bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mechanisms of survival of protozoan parasites in mononuclear phagocytes
Authors: Mauel J. 
Published: August 2011

SUMMARYThe understanding of the mechanisms whereby intracellular parasites counteract the microbicidal processes of macrophages has progressed considerably in recent years. Various factors contribute to intracellular parasite destruction; from a biochemical standpoint, particularly important is the oxidative burst triggered by phagocytosis and by macrophage ‘activation’, that leads to the generation of toxic metabolites of oxygen. At the ultrastructural level, fusion of the parasitophorous vacuole with surrounding lysosomes appears to be a pre-requisite for the final digestion and elimination of the infecting microorganisms. The counter-measures evolved by microorganisms to escape intracellular destruction are best illustrated by studiesin vitroon the interaction of parasites of theLeishmania, ToxoplasmaandTrypanosomaspp. with mononuclear phagocytes. Some microbes are able to inhibit the fusion of phagosomes with lysosomes, thus avoiding the potentially harmful action of lysosomal hydrolases. Other microorganisms are able to resist the effects of such enzymes, perhaps by secreting inhibitory substances. Others still avoid lysosomes by leaving the phagocytic vacuole, to reach the cytoplasmic matrix where their development is unhindered. Particularly critical is the capacity of certain parasites to subvert the lethal effects of the oxidative burst. This can be achieved either by failing to evoke this metabolic response, or by producing scavengers that can detoxify harmful oxygen metabolites. Intracellular death or survival will thus depend on a delicate balance between the potency of macrophage cidal mechanisms, and the efficacy of the protective measures evolved by the infecting agents.
Interference in general immune function by parasite infections; African trypanosomiasis as a model system
Authors: Askonas B. A. 
Published: August 2011

SUMMARYMany parasitic diseases are accompanied by an immunosuppression which may affect only parasite-specific responses in some infections or lead to a general dysfunction of the immune system in others. African trypanosomiasis causes a particularly severe disorder of the immune system and this serves as a model system for analysis of the cellular basis of a parasite-induced general immune dysfunction affecting nearly all T- or B-lymphoid cell subpopulations. The nature of the parasite products causing havoc in the immune system may well vary in different infections and still remains to be defined. Trypanosome membrane fractions are activein vitroorin vivobut we have no evidence for a direct action on B- or T-cells.In vitro, both in man and mouse, T-cells are stimulated, but only in the presence of accessory cells. This points to the importance of host-derived immunosuppressive factors in the immune dysfunction. We have evidence that macrophages, after uptake of parasites in the presence of antibodies, are at least one target cell for parasite action. They can mediate immunosuppression and undergo changes in phenotype and mediator release during the course of infection. The macrophages show all the characteristic signs of activation, which can also be induced by other means and other infective agents such as BCG. Thus, macrophage activation would provide a common pathway for induction of a general immunosuppression in different infections.
The Wellcome Trust Lecture: Inflammatory responses to filarial connective tissue parasites
Authors: Lichtenberg F. Von 
Published: August 2011

SUMMARYThe inflammatory responses to lymphatic filariae and toOnchocerca volvulusare reviewed with particular attention to (1) evolutionary biology; (2) inflammatory host spectrum; (3) non-specific components; (4) immunoregulation; (5) immune evasion versus immunomodulation; (6) chronic tissue damage and scarring and (7) disease models. Basic principles of pathogenesis are emphasized, comparisons drawn with schistosome infection, and critical items of missing information are highlighted.
Biomembrane structure and function: recent studies and new techniques
Authors: Chapman D. 
Published: August 2011

