bluuebunny/crossref_metadata_2025 huggingface dataset:
Microdissecting the proteome
Authors: von Eggeling Ferdinand , Melle Christian , Ernst Günther
Published: July 2007

The complexity of the proteome is extremely high, because every organ or even a part of it can differ considerably in its protein composition. Performing proteomic studies therefore means to separate these functional different tissue areas before analysis. Otherwise all gained results will be depending on the question whether they are incorrect or at least dubious and do they reflect the different functions of tissues at all. The separation of functional tissue areas can be achieved by laser‐based microdissection. In this review we will discuss the compatibly of microdissected formalin or cryofixed tissue with different proteomic techniques like 2‐DE, MS and protein arrays.
Piecing together the structure–function puzzle: Experiences in structure‐based functional annotation of hypothetical proteins
Authors: Adams Melanie A. , Suits Michael D. L. , Zheng Jimin , Jia Zongchao
Published: July 2007

The combination of genomic sequencing with structural genomics has provided a wealth of new structures for previously uncharacterized ORFs, more commonly referred to as hypothetical proteins. This rapid growth has been the direct result of high‐throughput, automated approaches in both the identification of new ORFs and the determination of high‐resolution 3‐D protein structures. A significant bottleneck is reached, however, at the stage of functional annotation in that the assignment of function is not readily automatable. It is often the case that the initial structural analysis at best indicates a functional family for a given hypothetical protein, but further identification of a relevant ligand or substrate is impeded by the diversity of function in a particular structural classification of proteins family, a highly selective and specific ligand‐binding site, or the identification of a novel protein fold. Our approach to the functional annotation of hypothetical proteins relies on the combination of structural information with additional bioinformatics evidence garnered from operon prediction, loose functional information of additional operon members, conservation of catalytic residues, as well as cocrystallization trials and virtual ligand screening. The synthesis of all available information for each protein has permitted the functional annotation of several hypothetical proteins from Escherichia coli and each assignment has been confirmed through generally accepted biochemical methods.
Applications of field‐flow fractionation in proteomics: Presence and future
Authors: Chmelik Josef
Published: July 2007

Field‐flow fractionation (FFF) represents a group of elution separation methods where external force fields act perpendicularly on analytes in a carrier liquid flows with nonuniform velocity profiles. It is an elution separation method that enables to separate analytes in relatively short times and collect fractions for further characterization or for investigation of their properties. Other advantages of FFF are small consumption of samples and gentle experimental conditions. These make FFF uniquely qualified for separation and purification of biological samples. The most promising are applications of different variants of flow FFF utilizing a cross flow through membrane channel walls to separate proteins. The separation is based on differences in protein diffusion coefficients, which allows calculating the size of macromolecules. Other FFF techniques (e.g., electrical, isoelectric, and sedimentation FFF) were also used for separation of biomolecules. FFF appears to be not only promising rapid technique for protein separation but it offers some other advantages in sample preparation, especially, focusing (hyperlayer) FFF techniques that enable preparation of homogeneous fractions of cells. Selected applications of FFF to protein analysis are described and future trends in application of FFF to proteomics are discussed.
Modulation of human cytidine deaminase by specific aminoacids involved in the intersubunit interactions
Authors: Vincenzetti S. , Quadrini B. , Mariani P. , De Sanctis G. , Cammertoni N. , Polzonetti V. , Pucciarelli S. , Natalini P. , Vita A.
Published: July 2007

An investigation was made of the role exerted by some residues supposed to be involved in the intersubunit interaction and also in the catalytic site of homotetrameric human cytidine deaminase (T‐CDA). Attention was focused on Y33, Y60, R68, and F137 residues that are a part of a conserved region in most T‐CDAs. Hence, a series of site‐directed mutagenesis experiments was set up obtaining seven mutants: Y60G, Y33G, Y33F Y33S, F137A, R68G, and R68Q. Each active purified mutant protein was characterized kinetically, with a series of substrates and inhibitors, and the effect of temperature on enzyme activity and stability was also investigated. Circular dichroism (CD) experiments at different temperatures and in presence of small amounts of sodium dodecyl sulphate (SDS) were performed in all the soluble mutant CDAs. The results obtained by site‐directed mutagenesis studies were compared to the crystallographic data of B. subtilis CDA and E. coli CDA and to molecular modeling studies previously performed on human CDA. The mutation of Y60 to glycine produced an enzyme with a more compact quaternary structure with respect to the wild‐type; this mutation did not have a dramatic effect on cytidine deamination, but it slightly affected the binding with the substrate. None of the mutant CDAs in Y33 showed enzymatic activity; they existed only as monomers, indicating that this residue, located at the intersubunit interface, may be responsible for the correct folding of human CDA. The insertion of an alanine instead of phenylalanine at position 137 led to a soluble but completely inactive enzyme unable to form a tetramer, suggesting that F137 residue may be important for the assembling of the tetramer and also for the arrangement of the CDA active site. Finally, R68G and R68Q mutations revealed that the presence of the amino group seems to be important for the catalytic process but not for substrate binding, as already shown in B. subtilis CDA. The quaternary structure of R68Q was not affected by the mutation, as shown by the SDS‐induced dissociation experiments and CD studies, whereas R68G dissociated very easily in presence of small amounts of SDS. These experiments indicated that in the human CDA, the side chain of arginine 68 involved in the catalytic process in one subunit active site might come from another subunit. The data obtained from these studies confirmed the presence of a complicated set of intersubunit interactions in the active site of human CDA, as shown in other T‐CDAs. Proteins 2008. © 2007 Wiley‐Liss, Inc.
Beyond Lumry–Eyring: An unexpected pattern of operational reversibility/irreversibility in protein denaturation
Authors: Rodriguez‐Larrea David , Ibarra‐Molero Beatriz , de Maria Leonardo , Borchert Torben V. , Sanchez‐Ruiz Jose M.
Published: July 2007

