[Bilateral periostitis and arthritis: about a case of hypertrophic osteoarthropathy]. / Périostite bilatérale et polyarthrite : à propos d'un cas d'ostéoarthropathie hypertrophique pneumique.

We report the case of a 67-year-old female patient presenting swelling of the hands and feet and pain in both legs. Clinical examination and bone scintigraphy identify the triad "digital clubbing - arthritis - bilateral periostitis of the long bones", leading to a diagnosis of hypertrophic osteoarthropathy, a syndrome usually associated with pulmonary neoplasia. The thoracic CT-scan, followed by a biopsy, effectively diagnosed a right upper lobe adenocarcinoma. Surgical treatment of the neoplasia allowed the resolution of the clinical complaints and the pathological scintigraphic findings.

Nous rapportons le cas d'une patiente de 67 ans présentant des gonflements des mains et des pieds ainsi que des douleurs des deux jambes. L'examen clinique et la scintigraphie osseuse identifient la triade «hippocratisme digital - arthrites - périostite bilatérale des os longs¼, permettant de poser un diagnostic d'ostéoarthropathie hypertrophique, un syndrome habituellement associé à une néoplasie pulmonaire. Le scanner thoracique, suivi d'une biopsie, ont en effet diagnostiqué un adénocarcinome localisé au niveau du lobe supérieur droit. La prise en charge chirurgicale de la néoplasie a permis la résolution des plaintes cliniques et de l'aspect scintigraphique pathologique.

Monitoring the effects of mobile phone use on the brain by proton magnetic resonance spectroscopy.

PURPOSE: To determine whether extensive use of mobile phones affects brain metabolites detectable by proton magnetic resonance spectroscopy (1H MRS). MATERIALS AND METHODS: Twenty-one extensive mobile phone users (average use = 5.5 +/- 2.2 years at 2.4 +/- 1.1 hours/day) and 15 control subjects were recruited and submitted to a 1H MRS brain examination at 1.5 Tesla. Data were recorded in the most exposed right temporal and pontobulbar areas as well as in the contralateral left temporal area. The ratios of N-acetylaspartate (NAA), choline (Cho) and myo-inositol (mI) to creatine/phosphocreatine (Cr) were measured. RESULTS: No statistically significant changes in the NAA/Cr, Cho/Cr and mI/Cr ratios were measured between mobile phone users and control subjects and between the exposed and contralateral temporal areas. CONCLUSION: These results indicate that extensive exposition to mobile phone radiation does not cause MRS-detectable brain metabolic changes.

Influence of post-treatment delay on the evaluation of the response to focused ultrasound surgery of breast cancer by dynamic contrast enhanced MRI.

The assessment of the effectiveness of MRI-guided focused ultrasound surgery (MRIgFUS) of breast carcinomas can be performed by dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) parameters which monitor the presence of residual tumour. The aim of this study was to evaluate the effect of the post-treatment delay on this assessment. DCE-MRI data were acquired immediately and 3-14 days after MRIgFUS treatment of 26 tumours (<7 days, n = 6; = or > ge;7 days, n = 20). The percentage of residual tumour was determined histologically on the resected mass and correlated with two DCE-MRI parameters: increase in signal intensity (ISI) and positive enhancement integral (PEI). No correlation could be found between DCE-MRI data acquired immediately after treatment and the percentage of residual tumour. Good correlation coefficients were found for data acquired several days after treatment (ISI, r = 0.749; PEI, r = 0.778). However, they were higher when the post-treatment time interval was 7 days or more (ISI, r = 0.962; PEI, r = 0.934). These results suggest that a post-treatment delay of 7 days is necessary for the accurate assessment of the presence of residual tumour by DCE-MRI parameters.

The glutaminyl-transfer RNA synthetase of Escherichia coli. Purification, structure and function relationship.

Glutaminyl-tRNA synthetase from Escherichia coli has been purified to homogeneity with a yield of about 50%. It is a monomer of about 69 000 daltons. Arginyl and glutamyl-tRNA synthetases are also monomeric synthetases of molecular weight significantly lower than 100 000. In addition it is well known that these three synthetases require their cognate tRNA to catalyze the [32P]PPi-ATP exchange. Like arginyl-tRNA synthetase, but unlike glutamyl-tRNA synthetase, glutaminyl-tRNA synthetase seems to contain some repeated sequences. Therefore no correlation can be established between the tRNA requirement of these synthetases for the catalysis of the isotope-exchange and the presence or the absence of sequence duplication. In the native enzyme four sulfhydryl groups react with dithiobisnitrobenzoic acid causing a loss of both the aminoacylation and the [32P]PPi-ATP exchange activities. The rate-limiting steps of the overall aminoacylation and its reverse reaction correspond, respectively, to the catalysis of the aminoacylation of tRNA Gln and of the the deacylation of glutaminyl-tRNA Gln. At acidic pH, glutaminyl-tRNA synthetase catalyzes the synthesis of the glutaminyl-tRNA Gln and its deacylation at significantly lower rates than the [32P]PPi-ATP exchange, indicating than glutaminyl-tRNA Gln cannot be an obligatory intermediate in this isotope exchange. These results suggest the existence of a two-step aminoacylation mechanism catalyzed by this enzyme.

