bluuebunny/crossref_metadata_2025_split huggingface dataset:
Crystal structure of a ring‐cleaving cyclohexane‐1,2‐dione hydrolase, a novel member of the thiamine diphosphate enzyme family
Authors: Steinbach Alma , Fraas Sonja , Harder Jens , Warkentin Eberhard , Kroneck Peter M. H. , Ermler Ulrich 
Published: February 2012

The thiamine diphosphate (ThDP) dependent flavoenzyme cyclohexane‐1,2‐dione hydrolase (CDH) (EC 3.7.1.11) catalyses a key step of a novel anaerobic degradation pathway for alicyclic alcohols by converting cyclohexane‐1,2‐dione (CDO) to 6‐oxohexanoate and further to adipate using NAD+ as electron acceptor. To gain insights into the molecular basis of these reactions CDH from denitrifying anaerobe Azoarcus sp. strain 22Lin was structurally characterized at 1.26 Å resolution. Notably, the active site funnel is rearranged in an unprecedented manner providing the structural basis for the specific binding and cleavage of an alicyclic compound. Crucial features include a decreased and displaced funnel entrance, a semi‐circularly shaped loop segment preceding the C‐terminal arm and the attachment of the C‐terminal arm to other subunits of the CDH tetramer. Its structural scaffold and the ThDP activation is related to that observed for other members of the ThDP enzyme family. The selective binding of the competitive inhibitor 2‐methyl‐2,4‐pentane‐diol (MPD) to the open funnel of CDH reveals an asymmetry of the two active sites found also in the dimer of several other ThDP dependent enzymes. The substrate binding site is characterized by polar and non‐polar moieties reflected in the structures of MPD and CDO and by three prominent histidine residues (His28, His31 and His76) that most probably play a crucial role in substrate activation. The NAD+ dependent oxidation of 6‐oxohexanoate remains enigmatic as the redox‐active cofactor FAD seems not to participate in catalysis, and no obvious NAD+ binding site is found. Based on the structural data both reactions are discussed.Database
Structural data are available in the Protein Data Bank database under accession number 2PGOStructured digital abstract
CDH and CDH bind by x‐ray crystallography (View interaction)
Synthesis and Characterization of Ceramic Membranes (W‐Type Zeolite Membranes)
Authors: Mohammadi Toraj , Maghsoodloorad Hojjatollah 
Published: February 2012

In this article, effects of synthesis parameters (synthesis temperature, synthesis time, and number of layers) on W‐type zeolite membranes synthesized over flat SUS supports for O2/SF6 gas separation were experimentally investigated. Experiments were carried out at these levels of synthesis temperature: 165°C, 185°C, and 200°C; synthesis time: 6, 12, and 18 h and number of layers: 1 and 2. Permeation measurements, XRD and SEM analysis were used for characterization of the synthesized membranes. The results showed that increasing synthesis temperature from 165°C up to 185°C increases separation factor of O2/SF6, however, further increasing decreases the separation performance. The same trend was observed for synthesis time for the single layer synthesized zeolite W membrane, although for the double layer synthesized zeolite W membrane, separation factor increased with increasing synthesis time. Repetition of layering has a net positive effect on separation factor of O2/SF6, and negative effect on permeation flux through the membranes. This behavior was attributed to the dual effect of synthesis temperature and synthesis time on selectivity. More zeolite crystals are deposited and larger crystals are formed at higher synthesis temperatures and longer synthesis times. Well W‐type zeolite membrane was synthesized at 185°C for 18 h with two repeating layers with a high separation factor of 20.1.
Dynamically evolving Mg ii broad absorption line flow in SDSS J133356.02+001229.1
Authors: Vivek M. , Srianand R. , Mahabal A. , Kuriakose V. C. 
Published: February 2012

