bluuebunny/crossref_metadata_2025_split huggingface dataset:
A prospective evaluation of the Essen titanium stapes prosthesis*
Authors: Dost P. , Arweiler‐Harbeck D. , Jahnke K. 
Published: March 2005

Objectives:  This is the first clinical trial to evaluate the suitability of a new titanium stapes prosthesis, which we developed jointly with the Kurz Company (Dußlingen).Design:  In a prospective clinical study, patients with otosclerosis underwent stapes surgery using our new titanium stapes prosthesis during a period of 14 months. One year after surgery pre‐ and postoperative audiograms were performed and all patients participated in a structured interview.Setting:  Tertiary otorhinolaryngological university departmentParticipants:  Of 49 patients with otosclerosis, entering the study, two patients were excluded, because they were not located any more.Main outcome measures and results:  All patients experienced a hearing improvement of 21 dB on average except one patient. Sixty percentage of patients achieved a reduction of the air–bone gap to less than 10 dB and 31% of patients having their air–bone gap closed to within 20 dB – averaged across 0.5, 1.0, 2.0 and 4 kHz. The hearing level improved significantly in the air and in the bone conduction thresholds.Conclusions:  This paper presents our first ‘1 year postimplantation’ results of our titanium stapes prosthesis. We consider the development of this implant to be beneficial. The results confirm significant improvement in hearing status and tinnitus levels.
Quality of life and voice following endoscopic resection or radiotherapy for early glottic cancer
Authors: Loughran S. , Calder N. , MacGregor F.B. , Carding P. , MacKenzie K. 
Published: March 2005

Objectives:  To assess whether proposed voice and quality of life (QoL) outcome measures were likely to be acceptable to patients previously treated for early glottic cancer by either radiotherapy or endoscopic resection, as well as looking for differences in QoL and voice between treatments.Design:  Questionnaire‐based cohort study.Setting:  Secondary care, three centres.Participants:  All patients treated for T1a or in situ glottic carcinoma between 1997 and 2003. Fifty‐three patients were identified; those who had undergone salvage surgery or radiotherapy were excluded. A proportion refused to participate or could not be contacted and two patients had died of unrelated causes. Thirty‐six patients completed the trial with 18 from each treatment arm.Main outcome measures:  Quality of voice as assessed by three questionnaires, Voice Handicap Index (VHI), Vocal Performance Questionnaire (VPQ), Voice Symptom Score (VoiSS) and perceptual analysis of voice by Grade, Roughness, Breathiness, Asthenia and Strained (GRBAS) assessment of vocal recordings. Quality of life as assessed by the Hospital Anxiety and Depression Scale (HADS), University of Washington Quality of Life Questionnaire (UW‐QoL), and the Functional Assessment of Cancer Therapy (FACT) questionnaire.Results:  All patients included in the trial were able to complete the questionnaires; however, 19% required assistance of some kind. GRBAS assessment showed no difference between groups for any criteria. All QoL questionnaires gave equivalent good scores. All of the voice questionnaires showed no statistical difference between groups except for the emotional subscale of the VoiSS which showed a significantly better score for the radiotherapy arm (P = 0.04).Conclusion:  All outcome measures were applicable and acceptable to the patient group. Overall QoL and voice appears similar despite treatment arm, apart from the emotional subscale of the VoiSS. A randomized controlled trial is required to further assess this question.
Dephosphorylation of Pyrimidine Nucleotides in the Soluble Fraction of Homogenates from Normal and Regenerating Rat Liver
Authors: Fritzson P. 
Published: March 2005

The dephosphorylation of the pyrimidine nucleotides UMP, CMP, dUMP, dCMP, and dTMP was determined in the soluble fraction of homogenates from normal rat liver and from regenerating liver during an 8‐day period after partial hepatectomy. The dephosphorylations were assayed at optimal pH in the presence of optimal concentrations of Mg++ ions and substrate. β‐Glycerophosphate was included among the substrates for measurement of non‐specific phosphatase activity. The intracellular origin of the enzymes was investigated by determining the rate of their appearance in the soluble fraction during homogenization and by estimating the rate at which the lysosomes were disrupted.The results showed that the dephosphorylation of the deoxyribonucleotides was mainly due to non‐specific acid phosphatase activity. This enzyme and the alkaline phosphatase activity were found to be localized in the soluble space of the liver cell. The dephosphorylation of the ribonucleotides was due largely to a specific 5′‐nucleotidase. The enzyme was adsorbed or loosely bound to some sedimentable cell constituent at the time of cell disruption, but it was quantitatively released into the soluble fraction during 2 minutes homogenization.During liver regeneration the acid and alkaline phosphatase activities showed slight variations which could not be related to the growth rate of the liver. In contrast, the 5′‐nucleotidase activity showed distinct, cyclic variations which were inversely related to the growth rate. The variations in the 5′‐nucleotidase activity were strikingly similar to the activity variations of uracil reductase and N‐carbamoyl‐β‐alanine amidohydrolase observed previously in regenerating liver.
Biosynthesis of Aristolochic Acid
Authors: Schütte H. R. , Orban U. , Mothes K. 
Published: March 2005

