bluuebunny/crossref_metadata_2025 huggingface dataset:
Lactate dehydrogenase and its isoenzymes in vaginal fluid in vaginitis/vaginosis cases and in healthy controls
Authors: Niklasson O , Skude G , Mårdh P-A
Published: April 2003

The objective of the study was to measure the lactate dehydrogenase (LD) activity in vaginal lavage fluid of women with vaginitis/vaginosis and in healthy pre- and post-menopausal controls. Also to analyse the LD isoenzyme patterns in such samples and compare the influence on the LD activity by different storage and sampling methods. Twenty of the women studied, who had no signs of inflammation as evidenced from vaginal wet smears, were pre-menopausal and 8 post-menopausal. Fifty-eight non-pregnant patients with vaginitis/vaginosis or non-inflammatory gynaecological conditions were analysed for LD isoenzyme patterns. The LD activity was correlated to vaginal pH. Furthermore, the LD activity was determined in another 100 women screened for Chlamydia trachomatis. Finally, the influence on the LD activity when sampling was made by a cytological brush vs vaginal lavage and analysed after different storage periods, as studied. The LD activity was elevated, i.e. >2 µkat/L, in all but two of the women with leucorrhoea. Only women with bacterial vaginosis (BV) without leucorrhoea, had an increased LD activity. An increased vaginal pH correlated to the LD concentration. The LD activity was elevated in cases with vulvovaginal candidiasis, trichomoniasis, chlamydial cervicitis and senile colpitis. Storage of samples for up to six hours had no influence on the test outcome. Brush and lavage fluid samples did not differ with regard to the rate of positive LD tests. In healthy women, the LD activity is low and predominated by slow-migrating isoenzymes, i.e. LD 4 and 5. The LD activity is generally increased in cases of vaginitis and in women with BV and chlamydial cervicitis. In trichomoniasis, particularly high concentrations of LD 5, are found.
The influence of health care organisations on health system performance
Authors: Hauck Katharina , Rice Nigel , Smith Peter
Published: April 2003

Objectives: The governments of many countries are undertaking initiatives to assess the extent to which health care organisations fulfil important objectives of health care, such as health improvement, fair access and efficiency. However, the extent to which these health care organisations can influence these objectives is unclear. The purpose of this study is to examine the potential influence of English National Health Service territorial health authorities on 14 indicators of system performance.

Methods: The study uses performance data relating to approximately 5000 small geographical areas with average populations of 10 000. Multi-level statistical models are used to attribute variation in the indicators to three hierarchical levels - small areas, district health authorities and regional health authorities - after controlling for socio-demographic characteristics. Variations in indicators attributable to district or regional level give an indication of the extent to which health authorities may influence performance.

Results: After adjusting for socio-demographic characteristics, the proportion of variation in performance attributable to district health authorities varies from about 8% (for standardised mortality ratios) to about 76% (for waiting time for elective surgery). Variation at the regional level is smaller than at the district level.

Conclusions: There appear to be very large variations between indicators in the extent to which health care organisations can influence health system performance. Choice of performance indicators and the managerial incentive regime based on the indicators should recognise this variability, as it is highly dysfunctional to hold managers accountable for measures of performance that are beyond their control.
Does organisational culture influence health care performance? A review of the evidence
Authors: Scott Tim , Mannion Russell , Marshall Martin , Davies Huw
Published: April 2003

Objective: To review the evidence for a relationship between organisational culture and health care performance.

Methods: Qualitative comprehensive review: all empirical studies exploring a relationship between organisational culture (broadly defined) and health care performance (broadly defined) were identified by a comprehensive search of the literature. Study methods and results were analysed qualitatively to provide a narrative review with integrative discussion.

Results: Ten studies met the inclusion criteria. There was considerable variation in the design, study setting, quality of reporting and aspects of culture/performance considered. Four of the ten studies reviewed in detail claimed to have uncovered supportive evidence for the hypothesis that culture and performance are linked. All the other studies failed to find a link, though none provided strong evidence against the hypothesis.

Conclusions: There is some evidence to suggest that organisational culture may be a relevant factor in health care performance, yet articulating the nature of that relationship proves difficult. Simple relationships such as 'strong culture leads to good performance' are not supported by this review. Instead, the evidence suggests a more contingent relationship, in that those aspects of performance valued within different cultures may be enhanced within organisations that exhibit those cultural traits. A striking finding is the difficulty in defining and operationalising both 'culture' and 'performance' as variables that are conceptually and practically distinct. Considerably greater methodological ingenuity will be required to unravel the relationship(s) between organisational culture(s) and performance(s). Current policy prescriptions, which seek service improvements through cultural transformation, are in need of a more secure evidential base.
Redesigning health care: new wine from old bottles?
Authors: Locock Louise
Published: April 2003

One of the latest remedies for poor quality services is seen as being redesign of the health care system. Redesign is charged with political meaning, representing a radical challenge to practitioners and managers. But is it really a new approach? Although it draws on theories of re-engineering and total quality management, it is a pragmatic blend of components of both. Early findings suggest that quality improvement has been achieved but this has not been as extensive as anticipated. Redesign is in danger of being seen as the new magic bullet and thus may be being set up to fail. It may prove to be one more in a succession of discarded change management fads.
Reversible Formation and Decomposition of LiF Clusters Using Transition Metal Fluorides as Precursors and Their Application in Rechargeable Li Batteries
Authors: Li H. , Richter G. , Maier J.
Published: April 2003