We have found that, contrary to naïve intuition, the degree of operational reversibility in the thermal denaturation of lipase from Thermomyces lanuginosa (an important industrial enzyme) in urea solutions is maximum when the protein is heated several degrees above the end of the temperature‐induced denaturation transition. Upon cooling to room temperature, the protein seems to reach a state with enzymatic activity similar to that of the initial native state, but with higher denaturation temperature and radically different behavior in terms of susceptibility to irreversible denaturation. These results show that patterns of operational reversibility/irreversibility in protein denaturation may be more complex than the often‐taken‐for‐granted, two‐situation classification (reversible vs. irreversible). Furthermore, they are consistent with the possibility of existence of different native or native‐like states separated by high kinetic barriers under native conditions and they suggest experimental procedures to reach and study such “alternative” native states. Proteins 2008. © 2007 Wiley‐Liss, Inc.
A model of the complex between the PfEMP1 malaria protein and the human ICAM‐1 receptor
Authors: Bertonati Claudia , Tramontano Anna
Published: July 2007

Malaria is caused by protozoan parasites of the genus Plasmodium. Four species of Plasmodium can infect humans: P. falciparum, P. malariae, P. vivax, and P. ovale. P. falciparum is the only able to cytoadhere to the surface of postcapillary endothelial cells. A key role in cytoadherence is played by the interaction between the PfEMP1 P. falciparum protein and the human intracellular adhesion molecule (ICAM‐1) although very little is known about the molecular details of this complex. Here we propose a model for this interaction on the basis of a homology model of the functional domain of PfEMP1 and of the ICAM‐1 three dimensional structures. Our model is consistent with the results of many experimental observations, provides a rational explanation for the different binding abilities of different strains of P. falciparum and explains the reduced binding affinity of the A4 strain of P. falciparum for the ICAM‐1Kilifi polymorphism. On the basis of our model, we can also explain why the murine ICAM‐1, although sharing 70% sequence similarity with its human homologue, does not bind PfEMP1, and why the binding of fibrinogen and PfEMP1 to ICAM‐1 is mutually exclusive. The model of the complex proposed here can serve as a useful tool for the design and interpretation of biochemical and immunological experimental results. Proteins 2007. © 2007 Wiley‐Liss, Inc.
Modeling survival data with informative cluster size
Authors: Williamson John M. , Kim Hae‐Young , Manatunga Amita , Addiss David G.
Published: July 2007

Analysis of clustered data focusing on inference of the marginal distribution may be problematic when the risk of the outcome is related to the cluster size, termed as informative cluster size. In the absence of censoring, Hoffmanet al.proposed a within‐cluster resampling method, which is asymptotically equivalent to a weighted generalized estimating equations score equation. We investigate the estimation of the marginal distribution for multivariate survival data with informative cluster size using cluster‐weighted Weibull and Cox proportional hazards models. The cluster‐weighted Cox model can be implemented using standard software. Simulation results demonstrate that the proposed methods produce unbiased parameter estimation in the presence of informative cluster size. To illustrate the proposed approach, we analyze survival data from a lymphatic filariasis study in Recife, Brazil. Copyright © 2007 John Wiley & Sons, Ltd.
Increased acylated plasma ghrelin, but improved lipid profiles 24-h after consumption of carob pulp preparation rich in dietary fibre and polyphenols
Authors: Gruendel Sindy , Garcia Ada L. , Otto Baerbel , Wagner Karen , Bidlingmaier Martin , Burget Lukas , Weickert Martin O. , Dongowski Gerhard , Speth Maria , Katz Norbert , Koebnick Corinna
Published: July 2007

We have recently shown that a polyphenol-rich insoluble dietary fibre preparation from carob pulp (Ceratonia siliqua L; carob fibre) decreased postprandial acylated ghrelin, TAG and NEFA during an acute liquid meal challenge test. However, delayed effects of carob fibre consumption are unknown. Therefore, a randomized controlled crossover study in nineteen healthy volunteers consuming foods with or without 50 g carob fibre was conducted. On the subsequent day (day 2), glucose, TAG, total and acylated ghrelin as well as insulin, NEFA and leptin were assessed at baseline and at timed intervals for 300 min after ingestion of standardized bread. Consumption of carob fibre-enriched foods did not affect fasting concentrations of glucose, TAG, total ghrelin, NEFA, insulin and leptin. Fasting acylated ghrelin was increased on the day subsequent to carob fibre consumption compared with control (P = 0·046). After consumption of the standard bread on day 2, glucose response (P = 0·029) was increased, and TAG (P = 0·033) and NEFA (P < 0·001) responses were decreased compared with control. Postprandial responses of total and acylated ghrelin, insulin and leptin on day 2 were unaffected by carob fibre consumption the previous day. In conclusion, an increase in total and acylated plasma ghrelin accompanied by enhanced lipid metabolism after carob fibre consumption suggests higher lipid utilization and suppressed lipolysis on the day subsequent to carob fibre consumption. However, elevated glucose levels after carob fibre consumption need to be addressed in future studies.
Intake of heterocyclic aromatic amines from meat in the European Prospective Investigation into Cancer and Nutrition (EPIC)-Heidelberg cohort
Authors: Rohrmann Sabine , Zoller Dorothee , Hermann Silke , Linseisen Jakob
Published: July 2007