SUMMARYThe consensus view of biomembrane structure is outlined. The present model is built upon a fluid lipid matrix, usually two molecules in length, into which the proteins are embedded. The lipid bilayer organization is discussed, such as their phase transition and fluid character and the effect of cholesterol upon the chain organization. The non-lamellar arrangement which some lipids adopt is described. The use of new physical techniques for obtaining information about the structure and dynamics of membrane proteins are described. These techniques include electron diffraction, electron microscopy and FTIR spectroscopy. Models of the structures of the Ca2+–ATPase and the glucose transporter from erythrocytes are shown, indicating the putative helices embedded in the lipid bilayer and the groups of amino acids in the aqueous environment. These models are based upon biochemical methods to obtain amino acid sequences using DNA cloning techniques. Finally, an experimental method using triplet probes is described for the study of the rotational dynamics of membrane proteins. Labelled monoclonal antibodies for studying the dynamics of the glucose transporter have been used.
Molecular mechanisms involved in the transport of antibiotics into bacteria
Authors: Chopra I. 
Published: August 2011

SUMMARYMany clinically useful antibacterial drugs have intracellular target sites. Therefore, in order to reach their targets, these compounds must be able to cross bacterial outer and cytoplasmic membranes. Considerable information is available on the mechanisms by which antibiotics cross bacterial membranes and, in many cases, it is now possible to define the molecular basis of their uptake. Passage of drugs across the outer membrane of Gram-negative bacteria can occur by diffusion through porin channels (e.g. β-lactams and tetracyclines), by facilitated diffusion using specific carriers (e.g. albomycin), or by self-promoted uptake (e.g. aminoglycosides and polymyxins). Transfer of antibiotics across the bacterial cytoplasmic membrane is usually mediated by active, carrier-mediated, transport systems normally operating to transport essential solutes into the cell. For example, the antibiotic streptozotocin bears sufficient structural resemblance toN-acetyl-D-glucosamine to be transported by the phosphoenolpyruvate : phosphotransferase system, and D-cycloserine is recognized by the D-alanine, proton motive force dependent transport system. However, in some cases (e.g. tetracycline) although carrier-mediated transport is implied by the observation that drug uptake is energy dependent, the nature of the membrane carrier(s) responsible is unknown. Knowledge acquired from studies on bacterial peptide transport has been successfully used to deliver (or smuggle) amino acid mimetics disguised as peptides into the bacterial cell. These amino acid mimetics, although often poorly transported in their own right, are frequently potent inhibitors of bacterial peptidoglycan or lipopolysaccharide synthesis once they have gained access to the interior of the cell.
Excretory–secretory products of helminth parasites: effects on host immune responses
Authors: Lightowlers M. W. , Rickard M. D. 
Published: August 2011

SUMMARYParasitic helminths excrete or secrete (ES) a variety of molecules into their mammalian hosts. The effects of these ES products on the host's immune responses are reviewed. Investigations into the source of antigenic or immunoregulatory ES products have identified the cuticular and tegumental surfaces of some nematodes and trematodes respectively as being important sources of ES products; other ES molecules are released through specialized excretory or secretory organs. It is proposed that the active shedding of surface antigens may serve as an important source of parasite antigens available to the immune system in a form in which they can be taken up and processed by antigen-presenting dendritic cells, macro-phages and certain B cells for presentation to T helper cells. The ES products of nematodes, trematodes and cestodes contribute to immune evasion strategies of the parasites through mechanisms including shedding of surface-bound ligands and cells, alteration of lymphocyte, macrophage and granulocyte functions and modulation of complement and other host inflammatory responses. Immunopathology may be induced by ES products as in the development of granulomas around entrapped schistosome eggs. In some host – parasite systems ES antigens may induce host-protective immune responses and this source of protective antigens has been utilized in the successful vaccination against helminth infections, particularly against infection with trichurid nematodes and the metacestode stage of cestode parasites. The use of ES antigens in immunodiagnosis of helminth infection is also briefly discussed.
Atmospheric change: effect on plant pests and diseases
Authors: Bell J.N.B. , McNeill S. , Houlden G. , Brown V. C. , Mansfield P. J. 
Published: August 2011