A LiF/M nanocomposite in which LiF is dispersed with a transition metal (TM) on an atomic or nanometer scale can be obtained by a complete electrochemical insertion of Li into TM fluoride. Thus Li–F bonds can be broken and reformed at room temperature, and Li can be reversibly stored in TM fluorides through heterogeneous solid‐state electrochemical reactions (see Figure).
Polymer precursor to diamondlike carbon prepared by the polymerization of α,α,α‐trichlorotoluene and acetonitrile
Authors: Ma Mingming , Shi Gaoquan , Xi Chanjuan
Published: April 2003

A novel liquid/solid two‐phase reaction of α,α,α‐trichlorotoluene (PhCCl3) and acetonitrile (AN) has been discovered that produces a carbon‐based polymer with diamondlike structure at the atomic level. The solid phase is potassium hydroxide particles, and the liquid phase is a tetrahydrofuran solution of PhCCl3 and AN containing a certain amount of tetrabutylammonium bromide as a phase‐transfer catalyst. The structure of the carbon‐based polymer has been characterized by elemental analysis, Fourier transform infrared spectroscopy, and 1H‐ and 13C‐NMR spectroscopy. The pyrolysis of the carbon‐based polymer at 800°C under a nitrogen atmosphere leads to the formation of a diamondlike carbonaceous material according to the results of X‐ray photoelectron spectroscopy and Raman spectroscopy. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 16–23, 2003
The polycondensation of lithium 11–bromoundecanoate in aqueous media
Authors: Shigetomi Yasumasa , Kojima Takehiro
Published: April 2003

To obtain a biodegradable plastic, polycondensation, the substitution of bromine by carboxylate was carried out on lithium 11–bromoundecanoate. Using water as a solvent, the formation of a double bond was detected between 70 and 100°C, yielding a good quantity of polymer. Water is recommended as the best solvent for the reaction. Thermodynamic investigations were carried out by using ethylene glycol and water. The reaction is believed to proceed according to the SN2 mechanism. The ΔH and ΔG values for condensation in ethylene glycol were slightly higher than for those in water, but the reaction rate in water at 70°C was 7 times greater than that in ethylene glycol. The enhancement of dissociation accounts for the advantageous condensation in aqueous media. Furthermore, ΔS shows negative values and ΔG shows positive values, meaning that the reaction should proceed exothermically and not spontaneously. Experiments to condense 11–bromoundecanoate in aqueous media were carried out for ten days in a water bath, kept at 70°C, using 25 mL of 0.05M 11–bromoundecanoate. The degree of polymerization for the resulting polymer was found to be 23 by the end group assay for both bromine and carboxylate. Neither a melting point nor glass transition point for the product were observed. The polymer formed decomposes at 300°C and instantly disperses. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 130–134, 2003
Morphology of rubber‐modified vinyl ester resins cured at different temperatures
Authors: Auad María L. , Borrajo Julio , Aranguren Mirta I.
Published: April 2003

The morphologies of styrene (St) crosslinked divinylester resins (DVER) modified with elastomers were analyzed. The primary focus of this study was on the effect of the molecular weight of the resins, the reactivity of the elastomeric modifiers, and the temperature of curing. All of these variables have a strong influence on both the miscibility and the viscosity of the system, affecting the phase‐separation process that takes place in the unreacted and the reacting mixture. The selected liquid rubbers were carboxyl‐terminated poly(butadiene‐co‐acrylonitrile) (CTBN), a common toughening agent for epoxy resins, and an almost unreactive rubber with the DVER; and St comonomers and vinyl‐terminated poly(butadiene‐co‐acrylonitrile (VTBN), a reactive rubber. Different morphologies potentially appear in these systems: structures formed by DVER–St nodules surrounded by elastomer and spanning the whole sample; dual cocontinuous micron‐size domains formed by elastomer‐rich or resin‐rich domains; and a continuous DVER–St‐rich phase with included complex nodular domains. These microstructures can be varied by just changing the nature and concentration of the elastomer, the molecular weight of the resin, or the curing temperature. The appearance of these morphologies is discussed as a function of the above variables. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 274–283, 2003
IR spectra of cytochrome c denatured with deuterated guanidine hydrochloride show increase in β sheet
Authors: Speare Jonathan O. , Rush Thomas S.
Published: April 2003

Attenuated total reflectance Fourier transform IR (ATR‐FTIR) spectra are obtained for horse heart ferricytochrome c in solutions of 0–7M guanidine hydrochloride and deuterated guanidine hydrochloride. Substitutions of deuterium for hydrogen in both the denaturant and protein provide resolvable amide I spectra over a wide range of denaturant concentrations. Deuteration enhances the ability to measure the true protein IR spectrum in the amide I region in which the secondary structure can be deduced, because spectra in D2O are less prone to spectral distortion upon background denaturant subtraction than spectra in H2O. Other investigators studying equilibrium unfolded cytochrome c were limited to guanidine concentrations below 3.0M because of detector saturation. Detector saturation is avoided with the use of ATR‐FTIR spectroscopy, allowing one to obtain protein spectra at high denaturant concentrations. Second derivative spectra of samples show reductions in α helix and increases in β sheet at high denaturant concentrations, contrary to expectations of finding primarily a random coil secondary structure. Using this new technique, the protein was estimated to consist of 51% β sheet and only 15% random coil in the presence of 6.6M deuterated guanidine hydrochloride. © 2003 Wiley Periodicals, Inc. Biopolymers (Biospectroscopy) 72: 193–204, 2003
Artbildung im Mikrokosmos
Authors: Kronberg Inge
Published: April 2003