It was the aim of the present study to estimate the intake of heterocyclic aromatic amines (HCA) from meat, which have been associated with cancer risk in several epidemiological studies, of 21 462 subjects who participated in the European Prospective Investigation into Cancer and Nutrition (EPIC) in Heidelberg. This was accomplished by using a detailed dietary questionnaire that assessed meat consumption, cooking methods, and degree of browning of the respective food items. Median total HCA intake from meat was 31 ng/d (mean 69 ng/d), which was lower than results observed in previous studies. 2-Amino-1-methyl-6-phenylimidazo[4,5b]pyridine was the most common HCA in this cohort (median 17; mean 48 ng/d). The present study offers the opportunity of a detailed examination of the associations between meat cooking as well as HCA intake from meat and cancer risk in a prospective way.
Failure of contrast enhanced computed tomography scans to identify an orbital abscess. The benefit of magnetic resonance imaging
Authors: Mcintosh D , Mahadevan M
Published: July 2007

Introduction:

Acute sinusitis is a relatively common condition, which usually responds to medical therapy. In most cases, there are no sequelae or complications subsequent to this infection. However, like many acute illnesses, there are well documented complications of acute sinusitis, and in particular these include peri-orbital and intracranial spread.

Objective:

The purpose of this paper is to highlight the importance of vigilance in peri-orbital involvement and the limitations of imaging techniques, such as computed tomography scanning. An illustrative case is presented to demonstrate this.

Conclusion:

Magnetic resonance imaging scanning is a valuable modality in assessing complex presentations of peri-orbital complications of acute sinusitis.
Acute mastoiditis in children: presentation and long term consequences
Authors: Glynn F , Osman L , Colreavy M , Rowley H , Dwyer T P O , Blayney A
Published: July 2007

Acute mastoiditis, a destructive bacterial infection of the mastoid bone and air cell system, is relatively uncommon today but remains a potentially serious condition. There is a lack of information in the literature regarding the long term otological problems that children may face following an episode of this condition.

Objectives:

Our aim was to examine the presentation, complications and hospital course in this patient population, and to ascertain whether these patients had long term otological problems.

Methods:

We retrospectively reviewed the medical records of all patients presenting with acute mastoiditis between January 1990 and December 2005. Patients' parents were contacted by telephone and questioned about further otological problems.

Results:

Twenty-nine patients were included in the study, and 27 of these patients' parents were contactable to complete the telephone questionnaire. Sixty-nine per cent of children had no previous history of acute otitis media prior to presentation. Forty-five per cent of patients had received oral antibiotics prior to presentation. Sixty-two per cent of patients developed complications, i.e. a subperiosteal abscess or failure to respond to medical therapy, resulting in the need for surgical intervention (in the form of incision and drainage of periosteal abscess, cortical mastoidectomy, or grommet insertion). Mean follow up of patients was eight years and one month; five (17 per cent) patients had been followed up for less than one year. Two (7 per cent) patients developed a further episode of mastoiditis within six weeks of initial presentation, both of whom required cortical mastoidectomy. Three (10 per cent) patients had further problems with recurrent acute otitis media, requiring tympanostomy tube insertion. One patient required a modified radical mastoidectomy for cholesteatoma (15 years later). Twenty-two patients (91 per cent) had been followed up for longer than one year; these patients had subjectively normal hearing and were asymptomatic at the time of study.

Conclusion:

The majority of patients who had suffered an episode of acute mastoiditis had no adverse long term otological sequelae.
New species of the Lepraria neglecta group (Stereocaulaceae, Ascomycota) from Europe
Authors: SLAVÍKOVÁ-BAYEROVÁ Štěpánka , FEHRER Judith
Published: July 2007

Lepraria granulata Slavíková, a new species from Eastern and Central Europe, is described. According to its morphology, ITS sequence and ecology, it belongs to the L. neglecta core group. Lepraria granulata is characterized by producing atranorin and two, so far unidentified, fatty acids (‘granulata unknown 1 & 2’) and phylogenetic analyses show that it is clearly distinguished from previously known species. Two additional taxa, provisionally named Lepraria sp. G and Lepraria sp. BG, are also discussed. According to their morphology and ITS sequences, they also belong to the L. neglecta group. Lepraria sp. G is sister to L. granulata whereas Lepraria sp. BG is basal and well separated from all taxa so far known in the group. Their taxonomic status is not yet entirely clear.
Gyalidea fruticola, a new corticolous lichen from Europe
Authors: SVENSSON Måns , THOR Göran
Published: July 2007

