesis that adverse early childhood environmental circumstances affect not only the vitality and health of the woman in later life but also the birthweight of her offspring, and suggest that the trans‐generational association between birthweight and cardiovascular disease is in part explained by early childhood maternal environmental circumstances.
Secular trends in neonatal macrosomia in Berlin: influences of potential determinants
Authors: Bergmann Renate L. , Richter Rolf , Bergmann Karl E. , Plagemann A. , Brauer M. , Dudenhausen Joachim W. 
Published: December 2004

SummaryTo investigate the trend in the prevalence of neonatal macrosomia and to evaluate the influences of potential determinants, key features of 206 308 hospital deliveries (97% of all) in Berlin in the years 1993–99, collected by the Berlin Medical Board, were analysed using SPSS 10.0.After exclusion of multiple births and preterm infants, there was a significant increase over 7 years (P < 0.01) in the prevalence of birthweights ≥ 4000 g, maternal age ≥ 30 years, height of ≥ 165 cm, prepregnancy BMI (body mass index) ≥ 26 kg/m2and pregnancy weight gain> 16 kg, but no substantial trend in the prevalence of recognised diabetes or maternal smoking. The adjusted model (OR [95% CI]) for delivering a newborn ≥ 4000 g was statistically significant for post‐term delivery (2.56 [2.39, 2.75]), women aged ≥ 30 years (1.06 [1.02–1.11]), ≥ 165 cm tall (1.94 [1.87,2.01]), multiparae (1.98 [1.91, 2.05]), not smoking in pregnancy (2.03 [1.93, 2.14]), prepregnancy BMI ≥ 26 compared with < 20 (4.01 [3.77, 4.26]), pregnancy weight gain ≥ 16 kg compared with < 10 kg (3.37.[3.22, 3.53]) and for recognised diabetes (1.85.[1.69, 2.04]).It is speculated that this increase in the prevalence of neonatal macrosomia may contribute to the secular trend of overweight and obesity under affluent living conditions.
Socio‐economic status and risk of conotruncal heart defects and orofacial clefts
Authors: Carmichael Suzan L. , Nelson Verne , Shaw Gary M. , Wasserman Cathy R. , Croen Lisa A. 
Published: December 2004

SummaryStudies of socio‐economic status (SES) have figured prominently in research related to a variety of health outcomes, although the question remains as to whether SES contributes to the aetiologies of congenital anomalies. This study examines the association of SES with risks of conotruncal heart defects and orofacial clefts, using interview data from 696 case mothers (86% of eligible) and 734 (78%) control mothers from a population‐based case–control study. Socio‐economic measures from maternal interview included mother's education and employment. Reported addresses were linked with the US census to characterise six measures of neighbourhood SES (education, poverty, unemployment, occupation, crowding and rental occupancy). Results were adjusted for race‐ethnicity, multivitamin/mineral supplement intake, cigarette smoking and binge drinking.Results for individual and neighbourhood measures suggested that low SES was associated with increased risk of d‐transposition of the great arteries (dTGA), reduced risk of tetralogy of Fallot (TOF), but was not associated with risk of orofacial clefts. For example, when examining odds ratios (OR) that compared risks among women whose neighbourhoods were in the lowest vs. highest quartile of the census‐based SES measures, ORs for five of the six measures were> 1.4 for dTGA, and ORs for all six measures were < 0.7 for TOF. ORs for clefts tended to be closer to 1. This study suggests that SES risks are birth defect specific.
Have studies of urinary tract infection and preterm delivery used the most appropriate methods?
Authors: S. O’Neill Marie , Hertz‐Picciotto Irva , Pastore Lisa M. , Weatherley Beth D. 
Published: December 2004