Parasiten wird eine bedeutende Rolle bei der Erhöhung der genetischen Vielfalt ihrer Wirtspopulation zugesprochen, die schließlich im Laufe der Evolution zu der Bildung neuer Arten führen kann. Wegen der langen Generationszeiten und unkalkulierbarer Wechselwirkungen sind solche Effekte im natürlichen Lebensraum kaum messbar. In einem künstlichen Mikrokosmos lassen sich dagegen Umwelt und genetische Variation kontrollieren.
Der große Wurf der frühen Jäger: Nachbau altsteinzeitlicher Speere
Authors: Rieder Hermann
Published: April 2003

Die sensationellen Speerfunde aus Schöningen werden in Bauart und Leistungsfähigkeit experimentell untersucht. Der Homo heidelbergensis vor 400.000 Jahren war zur Gruppenjagd auf Großwild fähig. Dabei halfen ihm Speere, die sowohl von der Wurfweite, als auch von der Zielsicherheit und der Eindringtiefe her den heutigen Speeren ebenbürtig sind. Es zeichnet sich eine Kulturgeschichte des Werfens ab mit den Kapiteln Jagd, Krieg und Sport.
Plateau's problem for parametric double integrals: I. Existence and regularity in the interior
Authors: Hildebrandt Stefan , von der Mosel Heiko
Published: April 2003

We study Plateau's problem for two‐dimensional parametric integrals

the Lagrangian F(x, z) of which is positive definite and at least semi‐elliptic. It turns out that there always exists a conformally para‐me‐trized minimizer. Any such minimizer X is seen to be Hölder‐continuous in the parameter domain B and continuous up to its boundary. If F possesses a perfect dominance function G of class C2, we can establish higher regularity of X in the interior. In fact, we prove X ⊆ Hloc2,2(B, ℝn) ∩ C1,σ(B, ℝn) for some σ > 0. Finally, we discuss the existence of perfect dominance functions.
Laparoscopic radiofrequency ablation of the liver in proximity to major vasculature: Effect of the Pringle maneuver
Authors: Shen Perry , Fleming Shawn , Westcott Carl , Challa Venkat
Published: April 2003

Background and Objectives

The Pringle maneuver has been shown to increase ablation size during radiofrequency ablation (RFA). Efficacy of laparoscopic Pringle in proximity to major vasculature has not been well described. Laparoscopic RFA was performed in proximity to major hepatic vessels to examine effects of the Pringle on ablation size and vascular damage.

Methods

Laparoscopic RFA was performed in 10 pigs. Each underwent ablation of a peripheral site, and sites adjacent to the portal and hepatic veins. Ultrasound was used to position the RFA adjacent to vascular structures. US flow characteristics verified occlusion of blood flow. Five pigs underwent laparoscopic RFA with Pringle and five underwent laparoscopic RFA alone. Animals were then sacrificed for gross and microscopic evaluation.

Results

Peripheral, hepatic, and portal vein ablations showed no significant differences in volume between non‐Pringle and Pringle lesions, though the median ablation volume for the peripheral site in the Pringle group was approximately twice that of the non‐Pringle group. Pringle group overall median time to target temperature was significantly shorter (P = 0.047). Histologic examination revealed no evidence of endothelial damage or thermal‐induced intravascular thrombosis of the hepatic or portal veins.

Conclusions

Laparoscopic RFA with Pringle in proximity to major vascular structures does not significantly increase ablation size, or cause acute vascular damage. Further studies are necessary to determine the utility of the Pringle in proximity to major intrahepatic blood vessels. J. Surg. Oncol. 2003;83:36–41. © 2003 Wiley‐Liss, Inc.
Contributions of side groups to the water diffusion in cured epoxy resins (2) study on physical aging
Authors: Liu Mojun , Ding Yifu , Wang Minghai , Li Shanjun , Liu Weihua , Wang Bo
Published: April 2003

Novolac epoxy resins cured with novolac resin, novolac acetate resin, novolac butyrate resin, and novolac phenylacetate resin named as EP, EPA, EPB, and EPP, respectively, were prepared. Their physical aging behavior at a Tg‐30 °C (30 °C below glass‐transition temperature) was examined by positron annihilation lifetime spectroscopy and differential scanning calorimetry. The ortho‐positronium annihilation lifetime τ3 variation extent of EP is less apparent than that of the other three esterified samples during physical aging. The time dependence of ops intensity I3 agreed with the Kohlrausch‐Williams‐Watts (KWW) equation. The relaxation time (τ0) and nonexponential parameter were calculated. The free volume and enthalpy relaxation rate characterized by the reciprocal of τ0 and ∂ΔH/∂logt, respectively, exhibit the same order—EPP > EPB > EPA > EP. These results suggest that the extend and rate of relaxation are not only related to the frozen free volume produced by quenching but also significantly influenced by segmental mobility of the network that attributed to the side‐group flexibility and their interaction with networks. This work also supports the fact that side‐group flexibility and the free‐volume fraction and distribution act in concert to control the water‐diffusion behavior in epoxy networks. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 1135–1142, 2003
Surface polarity of cellulose derivates observed by coumarin 151 and 153 as solvatochromic and fluorochromic probes
Authors: Fischer Kristin , Prause Silvio , Spange Stefan , Cichos Frank , Von Borczyskowski Christian
Published: April 2003

