bluuebunny/crossref_metadata_2025_split huggingface dataset:
Decreased concentration of apolipoprotein E in the cerebrospinal fluid after acute brain injury
Authors: Kay A. D. , Nicoll J. A. R. 
Published: March 2003

Introduction:  Possession of the apolipoprotein E (APOE) ε4 allele is associated with increased deposition of amyloid β‐protein in patients who die after traumatic brain injury (TBI) (Nicoll et al. Nat Medical 1995; 1: 135), and unfavourable outcome after TBI (Teasdale et al. Lancet 1997; 350: 1069) and subarachnoid haemorrhage (SAH) (Niskakangas et al. Stroke 2001; 32: 1181). Evidence from experimental brain injury studies confirm that apolipoprotein E (ApoE=protein, APOE=gene) plays an important role in the response of the brain to injury. We report findings from a study testing the hypothesis that ApoE is altered in the cerebrospinal fluid (CSF) of patients after acute brain injury, and these alterations are related to injury severity and clinical outcome.Materials and methods:  ApoE concentration was determined, by enzyme linked immunosorbant assay, in the CSF of patients with SAH (N = 19), TBI (N = 13), and controls (N = 13) investigated for hydrocephalus or suspected shunt dysfunction. Injury severity was determined using the Glasgow Coma Score (GCS) and clinical outcome using the Glasgow Outcome Score (GOS).Results:  The concentration of ApoE was significantly lower in the CSF of patients with acute brain injury (P < 0.001) compared with controls, and the magnitude of the reduction correlated with injury severity.Conclusion:  The concentration of ApoE in the CSF decreases substantially after acute brain injury despite the likely leakage of plasma ApoE into the subarachnoid space. We speculate that ApoE is retained within the parenchyma of the brain where it may participate in the injury response.
Timing subdural haematoma
Authors: Mohamed S. , Rezaie P. , Al‐Sarraj S. 
Published: March 2003

Introduction:  One specific technique by which subdural haematoma can be timed has been one of the most challenging problems faced by pathologists. Currently, the most documented technique used for timing trauma is the Perl's stain for haemosiderin indicative of two days time lag between trauma and death. Trauma leads to the activation of a group of cells known as macrophages and offers a possible new means of timing trauma. The aim of this project was to reach a sensible conclusion about timing subdural haematoma by using a variety of markers against macrophages.Materials and methods:  Using dural tissue from 28 subjects diagnosed with subdural haematoma, a three step amplification protocol (DAKO, UK) was applied to 5–7 µm sections of the dura, with DAB as chromogen, for subsequent light microscopic analysis.Results:  Both qualitative (using a simple scoring system) and quantitative analysis were carried out in this study. Quantitative analysis comprised image capture using a digital camera mounted on a Zeiss axioplan microscope and image analysis by calculation of the percent areas of immunoreactivity per section using Optimas v6.2.Conclusions:  PGM 1 and MHC II are not definitive at dating subdural haematoma within the first 48 h period. The early expression of these antibodies makes them good diagnostic tools for dating trauma when combined with other methods such as the Perl's stain.
Differential effects of antioxidants on amyloid β‐ and H2O2‐induced cell death in the SHSY‐5Y neuronal cell‐line
Authors: Shukla C. , Plant L. D. , Henderson Z. , Bridges L. R. , Pearson H. A. 
Published: March 2003

Introduction:  Amyloid β (Aβ) protein, a 38–42 amino acid peptide is the major component of senile plaques in Alzheimer's disease and has been suggested to exert its toxic effects via the direct and indirect production of reactive oxygen species.Materials and methods:  We have investigated the role of reactive oxygen species in the toxic actions of Aβ on a human neuronal cell line SHSY‐5Y, using the MTT assay for cellular viability and comparing the toxicity of Aβ with that of H2O2.Results:  The neurotoxic fragment of Aβ protein, Aβ25–35, had clear concentration‐ and time‐dependent toxic effects on SHSY‐5Y cells. The ability of antioxidants to reverse these toxic effects of 10 µm Aβ25–35 or 200 µm H2O2 were tested. Vitamin E (10–100 µm) did not affect either Aβ or H2O2. Trolox, a vitamin E analogue (5–200 µm) had protective effects on H2O2‐induced cell death but was ineffective in preventing the cell death induced by Aβ. Vitamin C (10–1000 µm) partially reversed H2O2‐induced toxicity but had no protective action when cells were exposed to Aβ.Discussion:  These results indicate that the mechanisms by which Aβ and H2O2 exert their toxic effects are different and suggest that in this experimental system, formation of reactive oxygen species do not have major role in Aβ‐induced cell death.
Farber's disease diagnosed by nerve biopsy
Authors: Jacobs J. , Groves M. , Martinez A. , Harding B. 
Published: March 2003