Structural studies on aminoacyl-tRNA synthetases. A tentative correlation between the subunit size and the occurrence of repeated sequences.

Recent studies have shown that those synthetases with subunits greater than 85,000 daltons contain extensive repeated sequences, whilst those with small subunits (40,000 daltons) do not. We have undertaken a comparative study of four aminoacyl-tRNA synthetases (glutamyl-, arginyl-, valyl-, and phenylalanyl-tRNA synthetases) with subunit sizes ranging from 56,000 to 130,000 daltons in an attempt to correlate the occurrence and extent of the repeats with the length of the polypeptide chain. Our results show that monomeric glutamyl-tRNA synthetase from Escherichia coli (56,000 daltons) contains few repeated sequences, whereas both subunits of yeast phenylalanyl-tRNA synthetase (alpha, 73,000 daltons; beta, 62,000 daltons) and yeast arginyl-tRNA synthetase (74,000 daltons) do have a significant amount of repeats. Thus 56,000 dalton appears to be the minimum size compatible with the existence of such repeats.

A 2H-NMR study on the interactions of the local anesthetic tetracaine with membranes containing phosphatidylserine.

The interaction of the local anesthetic tetracaine with phosphatidylserine-containing model membranes has been studied by 2H-NMR. Charged tetracaine exhibited an unusually large partition coefficient into multilamellar dispersions of phosphatidylserine. The 2H-NMR spectra consisted of a Pake doublet and a narrow line, with the former corresponding to tetracaine in the bilayer and the latter to tetracaine free in solution. A strong pH dependence of the quadrupole splittings indicated different membrane locations for charged and uncharged tetracaine. In equimolar mixtures of phosphatidylserine and phosphatidylcholine the partition coefficients and 2H-NMR spectra were much more like those observed in neat phosphatidylcholine than in neat phosphatidylserine. Dilution studies at pH 5.5 indicated that in phosphatidylserine/phosphatidylcholine mixtures tetracaine experiences a three-site exchange similar to that found earlier for tetracaine in phosphatidylcholine. Tetracaine is in fast exchange between sites weakly bound to membrane and free in solution, and in slow exchange with a strongly bound site in the membrane.

Charge and pH dependent drug binding to model membranes. A 2H-NMR and light absorption study.

The binding of the local anesthetics tetracaine and procaine to model membranes of egg phosphatidylcholine and bovine phosphatidylserine has been studied by 2H-NMR and light absorption. Dispersions of drug-lipid mixtures in 0.1 M NaCl were centrifuged and the concentration of drug in the supernatant was measured by ultraviolet light absorption. Several freeze-thaw cycles of the sample were used before centrifugation to facilitate equilibration of the drug between the bilayers. Binding curves for the drug were obtained as a function of pH. The results were simulated by a theoretical model based on the Gouy-Chapman theory, in which both the charged and the uncharged forms of the drug, and the equilibrium between them, were included. Two deuterated forms of the drugs, [2H6] tetracaine and [2H4] procaine, were used for the 2H-NMR experiments. In most cases the 2H-NMR spectrum contained a broad central resonance and an underlying quadrupolar pattern. However, after five freeze-thaw cycles only a single broad resonance was observed under most conditions. Particle size measurements showed that freeze-thawing resulted in a more uniform population of liposomes of smaller average diameter than those obtained by simple vortex mixing. The single broad resonance observed in both cases is interpreted as due to rapid exchange of the anesthetic between lipid and bulk solution. In the absence of freeze-thawing, the quadrupolar pattern is attributed to anesthetic species in exchange with only a limited amount of water. The data suggest that a true equilibrium between lipid, water and anesthetic is only attained after freeze-thawing.

Purification and reversible subunit dissociation of overproduced Escherichia coli phenylalanyl-tRNA synthetase.