Solvent‐dependent ultraviolet–visible (UV–vis) absorption and Stokes shifts including strong hydrogen‐bond‐donating (HBD) solvents such as 2,2,2‐trifluoroethanol and 1,1,1,3,3,3‐hexafluoro‐2‐propanol of two coumarine dyes (Co 151 and Co 153) were analyzed with multiple‐square analyses of linear solvation energy relationships and the Kamlet–Taft solvent parameter set to α (HBD capacity), β (hydrogen‐bond‐accepting capacity), and π* (dipolarity/polarizability). The UV–vis absorption and emission spectra of Co 151 and Co 153 were measured when adsorbed on various polysaccharides such as different cellulose batches, carboxymethylcelluloses with different degrees of substitution, and chitine. As a result of this evaluation, Co 153 is recommended as an alternative UV–vis probe for evaluating the dipolarity/polarizability of cellulose and cellulose derivates. Multiple adsorption of Co 153 on Linters cellulose took place indicating a wide‐surface polarity distribution, which makes the determination of a rigid polarity parameter questionable. Thus, fluorescence measurements of adsorbed Co 153 are suitable to detect inhomogenities on a surface but not for the determination of empirical polarity parameters. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 1210–1218, 2003
Realization of the universal‐NOT gate and of the universal quantum cloning
Authors: Sias C. , Sciarrino F. , De Martini F.
Published: April 2003

An arbitrary quantum state cannot be “cloned” perfectly, i.e. reproduced with “fidelity” F = 1 into M > 1 states identical to the original by any conceivable physical device. The main root of this impossibility resides in the linearity of quantum mechanics. A second “quantum impossibility” process, based on the complete positivity character of any quantum operation and conceivably subtly related to the first one, forbids the realization of a universal NOT gate i.e. one that flips exactly any input qubit into an orthogonal one. A detailed investigation of these results, representing the most fundamental difference between classical and quantum information, indeed can reveal the detailed structure of the latter one. We report an experimental demonstration of the process of cloning of N = 1 input qubit into M = 2 output qubits by a quantum‐injected optical parametric amplifier OPA. By the same apparatus the realization of a universal NOT gate is also demonstrated. The two processes will be found to be “universal” and optimal, i.e. the measured fidelity of both processes F < 1 will be found close to the theoretical values.
Single trapped ions interacting with low‐ and high‐finesse optical cavities
Authors: Eschner J. , Raab C. , Mundt A. , Kreuter A. , Becher C. , Schmidt‐Kaler F. , Blatt R.
Published: April 2003

The presence of mirrors modifies both the coherent coupling of an atom to a light mode and its spontaneous emission into the mode [1]. We study such cavity QED effects experimentally with single ions and optical cavities. We focus on two examples which are equally interesting as fundamental systems and for application in quantum information processing. (i) By retroreflecting the fluorescence of a single trapped Ba+ ion with a mirror 25 cm away, we observe inhibition and enhancement of the atom's spontaneous emission. When two ions are trapped, the distant mirror creates super‐ and subradiance. (ii) With a single trapped Ca+ ion we demonstrate coherent coupling of its narrow S1/2 – D5/2 “qubit” transition to a mode of a high‐finesse optical cavity. We also achieve deterministic coupling of the cavity standing wave to the ion's vibrational state by controlling the ion's position with nanometer‐precision and selectively exciting vibrational state‐changing transitions.
Quantum interferometry with intense optical pulses
Authors: Leuchs G. , Silberhorn C. , Glöckl O. , Marquardt C. , Korolkova N.
Published: April 2003

For intense optical pulses the optical Kerr interaction in matter such as an optical fiber is large enough to generate quantum states of light with significant non‐classical properties. On this basis pairs of entangled light pulses have been generated. This entanglement can be used for novel schemes in high precision interferometry and for quantum communication protocols such as quantum dense coding.
About the use of entanglement in the optical implementation of quantum information processing
Authors: Paris M.G.A. , D'Ariano G.M. , Lo Presti P. , Perinotti P.
Published: April 2003

We review some applications of entanglement to improve quantum measurements and communication, with the main focus on the optical implementation of quantum information processing. The evolution of continuos variable entangled states in active optical fibers is also analyzed.
Ty3/gypsy‐like retrotransposons in Candida albicans and Candida dubliniensis: Tca3 and Tcd3
Authors: Goodwin Timothy J. D. , Dalle Nogare Damian E. , Butler Margaret I. , Poulter Russell T. M.
Published: April 2003

Ty3/gypsy retrotransposons are a widespread group of eukaryote mobile genetic elements. They are similar in structure to, and may be ancestors of, the vertebrate retroviruses. Here we describe the first Ty3/gypsy retrotransposons from the pathogenic yeasts Candida albicans and Candida dubliniensis, which we refer to as Tca3 and Tcd3, respectively. Tca3 was first identified in a variety of strains as an element lacking a large part of its coding region. Comparative analyses between C. albicans and C. dubliniensis allowed us to identify the closely related full‐length Tcd3 element, and, subsequently, the full‐length Tca3 elements. The full‐length versions of Tca3 and Tcd3 are broadly similar in structure to other Ty3/gypsy elements, but have several features of special interest, e.g. both elements appear to have a novel mechanism for priming minus‐strand DNA synthesis, probably involving conserved secondary structures adjacent to the 5′ LTRs. Also, while closely related to each other, the two elements appear to be fairly distantly related to other known Ty3/gypsy‐like elements. Finally, the occurrence of the internally deleted forms of Tca3 in many strains raises interesting questions concerning the evolution of these transposable elements in Candida and the evolution of Candida itself. The sequences reported in this paper have been assigned GenBank Accession Nos AF499463, AF499464 and AF510498. Copyright © 2003 John Wiley & Sons, Ltd.
Purification and characterization of the Rieske iron‐sulfur protein from the thermoacidophilic crenarchaeon Sulfolobus acidocaldarius
Authors: Schmidt C.L. , Anemüller S. , Teixeira M. , Schäfer G.
Published: April 2003