Introduction:  Farber's disease (granulomatosis) is a rare inherited lipid storage disease caused by a deficiency of lysosomal acid‐ceramidase. Clinical features include contractures of limbs with swelling of joints and multiple subcutaneous nodules. In a few cases there is prominent involvement of central and peripheral nervous systems. Ceramide accumulates in the nodules and in cells of many other tissues including brain. Electron microscopy of affected cells shows membrane‐bound inclusions, some of which have a highly characteristic curved or ‘banana’ shape (Farber bodies). Nerve biopsy findings have been described in a few cases but our patient appears to be the first to have been diagnosed by nerve biopsy.Case report:  This male infant presented at 6 months with joint pain and swelling, fever weakness and nystagmus: EMNG demonstrated sensory‐motor polyneuropathy with features of demyelination. Semi‐thin resin sections show a moderately reduced density of myelinated fibres. The myelin sheaths of most fibres are inappropriately thin, which was confirmed morphometrically: some axons are demyelinated. Vacuolar inclusions are seen in some Schwann cells. Teased fibres show de‐ and remyelination. Electron microscopy shows oval, boomerang‐ or banana‐shaped inclusions in Schwann cells associated with myelinated and unmyelinated axons, but not in other cell types.Conclusion:  Farber's disease is associated with a demyelinating neuropathy.
Trends and characteristics of induced labour in the United States, 1989–98
Authors: MacDorman Marian F. , Mathews T. J. , Martin Joyce A. , Malloy Michael H. 
Published: March 2003

SummaryInduction of labour is one of the fastest growing medical procedures in the United States. In 1998, 19.2% of all US births were a product of induced labour, more than twice the 9.0% in 1989. Induction of labour has been efficacious in the management of post‐term pregnancy and in expediting delivery when the mother or infant is sufficiently ill to make continuation of the pregnancy hazardous. However, the recent rapid increase in induction, and particularly the doubling of the induction rate for preterm pregnancies (from 6.7% in 1989 to 13.4% in 1998), has generated concern among some clinicians. The present study uses vital statistics natality data to examine the epidemiology of induced labour in the US. Multivariable analysis is used to examine the probability of having an induced delivery in relation to a wide variety of socio‐demographic and medical characteristics, and also in relation to relative indications and contraindications for induced labour as outlined by the American College of Obstetricians and Gynecologists (ACOG).Induction rates were higher for women who were non‐Hispanic white, college educated, born in the US, primaparae and those with intensive prenatal care utilisation. Induction rates were also higher for women with various medical conditions including hypertension, eclampsia and renal disease. For non‐Hispanic white women with singleton births, 59% of the increase in the preterm birth rate from 1989 to 1998 can be accounted for by the increase in preterm inductions. The adjusted odds ratio for neonatal mortality among preterm births with induced labour was 1.20 [95% confidence interval 1.11, 1.31]. The rapid increase in induction rates, particularly among preterm births, marks a shift in the obstetric management of pregnancy. More detailed studies are needed to examine physician decision‐making protocols, particularly for preterm induction, and to assess the impact of these practice changes on patient outcomes.
Effect of oxygen radicals and differential expression of catalase and superoxide dismutase in adult Heligmosomoides polygyrus during primary infections in mice with differing response phenotypes
Authors: Ben‐Smith A. , Lammas D. A. , Behnke J. M. 
Published: March 2003