SUMMARYThe atmosphere plays a key role in plant disease, but only recently has it become understood that atmospheric pollutants can influence the response of plants to attack by pests and pathogens. This paper reviews the evidence for this phenomenon, considering impacts of sulphur dioxide, nitrogen dioxide and ozone, mainly on fungal pathogens and aphid pests. Field observations in polluted areas have indicated changes in abundance of pests and pathogens and in some cases a causal link has been demonstrated in controlled experiments. A major study is described in which consistent marked positive impacts of SO2 and NO2 have been shown on a range of British agricultural aphid pests, using four different approaches: fumigations, nitration studies, exposure along air pollution gradients and a nation-wide field survey. Ozone, in contrast, produces a more complex range of responses. These effects are apparently mediated via chemical changes in the plant. Fungal pathogens show both positive and negative responses to air pollutants. A study is described in which these opposite responses in two different fungal species were observed in a field SO2–fumigation system and confirmed in controlled laboratory fumigations. Models are presented to describe the complex pathways by which air pollutants could influence host plant performance via impacts on pests and pathogens.
Improving food provision in child care in England: a stakeholder analysis
Authors: Buttivant Helen , Knai Cécile 
Published: August 2011

AbstractObjectiveTo review national policy governing nutrition in child-care settings and explore policy translation at a regional and local level in the South East of England.DesignSemi-structured interviews with regional experts.SettingChild-care settings in Southampton, England, registered by OFSTED (Office for Standards in Education Children's Services and Skills).SubjectsThirteen subjects including child-care professionals in Southampton and policy advisors from the Government Office of the South East.ResultsPolicy regarding early years food provision varies across the country. Although there appears to be consensus between local stakeholders on the importance of improving early years nutrition in Southampton, intentions have yet to be translated into cohesive action, with differences in food and nutrition practice in child-care settings across the city. There are also areas of incoherence, inequalities in access to training and development, and duplication in local and regional support mechanisms.ConclusionsThe importance of proper early nutrition to provide the building blocks for life-long health and well-being is grounded in a substantial evidence base. Outside the home, early years child-care settings are an ideal place for providing a strong foundation in nutritional health and dietary habits for young children. The long-term benefits of achieving optimum nutrition in the early years should be secured through the coherent efforts of national, regional and local policy makers, child-care practitioners and parents. Existing commitment and capacity to achieve this objective at a local and regional level must be supported and matched at a national level with the acceleration of policy development, including quality control and support mechanisms.
Validity of two short screeners for diet quality in time-limited settings
Authors: Schröder Helmut , Benitez Arciniega Alejandra , Soler Cristina , Covas Maria-Isabel , Baena-Díez José Miguel , Marrugat Jaume 
Published: August 2011

AbstractObjectiveAn urgent need in dietary assessment is the development of short tools that provide valid assessments of dietary quality for use in time-limited settings. The present study assessed concurrent and construct validity of the short Diet Quality Screener (sDQS) and brief Mediterranean Diet Screener (bMDSC) questionnaires.DesignRelative validity was measured by comparing three dietary quality indices – the Diet Quality Index (DQI), the modified Mediterranean Diet Score (mMDS) and the Antioxidant Score (ANTOX-S) – derived from the two questionnaires with those from multiple 24 h recalls over 12 months. Construct validity was demonstrated by correlations between average nutrient intake recorded on multiple 24 h recalls and the DQI, mMDS and ANTOX-S derived by the short screeners.SettingBoth short questionnaires were administered to 102 participants recruited from a population-based survey in Spain.ResultsDQI, mMDS and ANTOX-S correlated (P < 0·001) with the corresponding 24 h recall indices (r = 0·61, 0·40 and 0·45, respectively). Limits of agreement lay between 96 and 126 %, 59 and 144 % and 61 and 118 % for the DQI, ANTOX-S and mMDS, respectively. Dietary intakes of fibre, vitamin C, vitamin E, Mg and K reported on the 24 h recalls were positively associated (P < 0·04) with the DQI, mMDS and ANTOX-S indices.ConclusionsThe sDQS and bMDSC provide reasonable approximations to food-based dietary indices and accurately situate subjects within the indices constructed for the present validation study.
Serum retinol in 1–6-year-old children from a low socio-economic South African community with a high intake of liver: implications for blanket vitamin A supplementation
Authors: van Stuijvenberg Martha E , Schoeman Serina E , Lombard Carl J , Dhansay Muhammad A 
Published: August 2011