The previously detected Rieske iron‐sulfur protein from the membranes of the thermoacidophile Sulfolobus acidocaldarius [Anemüller, S., et al. (1993) FEBS Lett. 318, 61–64] was purified to electrophoretic homogeneity and the N‐terminal amino acids determined. The apparent molecular weight was estimated to be 32 kDa. The reduced protein displays a rhombic EPR spectrum with gxyz = 1.768, 1.895, 2.035. The average g‐value of 1.902 is typical for nitrogen ligand‐containing clusters. EPR spin quantification and the iron content indicate the presence of one [2Fe‐2S] cluster. The purified protein displaus ubiquinol cytochrome c reductase activity. The pH optimum of this reaction is temperature dependent and was determined to be pH 7 at 56°C. The results presented in this study clearly prove that the Sulfolobus Rieske protein belongs to the family of the true Rieske iron‐sulfur proteins.
Specificity of the purified inositol (1,3,4,5) tetrakisphosphate‐binding protein from porcine platelets
Authors: Cullen Peter J. , Chung Sung-Kee , Chang Young-Tae , Dawson Alan P. , Irvine Robin F.
Published: April 2003

The specificity of the inositol 1,3,4,5‐tetrakisphosphate binding protein purified from porcine platelets [Cullen et al. (1995) Biochem. J. 305, 139–143] was examined using all the isomers of myo‐inositol tetrakisphosphate. From the relative potencies of these compounds it appears that phosphorylation of the 1, 3 and 5 positions is essential for high affinity binding, that there is some tolerance of phosphorylation of the 6‐hydroxyl, but none of a phosphate in the 2‐position, and that phosphorylation of the 4‐hydroxyl has very little influence. The binding of Ins(1,3,4,5)P4 was not appreciably altered by physiological Mg2+ concentrations, and the pH dependence of binding under physiological conditions showed a decline from pH 5.5 to pH 9.0.
Melanin‐concentrating hormone binding to mouse melanoma cells in vitro
Authors: Drozdz Roma , Siegrist Walter , Baker Bridget I. , Chluba-de Tapia Johanna , Eberle Alex N.
Published: April 2003

An analogue of human melanin‐concentrating hormone (MCH) suitable for radioiodination was designed in which Tyr13 was replaced by Phe and Val19 by Tyr. The resulting monoiodinated [125I][Phe13,Tyr19]‐MCH radioligand was biologically active and led to the discovery of high‐affinity binding sites on mouse B16‐F1, G4F and G4F‐7 melanoma cells. Saturation binding analysis with G4F‐7 cells revealed 1090 MCH receptors per cell and a K
D of 1.18 × 10−10 mol/l. Receptors for MCH were also found on rat PC12 phaeochromocytoma cells, human RE melanoma cells and COS‐7 cells. Competition binding analyses with other peptides such as α‐MSH, NPY and PACAP demonstrated that MCH receptor binding is specific. rANF(1–28) was found to be a weak competitor of MCH, indicating topological similarities between MCH and rANF(1–28) when interacting with MCH receptors.
Changes in redox affect the activity of erythropoietin RNA binding protein
Authors: Rondon Isaac J. , Scandurro Aline B. , Wilson Russell B. , Beckman Barbara S.
Published: April 2003

We have previously identified a cytosolic protein, erythropoietin RNA binding protein (ERBP), which is up‐regulated in certain tissues in response to hypoxia. To further characterize the interaction of ERBP and erythropoietin (EPO) mRNA, we have examined the role of reduction‐oxidation in the EPO mRNA binding mechanism of ERBP isolated from human hepatoma cells (Hep3B). Reducing agents dithiothreitol (DTT) and 2‐mercaptoethanol (2‐ME) increased ERBP binding activity in a concentration‐dependent manner, whereas the oxidizing agent, diamide, abolished ERBP binding activity. In addition, treatment of Hep3B cell lysates with the irreversible sulfhydryl alkylating agent N‐ethylmaleimide resulted in inhibition of the EPO mRNA‐ERBP complex. Taken together, these findings suggest that sulfhydryl groups may play a role in vivo in the regulation of EPO production through the modulation of ERBP binding activity.
Hydrophobic cluster analysis and secondary structure predictions revealed that major and minor structural subunits of K88‐related adhesins of Escherichia coli share a common overall fold and differ structurally from other fimbrial subunits
Authors: Méchin Marie-Claire , Bertin Yolande , Girardeau Jean-Pierre
Published: April 2003

The structural relatedness of K88‐related major and minor subunits was deduced from their sequences by hydrophobic cluster analysis (HCA) and secondary structure predictions produced by the profile neural network prediction program (PHD) on multiple sequence alignments. Although the weak residue identity between major and minor subunits is evidence of a high evolutionary distance, an overall structural similarity was observed. In addition, clear amphipathic conformations were conserved in predicted secondary structure. On the basis of this predicted structural similarity, a schematic 2D model of ClpG subunit was developed.
The TRH‐like peptides in rabbit testis are different from the TRH‐like peptide in the prostate
Authors: Linden Helena , del Rio Garcia Jesus , Huber Ariana , Kreil Günther , Smyth Derek
Published: April 2003