The diminutive species Gyalidea fruticola is described from Central Sweden and northern Italy. It is typically found on decaying bark, on semi-shaded Lonicera spp. in deciduous, mixed deciduous/coniferous or coniferous forests. The species is characterized by its small and pale apothecia, its submuriform ascospores and its habitat preference.
The New Zealand lichen Pannaria leproloma (Nyl.) P. M. Jørg. and its panaustral relative P. farinosa nom. nov.
Authors: ELVEBAKK Arve , FRITT-RASMUSSEN Janne , ELIX John A.
Published: July 2007

Pannaria leproloma is shown to be a New Zealand endemic, and is characterized by coarse isidiomorphs/isidia, a high frequency of apothecia and the presence of two cytotoxic scabrosin esters, previously unknown from Pannariaceae, and present in 40 of the samples studied. It is not a member of the Pannaria sphinctrina group, as previously thought. It has frequently been confused with a related, finely sorediate, very sparingly fertile species, which lacks scabrosin esters in more than 99 of the specimens studied. This latter species is widely distributed both in southern South America (where it is one of the most common corticolous lichens), south-eastern areas of Australia and in New Zealand. It was originally described as Psoroma isidiosum, but had to be renamed when transferred to Pannaria, and is here named Pannaria farinosa.
A new lichenicolous Enterographa species from Britanny (France)
Authors: SPARRIUS Laurens B. , APTROOT André
Published: July 2007

Enterographa brezhonega, a fourth lichenicolous species in the genus is described. The species has been collected in an ancient woodland in western France growing on Porina rosei and probably other crustose lichens with a Trentepohlia photobiont. It shows affinities with the similar Enterographa epiphylla, but has an even number of septa and short-lirelliform ascomata.
Fellhanera colchica, relocating a forgotten taxon, and Byssoloma llimonae new for Italy
Authors: Llop Esteve
Published: July 2007

The foliicolous species Bacidia colchica Vězda was described from the eastern coast of the Black Sea (Vězda 1979, 1983) and is also known from SW France (Sérusiaux 1989; Sérusiaux et al. 2002) and S Italy (Puntillo 2000; Puntillo et al. 2000). However, its morphological features, such as the structure of the exciple, morphology of the paraphyses and ascus type, do not fit the current concept of Bacidia De Not. (Ekman 1996, 2001) but place this taxon in the Pilocarpaceae. The current circumscription of Pilocarpaceae is still under discussion, as well as the concept of some genera at present included in this family (Sérusiaux 1993; Lücking et al. 1994; Kalb et al. 2000; Lücking et al. 2001a; Sérusiaux et al. 2002; Andersen & Ekman 2005). In particular, the position of B. colchica should be in Fellhanera Vězda (Vězda 1986; Lücking et al. 1994; Sérusiaux 1996; Lücking 1997). Although several recent works have dealt with the European species of the genus Fellhanera (Sérusiaux 1996; Aptroot et al. 1998; Sparrius & Aptroot 2000; Sérusiaux et al. 2001; Sparrius 2002; Spier et al. 2002), none of them included B. colchica, despite some of the papers considering foliicolous taxa.
The Recent Decline in Economic Caseloads in Chinese Courts: Exploration of a Surprising Puzzle
Authors: He Xin
Published: July 2007

This article explores why the economic caseloads in China have declined in recent years. Based on data collected at the national, provincial and local levels, it evaluates four possible explanations – structural changes in dispute resolution, economic development, social transformation and dysfunctional courts. It suggests that all four hypotheses are plausible to a certain extent but none provides a single, straightforward and adequate solution, and the degree of each factor's impact varies across time and region. The cause for decline must lie either in the total volume of disputes generated in society or in the unwillingness of potential litigants to use the courts. The difficulty of locating an overarching explanation in a way suggests that China's case might have imposed a challenge on the relationship between caseload change and socio-economic conditions which has conventionally been regarded as a settled issue.
Differential distribution of glycine transporters in Müller cells and neurons in amphibian retinas
Authors: JIANG ZHENG , LI BAOQIN , JURSKY FRANTISEK , SHEN WEN
Published: July 2007

Amphibian retinas are commonly used for electrophysiological studies on neural function and transduction because they share the same general properties as higher vertebrate retinas. Glycinergic synapses have been well described in amphibian retinas. However, the role of glycine transporters in the synapses is largely unknown. We studied the distribution and function of glycine transporters in the retinas from tiger salamanders, mudpuppies, and leopard frogs by immunofluorescence labeling and whole-cell recording methods. Our results indicated that GlyT1- and GlyT2-like transporters were present in Müller cells and neurons, respectively. GlyT1 labeling was present in Müller glial cells and co-localized with Glial fibrillary acidic protein (GFAP), a Müller cell marker, whereas the GlyT2 immunoreactivity was present in the somas of amacrine cells (ACs) and processes in the inner plexiform layer (IPL) and the outer plexiform layer (OPL). Because the axon processes of glycinergic interplexiform cells (IPCs) are the only source of glycine input in the OPL, GlyT2 staining revealed a spatial pattern of the axon processes of IPCs in the OPL. The function of GlyT2 in the IPCs was studied in tiger salamander retinal horizontal cells (HCs) by whole-cell gramicidin perforated recording. The results demonstrated that inhibition of GlyT2 by a specific inhibitor, amoxapine, increased a tonic glycine input to HCs. Thus, the GlyT2 transporter is responsible for uptake of synaptic glycine in the outer retina. We also compared the distribution of glycine transporters in other amphibian species: salamander, mudpuppy, and frog. The results are consistent with the general pattern that GlyT1-like transporters are present in Müller cells and GlyT2-like transporters in neurons in amphibian retinas.
Central factors contributing to para-contrast modulation of contour
and brightness perception
Authors: BREITMEYER BRUNO G. , ZIEGLER RALPH , HAUSKE GERT
Published: July 2007