AbstractObjectiveTo assess serum retinol, liver intake patterns, breast-feeding history and anthropometric status in pre-school children of a low socio-economic community where liver is regularly consumed.DesignCross-sectional study.SettingNorthern Cape Province, South Africa.SubjectsChildren aged 1–6 years (n243) who attended the local primary health-care facility and had not received a vitamin A supplement in the 6 months preceding the study. Non-pregnant female caregivers (n225), below 50 years of age, were also assessed.ResultsDespite stunting, underweight and wasting being prevalent in 40·5 %, 23·1 % and 8·4 % of the children, only 5·8 % had serum retinol concentrations < 20 μg/dl, which is in sharp contrast to the national prevalence of 63·6 %. None of the caregivers were vitamin A deficient. Liver was eaten by 89·2 % of children, with 87 % of households eating liver at least once monthly and 30 % eating it at least once weekly; liver was introduced into the diet of the children at a median age of 18 months. Ninety-three per cent of the children were being breast-fed or had been breast-fed in the past; children were breast-fed to a median age of 18 months. A significant negative correlation was found between educational level of the caregiver and frequency of liver intake (r= −0·143,P=0·032). There was no correlation between serum retinol and indicators of anthropometric or socio-economic status.ConclusionsThe blanket approach in applying the national vitamin A supplementation programme may not be appropriate for all areas in the country, even though the community may be poor and undernourished.
In situ molecular NMR picture of bioavailable calcium stabilized as amorphous CaCO3biomineral in crayfish gastroliths
Authors: Akiva-Tal Anat , Kababya Shifi , Balazs Yael S. , Glazer Lilah , Berman Amir , Sagi Amir , Schmidt Asher 
Published: August 2011

Bioavailable calcium is maintained by some crustaceans, in particular freshwater crayfish, by stabilizing amorphous calcium carbonate (ACC) within reservoir organs—gastroliths, readily providing the Ca2+needed to build a new exoskeleton. Despite the key scientific and biomedical importance of the in situ molecular-level picture of biogenic ACC and its stabilization in a bioavailable form, its description has eluded efforts to date. Herein, using multinuclear NMR, we accomplish in situ molecular-level characterization of ACC withinintactgastroliths of the crayfishCherax quadricarinatus. In addition to the known CaCO3, chitin scaffold and inorganic phosphate (Pi), we identify within the gastrolith two primary metabolites, citrate and phosphoenolpyruvate (PEP) and quantify their abundance by applying solution NMR techniques to the gastrolith “soluble matrix.” The long-standing question on the physico-chemical state of ACC stabilizing, P-bearing moieties within the gastrolith is answered directly by the application of solid state rotational-echo double-resonance (REDOR) and transferred-echo double-resonance (TEDOR) NMR to the intact gastroliths: Pi and PEP are found molecularly dispersed throughout the ACC as a solid solution. Citrate carboxylates are found < 5 Åfrom a phosphate (intermolecular C⋯P distance), an interaction that must be mediated by Ca2+. The high abundance and extensive interactions of these molecules with the ACC matrix identify them as the central constituents stabilizing the bioavailable form of calcium. This study further emphasizes that it is imperative to characterize the intact biogenic CaCO3. Solid state NMR spectroscopy is shown to be a robust and accessible means of determining composition, internal structure, and molecular functionality in situ.
The effects of hyperosmosis or high pH on a dual‐species biofilm of Enterococcus faecalis and Pseudomonas aeruginosa: an in vitro study
Authors: van der Waal S. V. , van der Sluis L. W. M. , Özok A. R. , Exterkate R. A. M. , van Marle J. , Wesselink P. R. , de Soet J. J. 
Published: August 2011