Human seminal fluid contains a number of tripeptide amides with similar structures to thyrotropin releasing hormone (TRH), two of which have been identified as pGlu‐Glu‐Pro amide and pGlu‐Phe‐Pro amide. To determine whether these peptides originate in the same tissues and have the same molecular origin, TRH‐immunoreactive peptides were extracted from the prostate and testis of the rabbit, purified by ion exchange chromatography and HPLC, and identified by co‐chromatography with 3H‐labelled marker peptides. In addition, trypsin digestion was used to release TRH‐like tripeptides from N‐extended forms of these peptides. The sole TRH‐like peptide in the prostate was shown to be pGlu‐Glu‐Pro amide; it was not accompanied by a detectable amount of pGlu‐Phe‐Pro amide. The prostate also appeared to contain a very small amount of N‐extended forms of these peptides. In contrast to the prostate, the testis contained high concentrations of N‐extended forms of pGlu‐Phe‐Pro amide but essentially no tripeptide. The testis also contained N‐extended forms of two other neutral TRH‐like peptides which were less hydrophobic than pGlu‐Phe‐Pro amide. Neither the prostate nor the testis contained a significant amount of TRH. The results show that in the rabbit the TRH‐like peptides pGlu‐Glu‐Pro amide and pGlu‐Phe‐Pro amide occur in different tissues and appear to be formed from different precursors.
Yeast Cls2p/Csg2p localized on the endoplasmic reticulum membrane regulates a non‐exchangeable intracellular Ca2+ pool cooperatively with calcineurin
Authors: Tanida Isei , Takita Yoko , Hasegawa Akira , Ohya Yoshikazu , Anraku Yasuhiro
Published: April 2003

Saccharromyces cerevisiae CLS2 gene product (Cls2p) that is localized on the endoplasmic reticulum is important for the regulation of intracellular Ca2+ in a compartment distinct from the vacuole. Using a vma3 mutation that impairs the Ca2+ sequestering activity into the vocuole, we have shown that the cls2 mutation results in 3.4‐fold increase in the Ca2+ pool that is not exchangeable with extracellular Ca2+. Accumulation of Ca2+ within the cls2 cells is synergistically elevated by the addition of immunosuppressant, FK506. Moreover, in the vma3 background, toxicity caused by the cls2 mutation is greatly enhanced by FK506. Given that FK506 inhibits the calcineurin activity, Cls2p likely functions in releasing Ca2+ flux from the endoplasmic reticulum, somehow cooperating with calcineurin.
Transacylase‐like structure and its role in substrate channeling of 6‐hydroxymellein synthase, a multifunctional polyketide biosynthetic enzyme in carrot cell extracts
Authors: Kurosaki Fumiya
Published: April 2003

6‐Hydroxymellein synthase, a multifunctional polyketide biosynthetic enzyme of carrot, lost the binding ability toward its co‐substrates, acetyl‐ and malonyl‐CoAs, by the treatment with the blocking reagents for serine‐OH. In contrast, the enzyme retained the binding ability even when the two SH groups at the reaction center (cysteine‐SH of the condensation enzyme and cysteamine‐SH of acyl carrier protein) were blocked, and one substrate bound to the SH‐blocked enzyme was readily replaced by the other. It appeared that the cysteine‐SH accepted only acetyl moiety while cysteamine‐SH was preferentially malonylated in the presence of both of the substrates. These results suggest that transacylase‐like domain is involved in the structure of 6‐hydroxymellein synthase as a common primary binding site of its co‐substrates, and acetyl and malonyl moieties are properly channeled from their CoA esters to cysteine‐SH and acyl carrier protein‐SH via this domain, respectively.
20S proteasome from LMP7 knock out mice reveals altered proteolytic activities and cleavage site preferences
Authors: Stohwasser R. , Kuckelkorn U. , Kraft R. , Kostka S. , Kloetzel P.-M.
Published: April 2003

20S proteasomes of tissues from LMP7 knock out mice which show reduced MHC class I restricted antigen presentation were analyzed with regard to their subunit composition, peptide hydrolyzing activity and their ability to cleave a synthetic 25‐mer polypeptide. LMP7 deficiency results in an enhanced incorporation of subunit MB1 and in a 2–3.8‐fold increase in V
max for the Suc‐LLVY‐MCA hydrolyzing activity. Since LMP7 deficiency also affects the cleavage site preference of 20S proteasomes the reduced MHC class I antigen presentation of LMP7 knock out mice is most likely due to an impairment in peptide generation.
Femtosecond kinetics of electron transfer in the bacteriochlorophyllM‐modified reaction centers from Rhodobacter sphaeroides (R‐26)
Authors: Yakovlev A.G. , Shkuropatov A.Ya. , Shuvalov V.A.
Published: April 2003

Formation of the vibronic wavepacket by 90‐fs excitation of the primary electron donor P in bacteriochlorophyllM‐modified reaction centers is shown to induce nuclear motions accompanied by (1) oscillation of the stimulated emission from excited primary electron donor P∗ and (2) wavepacket motions leading to electron transfer at 293 K from P∗ to bacteriochlorophyll (BL) and then to bacteriopheophytin (HL). The latter motions have low frequency (about 15 cm−1) and are related to protein‐nuclear motions which are along the reaction coordinate. When the wavepacket approaches the intersection of the reactant (P∗BL) and product (P+BL−) potential energy surfaces (∼1.5 ps delay), about 60% of P∗ is converted to the P+BL− state. The P+HL− state formation is delayed by ∼2 ps with respect to that of P+BL−. It is suggested that the wavepacket is transferred to and moves also slowly on the P+BL− potential energy surface and approaches the intersection of the surfaces of P+BL− and P+HL− within ∼2 ps (∼8 cm−1), indicating the electron transfer to HL.
Characterization of the dystrophin‐syntrophin interaction using the two‐hybrid system in yeast
Authors: Castelló Anna , Brochériou Valérie , Chafey Philippe , Kahn Axel , Gilgenkrantz Hélène
Published: April 2003