Some Aristolochia species were investigated for the presence of aristolochic acid and magnoflorine. In all cases these two compounds were found in the roots and rhizomes of the plants,[4‐14C]‐Tetrahydropapaverine · HCl feeding to Aristolochia sipho gave no radioactive aristolochic acid I. Feeding of [4‐14C]‐norlaudanosoline‐HCl yielded radioactive aristolochic acid I. The carboxyl group contained 69% of the radioactivity.
Synthèse du poly U par la RNA polymérase avec l'acide octoadénylique (hepta adénylyl‐(3′,5′)‐adénosine) comme matrice
Authors: Hayes D. H. , Cukier R. , Gros F. 
Published: March 2005

The octoadenylic acid (Ap)7A serves as a template for poly U synthesis by Escherichia coli RNA polymerase. Two types of polymerisation reaction can be observed by varying the divalent cation concentration in the reaction mixture. High divalent cation concentrations (4–6 × 10−3 M MnCl2) permit a limited poly U synthesis which stops when the quantity of UTP polymerised corresponds to approximately 2 moles per mole of template A. When reaction is carried out at 27° polymerisation stops completely after the plateau level of 2 U/A is reached but at 37° it continues slowly beyond this point. Addition of template to an incubation mixture in which poly U synthesis has stopped causes reaction to start again, and to continue to a new plateau corresponding to polymerisation of 2 moles of UTP per mole of additional template A. These results show that at high divalent cation concentrations poly U synthesis stops because the template is consumed, probably by its immobilisation in a complex of the type poly A–2 poly U. In media containing low concentrations of divalent cations (10−3 M MnCl2) poly U synthesis is not limited by the amount of template used. Under these conditions the template functions catalytically. A biphasic incorporation curve is observed with a small reduction in the reaction rate at a point corresponding to the polymerisation of 2–3 moles of UTP per mole of template A. Beyond this point reaction continues at a linear rate for long periods and incorporations of up to 20 moles of UTP per mole of template A have been observed.The average chain length of the poly U synthesised in the presence of high or low divalent cation concentrations varies between 60 and 160 residues i.e. between 10 and 20 times that of the template. Some evidence has been obtained indicating the progressive elongation of poly U chains as a function of the duration of synthesis but the maximum variation in chain length observed was only twofold.Sedimentation analysis of the reaction products present in incubation mixtures containing both high and low concentrations of divalent cations shows that no significant amount of poly U is free at any time. The poly U is found in fast sedimenting (> 100 S) complexes dissociable by removal of divalent cations or by sodium dodecyl sulphate treatment. Both procedures liberate poly U with a sedimentation coefficient of approximately 10 S.An interpretation of the effects of divalent cation concentration on the type of reaction catalysed by RNA polymerase is proposed.
Regulation der Biosynthese der aromatischen Aminosäuren in Saccharomyces cerevisiae
Authors: Lingens F. , Goebel W. , Uesseler H. 
Published: March 2005