SummaryPublished investigations of the association between urinary tract infection (UTI) and preterm delivery used logistic regression or chi‐squared tests. Because both exposure and outcome are time dependent, these methods were not optimal and did not account for person–time under observation, potentially an important feature given the variability of women's entry to prenatal care as well as of gestational lengths. Previous researchers probably classified as exposed some women whose UTI occurred after their pregnancies exceeded 37 weeks. We applied the previous analytical methods to 1990–93 births from two Durham, NC, USA, hospitals (n = 4053) and demonstrate survival methods as an alternative. Two logistic regression models were fitted with differing exposure definitions: model 1 in which exposed = UTI diagnosed after 20 weeks’ gestation; and model 2 in which exposed = UTI diagnosed between 20 weeks’ and 37 weeks’ gestation. Model 3 used proportional hazards regression with person–time after 20 weeks and before UTI diagnosis as unexposed, and person–time after diagnosis as exposed. Models were fit with and without five time‐constant potential confounders. Model 1 yielded an adjusted odds ratio (OR) of 0.8 [95% confidence interval (CI) 0.5, 1.2], and model 2, which did not include UTI diagnoses after 37 weeks, an adjusted OR of 0.9 [95% CI 0.6, 1.4]. The Cox model hazard ratio (HR) for preterm delivery was 1.1 (adjusted) [95% CI 0.7, 1.7]. As these results indicated some bias, but not remarkable differences, we conducted a sensitivity analysis using 100 samples of 80% of the original data set, with replacement to determine how large the differences might be in other, similar data sets. The Cox method consistently produced higher effect estimates than either logistic model. The two samples with the greatest differences between the Cox and logistic model estimates yielded an OR of 1.47 [95% CI 0.95, 2.29] for model 1 vs. HR of 2.06 [95% CI 1.39, 3.06] for model 3, and an OR of 1.41 [95% CI 0.88, 2.25] for model 2 vs. HR of 1.79 [95% CI 1.17, 2.71] for model 3 respectively.Previous published results on UTI and preterm delivery require cautious interpretation. Data on UTI timing should be gathered to allow appropriate analyses; survival methods account for person–time under observation and ensure that studied exposures precede effects.
Immunomodulatory properties of Ascaris suum glycosphingolipids – phosphorylcholine and non‐phosphorylcholine‐dependent effects
Authors: Deehan Maureen R. , Goodridge Helen S. , Blair Derek , Lochnit Gunter , Dennis Roger D. , Geyer Rudolf , Harnett Margaret M. , Harnett William 
Published: December 2004

SUMMARY Immunomodulatory properties of phosphorylcholine (PC)‐containing glycosphingolipids from Ascaris suum were investigated utilizing immune cells from BALB/c mice. Proliferation of splenic B cells induced either via F(ab′)2 fragments of anti‐murine Ig (anti‐Ig) or LPS was significantly reduced when the glycosphingolipids were present in the culture medium. However whereas the LPS‐mediated effect was dependent on the PC moiety of the glycosphingolipids, the result generated when using anti‐Ig was not. Analysis of cell cycle status and mitochondrial potential indicated that the combination of the glycosphingolipids and anti‐Ig reduced B cell proliferation, at least in part, by inducing apoptosis. Consistent with the observed suppression of B cell activation/cell cycle progression, investigation of the effect of glycosphingolipid pre‐exposure on mitogenic B cell signal transduction pathways activated by anti‐Ig, revealed a PC‐independent inhibitory effect on dual (thr/tyr) phosphorylation and activation of ErkMAPKinase. The glycosphingolipids were also investigated for their inhibitory effect on LPS/IFN‐γ induced Th1/pro‐inflammatory cytokine production by peritoneal macrophages. It was found that IL‐12 p40 production was inhibited and in an apparently PC‐dependent manner. Overall these data indicate that PC‐containing glycosphingolipids of A. suum appear to have at least two immunomodulatory constituents – PC and an as yet unknown component.
NK1.1+ cell depletion in vivo fails to prevent protection against infection with the murine nematode parasite Trichuris muris
Authors: Koyama Koichi 
Published: December 2004

SUMMARY Protection against the murine nematode parasite Trichuris muris has been shown to involve interleukin 4 (IL‐4). NK1.1+ T cell receptor αβ+ cells, designated Natural Killer T (NKT) cells, produce a large amount of IL‐4 in response to anti‐CD3 stimulation and numerous pieces of evidence suggest that NKT cells provide the initial source of IL‐4 for T helper 2 (Th2) priming. These observations allow the hypothesis that NKT cells produce a large amount of IL‐4 in response to T. muris infection and augment Th2 responses and IL‐4 production, thus achieving protection against T. muris. To investigate the involvement of NKT cells in protection against T. muris infection, NK1.1+ cell‐depleted B10.BR mice were prepared by anti‐NK1.1 monoclonal antibody injection. Efficient expulsion of T. muris worms occurred in NK1.1+ cell‐depleted infected mice, and the expulsion kinetics of T. muris worms, the levels of IL‐4 production by mesenteric lymph node cells, and the kinetics of the specific IgG1 and IgG2a responses to T. muris were similar to those in mouse IgG‐treated or non‐treated control B10.BR mice. These observations suggest that NK1.1+ cells and NKT cells are not involved in the induction of Th2 responses and protective immunity to T. muris infection.
Ixodes ricinus tick salivary gland extract inhibits IL‐10 secretion and CD69 expression by mitogen‐stimulated murine splenocytes and induces hyporesponsiveness in B lymphocytes
Authors: Hannier Sigrid , Liversidge Janet , Sternberg Jerry M. , Bowman Alan S. 
Published: December 2004