Summary The ability of oxygen radicals to kill Heligmosomoides polygyrus adult worms was examined by assessing parasite survival following incubation with hydrogen peroxide and acetaldehyde/xanthine oxidase, generators ofH2O2and H2O2/O2–, respectively. H. polygyrus worms could tolerate levels of < 0·25 mMhydrogen peroxide and < 0·5 mM/20 mU acetaldehyde/xanthine oxidase for 20 h, but, at higher concentrations, marked sex‐dependent susceptibility was observed, with males being more sensitive toH2O2and O2–than female worms. The ability to evade free radical‐mediated damage was also evaluated by measuring superoxide dismutase (SOD) and catalase levels in worms isolated at different time points from four strains of mice with differing resistance phenotypes. Levels of both catalase and SOD in female worms isolated from ‘rapid’[(SWRxSJL)F1], ‘fast’ (SWR) or ‘intermediate’ (BALB/c), but not ‘slow’ (C57BL/10), responder mice showed a strain‐dependent increase with time. Moreover, male worms were rejected faster than female worms in the ‘rapid’, ‘fast’ and ‘intermediate’ responder strains of mice. The results suggest that host‐derived free radicals can damage adult worms and that female worms can increase production of their scavenging enzymes in response to the immune onslaught that eventually leads to worm expulsion in mice with ‘fast’, ‘rapid’ or ‘intermediate’ response phenotypes.
Quantifying the symbiont contribution to essential amino acids in aphids: the importance of tryptophan for Uroleucon ambrosiae
Authors: Bernays E. A. , Klein B. A. 
Published: March 2003

Abstract.A complete amino acid budget was constructed using the aphid Uroleucon ambrosiae (Strecker), feeding on a suboptimal host, Tithonia fruticosa. The availability of amino acids was estimated from phloem analyses and phloem intake rates at each stage of development. Requirements for amino acids were estimated from gravimetric studies and from analyses of body amino acids. Because the budget was found to be well balanced, estimates of specific needs and shortfalls of essential amino acids were calculated, thus quantifying the role of symbiotic bacteria in fulfilling needs for these amino acids. The most dramatic shortfall was for tryptophan, consistent with the amplification of relevant genes in the symbiont.
Acclimation of photosynthesis, H2O2 content and antioxidants in maize (Zea mays) grown at sub‐optimal temperatures
Authors: Kingston‐Smith A. H. , Harbinson J. , Foyer C. H. 
Published: March 2003

ABSTRACTMaize plants were grown at 14, 18 and 20 °C until the fourth leaf had emerged. Leaves from plants grown at 14 and 18 °C had less chlorophyll than those grown at 20 °C. Maximal extractable ribulose‐1,5‐bisphosphate carboxylase/oxygenase (Rubisco) activity was decreased at 14 °C compared with 20 °C, but the activation state was highest at 14 °C. Growth at 14 °C increased the abundance (but not the number) of Rubisco breakdown products. Phosphoenolpyruvate carboxylase (PEPC) activity was decreased at 14 °C compared with 20 °C but no chilling‐dependent effects on the abundance of the PEPC protein were observed. Maximal extractable NADP‐malate dehydrogenase activity increased at 14 °C compared with 20 °C whereas the glutathione pool was similar in leaves from plants grown at both temperatures. Foliar ascorbate and hydrogen peroxide were increased at 14 °C compared with 20 °C. The foliar hydrogen peroxide content was independent of irradiance at both growth temperatures. Plants grown at 14 °C had decreased rates of CO2 fixation together with decreased quantum efficiencies of photosystem (PS) II in the light, although there was no photo‐inhibition. Growth at 14 °C decreased the abundance of the D1 protein of PSII and the PSI psaB gene product but the psaA gene product was largely unaffected by growth at low temperatures. The relationships between the photosystems and the co‐ordinate regulation of electron transport and CO2 assimilation were maintained in plants grown at 14 °C.
New approach of monitoring changes in chlorophyll a fluorescence of single guard cells and protoplasts in response to physiological stimuli
Authors: Goh C.‐H. , Schreiber U. , Hedrich R. 
Published: March 2003

ABSTRACTA new type of microfluorometer was applied to assess photosynthesis at the single‐cell level by chlorophyll fluorescence using the saturation pulse method. A microscopy–pulse amplitude modulation (PAM) chlorophyll fluorometer was combined with a Zeiss Axiovert 25 inverted epifluorescence microscope for high‐resolution measurements on single mesophyll and guard cells and the respective protoplasts. Available information includes effective quantum yield of photosystem II, relative electron transport rate and energization of the thylakoid membrane due to the transthylakoidal proton gradient. Dark–light induction curves of guard cell (GCPs) and mesophyll cell protoplasts (MCPs) displayed very similar characteristics, indicating similar functional organization of thylakoid membranes in both types of chloroplasts. Light response curves, however, revealed much earlier saturation of photosynthetic electron flow in GCPs than in MCPs. Under anaerobiosis, photosynthetic electron flow and membrane energization were severely suppressed. A similar effect was observed in guard cells when epidermal peels were incubated with the fungal toxin fusicoccin which activates the plasma membrane H+‐ATPase and causes irreversible opening of stomata. The drop in electron transport rate was prevented by blocking ATP consumption of the H+ pump or by glucose addition. These results show that chlorophyll fluorescence quenching analysis allows profound insights into stomatal physiology.
Blue‐light requirement for the biosynthesis of an NO2− transport system in the Chlamydomonas reinhardtii nitrate transport mutant S10*
Authors: Quiñones Miguel A. , Galván Aurora , Fernández Emilio , Aparicio Pedro J. 
Published: March 2003