We have studied the repression of the first enzymes of the main branch and the pathways after the branchpoint in the aromatic biosynthesis of Saccharomyces cerevisiae. Anthranilate synthetase is repressed by l‐tryptophan and prephenate dehydratase by l‐phenylalanine. 3‐Deoxy‐d‐arabinoheptulosonic acid 7‐phosphate (DAHP) synthetases are not repressed by l‐phenylalanine, l‐tyrosine and l‐tryptophan, chorismate mutases are repressed neither by l‐phenylalanine nor by l‐tyrosine, and prephenate dehydrogenase shows no repression by l‐tyrosine. l‐Tryptophan exhibits an induction of the chorismate mutase. Besides chorismate mutase is activated by l‐tryptophan. l‐Phenylalanine exhibits an induction and also an activation of the prephenate dehydrogenase. By simultaneous addition of l‐tryptophan, l‐phenylalanine, and l‐tyrosine p ‐aminobenzoic acid was accumulated and the production of p ‐aminobenzoate synthetase was induced. The tyrosine‐sensitive and phenylalanine‐sensitive isoenzymes of DAHP synthetase belong to the V‐system of the allosteric enzymes. Chorismate mutase and prephenate dehydrogenase are members of the K‐system.In an earlier publication we have discussed the feedback inhibition of the described enzymes. In this paper we discuss the whole events of the regulation phenomena in Saccharomyces cere‐visiae. We also considered the degradation of l‐tryptophan, l‐phenylalanine, and l‐tyrosine to tryptophol, phenylethanol, and tyrosol respectively in connection with the regulatory events.
Comparison of IgG and IgM Antibodies Specific for Uridine
Authors: Jaton J.‐C. , Ungar‐Waron H. , Sela M. 
Published: March 2005

Uridine‐specific IgG and IgM antibodies, obtained by immunization of rabbits with a uridylated synthetic polypeptide, were isolated and purified by the use of a uridine‐acetyl cellulose conjugate as immunosorbent. The IgM antibodies were separated from the IgG antibodies by gel filtration on Sephadex G‐200. Both antibody preparations were pure by ultracentrifugation and immunoelectrophoresis criteria. The precipitating activities of IgM and IgG antibodies were similar on a weight basis, although the equivalence zone in the case of IgM antibody is broader. In spite of its inability to precipitate the homologous antigen, the reduced alkylated IgM subunits were still able to inhibit specifically the homologous precipitation in the U‐pAla — pLys — IgG antibody system. The average association constants for uridine of both IgG and IgM antibodies, measured by the equilibrium dialysis technique, were low and of a similar order of magnitude.The complement fixing ability of purified IgM and IgG anti uridine antibodies upon reaction with the homologous antigen displayed significant differences: low complement fixation activity was found in the IgM fraction either at 4° or at 37°, while a high activity was found in the IgG fraction at both temperatures. The IgM fraction lost all of its ability to fix complement when the macroglobulin was reduced and carboxymethylated. PCA reaction, using a highly immuno‐specifically purified 19 S anti‐uridine antibody, was found to be negative when assayed up to an amount of 100 μg.
Thioredoxin 2: Cleavage with Cyanogen Bromide
Authors: Holmgren A. , Reichard P. 
Published: March 2005

A simple and highly reproducible method for the preparation of thioredoxin from Escherichia coli B was worked out.On treatment with cyanogen bromide thioredoxin was cleaved into two peptides which were separated by chromatography on Sephadex G‐50. The smaller peptide (peptide B) contained 37 amino acids and represented the N‐terminal fragment of thioredoxin, while the larger peptide (peptide A) contained the remaining 71 or 72 C‐terminal amino acids. The cystine and tryptophan residues of thioredoxin were found in peptide B.Both peptides were characterized with respect to amino acid composition and were studied by spectrofluorimetry. The increase in quantum yield of the tryptophan emission resulting from the reduction of the disulfide bridge of peptide B was considerably smaller than the corresponding increase resulting from the reduction of the disulfide bridge of thioredoxin [1].Peptide B was not reduced by TPNH and thioredoxin reductase and showed no activity in the reduction of cytidine diphosphate with ribonucleoside diphosphate reductase from Escherichia coli.
The Role of Phosphatidate Phosphohydrolase in Glyceride Biosynthesis
Authors: Smith M. E. , Sedgwick B. , Brindley D. N. , Hübscher G. 
Published: March 2005