ABSTRACT
We report a dynamically evolving low-ionization broad absorption line (BAL) flow in the QSO SDSS J133356.02+001229.1 (at zem∼ 0.9197). These observations are part of our ongoing monitoring of low-ionization BAL QSOs with the 2-m telescope at IUCAA Girawali Observatory (IGO). The broad Mg ii absorption with an ejection velocity of 1.7 × 104 km s−1, found in the Sloan Digital Sky Survey (SDSS) spectra, has disappeared completely in our IGO spectra. We found an emerging new component at an ejection velocity of 2.8 × 104 km s−1. During our monitoring period this component has shown strong evolution both in its velocity width and optical depth and nearly disappeared in our latest observations. Acceleration of a low-velocity component seen in SDSS spectrum to a higher velocity is unlikely as the Mg ii column densities are always observed to be higher for the new component. We argue that the observed variations may not be related to ionization changes and are consistent with absorption produced by multistreaming flow transiting across our line of sight. We find a possible connection between flux variation of the QSO and N(Mg ii) of the newly emerged component. This could mean the ejection being triggered by changes in the accretion disc or dust reddening due to the outflowing gas.
Nursing care for patients on the edge of life in nursing homes: obstacles are overshadowing opportunities
Authors: Hov Reidun , Hedelin Birgitta , Athlin Elsy 
Published: February 2012

Background.  Patients in nursing homes have comprehensive needs for nursing care and medical treatment. Most patients benefit from the treatment, but some are ‘on the edge of life’‐in a borderland between living and dying with an unpredictable outcome, and questions are sometimes raised whether to withhold/withdraw curative treatment.Aim.  The aim was to describe nurses’ conceptions of good nursing care, and how this could be carried out for patients on the edge of life in nursing homes.Design.  In order to discover variations in the nurses’ understandings a phenomenographic approach was chosen. Phenomenography is concerned with qualitatively different ways of conceiving a phenomenon.Methods.  Fourteen nurses from two nursing homes were individually interviewed twice. A phenomenographic analysis was used.Results.  The outcome‐space included two main categories. The first, ‘good nursing care is to meet patients’ needs for dignity,’ included three description‐categories: needs for ‘preparedness’, ‘human relationship’ and ‘bodily comfort and safety’. The second, ‘opportunities were overshadowed by obstacles’ in carrying out nursing care encompassed three description‐categories: ‘organisational factors,’‘relational factors’ and ‘personal factors’.Conclusions.  This study shows nurses’ conceptions of the importance of good nursing care for comforting patients on the edge of life.Implications for practice.  Several obstacles related to resources, communication, cooperation and nurses' professional strength and power need to be overcome if good nursing care can be performed.
Hyaluronic acid‐degrading enzymes in rat alveolar macrophages and in alveolar fluid: stimulation of enzyme activity after oral treatment with the immunomodulator RU 41740
Authors: Fiszer‐Szafarz Berta , Rommain Michèle , Brossard Claudine , Smets Pierre 
Published: February 2012

RU 41740 (Biostim®) is an immunomodulator clinically used for the treatment of chronic bronchitis and recurrent pulmonary infections. In these diseases large amounts of mucus are produced which congest the bronchi. A major glycosaminoglycan constituent of this mucus is hyaluronic acid, one of the largest molecules in nature; its metabolic degradation is carried out by 3 acid hydrolases: hyaluronidase, β‐N‐acetylglucosaminidase, and β‐glucuronidase.In the lung these enzymes are especially synthesized and active in alveolar macrophages. It was thus interesting to study the effect of RU 41740 administration on the hyaluronic acid‐degrading activity of these cells.This compound was given by gastric gavage to rats and the activities of lung alveolar macrophage and alveolar fluid hyaluronidase, β‐N‐acetylglucosaminidase, β‐glucuronidase, and acid phosphatase as a lysosomal marker were determined. The effect on macrophage proliferation was also examined.The results obtained showed that: (1) unstimulated alveolar macrophages display the remarkable property, compared with other cell types, that hyaluronidase activity is about equally distributed between the inside and the outside of the cell; (2) RU 41740 administration increases the total activity of the 4 enzymes studied in the alveolar macrophages without inducing any increase in the number of macrophages; (3) the intracellular activities of β‐N‐acetylglucosaminidase and β‐glucuronidase are markedly increased, whereas intracellular hyaluronidase activity is not changed. However, in the extracellular fluid only hyaluronidase activity is highly increased; (4) even the lysosomal marker enzyme acid phosphatase has only its intracellular activity is increased. This would suggest the possibility that other lysosomal enzymes may also be increased by this immunomodulator.Most probably, the activation of the hyaluronic acid‐degrading enzymes by RU 41740 has the following consequences: extracellular hyaluronidase degrades hyaluronic acid to smaller molecules, which are then phagocytized by the macrophages; the intracellular hydrolytic enzymes, also strongly stimulated, complete the hydrolysis. Moreover, it was observed that the molecular form of rat macrophage hyaluronidase is the same as that of serum and other somatic cell hyaluronidase.
Microtubules and actin microfilaments in the amphibian bladder granular cells
Authors: Hugon J.S. , Ibarra C. , Valenti G. , Bourguet J. 
Published: February 2012