SUMMARY Tick saliva contains immunosuppressive factors allowing this blood‐feeding ectoparasite to remain on hosts and enhancing pathogen transmission. In this study, we examined the modulation of mitogen‐induced activation of naive murine splenocytes by the saliva and salivary gland extract (SGE) of I. ricinus ticks. We found that saliva‐specific factors reduced IL‐10 production by both concanavalin A (ConA) and lipopolysaccharide (LPS) stimulated splenocytes. The LPS‐induced IL‐10 production is 10 times more sensitive to SGE than the ConA‐induced IL‐10 production. Flow cytometric analysis determined that SGE particularly inhibited B (B220+) cell IL‐10 production in mitogen‐stimulated splenocyte preparations. Moreover, SGE reduced the early activation marker CD69 expression on ConA‐activated T cells and also on B cells in presence of ConA or LPS. Annexin V and Via‐probe staining demonstrated that SGE did not increase cell death in activated splenocytes and slightly decreased apoptosis in B lymphocytes. By employing assays with isolated B cells, we further showed that SGE had a direct effect on B cells and inhibited LPS‐induced B cell proliferation. Taken together, our results indicate that salivary immunomodulators induce hyporesponsiveness to mitogen in both T and B cells, and that a direct B‐cell inhibitory activity is present in tick saliva.
The effect of short‐term low‐temperature treatments on gene expression in Arabidopsis correlates with changes in intracellular Ca2+ levels
Authors: NORDIN HENRIKSSON K. , TREWAVAS A. J. 
Published: December 2004

ABSTRACTThe role of changes in intracellular calcium ion concentration ([Ca2+]i) in low‐temperature signal transduction in plants has lately been supported by several studies. An analysis to determine whether the low‐temperature‐induced increase in cytosolic Ca2+ concentration ([Ca2+]cyt) could be correlated with a downstream response such as gene expression was carried out. The induction of the low‐temperature‐regulated gene LTI78 was used as an end point marker of the signal transduction pathway. It was found that this gene is induced by very brief low‐temperature exposures and that the induction does not depend on a continuous exposure to low temperature. By altering the cooling rate, different patterns of the Ca2+ response were obtained which could be correlated with different patterns of LTI78 induction. Furthermore, reducing the Ca2+ transients by pre‐treatment with the Ca2+ channel blocker La3+ also led to a reduced level of gene induction. The results show that brief exposures to low temperature results in the onset of a signalling pathway that leads to the induction of gene expression. This indicates the involvement of changes in [Ca2+]cyt in low‐temperature signalling leading to LTI78 expression but the presence of multiple signalling pathways is suggested.
Does the photosynthetic light‐acclimation need change in leaf anatomy?
Authors: OGUCHI R. , HIKOSAKA K. , HIROSE T. 
Published: December 2004

ABSTRACTThere is a strong correlation between leaf thickness and the light‐saturated rate of photosynthesis per unit leaf area (Pmax). However, when leaves are exposed to higher light intensities after maturation, Pmax often increases without increasing leaf thickness. To elucidate the mechanism with which mature leaves increase Pmax, the change in anatomical and physiological characteristics of mature leaves of Chenopodium album, which was transferred from low to high light condition, were examined. When compared with leaves subjected to low light continuously (LL leaves), the leaves transferred from low to high light (LH leaves) significantly increased Pmax. The transfer also increased the area of chloroplasts facing the intercellular space (Sc) and maintained a strong correlation between Pmax and Sc. The mesophyll cells of LL leaves had open spaces along cell walls where chloroplasts were absent, which enabled the leaves to increase Pmax when they were exposed to high light (LH). However, the LH leaves were not thick enough to allow further increase in Pmax to the level in HH leaves. Thus leaf thickness determines an upper limit of Pmax of leaves subjected to a change from low to high light conditions. Shade leaves would only increase Pmax when they have open space to accommodate chloroplasts which elongate after light conditions improve.
Endopolyploidy in seed plants is differently correlated to systematics, organ, life strategy and genome size
Authors: Barow M. , Meister A. 
Published: December 2004