Glyceride biosynthesis castalysed by the mitochondrial fraction of rat liver or by the microsomal fraction of cat intestinal mucosa is greatly stimulated by the supernatant fraction (6,000,000 ×g× min). This stimulation is due to the presence of several factors and evidence is presented that one of these factor is a phosphatidate phosphohydrolase. The catalytic activities of the phosphatidate phosphohydrolases present in the mitochondrial and supernatant fractions were studied using as subxtrates either an aqueous dispersion of phosphatidate or membrane‐bound phosphatidate formed as an intermediate in the biosynthesis of glycerides.The mitochondrial phosphatidate phosphohydrolase has a high activity with aqueous phosphatidate dispersions and a low activity with membrane‐bound phosphatidate present as internal or added substrate. In contrast, the phosphatidate phosphohydrolase of the supernatant fraction has a low activity with aqueous phosphatidate dispersions and a high activity with membrane‐bound phosphatidate.As Mg++ and F− ions are usually included in the assay systems employed for measuring glyceride biosynthesis, the effect of these ions on the particulate and soluble phosphatidate phosphohydrolases was studied to exclude the possibility that the stimulation of glyceride biosynthesis by the phosphohydrolase of the supernatant fraction was due to an artefact. It is suggested that the phosphatidate phosphohydrolase isolated in the supernatant fraction is the major phosphohydrolase activity involved in glyceride biosynthesis.
Isotope Exchange Studies of the Reaction Catalyzed by ATP: Creatine Phosphotransferase
Authors: Morrison J. F. , White A. 
Published: March 2005

The technique of isotope exchange at equilibrium has been used to determine if the nature of the metal‐nucleotide substrate influences the mechanism of the creatine kinase reaction.Studies of the creatine‐phosphocreatine and ADP‐ATP exchanges in the presence of Mg2+, Ca2+ and Mn2+ showed that the initial rates varied with the total metal ion concentration, that approximately equal rates were obtained for the two exchanges under a particular set of conditions for each metal ion and that these rates were affected to only a small extent by the identity of the metal ion.The creatine‐phosphocreatine and nucleoside diphosphate‐nucleoside triphosphate exchange rates with the cytidine, guanosine and uridine nucleotides in the presence of Mg2+ were of a similar magnitude although very much less than those obtained with the adenine nucleotides. The two exchange rates could be considered as being approximately equal only with the cytidine nucleotides us substrates.The results have been interpreted as indicating that the creatine kinase reaction has a rapid equilibrium, random mechanism, irrespective of the nature of the activating metal ion, when adenine nucleotides are used as substrates and also in the presence of the magnesium complexes of the cytidine nucleotides. No definitive conclusions could be reached about the mechanism from the results obtained with the guanosine and uridine nucleotides.The apparent equilibrium constant of the reaction has been shown to be dependent on the total concentration of metal ions. True equilibrium constants for the reaction in the presence of Mg2+ and Ca2+ have been determined.
Konstitution von Fusigen und dessen Abbau zu Δ2‐Anhydromevalonsäurelacton
Authors: Diekmann H. , Zähner H. 
Published: March 2005

Alkaline degradation of fusigen, a sideramine from fungi, yields the known monohydroxamic acid fusarinine. l‐Ornithine and cis‐5‐hydroxy‐3‐methylpentenoic‐2‐acid occur in fusigen in equal amounts, and ornithine is the only amino acid. Amino group(s) with pK 7,1, but no free carboxyl group can be found in fusigen. The calculated equivalent weight is 280, which again points to fusarinine as a structural subunit.By acetylation of fusigen three products are obtained, which can be separated by electrophoresis or chromatography. The titration data of the partially acetylated fusigen and the molecular weight estimation by vapour pressure osmometry of the desferriform of the fully acetylated fusigen show that fusigen is a trimeric fusarinine.These data together with those obtained from IR‐ and NMR‐absorption spectra lead to the proposed structure: three fusarinine molecules are esterified head‐to‐tail to build a 36‐membered ring.The quantitative estimation of all hydroxamic acids in the culture fluid of Fusarium cubense from the 2nd to the 9th day of fermentation and structural studies on some of these compounds revealed the spontaneous degradation of fusigen by ring opening and sequential split‐off of fusarinine units. An analogous degradation pathway starts from N‐acetyl‐fusigen.The Δ2‐anhydromevalonic lactone, found in the cultures of several fungi, seems to stem from the degradation of fusarinine. The total yield of Δ2‐anhydromevalonic lactone can be increased severalfold by treatment of the culture fluid with hydrochloric acid prior to extraction.
Evidence for a Faster Degradation of an Atypical Hydroxyproline and Hydroxylysine Deficient Collagen Formed under the Effect of 2,2′‐Dipyridyl
Authors: Hurych J. , Cchvapil M. , Tichý M. , Beniač F. 
Published: March 2005