Following up on a prior study of contour and brightness processing in
visual masking (Breitmeyer et al., 2006), we
investigated the effects of a binocular and dichoptic para-contrast
masking on the visibility of the contour and brightness of a target
presented to the other eye. Combined, the results support the
contributions of several cortical processes to para-contrast: (1) two
central sources of inhibition, one long-latency and prolonged and the
other short-latency and brief; (2) binocular rivalry suppression; and (3)
a facilitatory effect peaking at different SOAs for the contour and the
brightness tasks, reflecting; (4) known properties of two separate
cortical systems, one a fast contour-processing pathway and the other a
slower brightness-processing pathway.
A model of the dynamics of retinal activity during natural visual
fixation
Authors: DESBORDES GAËLLE , RUCCI MICHELE
Published: July 2007

During visual fixation, small eye movements keep the retinal image
continuously in motion. It is known that neurons in the visual system are
sensitive to the spatiotemporal modulations of luminance resulting from
this motion. In this study, we examined the influence of fixational eye
movements on the statistics of neural activity in the macaque's
retina during the brief intersaccadic periods of natural visual fixation.
The responses of parvocellular (P) and magnocellular (M) ganglion cells in
different regions of the visual field were modeled while their receptive
fields scanned natural images following recorded traces of eye movements.
Immediately after the onset of fixation, wide ensembles of coactive
ganglion cells extended over several degrees of visual angle, both in the
central and peripheral regions of the visual field. Following this initial
pattern of activity, the covariance between the responses of pairs of P
and M cells and the correlation between the responses of pairs of M cells
dropped drastically during the course of fixation. Cell responses were
completely uncorrelated by the end of a typical 300-ms fixation. This
dynamic spatial decorrelation of retinal activity is a robust phenomenon
independent of the specifics of the model. We show that it originates from
the interaction of three factors: the statistics of natural scenes, the
small amplitudes of fixational eye movements, and the temporal
sensitivities of ganglion cells. These results support the hypothesis that
fixational eye movements, by shaping the statistics of retinal activity,
are an integral component of early visual representations.
Massive systemic-to-pulmonary collateral arteries in the setting of a cavopulmonary shunt and pulmonary venous stenosis
Authors: Grosse-Wortmann Lars , Hamilton Robert , Yoo Shi-Joon
Published: July 2007

We report a patient in whom a cavopulmonary anastomosis had been constructed, along with repair of anomalous pulmonary venous drainage. Left-sided pulmonary venous obstruction led to redistribution of the flow to the right lung. The reversal of flow in the left pulmonary artery was accentuated by flow through collateral arteries feeding the left lung. Within 14 months, the collateral flow increased six-fold, resulting in a doubling of the cardiac output.
Molecular targets for disrupting leukocyte trafficking during multiple sclerosis
Authors: McCandless Erin E. , Klein Robyn S.
Published: July 2007

Autoimmune diseases of the central nervous system (CNS) involve the migration of abnormal numbers of self-directed leukocytes across the blood–brain barrier that normally separates the CNS from the immune system. The cardinal lesion associated with neuroinflammatory diseases is the perivascular infiltrate, which comprises leukocytes that have traversed the endothelium and have congregated in a subendothelial space between the endothelial-cell basement membrane and the glial limitans. The exit of mononuclear cells from this space can be beneficial, as when virus-specific lymphocytes enter the CNS for pathogen clearance, or might induce CNS damage, such as in the autoimmune disease multiple sclerosis when myelin-specific lymphocytes invade and induce demyelinating lesions. The molecular mechanisms involved in the movement of lymphocytes through these compartments involve multiple signalling pathways between these cells and the microvasculature. In this review, we discuss adhesion, costimulatory, cytokine, chemokine and signalling molecules involved in the dialogue between lymphocytes and endothelial cells that leads to inflammatory infiltrates within the CNS, and the targeting of these molecules as therapies for the treatment of multiple sclerosis.
61-jährige Frau mit atypischer koronarer Symptomatik und erhöhtem Globalrisiko
Authors: Steiger  , Koch  , Hilfiker
Published: July 2007