The carboxy‐terminal region of dystrophin has previously been shown to interact directly with α1 syntrophin, a cytoplasmic component of the dystrophin‐glycoprotein complex, by in vitro biochemical studies such as overlay assay or immunoprecipitation. Using the two‐hybrid system, we have isolated from a human heart cDNA library the entire coding sequence of human α1 syntrophin, therefore confirming for the first time this interaction via an in vivo approach. In addition, we have reduced the interaction domain to the distal half of α1 syntrophin.
Constructing an efficient trans‐acting genomic HDV ribozyme
Authors: Kawakami Junji , Yuda Kazuhiro , Suh Young-Ah , Kumar Penmetcha K.R. , Nishikawa Fumiko , Maeda Hidekatsu , Taira Kazunari , Ohtsuka Eiko , Nishikawa Satoshi
Published: April 2003

We have engineered a genomic HDV ribozyme to construct several trans‐acting ribozymes for use in trans to cleave target RNAs. Among the 10 different combinations attempted, only HDV88‐Trans had cleavage activity on the 13‐nucleotide substrate, R13, in vitro. To improve the cleavage efficiency, at least in vitro, of the HDV88‐Trans ribozyme (kclv = 0.022 min−1), we have constructed several variants that differ in forming stem II (length) in the pseudoknot secondary structure model. When cleavage rate constants were analyzed and compared among variants of HDV88‐Trans, HDV88‐Trans‐4 yielded kclv = 1.7 min−1. HDV88‐Trans‐4 thus represents the highest active genomic HDV ribozyme that functions in trans thus far constructed, and has activity under physiological conditions (pH 7.1 at 37°C with 1 mM of MgCl2).
Modified, cyclic dodecapeptide analog of neuropeptide Y is the smallest full agonist at the human Y2 receptor
Authors: Rist Beate , Zerbe Oliver , Ingenhoven Nikolaus , Scapozza Leonardo , Peers Chris , Vaughan Peter F.T. , McDonald Ruth L. , Wieland Heike A. , Beck-Sickinger Annette G.
Published: April 2003

In order to stabilize the C‐terminal dodecapeptide of neuropeptide Y (NPY) we replaced Leu28 and Thr32 by Lys and Glu, respectively, and subsequently linked these residues by lactamization. This peptide analog of NPY shows a more than 100‐fold increase in affinity compared to the C‐terminal linear dodecapeptide in receptor binding studies performed at human neuroblastoma cells SMS‐KAN, which exclusively express the Y2 receptor subtype. Signal transduction was investigated by measuring Ca2+ current inhibition in human SH‐SY5Y cells and cyclic [Lys28‐Glu32] NPY Ac‐25–36 and NPY were shown to be equipotent in this assay. Thus, this molecule is the smallest Y2 receptor selective full agonist of NPY. Using 2D‐NMR experiments and molecular modelling techniques, the structures of the linear and cyclic peptides have been investigated and significant differences have been found, which may explain the improvement in biological activity. Thus, a model of the bioactive conformation of NPY at the human Y2 receptor is suggested.
Reconstitution of proteasome activator PA28 from isolated subunits: optimal activity is associated with an α,β‐heteromultimer
Authors: Kuehn Lothar , Dahlmann Burkhardt
Published: April 2003

PA28, a 200 kDa activator of 20S proteasomes, was purified from human placenta and was gel electrophoretically resolved into two different subunits, α and β. In reconstitution experiments, α‐subunits alone were found to re‐associate forming homooligomers with an M

r
of about 200 kDa, which elicit a stimulatory effect on proteasomal peptide‐hydrolyzing activity, albeit at a moderate level. Under the same conditions, isolated β‐subunits were neither found to associate nor did they display stimulatory activity. Significantly, when both α‐ and β‐subunits were present in the reconstitution assay, heteromultimers formed, concomitant with a marked increase in stimulatory activity when compared with that of α‐homooligomers. The reconstituted PA28α,β protein is indistinguishable from purified PA28 by several criteria: it displays the same molecular mass, shows the same abundance of α‐ and β‐subunits and has a similar stimulatory activity toward 20S proteasomes. These results indicate that optimal PA28 activity is associated with a heteromultimeric structure which contains the α‐ and β‐subunits in fixed stoichiometry, most likely as an α
3
β
3‐heterohexamer.
A molecular model for human Big‐Endothelin‐1 (Big ET‐1)
Authors: Peto Heather , Corder Roger , Janes Robert W. , Wallace B.A.
Published: April 2003

A molecular model has been developed for human Big Endothelin‐1, which is the immediate precursor to the potent vasoconstrictor polypeptide endothelin‐1 and the target of the highly specific endothelin converting enzyme. This model is produced by a threading algorithm protocol and is consistent with all the currently available structural and biochemical data for this molecule.
Isolation and characterization of a novel monomeric zinc‐ and heme‐containing protein from bovine brain
Authors: Fundel Sibylle M. , Pountney Dean L. , Bogumil Ralf , Gehrig Peter M. , Hasler Daniel W. , Faller Peter , Vašák Milan
Published: April 2003

An acidic zinc‐ and heme‐containing protein was isolated from the soluble fraction of bovine brain and has been purified to homogeneity. The zinc‐heme protein is a monomeric globular protein with a molecular mass of 31200 Da as determined by electrospray mass spectrometry. The protein was isolated with 0.90±0.05 zinc per protein and with substoichiometric amounts of heme. Amino acid sequences of four peptides (ca. 20% of the protein) were determined and the comparison of these sequences with those of protein and gene sequence databases revealed no significant correlation with any known protein. Thus, it is concluded that it is a novel protein of currently unknown biological function.
Specific photoaffinity labelling of a ferripyoverdin outer membrane receptor of Pseudomonas aeruginosa
Authors: Ocaktan Aydin , Schalk Isabelle , Hennard Christophe , Linget-Morice Caroline , Kyslik Pavel , Smith Anthony W. , Lambert Peter A. , Abdallah Mohamed A.
Published: April 2003