Chick embryo skin slices were incubated with [14C]proline without and in the presence of 1 mM 2,2′‐dipyridyl. Collagen was isolated and digested with collagenase. The kinetics of the splitting off of small radioactive fragments showed a more rapid degradation of the undenatured hydroxyproline and hydroxylysine deficient collagen which had been formed in the presence of 2,2′‐dipyridyl, compared to the control sample. No differences in the rate of digestion have been found between heat denatured control and atypical collagen.
In parallel experiments the rate of collagenase degradation of proline rich Ascaris cuticle collagen was several times greater than that of calf skin collagen.
Skin slices incubated simultaneously with [14C]glutamic acid and 0.5 mM dipridyl showed more radioactive proline than did control samples. This is further evidence for increased degradation of atypical collagen because under these experimental conditions the metabolism of non‐collagenous protein was the same in control and dipyridyl treated samples. It is apparent that hydroxyproline and hydroxylysine decicient collagen is more susceptible to the action of collagenase and other tissue proeases.
Associations de poly A et poly U en milieu acide
Authors: Massoulié J. 
Published: March 2005

In this paper the thermal stability of poly (A + U) and poly (A + 2U) in acid solution is studied. It is known that at low pH poly A associates with itself to form a double protonated helical structure, poly (A + A). The dissociation Tm's of poly (A + U) and poly (A + 2U) do not vary with pH as long as they are higher than TmA [the dissociation temperature of poly (A + A)]. TmA itself varies with the pH (it increases as the pH is lowered) and thus, there are pH values at which TmA equals the dissociation Tm's of the complexes poly (A + U) and poly (A + 2U). Below such pH's, Tm2–3, Tm3–1, Tm2–1 decrease as the pH becomes more acid. In contrast, Tm3–2 does not exhibit such a variation. The transition corresponding to this last Tm [the partial dissociation of poly (A + 2U) into poly (A + U)] does not change the concentration of “free” poly A.We conclude that the change in thermal stability of the complexes in this region of pH is due only to their competition with poly (A + A) and that poly (A + U) and poly (A + 2U) are not modified.At low ionic strength, the transitions observed change with the pH and, by identifying them by means of two independent methods (continuous variation method, and comparison of spectral variations) we have shown that the stability diagram (temperature versus pH) formally resembles the stability diagram (temperature versus ionic strength) at neutral pH (Fig.3), when pH is decreased and/or ionic strength is increased, poly (A + 2U) is relatively more stable than poly (A + U): The formation of poly (A + A) lowers the stability of both poly (A + U) and poly (A + 2U), but, since the proportion of adenylic residues is 1/3 in this last complex, against 1/2 in the former, poly (A + 2U) is less destabilized, and is more sensitive to the diminution of electrostatic repulsion brought about by the sodium ion concentration. These effects are summarized in a three‐dimensional diagram temperature‐pH‐ionic strength (Fig.9).Some of the transitions occuring in acidic solution appear to be irreversible, or very slowly reversible. Such is the case of the formation of poly (A + U). We have shown that this effect is due to the structure poly (A + A). When the dissociation temperature (TmA) of this structure is higher than that of poly (A + U), it is necessary to form two A – U pairs replacing one A – A pair in order to obtain the free energy decrease. Therefore, such a reaction cannot occur in two steps, and this suggests a third order mechanism. Another example is given by the rearrangement of poly (A + U) into poly (A + 2U) and poly (A + A). This observation leads us to a general rule concerning the possibility of reorganization in a system of polynucleotides where several associations are possible [for instance it answers the question as to why poly G cannot expel poly I from poly (I + C)].
The Stereochemistry of α‐Oxidation of Fatty Acids in Plants
Authors: Hitchcock C. , Morris L. J. , James A. T. 
Published: March 2005

When [1‐14C] palmitic acid was incubated with young pea leaves or solutions of their acetonedried powders, 2‐hydroxy [1‐14C]palmitic acid accumulated. This metabolite has been isolated as its methyl ester. When diluted with unlabelled synthetic methyl D‐2‐hydroxypalmitate to known specific activity, and recrystallised, the crystals and mother liquor residues retained the same specific activity. When diluted with unlabelled synthetic methyl L‐2‐hydroxypalmitate to known specific activity and recrystllised, the crystals were almost non‐radioactive. The radoactive metabolite therefore has the D‐configuration.Unlabelled 2‐hydroxypalmitic acid isolated from pea leaves was shown to have the D‐configuration by direct measurement.