Bei einer 61-jährigen Frau mit blander Vorgeschichte entwickelt sich eine Dyspnoesymptomatik, die von einer labilen Hypertonie begleitet ist. Die kardiologische Abklärung ergibt bei Hyperventilationsneigung ein pathologisches Belastungs-EKG, jedoch eine überdurchschnittlich gute ergometrische Leistungsfähigkeit. Die Befundkonstellation spricht gegen eine koronare Problematik, sodass auf eine zusätzliche funktionelle oder invasive Abklärung verzichtet wird. Angesichts des auf 19% erhöhten, intermediären Globalrisikos wird zum Ausschluss einer koronaren Herzkrankheit eine CT-Koronarangiographie durchgeführt. Diese ergibt überraschend eine ca. 50%ige weiche Plaque im proximalen RIVA. Die hsCRP ist erhöht, was eine potentielle Plaque-Vulnerabilität anzeigen könnte. Trotz einem Calcium-Score von 0 wird die Patientin als hohes Risiko eingestuft und mit Aspirin und einem hoch dosierten Statin behandelt. Für dieses Vorgehen besteht bisher keine Evidenz. Auf Grund des Calcium-Score allein wäre nach geltender Empfehlung das intermediäre Risiko auf ein niedriges zurückgestuft worden [4].
From Miami to Madison: Investigating the relationship between climate and terrestrial net primary production
Authors: Zaks David P. M. , Ramankutty Navin , Barford Carol C. , Foley Jonathan A.
Published: July 2007

The 1973 “Miami Model” was the first global‐scale empirical model of terrestrial net primary productivity (NPP), and its simplicity and relative accuracy has led to its continued use. However, improved techniques to measure NPP in the field and the expanded spatial and temporal range of observations have prompted this study, which reexamines the relationship of climatic variables to NPP. We developed several statistical models with paired climatic variables in order to investigate their relationships to terrestrial NPP. A reference data set of 3023 NPP field observations was compiled for calibration and parameter optimization. In addition to annual mean temperature and precipitation, as in the Miami Model, we chose more ecologically relevant climatic variables including growing degree‐days, a soil moisture stress index, and photosynthetically active radiation (PAR). Calculated annual global NPP ranged from 36 to 74 Pg‐C yr−1, comparable with previous studies. Comparisons of geographic patterns of NPP were made using biome and latitudinal averages.
A method to ingest GPS‐TEC into the NeQuick ionospheric model
Authors: Brunini C. , Gularte E. , Meza A. , Radicella S. M. , Nava B. , Coisson P. , Mosert M.
Published: July 2007

This paper presents a method to ingest Total Electron Content measurements from ground‐based GPS receivers into the empirical NeQuick model. The method here presented relies upon optimizing the parameter that primarily drives the NeQuick profile, i.e., the electron density of the F2 peak, NmF2. The effectiveness of the method is assessed in a rather benevolent ionospheric scenario: a midlatitude region and quiet geomagnetic days that cover solstices and equinoxes conditions during a medium‐high solar activity year. Thus, the procedure demonstrated to be capable of improving the climatological value of NmF2 computed from the Radioscience Section of the International Telecommunication Union (ITU‐R) database. This capability was assessed by comparing the ITU‐R value and the corrected value produced by our method to the value measured with a Digisonde. The result of this comparison was an overall reduction of the error of the NmF2 parameter to approximately half of its original value.
Patterns of predictability in hydrological threshold systems
Authors: Zehe E. , Elsenbeer H. , Lindenmaier F. , Schulz K. , Blöschl G.
Published: July 2007

Observations of hydrological response often exhibit considerable scatter that is difficult to interpret. In this paper, we examine runoff production of 53 sprinkling experiments on the water‐repellent soils in the southern Alps of Switzerland; simulated plot scale tracer transport in the macroporous soils at the Weiherbach site, Germany; and runoff generation data from the 2.3‐km2 Tannhausen catchment, Germany, that has cracking soils. The response at the three sites is highly dependent on the initial soil moisture state as a result of the threshold dynamics of the systems. A simple statistical model of threshold behavior is proposed to help interpret the scatter in the observations. Specifically, the model portrays how the inherent macrostate uncertainty of initial soil moisture translates into the scatter of the observed system response. The statistical model is then used to explore the asymptotic pattern of predictability when increasing the number of observations, which is normally not possible in a field study. Although the physical and chemical mechanisms of the processes at the three sites are different, the predictability patterns are remarkably similar. Predictability is smallest when the system state is close to the threshold and increases as the system state moves away from it. There is inherent uncertainty in the response data that is not measurement error but is related to the observability of the initial conditions.
Elastic wave velocities of garnetite with a MORB composition up to 14 GPa
Authors: Kono Yoshio , Higo Yuji , Ohfuji Hiroaki , Inoue Toru , Irifune Tetsuo
Published: July 2007

Ultrasonic P‐ and S‐wave velocities of a garnetite sample synthesized from MORB glass at around 17 GPa and 1200°C were measured up to 14.3 GPa at room temperature. The garnetite consists of well‐sintered microcrystalline majorite garnet and a minor amount of stishovite. P‐ and S‐wave velocities of the garnetite at room temperature are significantly lower than those of (Mg0.9, Fe0.1)2SiO4 wadsleyite and ringwoodite, which are the major high‐pressure phases in the mantle transition region. Bulk and shear moduli of the garnetite are determined from the P‐ and S‐wave velocities, and those of majorite garnet in the MORB composition (MORB majorite) are calculated using the modal abundance data and elastic properties of stishovite. The MORB majorite is estimated to have quite different bulk and shear moduli (up to 19% and 9%, respectively) from those of Mg end‐member garnets with simpler chemical compositions.
Comparative expression of different antibody formats in mammalian cells and Pichia pastoris
Authors: Braren Ingke , Greunke Kerstin , Umland Oliver , Deckers Susanne , Bredehorst Reinhard , Spillner Edzard
Published: July 2007