Phenylalanyl-tRNA synthetase (EC 6.1.1.20) has been purified to homogeneity from a 100-fold overproducing Escherichia coli strain carrying a hybrid pBR322 plasmid containing the pheS-pheT locus. The purified enzyme is identical to the phenylalanyl-tRNA synthetase isolated form an haploid strain. The enzyme was found to dissociate in the presence of 0.5 M NaSCN and the alpha- and beta-subunits composing the native alpha 2 beta 2 enzyme were separated by gel filtration. Neither isolated subunit showed significant catalytic activity. A complex indistinguishable from the native enzyme with full catalytic activity is recovered upon mixing the subunits. The N- and C-terminal sequences and the amino acid composition of each subunit were determined. They are compared to the available data concerning the primary structure of the subunits, as deduced from nucleotide sequencing of the pheS-pheT operon.

Chloroplastic and cytoplasmic valyl- and leucyl-tRNA synthetases from Euglena gracilis. Comparative study of their structural properties.

Chloroplastic and cytoplasmic valyl- and leucyl-tRNA synthetases purified from Euglena gracilis show a monomeric structure. The molecular weights of the two valyl-tRNA synthetases are identical (126,000) while those of the leucyl-tRNA synthetases are different (100 000 for the chloroplastic and 116 000 for the cytoplasmic enzyme). The tryptic maps and the amino acid compositions reveal differences between the chloroplastic valyl- and leucyl-tRNA synthetases and their cytoplasmic homologues. These results suggest that a chloroplastic aminoacyl-tRNA synthetase and its cytoplasmic counterpart are coded for by distinct genes.

Glycosylation of yeast aspartyl-tRNA synthetase. Affinity labelling by glucose and glucose 6-phosphate.

Several lines of evidence establish that the crystallizable aspartyl-tRNA synthetase from Baker's yeast contains some covalently bound glucose: (i) a positive staining of the enzyme was obtained after polyacrylamide gel electrophoresis followed by the concanavalin A-peroxidase test which is specific for glucose and mannose containing proteins; (ii) thin-layer chromatography and gas-liquid chromatography revealed the presence of glucose in enzyme hydrolysates; (iii) immunoaffinoelectrophoresis in agarose gels containing concanavalin A and antibodies raised against aspartyl-tRNA synthetase showed that the enzyme was able to precipitate entirely in the lectin. Finally incubation of the enzyme with [14C]glucose or [14C]glucose 6-phosphate led to the incorporation of radioactivity into trichloroacetic acid-precipitable protein. Indeed immunoprecipitation of [14C]glucose-labelled aspartyl-tRNA synthetase with specific antibodies using the rocket method followed by autoradiography gave a radioactive peak. This last result also demonstrates the possibility of in vitro glycosylation of yeast aspartyl-tRNA synthetase.

Identification of the major tRNA(Phe) binding domain in the tetrameric structure of cytoplasmic phenylalanyl-tRNA synthetase from baker's yeast.

Native cytoplasmic phenylalanyl-tRNA synthetase from baker's yeast is a tetramer of the alpha 2 beta 2 type. On mild tryptic cleavage it gives rise to a modified alpha 2 beta 2 form that has lost the tRNA(Phe) binding capacity but is still able to activate phenylalanine. In this paper are presented data concerning peptides released by this limited proteolytic conversion as well as those arising from exhaustive tryptic digestion of the truncated beta subunit. Each purified peptide was unambiguously assigned to a unique stretch of the beta subunit amino acid sequence that was recently determined via gene cloning and DNA sequencing. Together with earlier results from affinity labelling studies the present data show that the Lys 172-Ile 173 bond is the unique target of trypsin under mild conditions and that the N-terminal domain of each beta subunit (residues 1-172) contains the major tRNA(Phe) binding sites.

Primary structure of aspartyl-tRNA synthetase from baker's yeast: tryptic and CNBr peptides.

The cristallizable aspartyl-tRNA synthetase from Baker's yeast is a dimer made up of identical subunits (Mr 60,000). We report here the results of tryptic digestion and cyanogen bromide cleavage which enabled us to align two lon stretches of sequence of 106 and 111 amino acids, respectively.

Isolation and structure of a pseudopeptide gamma-L-glutamyl-L-aspartic acid from Datura stramonium that impairs learning retention in mice.

Datura stramonium contains a compound that impairs learning retention in mice. It has been purified to homogeneity and its structure has been established as that of a gamma-L-glutamyl-L-aspartate. The biological activity of this pseudodipeptide has been found to be identical with that of the corresponding synthetic one. It has also been compared to those of various synthetic di- and tripeptides containing L- and/or D-enantiomers of the constitutive amino acids. The results show that the activity is associated with a peptidic structure containing only one type of enantiomer.

The complete amino acid sequence of cytoplasmic aspartyl-tRNA synthetase from Saccharomyces cerevisiae.