ABSTRACTEndopolyploidy is a systemic feature in seed plants. A negative correlation between genome size and endopolyploidization has been claimed previously, assuming that a minimum amount of DNA, necessary for certain cell functions, has to be acquired by endopolyploidization of the corresponding cells in plants with small genomes. This assumption was based on the analysis of only a limited set of data from few species. In the present study the endopolyploidization of several organs of 54 seed plant species belonging to two gymnosperm and 14 angiosperm families was investigated. The results revealed a low negative correlation between genome size and endopolyploidization. However, differences between the families, between the different organs of a given species and between the different life‐cycle types with regard to endopolyploidization became obvious. A three‐way analysis of variance with covariate to quantify the impact of the different factors on the extent of endopolyploidization suggested that taxonomic position is the major factor determining the degree of endopolyploidy within a species, while life cycle, genome size and organ type have a minor but also significant effect on endopolyploidization. The comparison of habitats of 16 investigated Central European species implies that endopolyploidization represents a mean to accelerate the growth of plant species in niches, which require and support fast development.
The use of low [CO2] to estimate diffusional and non‐diffusional limitations of photosynthetic capacity of salt‐stressed olive saplings
Authors: CENTRITTO M. , LORETO F. , CHARTZOULAKIS K. 
Published: December 2004

ABSTRACTIn this study it has been shown that increased diffusional resistances caused by salt stress may be fully overcome by exposing attached leaves to very low [CO2] (∼ 50 µmol  mol−1), and, thus a non‐destructive‐in vivo method to correctly estimate photosynthetic capacity in stressed plants is reported. Diffusional (i.e. stomatal conductance, gs, and mesophyll conductance to CO2, gm) and biochemical limitations to photosynthesis (A) were measured in two 1‐year‐old Greek olive cultivars (Chalkidikis and Kerkiras) subjected to salt stress by adding 200 mm NaCl to the irrigation water. Two sets of A–Ci curves were measured. A first set of standard A–Ci curves (i.e. without pre‐conditioning plants at low [CO2]), were generated for salt‐stressed plants. A second set of A–Ci curves were measured, on both control and salt‐stressed plants, after pre‐conditioning leaves at [CO2] of ∼ 50 µmol mol−1 for about 1.5 h to force stomatal opening. This forced stomata to be wide open, and gs increased to similar values in control and salt‐stressed plants of both cultivars. After gs had approached the maximum value, the A–Ci response was again measured. The analysis of the photosynthetic capacity of the salt‐stressed plants based on the standard A–Ci curves, showed low values of the Jmax (maximum rate of electron transport) to Vcmax (RuBP‐saturated rate of Rubisco) ratio (1.06), that would implicate a reduced rate of RuBP regeneration, and, thus, a metabolic impairment. However, the analysis of the A–Ci curves made on pre‐conditioned leaves, showed that the estimates of the photosynthetic capacity parameters were much higher than in the standard A–Ci responses. Moreover, these values were similar in magnitude to the average values reported by Wullschleger (Journal of Experimental Botany 44, 907–920, 1993) in a survey of 109 C3 species. These findings clearly indicates that: (1) salt stress did affect gs and gm but not the biochemical capacity to assimilate CO2 and therefore, in these conditions, the sum of the diffusional resistances set the limit to photosynthesis rates; (2) there was a linear relationship (r2 = 0.68) between gm and gs, and, thus, changes of gm can be as fast as those of gs; (3) the estimates of photosynthetic capacity based on A–Ci curves made without removing diffusional limitations are artificially low and lead to incorrect interpretations of the actual limitations of photosynthesis; and (4) the analysis of the photosynthetic properties in terms of stomatal and non‐stomatal limitations should be replaced by the analysis of diffusional and non‐diffusional limitations of photosynthesis. Finally, the C3 photosynthesis model parameterization using in vitro‐measured and in vivo‐measured kinetics parameters was compared. Applying the in vivo‐measured Rubisco kinetics parameters resulted in a better parameterization of the photosynthesis model.
Water relations of tropical dry forest flowers: pathways for water entry and the role of extracellular polysaccharides
Authors: CHAPOTIN S. M. , HOLBROOK N. M. , MORSE S. R. , GUTIÉRREZ M. V. 
Published: December 2004

ABSTRACTMany trees in tropical dry forests flower during the dry season when evaporative demand is high and soil water levels are low. In this study the factors influencing the water balance of flowers from three species of dry forest trees were examined. Flowers had greater mucilage contents than leaves, high intrinsic and absolute capacitances, long time constants for water exchange and high transfer resistances. Flower water potentials were higher than in leaves and did not fluctuate over the lifespan of the flower. Flower water content also remained constant even though evaporation rates were high, suggesting that water was being supplied from the stem. In two of the species, the water potential gradient between flowers and leaves was opposite to that necessary for water transport from stem to flowers through the xylem, and it was therefore hypothesized that water may enter the flower through the phloem. Calculations showed that nectar production in these flowers could drive a sink of sufficient magnitude to allow water input via the phloem equal to water lost from the flower to the atmosphere.