Generation of recombinant antibody fragments has been advanced by phage display technology but their broad use in biochemical or analytical applications is often hindered by their univalence. For enhancement of functional affinity and overall applicability, the fusion of scFvs (single‐chain variable fragments) to IgG constant domains has become an attractive approach. In order to evaluate characteristics and expression behaviour of different IgG‐analogous antibody formats, we fused an scFv to different portions of the heavy chain constant region of human IgG1. Two types of antibodies, an scFv–CH2–3 antibody and an scFv–CH1–3 antibody, a new intermediate with retained CH1 domain, were generated with or without an affinity tag for purification. Additionally, the scFv was reconverted into the heterotetrameric IgG molecule. To allow a reliable comparison of expression behaviours of different antibodies, we established vector systems that allow isogenetic and efficient expression of the recombinant antibodies based on site‐specific recombination. Upon recombinant expression in mammalian cells and the methylotrophic yeast Pichia pastoris, disulfide‐linked and glycosylated oligomers were obtained. Establishment of isogenetic cell lines revealed that the presence of the CH1 domain is not critical for secretion efficiency. Reactivity of the different constructs with antigen and Fc receptors was verified by ELISA, surface plasmon resonance approaches, as well as FACS analysis of HEK‐293 cells (human embryonic kidney cells) stably transfected with human FcγRI (high‐affinity IgG receptor) (CD64). In summary, the results obtained provide evidence for comparable behaviour of the different antibody formats and the vectors for isogenetic expression will contribute to a broader application of phage display‐derived antibodies.
One‐step purification of histidine‐tagged profilin with high purity and yield by using metal precipitation
Authors: Sankian Mojtaba , Yousefi Mitra , Pazouki Nazanin , Varasteh Abdolreza
Published: July 2007

A simple one‐step method for the purification of recombinant His‐tagged profilin from the bacterial cell lysate is reported. Noting the greater ease with which hexahistidine‐tagged proteins can be metalprecipitated compared with unwanted protein impurities, we investigated the effect of lysis‐buffer additives and optimization of other conditions to recover selectively desired proteins in a one‐step metal precipitation without using biopolymers. Purification of the His‐tagged melon (Cucumis melo) profilin was used to demonstrate the utility of this method and up to 80% recovery with a purity of 98% was achieved. This method obtained a yield of the protein nearly comparable with that obtained using metal‐affinity chromatography. This purification procedure can reduce the time and cost of the purification process, especially on a large scale.
Comparative studies on the thermostability of five strains of transmissible‐spongiform‐encephalopathy agent
Authors: Fernie Karen , Steele Philip J. , Taylor David M. , Somerville Robert A.
Published: July 2007

The causal infectious agents of TSEs (transmissible spongiform encephalopathies or prion diseases) are renowned for their resistance to complete inactivation. Survival of TSE infectivity after autoclaving potentially compromises many procedures where TSE infectivity may be present, including surgical instrument sterilization. In the present study, the heat inactivation properties of five different TSE agents were tested in a variety of experiments by exposing them to a range of heat inactivation conditions. Although TSE infectivity was reduced after heating to 200 °C in a hot air oven, substantial amounts of infectivity remained. Unlike wet heat inactivation, no TSE strain‐dependent differences were observed in the reduction in the amounts of infectivity produced by dry heat inactivation. However, the incubation periods of mice infected with one dry heated TSE strain, ME7, were substantially prolonged, whereas there was little or no effect for two other TSE models. Varying autoclaving conditions for three TSE strains between 132 and 138 °C, and times of exposure between 30 and 120 min, had little or no effect on the recovery of TSE infectivity. The results illustrate the limitations of TSE agent inactivation using heat‐based methods. The results support the hypothesis that the structures of TSE agents are stabilized during heat‐inactivation procedures, rendering them much more refractory to inactivation. This may occur through dehydration of the causal agents, specifically through the removal of the water of solvation from agent structures and hence stabilize interactions between prion protein and TSE agent‐specific ligands.
A semi‐empirical mathematical model useful for describing the relationship between carbon dioxide, pH, lactate and base in a bicarbonate‐buffered cell‐culture process
Authors: Gramer Michael J. , Ogorzalek Tad
Published: July 2007