ABSTRACTThe blue‐light requirement for the biosynthesis of nitrite reductase and an NO2– transport system was studied in Chlamydomonas reinhardtii mutant S10. The only oxidized nitrogen species that could be taken up by this mutant was NO2–, due to the presence of NO2– transport systems and the absence of high‐affinity NO3– transporters. NH4+‐grown cells required illumination with blue light to recover the ability to take up NO2– when resuspended in an NO2–‐containing NH4+‐deprived medium. This blue‐light‐ dependent recovery, which took 1 h, could be suppressed by cycloheximide, indicating that protein biosynthesis was involved. The biosynthesis of nitrite reductase took place in cell suspensions irradiated with red light, even in the absence of NO2–, thus suggesting that the process requiring blue light was the biosynthesis of an NO2– transport system. Nitrite reductase‐containing cells (pre‐irradiated with red light) took 1 h to start consuming NO2– when they were additionally irradiated with blue light in the presence of this anion, and this process was also cycloheximide‐sensitive. The NO2– transport system operated either under red plus blue light or red light only. Thus, in C. reinhardtii mutant S10 cells, blue light was only required for the biosynthesis of an NO2– transport system and not for its activity.
Phosphate uptake in Arabidopsis thaliana: dependence of uptake on the expression of transporter genes and internal phosphate concentrations
Authors: Dong B. , Ryan P. R. , Rengel Z. , Delhaize E. 
Published: March 2003

ABSTRACTChanges in the expression of phosphate transporter genes APT1 and APT2, phosphate uptake and internal phosphate concentrations were monitored in Arabidopsis thaliana plants grown with different supplies of inorganic phosphate. When plants were deprived of phosphate, APT1/APT2 expression and phosphate uptake, measured by both 32P and phosphate‐dependent changes in membrane potential, increased steadily over 4 to 7 d and both were inversely related to the internal phosphate concentrations in roots and shoots. When phosphate was resupplied to phosphate‐starved plants, the internal phosphate concentration and APT1/APT2 expression in roots were restored to control levels within 1 d whereas phosphate uptake took several days to decline to control rates. The increased expression of APT1/ATP2 genes when phosphate supply is restricted, and its close relationship with the internal phosphate concentrations in the root, provides evidence that phosphate uptake in Arabidopsis is controlled, at least in part, by the synthesis of transporter proteins as a result of increased transcription of phosphate transporter genes.
Sucrose‐phosphate synthase responds differently to source‐sink relations and to photosynthetic rates: Lolium perenne L. growing at elevated pCO2 in the field
Authors: Isopp H. , Frehner M. , Long S. P. , Nösberger J. 
Published: March 2003

ABSTRACT Lolium perenne, a main component species in managed grassland, is well adapted to defoliation, fertilization, and regrowth cycles; and hence, to changes in the assimilatory carbon source‐sink ratio. In the Swiss Free Air CO2 Enrichment experiment the source‐sink ratio is (i) increased by elevated partial pressure of CO2 (pCO2), (ii) decreased by enhanced carbon use under high N fertilization, and (iii) gradually increased during regrowth after defoliation. Since sucrose synthesis plays a central role in leaf carbohydrate metabolism in this fructan‐accumulating species, we investigated how sucrose‐phosphate synthase (SPS) responds to the differing assimilatory carbon fluxes and source‐sink ratios in the field. Assimilatory carbon flux, as estimated by leaf gas exchange, strongly depended on pCO2. Surprisingly, the SPS content per leaf area did not increase with pCO2, but increased with N fertilization. During later regrowth, when a dense canopy had formed, the SPS content decreased; in particular, SPS was decreased at high N under elevated pCO2. Further, the higher assimilatory carbon flux through SPS at elevated pCO2 was accompanied by a higher activation state of SPS. The SPS content correlated very strongly with the ratio of free sucrose to free amino acid in leaves, which represents the carbon source‐sink ratio. Hence, SPS content in L. perenne appears to be regulated by the current, strongly nitrogen‐dependent, source‐sink relation.
Expression of pH‐sensitive green fluorescent protein in Arabidopsis thaliana
Authors: Moseyko N. , Feldman L. J. 
Published: March 2003