Microtubules and microfilaments were localized by an immunocytochemical method in the granular cells of the frog bladder after fixation and isolation.An extensive array of microtubules was observed in the granular cells with an orientation towards the luminal plasma membrane in the supranuclear zone. Actin filaments formed a continuous bundle that underlined the cellular membrane.After incubation in the presence of colchicine, nocodazole, or tubulozole, the microtubular network appeared fragmented but did not disappear completely.These observations are related to the role of the cytoskeleton in the permeability response of the frog bladder epithelium to vasopressin.
(Na,K)‐pump: cellular role and regulation in nonexcitable cells
Authors: Cohen Brian J. , Lechene Claude 
Published: February 2012

The (Na,K)‐pump develops and maintains ionic gradients that are of fundamental importance for proper function of most animal cells. These gradients are utilized in the form of ionic leak pathways by a number of special and general cell processes (e.g., nerve conduction, nutrient transport, pH regulation). As the sodium gradient in particular energizes many vital cell processes, alterations in cell activity will often be manifest as changes in sodium entry. The (Na,K)‐pump rate varies accordingly, in order to maintain balance between Na entry and exit thereby maintaining the potential energy of the cell.Acute changes in sodium influx are balanced by increases in activity of existing pump units, with only a small change in intracellular sodium concentration. This is posible because intracellular is normally poised on the steep limb of the concentration versus activity curve for the (Na,K)‐pump, at a point well below maximal activity, allowing large increases in (Na,K)‐pump rate with only small changes in sodium concentration. If the increase in sodium influx is prolonged, it appears that the cell responds by synthesizing new pumps, allowing intracellular sodium concentration to return to its original values.Though increases in (Na,K)‐pump activity must be accompanied by increases in potassium leak rates, in the experiments we have presented, there does not appear to be direct functional coupling between the (Na,K)‐pump and the K leak pathways. In these situations the matching of active influx and passive efflux of K short‐term appears to occur by mechanisms not directly related to (Na,K)‐pump activation.
Differential expression of 240 kDa ConA‐binding glycoprotein in vitro and in vivo detected by immunochemical methods
Authors: Barakat Ibtissam , Bezamahouta César , Zanetta Jean‐Pierre , Vincendon Guy 
Published: February 2012

The expression of the 240 ConA‐binding glycoprotein (240 kDa), a marker of synaptic junctions isolated from the rat cerebellum, was studied by immunocytochemical techniques in forebrain and cerebellum from rat and chicken, and in chick dorsal root ganglia. Parallel studies were carried out either on tissue sections or in dissociated cell cultures. In all cases non neuronal cells were not immunostained.The tissue sections of cerebellum from rat and chick exhibited 240 kDa glycoprotein immunoreactivity, especially in the molecular layer, while the forebrain sections from rat and chick did not show any significant immunostaining. In contrast, in dissociated forebrain cell cultures, all neuronal cells expressed 240 kDa glycoprotein immunoreactivity, while glial cells remained totally unlabelled. In tissue sections of dorsal root ganglion (DRG), sensory neurons expressed the 240 kDa only after the embryonic day (E 10). A large number of small neurons in the dorsomedial part of DRG were immunostained with 240 kDa glycoprotein antiserum, whereas only a small number of neurons in the ventrolateral part of the ganglia displayed 240 kDa immunoreactivity. In dissociated DRG cell cultures (mixed or neuron‐enriched DRG cell cultures) all the neuronal perikarya but not their processes were stained. These studies indicate that 240 kDa glycoprotein expression is completely modified in cultures of neurons of CNS or PNS since the antigen becomes synthetized in high amount by all cells independent of synapse formation. This demonstrates that the expression of 240 kDa is controlled by the cell environment.
Heterogeneity of progesterone receptor expression in epithelial cells of immature and differentiating quail oviduct
Authors: Pageaux Jean‐François , Dufrene Laurent , Laugier Christian , Perche Olivier , Sandoz Daniel 
Published: February 2012