The purpose of the present study was to develop a quantitative relationship between the primary factors of state affecting pH control in a bicarbonate‐buffered medium. Starting with the Henderson–Hasselbach equation, several assumptions led to the following equation:
image

where L is the lactate concentration (mM), BT is the total amount of base added (mM), s is the solubility of CO2 (mM/%), dCO2 is the dissolved CO2 concentration (%) and pK is the acid ionization constant for bicarbonate. This equation appropriately described the relationship of these factors when using bicarbonate, carbonate and HCl (as a lactic acid surrogate) in water. However, the equation required modification to describe the relationship in cell culture medium, due presumably to the presence of other buffers and components; the final form of the equation from an empirical fit in the absence of cells was:

image

This equation was tested against actual cell culture data, from inoculum preparation in a T‐flask through a 10000‐litre fed‐batch bioreactor, by comparing the lactate concentration calculated from base, pH and dCO2 data with that actually measured in the bioreactor using a YSI 8500 SELECT™ Biochemistry Analyzer (YSI Inc., Yellow Springs, OH, U.S.A.). In every case, the calculated and actual lactate concentrations were in good agreement. The equation was useful for isolating the mechanisms leading to varied base addition across 2‐, 600‐ and 10 000‐litre‐scale bioreactors. This procedure enables a new approach for quantitatively evaluating and understanding factors associated with bioreactor pH control.
Epigenetic silencing of a Ca
2+
-regulated Ras GTPase-activating protein RASAL defines a new mechanism of Ras activation in human cancers
Authors: Jin Hongchuan , Wang Xian , Ying Jianming , Wong Ada H. Y. , Cui Yan , Srivastava Gopesh , Shen Zhong-Ying , Li En-Min , Zhang Qian , Jin Jie , Kupzig Sabine , Chan Anthony T. C. , Cullen Peter J. , Tao Qian
Published: July 2007

Ras has achieved notoriety as an oncogene aberrantly activated in multiple human tumors. Approximately 30% of all human tumors express an oncogenic form of this GTPase that is locked in an active conformation as a result of being insensitive to Ras GTPase-activating proteins (GAPs), proteins that normally regulate the inactivation of Ras by enhancing its intrinsic GTPase activity. Besides oncogenic mutations in Ras, signaling by wild-type Ras is also frequently deregulated in tumors through aberrant coupling to activated cell surface receptors. This indicates that alternative mechanisms of aberrant wild-type Ras activation may be involved in tumorigenesis. Here, we describe another mechanism through which aberrant Ras activation is achieved in human cancers. We have established that Ras GTPase-activating-like protein (RASAL), a Ca
2+
-regulated Ras GAP that decodes the frequency of Ca
2+
oscillations, is silenced through CpG methylation in multiple tumors. With the finding that ectopic expression of catalytically active RASAL leads to growth inhibition of these tumor cells by Ras inactivation, we have provided evidence that epigenetically silencing of this Ras GAP represents a mechanism of aberrant Ras activation in certain cancers. Our demonstration that RASAL constitutes a tumor suppressor gene has therefore further emphasized the importance of Ca
2+
in the regulation of Ras signaling and has established that deregulation of this pathway is an important step in Ras-mediated tumorigenesis.
Prestin-based outer hair cell electromotility in knockin mice does not appear to adjust the operating point of a cilia-based amplifier
Authors: Gao Jiangang , Wang Xiang , Wu Xudong , Aguinaga Sal , Huynh Kristin , Jia Shuping , Matsuda Keiji , Patel Manish , Zheng Jing , Cheatham MaryAnn , He David Z. , Dallos Peter , Zuo Jian
Published: July 2007

The remarkable sensitivity and frequency selectivity of the mammalian cochlea is attributed to a unique amplification process that resides in outer hair cells (OHCs). Although the mammalian-specific somatic motility is considered a substrate of cochlear amplification, it has also been proposed that somatic motility in mammals simply acts as an operating-point adjustment for the ubiquitous stereocilia-based amplifier. To address this issue, we created a mouse model in which a mutation (C1) was introduced into the OHC motor protein prestin, based on previous results in transfected cells. In C1/C1 knockin mice, localization of C1-prestin, as well as the length and number of OHCs, were all normal. In OHCs isolated from C1/C1 mice, nonlinear capacitance and somatic motility were both shifted toward hyperpolarization, so that, compared with WT controls, the amplitude of cycle-by-cycle (alternating, or AC) somatic motility remained the same, but the unidirectional (DC) component reversed polarity near the OHC's presumed
in vivo
resting membrane potential. No physiological defects in cochlear sensitivity or frequency selectivity were detected in C1/C1 or C1/+ mice. Hence, our results do not support the idea that OHC somatic motility adjusts the operating point of a stereocilia-based amplifier. However, they are consistent with the notion that the AC component of OHC somatic motility plays a dominant role in mammalian cochlear amplification.
Single-molecule and ensemble fluorescence assays for a functionally important conformational change in T7 DNA polymerase
Authors: Luo Guobin , Wang Mina , Konigsberg William H. , Xie X. Sunney
Published: July 2007

We report fluorescence assays for a functionally important conformational change in bacteriophage T7 DNA polymerase (T7 pol) that use the environmental sensitivity of a Cy3 dye attached to a DNA substrate. An increase in fluorescence intensity of Cy3 is observed at the single-molecule level, reflecting a conformational change within the T7 pol ternary complex upon binding of a dNTP substrate. This fluorescence change is believed to reflect the closing of the T7 pol fingers domain, which is crucial for polymerase function. The rate of the conformational change induced by a complementary dNTP substrate was determined by both conventional stopped-flow and high-time-resolution continuous-flow fluorescence measurements at the ensemble-averaged level. The rate of this conformational change is much faster than that of DNA synthesis but is significantly reduced for noncomplementary dNTPs, as revealed by single-molecule measurements. The high level of selectivity of incoming dNTPs pertinent to this conformational change is a major contributor to replicative fidelity.