van der Waal SV, van der Sluis LWM, Özok AR, Exterkate RAM, van Marle J, Wesselink PR, de Soet JJ. The effects of hyperosmosis or high pH on a dual‐species biofilm of Enterococcus faecalis and Pseudomonas aeruginosa: an in vitro study. International Endodontic Journal, 44, 1110–1117, 2011.AbstractAim  To investigate the effect of hyperosmotic hyperosmosis or alkaline stress on a dual‐species biofilm of Enterococcus faecalis and Pseudomonas aeruginosa.Methodology  Biofilms were grown on glass cover slips suspended in bacterial inoculate for 96 h, after which the cover slips with attached biofilms were immersed in brain heart infusion broth (BHI‐broth) with 6 mol L−1 sodium chloride (NaCl) representing the hyperosmotic group or Ca(OH)2, pH 12.1, representing the alkaline group. Two per cent sodium hypochlorite and BHI‐ broth served as positive and negative controls, respectively. After treatment, the biofilms were washed, harvested and plated on blood‐agar plates after serial dilution. The bactericidal effect was assessed by determining the colony‐forming units (CFU). The effect on the biofilm mass was imaged with confocal laser scanning microscopy (CLSM).Results  Hyperosmosis reduced the CFU of both species significantly after 72 h (P < 0.0001). After 168 h, P. aeruginosa was eradicated and the E. faecalis reduction was more than 99%. High pH could not induce a significant bacterial reduction. CLSM revealed dense flocculation of the biofilms incubated in alkaline broth.Conclusion  Hyperosmosis effectively reduced a dual‐species biofilm of E. faecalis and P. aeruginosa, whilst high pH had limited bactericidal effect in this model.
Evaluation of trace elements, calcium, and magnesium levels in the plasma and erythrocytes of patients with essential hyperhidrosis
Authors: Güder Hüsna , Karaca Şemsettin , Cemek Mustafa , Kulaç Mustafa , Güder Semih 
Published: August 2011

AbstractBackground  Essential hyperhidrosis is a disease that expresses itself with excessive sweating in palmar, plantar, axillary, and craniofacial regions. The etiopathogenesis of the disease, which has particular importance because of leading to psychosocial morbidity, could have not been completely elucidated. In previous studies, it has been shown that oxidative stress might play a role in the pathogenesis.Aims  Assessing the levels of trace elements such as Se, Zn, Cu, Fe, and Mg that have an important role in oxidative stress, as well as Ca and Mg that have an important role in membrane physiology, in patients with essential hyperhidrosis.Materials and methods  Blood samples taken from the patient group with essential hyperhidrosis (42) and the control group (37) were separated into plasma and erythrocytes, and the levels of the bioelements were measured by use of ICP‐OES device.Results  Erythrocyte levels of Se, Fe, Cu, Zn, Ca, and Mg were detected significantly higher in patients with essential hyperhidrosis. Furthermore, plasma levels of Cu, Ca, and Mg were significantly lower in patients with essential hyperhidrosis. Plasma levels of Se, Fe, and Zn showed no statistical difference between two groups.Dicussion  It was thought that the high levels of Cu and Fe in erythrocytes may play a role in increased intracellular oxidative stress, whereas the increase in Se and Zn levels may be secondary to increased oxidative stress. Low extracellular concentrations of Ca and Mg raise the thought that they play a role either enhancing the membrane excitability of eccrine sweat glands or influencing the autonomic nerve system.Conclusion  The levels of trace elements, which were determined to be different from the control group, may play a role in the pathogenesis of essential hyperhidrosis either in direct relation with or without oxidative mechanisms.
Cutaneous simulants of infectious disease
Authors: Ricketts Janelle R. , Rothe Marti J. , Grant‐Kels Jane M. 
Published: August 2011

AbstractMany cutaneous conditions can mimic infection. If these lesions are not accurately recognized, they may be treated with antimicrobial agents, which adds cost, potential risk, and inconvenience to the patient and the healthcare system. The presenting signs and symptoms of many ulcerating, pustular, morbilliform, bullous, neoplastic, granulomatous, autoimmune, and neutrophilic conditions, as well as clinical vasculitis, cellulitis, folliculitis, and panniculitis, have been mistaken for infection. This review emphasizes the clinical presentation, physical exam, and diagnostic workup of many of these conditions to assist the clinician in ascertaining the correct diagnosis. In addition, general treatment options are provided for each disease category.