The crystallizable cytoplasmic aspartyl-tRNA synthetase from Saccharomyces cerevisiae is a dimer made up of identical subunits (Mr 63 000). Its primary structure was established using peptide sequences from four different digests of the native and citraconylated enzyme with trypsin, cyanogen bromide and staphylococcal protease. The oligonucleotide sequence of the structural gene was used as a template for the final alignment of the various peptides in the correct order.

Purification and characterization of a toxin inhibiting protein synthesis from Croton mongue, a Madagascar Euphorbiaceae.

Monguine, a thermostable toxic protein was extracted from the seeds of Croton mongue (Euphorbiaceae) and purified by ion-exchange chromatography on DEAE-cellulose and gel filtration on Sephadex G-25 and G-15. Polyacrylamide gel electrophoresis of purified monguine in the presence of sodium dodecyl sulfate and after treatment with 2-mercaptoethanol showed one band corresponding to a molecular weight of 9000. The same molecular weight was determined by analytical centrifugation. Amino acid analysis revealed a high content in both aspartic and glutamic acids (or the corresponding amides). The LD50 (24 h) is 12 mg/kg of mouse body weight. Monguine inhibits protein synthesis in hepatoma tissue culture cells and globin synthesis in a rabbit reticulocyte lysate.

Purification and characterization of bolaffinine, a toxic protein from Boletus affinis Peck (Boletaceae).

A toxic protein of Mr 22,000, called bolaffinine, has been purified from the mushroom, Boletus affinis Peck (Boletaceae), with a 0.65% yield using a procedure involving four steps: ammonium sulfate precipitation, two chromatographies on ion-exchange columns and gel filtration on Sephadex G-75. It is thermolabile and can be inactivated by organic solvents. Its isoelectric point lies between pH 9 and 10. It contains 234 amino acids, no free SH groups and one disulfide bridge as evidenced by reactions with 5-5'-dithiobis-nitrobenzoate (DTNB) and 2-mercaptoethanol. When injected into mice, it provokes the death of animals within 16-24 h. The 24 h LD50 is 61 mg/kg of body weight. Bolaffinine inhibits protein synthesis in hepatoma tissue culture and in a rabbit reticulocyte lysate.

Complete purification and studies on the structural and kinetic properties of two forms of yeast valyl-tRNA synthetase.

Two forms of baker's yease valyl-tRNA synthetase have been purified to apparent homogeneity by classical methods. It was demonstrated that one of the two forms of the enzyme originates from the other by proteolysis, the respective amounts of each form depending on the physiological state of the yeast. The species mainly isolated from exponential growing yeast cells is a monomer of 130,000 daltons molecular weight. In stationary phase cells or in commercial yeast the major species is a degraded monomer of 120,000 daltons molecular weight ; however when the purification is carried out in the presence of phenylmethyl-sulphonyl fluoride, or diisopropylfluorophosphate large amounts of the not - degreded monomer can be obtained. Of great practical usefulness is the fact that large amounts of the native enzyme can be obtained pure after only two chromatographic steps on DEAE-cellulose and hydroxylapatite. The kinetic constants for valine, ATP and tRNAVal were determined, as well as the optimum aminoacylation conditions. It was found that the specific activity of the nondegraded valyl-tRNA synthetase is higher than that of the proteolysed enzyme for the aminoacylation reaction. On the contrary, both forms have the same ATP-pyroposphate exchange activity. The amino acids composition of the native enzyme was established. The tryptic fingerprints of the two valyl-tRNA synthetases were studied. Essentially similar maps were obtained. The number of the spots in the fingerprints indicates that the enzymes contain a high proportion of repeated sequences.

Structural differences between the free and bound states of the DNA-bisintercalating peptide YSPTSPSY.

The YSPTSPSY peptide is a DNA-bisintercalator that can adopt nonrandom conformations in solution. Strategies based on random conformational search and energy minimizations have been applied to generate populations of conformers characterizing YSPTSPSY. Subsequent analysis based on statistical methods and clustering allowed to determine the existence of four classes of conformers containing beta- and/or gamma-turns. NMR spectra of YSPTSPSY in solution provide evidence for such structures. Employing a Monte Carlo-based docking procedure, the YSPTSPSY peptide was docked in a DNA double-helical fragment with the sequence [d(GACGTC)]2. The peptide binds on the minor groove of DNA stacking the central CG base pairs, in a manner similar to that observed in complexes of triostin A with DNA. Upon binding, the structure of the C-terminal segment is modified into a type I beta-turn. Five intermolecular hydrogen bonds are observed, but the van der Waals interactions constitute the major stabilization factor for the complex. NMR chemical shifts, coupling constants, and NOESY connectivities are in agreement with the molecular model.