In order to identify and characterize the receptors involved in pyoverdin‐mediated iron transport in Pseudomonas aeruginosa ATCC 15692, a photoactivatable siderophore has been synthesized. In the dark, this probe is stable and is able to promote iron transport at the same rate as the native pyoverdin. Under irradiation at 312 nm, the molecule is photodecomposed and a clear inhibition of the iron transport is observed. With the radioactive form of this photoactivatable probe, we were able to visualize on a SDS‐PAGE gel a labelled protein of approximately 90 kDa molecular mass, which is very likely the FpvA receptor or a yet unknown pyoverdin receptor.
A natural variant of bovine dopamine β‐monooxygenase with phenylalanine as residue 208: purification and characterization of the variant homo‐ and heterotetramers of (F208)4 and (F208)2(L208)2
Authors: Narita Mitsuhiro , Ishida Tetsuo , Tomoyoshi Tadao , Nozaki Mitsuhiro , Horiike Kihachiro
Published: April 2003

Bovine dopamine β‐monooxygenase was purified from each of 18 individual adrenal glands by the method we have developed for the rapid purification of the enzyme from a single adrenal gland. Differential peptide mapping of the 18 enzyme preparations following fluorescence labeling of their cysteine residues revealed the presence of a novel variant with Phe as residue 208 in 14 adrenal glands; seven of them were homozygous for the variant allele and the remaining seven heterozygous. The variant enzyme was a tetramer and exhibited kinetic and structural properties similar to those of the wild‐type tetramer (L208)4. These results indicate an allelic polymorphism and codominant expression of the two alleles of the enzyme gene.
Isolation and partial characterization of a small chitin‐binding lectin from mistletoe (Viscum album)
Authors: Peumans Willy J. , Verhaert Peter , Pfüller Uwe , Van Damme Els J.M.
Published: April 2003

A novel lectin, called VisalbCBA, was isolated from European mistletoe (Viscum album). This lectin differs completely from the classical galactose/N‐acetylgalactosamine‐binding mistletoe lectins MLI, MLII and MLIII. Biochemical analyses indicated that VisalbCBA is a dimeric protein composed of two identical subunits of approx. 10 kDa. VisalbCBA exhibits specificity towards oligomers of N‐acetylglucosamine and shows sequence homology to the previously isolated chitin‐binding plant proteins. Although VisalbCBA is less toxic than the other mistletoe lectins, it definitely exhibits cytotoxic properties. The possible involvement of VisalbCBA in the biological and therapeutic effects of mistletoe is discussed.
Isolation of the active form of RAC‐protein kinase (PKB/Akt) from transfected COS‐7 cells treated with heat shock stress and effects of phosphatidylinositol 3,4,5‐trisphosphate and phosphatidylinositol 4,5‐bisphosphate on its enzyme activity
Authors: Matsuzaki Hidenori , Konishi Hiroaki , Tanaka Motonari , Ono Yoshitaka , Takenawa Tadaomi , Watanabe Yutaka , Ozaki Shoichiro , Kuroda Shun'ichi , Kikkawa Ushio
Published: April 2003

RAC‐protein kinase (PKB/Akt) has been shown to be activated by growth factor stimulation as a downstream target of phosphatidylinositol 3‐kinase and also by heat shock through a pathway independent of phosphatidylinositol 3‐kinase. RAC‐protein kinase was purified by antibody affinity chromatography from COS‐7 cells transfected with the epitope‐tagged expression plasmid. The protein kinase activity of RAC‐protein kinase purified from heat‐treated cells was 9‐fold higher than the enzyme isolated from untreated control cells. Phosphatidylinositol 3,4,5‐trisphosphate did not enhance the activity of RAC‐protein kinase purified from either heat‐treated cells or control cells, whereas phosphatidylinositol 4,5‐bisphosphate suppressed the enzyme isolated from heat‐treated cells. These results indicate that RAC‐protein kinase may interact with phosphoinositides, however, it could not be activated by simple association with the product of phosphatidylinositol 3‐kinase reaction.
Bringing judgment into combination forecasts
Authors: Sanders Nada R. , Ritzman Larry P.
Published: April 2003

This research investigates the benefits in forecast accuracy by combining judgmental forecasts with those generated by statistical models. Our study differs from prior research efforts in this area along two important dimensions. First, two different types of judgmental forecasts are evaluated for combination with statistical forecasts — one based on contextual knowledge and one based on technical knowledge. Contextual knowledge is information gained through experience on the job with the specific time series and products being forecasted. Technical knowledge is information gained from education on formal forecasting models and data analysis. Second, we investigate the conditions under which adding judgment to combination forecasts helps the most. Specifically, we test the improvement as a function of time series variability.

Our results show that judgmental forecasts based on contextual knowledge, rather than technical knowledge, are the better input into combination forecasts. Bringing judgmental forecasts based on contextual knowledge into combination forecast improves forecast accuracy over the individual statistical and judgmental forecasts. However, the benefit attained from including contextual knowledge in the combination depends on the amount of inherent variability in the time series being forecast. More contextual knowledge is needed for combination forecasts if a time series has more data variability. If the amount of variability is low, less emphasis should be given to contextual knowledge when making combination forecasts. In general, our findings suggest a linear relationship between the amount of contextual knowledge needed and data variability.