ABSTRACTThis is the first report on using green fluorescent protein (GFP) as a pH reporter in plants. Proton fluxes and pH regulation play important roles in plant cellular activity and therefore, it would be extremely helpful to have a plant gene reporter system for rapid, non‐invasive visualization of intracellular pH changes. In order to develop such a system, we constructed three vectors for transient and stable transformation of plant cells with a pH‐sensitive derivative of green fluorescent protein. Using these vectors, transgenic Arabidopsis thaliana and tobacco plants were produced. Here the application of pH‐sensitive GFP technology in plants is described and, for the first time, the visualization of pH gradients between different developmental compartments in intact whole‐root tissues of A. thaliana is reported. The utility of pH‐sensitive GFP in revealing rapid, environmentally induced changes in cytoplasmic pH in roots is also demonstrated.
Sexual reproduction of Lolium perenne L. and Trifolium repens L. under free air CO2 enrichment (FACE) at two levels of nitrogen application
Authors: Wagner J. , Lüscher A. , Hillebrand C. , Kobald B. , Spitaler N. , Larcher W. 
Published: March 2003

AbstractField experiments in managed grassland have shown that the response of vegetative growth to elevated CO2 is nitrogen‐dependent in grasses, but independent in N2‐fixing legumes. In the present study, we tested whether this is also true for reproduction. We evaluated reproductive growth, flowering phenology, seed development, reproductive success and seed germination in the grass Lolium perenne L. and the legume Trifolium repens L., growing in monocultures in a free air carbon dioxide enrichment (FACE) system at ambient (35 Pa) and elevated (60 Pa) partial pressure of CO2 and two levels of nitrogen fertilization (14 and 56 g N m−2 a−1). In both species, elevated CO2 had no significant effect on sexual reproduction. In L. perenne, reproduction was mainly nitrogen‐dependent. The weak interactions between CO2 and mineral N supply (13% more flowers and 8% more grains per spike at high N, 7% less flowers and 8% less grains at low N) were not significant. Under elevated CO2, grain maturation was slightly enhanced and grain weight tended to decrease. No influence could be ascertained in the date of anthesis, the temporal pattern of grain growth, the rate of grain abortion and germination. Trifolium repens, grown under CO2 enrichment at both levels of N fertilization, flowered 10 d earlier, tended to form more inflorescences per ground area and more flowers (8–12%) and seeds (>18%) per inflorescence than at ambient CO2. The temporal pattern of seed growth was about the same in all treatments; embryo development, however, was accelerated in fumigated plants. The number of aborted seeds per pod, seed size, thousand‐seed weight and germinability did not show any influence of CO2. Fumigated plants at high N were attacked slightly more frequently by seed‐eating weevils, which lowered the seed output per pod. In summary, the reproductive response of L. perenne and T. repens to CO2 enrichment on the flower and inflorescence level was far weaker than expected from the results on vegetative growth.
Contribution of the UV component of natural sunlight to photoinhibition of photosynthesis in six species of subtidal brown and red seaweeds
Authors: Dring M. J. , Wagner A. , Lüning K. 
Published: March 2003

AbstractField‐collected specimens of three species of Laminaria and three species of subtidal red algae (Delesseria sanguinea, Plocamium cartilagineum and Phyllophora pseudoceranoides) were exposed to natural summer sunlight on Helgoland (southern North Sea) for up to 4 h at 15 °C. Dark‐adapted variable fluorescence (Fv : Fm) was measured immediately after these treatments, and following 6, 24 and 48 h of recovery in moderate irradiances of white light. The response of plants to the full spectrum of natural sunlight was compared with that to PAR alone, UV‐A + visible, UV‐A + UV‐B, or UV‐A alone. The Fv : Fm values of all species were reduced to minimal values after 4 h in all of these treatments, but those of the more resistant species (Laminaria spp. and P. pseudoceranoides) were higher after shorter exposures to UV radiation alone than to PAR with or without UV. The recovery of Fv : Fm in all species was also more rapid in the two treatments that contained UV radiation alone than in those that included PAR. These results suggest that it is the high irradiances of PAR in natural sunlight which are responsible for the photoinhibition of photosynthesis of subtidal seaweeds and that the current ambient irradiances of UV radiation (either UV‐B or UV‐A) in northern temperate latitudes would not contribute significantly to this photoinhibition.