The localization of progesterone receptor (PR) in the quail oviduct was investigated before and after the onset of sexual maturation using an immunohistochemical technique. PR was revealed exclusively in nuclei of target cells whatever the hormonal state of the tissue (immature or not, pretreated or not with progesterone).In the immature or ovariectomized quail oviduct, PR was principally localized in the undifferentiated epithelial cells; some mesothelial cells and a very few stromal cells expressed the PR. Only 40–45% of the epithelial cells were immunoreactive. These positive cells were mainly localized in the furrows of the villi where further evagination of the epithelium will occur to form the tubular glands.The onset of sexual maturation was accompanied by an increase of the proportion of positive epithelial cells and stromal cells. In estradiol‐treated animals, more than 90% of the tubular gland cells were strongly stained while only 40% of the luminal epithelial cells were immunoreactive.Our results show that there are two subpopulations of epithelial cells: those expressing the PR before the onset of sexual maturation even in ovariectomized quails (constitutive expression) and those expressing the PR during sexual maturation or after estrogen injection (inductive expression). These results, associated with previously published studies dealing with the cytodifferentiation of epithelial cells during natural development or after various hormonal treatments in ovarectomized animals, suggest that the first are the progenitors of tubular gland cells, and the second the progenitors of ciliated and goblet cells. In stromal cells, PR expression is also inducuible.
A technique for labelling the sample surface for quick‐freeze, deep‐etch, rotary replication electron microscopy: application to the study of geletin gel structure
Authors: Favard Pierre , Lechaire Jean‐Pierre , Maillard Maryvonne , Favard Nina , Djabourov Madeleine , Leblond Jacques 
Published: February 2012

A method using magnesium oxide crystals to label the surface of physical gels, such as gelatin gel before quick‐freezing is described and discussed. The quick‐freeze, deep‐etch, rotary replication technique is most adapted to 3‐D visualization of physical gel structure. However, it is known that the depth which ultrarapid freezing may reach is limited by the growth of ice crystals as the distance from the surface of the specimen (rapidly cooled by smashing against a cooled metal plate) increases. Consequently, intact preservation of structures occurs only in superficial zones of the specimen.The MgO surface labelling technique provides a simple means for surface recognition. It enables the estimation of a given replicated area depth, taking into account the angle of specimen scraping before etching and replicating. By comparison of views of the same replica at different depths, freezing artifacts may be recognized even when they cause only slight deformations in the structure. This is particularly necessary for interpretation of gel network geometry: interpretation can be made with certainty only if a reliable surface reference marker exists.For gelatin gels, the depth of best freezing can be estimated to be around 5 μm from the frozen sample surface.
X‐ray microanalysis of freeze‐dried digestive mucus in Anguilla anguilla L: modifications of ion content during the early steps of secretion
Authors: Humbert Willy , Simonneaux Valérie , Kirsch Raymond 
Published: February 2012

Summary— Digestive mucus of sea‐water adapted eels has been observed and analyzed by the scanning electron microscope (SEM) after rapid freezing at liquid nitrogen temperature followed by freeze‐drying. No chemical procedures were used in this technique. This allowed the maintenance of the mucous coating.Preliminary X‐ray microanalysis carried out on freeze‐fractured and freeze‐dried samples of the oesophagus showed a decrease of K+ and an increase of Ca2+ and Cl− from the basal part of the mucous cell towards its the apical part. This technique has proven to be satisfactory for it prevents translocation and loss of diffusible elements in situ and allows X‐ray microanalysis in the SEM.
Firing patterns of spontaneously active motor units in spinal cord‐injured subjects
Authors: Zijdewind Inge , Thomas Christine K. 
Published: February 2012

Key points
Muscles below a human spinal cord injury start to contract involuntarily a few weeks after trauma. The basis for this spontaneous activity is still unclear.
We show motor units in these muscles exhibited regular or irregular activity for several minutes. The regularly firing motor units had longer estimated afterhyperpolarisation potentials, higher mean firing rates and generated weaker forces.
These observations suggest that regularly firing motor units are more excitable than those that fire irregularly.
Spontaneous firing of motor units at regular rates may reflect active properties (such as persistent currents) within motoneurones, visible here in the absence of voluntary drive.
This basic motor unit firing behaviour may underlie the firing patterns typically recorded during voluntary contractions.
Comparative Efficacies of Artemisinin Combination Therapies in Plasmodium falciparum Malaria and Polymorphism of
pfATPase6
,
pfcrt
,
pfdhfr
, and
pfdhps
Genes in Tea Gardens of Jalpaiguri District, India
Authors: Saha Pabitra , Guha Subhasish K. , Das Sonali , Mullick Shrabanee , Ganguly Swagata , Biswas Asit , Bera Dilip K. , Chattopadhyay Gaurangadeb , Das Madhusudan , Kundu Pratip K. , Ray Krishnangshu , Maji Ardhendu K. 
Published: February 2012

