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Biomedical subjects

F Brun

Publications and source records attributed to F Brun.

At least 19 recordsLinked to original sources
PubMed2001

Photoaffinity labelling with the cytokinin agonist azido-CPPU of a 34 kDa peptide of the intracellular pathogenesis-related protein family in the moss Physcomitrella patens.

As in higher plants, the development of the moss Physcomitrella patens is regulated by environmental signals and phytohormones. At the protonema level transition from chloronema to caulonema cells is under auxin control. The formation on second sub-apical caulonema cells of buds that will give rise to the leafy gametophore requires cytokinins. Using [3H]azidoCPPU (1-(2-azido-6-chloropyrid-4-yl)-3-(4-[3H])phenylurea), a photoactivatable cytokinin agonist, we have specifically photolabelled a soluble 34 kDa protein of P. patens. Urea derivatives were very efficient competitors of photolabelling while purine-type cytokinins were poor competitors. The protein UBP34 was purified by affinity chromatography and the sequences of six internal peptides obtained. A cDNA encoding UBP34 was cloned by screening a P. patens protonema cDNA library with a probe amplified by PCR using degenerate primers designed from the peptide sequences. The UBP34 amino acid sequence shows an average sequence identity of 42% with both intracellular PR proteins and the BetV1-related family of plant allergens. Recombinant UBP34 expressed in Escherichia coli was confirmed to bind azidoCPPU.

Amino Acid Sequence↗
PubMed1996

Validation of high-performance liquid chromatographic methods on two silica base-deactivated reversed phases for the determination of chloroprocaine and bupivacaine.

The separation of HPLC of basic drugs on silica-based reversed phases remains a major problem because of the interaction between the residual silanol groups of the silica and the amino function of the drug. This paper describes the validation of HPLC methods for the determination of two injectable solutions of basic drugs (two local anaesthetics, chloroprocaine and bupivacaine), with two commercial base-deactivated reversed phases. These columns improve the chromatographic performances without adding a blocking agent to the mobile phase. With a simple aqueous-organic mobile phase, these base-deactivated reversed phases give high theoretical plate numbers (N) and small tailing factors. The optimized methods show good linearity, precision (RSD < 2%) and accuracy (bias < 2% for dosage forms). The limits of detection and quantitation are lower than the maximal accepted limits for impurities. These methods are currently in routine use in stability studies.

Anesthetics, Local↗
PubMed1996

[MRI and CT of parotid diseases in HIV-positive patients].

We report five cases of HIV patients with parotid pathology during a period of one year. All patients (4 men and 1 woman between the ages of 32 and 47 years) had a MRI or a CT confirmation of the parotid gland lesion. Three patients exhibited parotid gland cysts, one a nonspecific chronic inflammation and one an enlargement of the parotid gland with some benign lymphoepithelial lesions. Two patients underwent ultrasound-guided fine-needle aspiration biopsy. The cytology examination confirmed the benignity of the lesions. Finally, we expose the clinical management of parotid enlargements in HIV-positive patients.

Adult↗
PubMed1993

Isolation of gram-positive rods that resemble but are clearly distinct from Actinomyces pyogenes from mixed wound infections.

Beginning in 1990, gram-positive rods resembling Actinomyces pyogenes were found with increasing frequency in mixed cultures from various infectious processes, most of them from patients with otitis, empyema, pilonidal cysts, perianal abscesses, and decubitus ulcers. Ribotyping and hybridization showed that these gram-positive rods could be divided into five groups not related to known Actinomyces species. Biochemical markers for reliable differentiation into these groups, however, could not be found. Therefore, naming new species is not warranted unless parameters are discovered that allow identification without DNA hybridization. These gram-positive rods have been isolated only in mixed cultures with anaerobes, Staphylococcus aureus, Streptococcus "milleri," enterococci, and gram-negative rods. Their exact role in these possibly synergistic infections needs further investigation.

Adult↗
PubMed1975

Interactions of aromatic residues of proteins with nucleic acids. Fluorescence studies of the binding of oligopeptides containing tryptophan and tyrosine residues to polynucleotides.

The binding of oligopeptides of general structure Lys-X-Lys (where X is an aromatic residue) to several polynucleotides has been studied by fluorescence spectroscopy. Two types of complexes are formed, both involving electrostatic interactions between lysyl residues and phosphate groups as shown by the ionic strength and pH dependence of binding. The fluorescence quantum yield of the first complex is identical with that of the free peptide. The other complex involves a stacking of the nucleic acid bases with the aromatic amino acid whose fluorescence is quenched. Fluorescence data have been quantitatively analyzed according to a model involving these two types of complexes. Association constants and the size of binding sites have been determined. Stacking interactions are favored in single-stranded polynucleotides as compared to double-stranded ones. A short oligopeptide such as Lys-X-Lys is thus able to distinguish between single-stranded and double-stranded nucleic acids. Fluorescence results are compared to those obtained by proton magnetic resonance and circular dichroism.

Binding Sites↗
PubMed1972

[Case reports].

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Adult↗