ABSTRACT

In India, chloroquine has been replaced by a combination of artesunate and sulfadoxine-pyrimethamine (AS-SP) for uncomplicated
P. falciparum
malaria. Other available combinations, artemether-lumefantrine (AM-LF) and artesunate-mefloquine (AS-MQ), not included in the national program, are widely used by private practitioners. Little is known about the therapeutic efficacy of these artemisinin combinations and the prevalence of molecular markers associated with antimalarial drug resistance. A total of 157 patients with
P. falciparum
monoinfection were recruited and randomized into three study groups (AS-SP, AM-LF, and AS-MQ). All patients were followed up for 42 days to study the clinical and parasitological responses according to the WHO protocol (2009). We assessed the polymorphism of the
pfATPase6
,
pfcrt
,
pfdhfr
, and
pfdhps
genes by the DNA-sequencing method. The PCR-corrected therapeutic efficacies of AS-SP, AM-LF, and AS-MQ were 90.6% (95% confidence interval [CI], 0.793 to 0.969), 95.9% (95% CI, 0.860 to 0.995), and 100% (95% CI, 0.927 to 1.00), respectively. No specific mutational pattern was observed in the
pfATPase6
gene. All isolates had a K76T mutation in the
pfcrt
gene. In the
pfdhfr-pfdhps
genotype, quadruple mutation was frequent, and quintuple mutation was documented in 6.3% of
P. falciparum
isolates. The significant failure rate of AS-SP (9.5%), although within the limit (10%) for drug policy change, was due to SP failure because of prevailing mutations in
pfdhfr
, I
51
R
59
N
108
, with
pfdhps
, G
437
and/or E
540
. The efficacy of this ACT needs periodic monitoring. Artemether-lumefantrine and artesunate-mefloquine are effective alternatives to the artesunate-sulfadoxine-pyrimethamine combination.
Wild Coastline Birds as Reservoirs of Broad-Spectrum-β-Lactamase-Producing Enterobacteriaceae in Miami Beach, Florida
Authors: Poirel Laurent , Potron Anaïs , De La Cuesta Carolina , Cleary Timothy , Nordmann Patrice , Munoz-Price L. Silvia 
Published: February 2012

ABSTRACT

A high rate of broad-spectrum-β-lactamase-producing
Escherichia coli
isolates was identified from seagull and pelican feces collected in the Miami Beach, Florida, area. The most commonly identified resistance determinants were CMY-2 and CTX-M-15. Those wild birds might be therefore considered vehicles for wide dissemination of multidrug-resistant
Enterobacteriaceae
in the United States.
Microbiological Aetiology, Epidemiology, and Clinical Profile of Prosthetic Joint Infections: Are Current Antibiotic Prophylaxis Guidelines Effective?
Authors: Peel Trisha N. , Cheng Allen C. , Buising Kirsty L. , Choong Peter F. M. 
Published: February 2012

ABSTRACT

Prosthetic joint infections remain a major complication of arthroplasty. At present, local and international guidelines recommend cefazolin as a surgical antibiotic prophylaxis at the time of arthroplasty. This retrospective cohort study conducted across 10 hospitals over a 3-year period (January 2006 to December 2008) investigated the epidemiology and microbiological etiology of prosthetic joint infections. There were 163 cases of prosthetic joint infection identified. From a review of the microbiological culture results, methicillin-resistant
Staphylococcus aureus
(MRSA) and coagulase-negative staphylococci were isolated in 45% of infections. In addition, polymicrobial infections, particularly those involving Gram-negative bacilli and enterococcal species, were common (36%). The majority (88%) of patients received cefazolin as an antibiotic prophylaxis at the time of arthroplasty. In 63% of patients in this cohort, the microorganisms subsequently obtained were not susceptible to the antibiotic prophylaxis administered. The results of this study highlight the importance of ongoing reviews of the local ecology of prosthetic joint infection, demonstrating that the spectrum of pathogens involved is broad. The results should inform empirical antibiotic therapy. This report also provokes discussion about infection control strategies, including changing surgical antibiotic prophylaxis to a combination of glycopeptide and cefazolin, to reduce the incidence of infections due to methicillin-resistant staphylococci.