[Abscess of the atrium: a complication of central venous catheters].

A 27-year-old female patient was admitted for parenteral feeding and treatment of an acute episode of her steroid dependent Crohn's disease. An intravenous catheter was inserted, the tip being located in the right atrium. This central line was accidentally removed ten days later and replaced with another one also ending in the right atrium.

[Bacteriological relationship between organ donor and recipient. A survey apropos of 100 brain dead patients].

The aim of the study was to evaluate the relationship between germs found in samples systematically taken in the organ donors and germs found in the corresponding recipients in the 8 post-operative days. The 100 brain-dead patients received oxacillin (2g every 4 hours) when the bacteriological samples were taken. 41% of the donors were germ carriers.

The mutation Lys234His yields a class A beta-lactamase with a novel pH-dependence.

The lysine-234 residue is highly conserved in beta-lactamases and in nearly all active-site-serine penicillin-recognizing enzymes. Its replacement by a histidine residue in the Streptomyces albus G class A beta-lactamase yielded an enzyme the pH-dependence of which was characterized by the appearance of a novel pK, which could be attributed to the newly introduced residue. At low pH, the kcat, value for benzylpenicillin was as high as 50% of that of the wild-type enzyme, demonstrating that an efficient active site was maintained.

The importance of the negative charge of beta-lactam compounds in the interactions with active-site serine DD-peptidases and beta-lactamases.

The interaction between various penicillins and cephalosporins the carboxylate group of which at C-3 or C-4 had been esterified or amidated and different penicillin-recognizing enzymes was studied. In general, our findings reinforced the common assumption that an anionic group at that position is necessary for the effective acylation of these enzymes. However, the relative activities of the modified beta-lactams as inactivators of the Streptomyces R61 DD-peptidase or as substrates of the Bacillus licheniformis, Streptomyces albus G and Enterobacter cloacae beta-lactamases did not fit a general scheme in which the intrinsic electronic and geometric properties of the beta-lactam compounds would be sufficient to explain their substrate or inactivator properties towards the various types of enzymes investigated.

Active-site serine mutants of the Streptomyces albus G beta-lactamase.

By using site-directed mutagenesis, the active-site serine residue of the Streptomyces albus G beta-lactamase was substituted by alanine and cysteine. Both mutant enzymes were produced in Streptomyces lividans and purified to homogeneity. The cysteine beta-lactamase exhibited a substrate-specificity profile distinct from that of the wild-type enzyme, and its kcat.

Diversity of the mechanisms of resistance to beta-lactam antibiotics.

The sensitivity of a bacterium to beta-lactam antibiotics depends upon the interplay between 3 independent factors: the sensitivity of the essential penicillin-binding enzyme(s), the quantity and properties of the beta-lactamase(s) and the diffusion barrier that the outer-membrane of Gram-negative bacteria can represent. Those three factors can be modified by mutations or by the horizontal transfer of genes or portions of genes.

[Value of hormonal treatment with triiodothyronine and cortisone in brain dead patients].

Brain death leads to substantial falls in the plasma levels of cortisol and tri-iodothyronine (T3). These alterations may be responsible for physiological instability in these patients, and impairment in donor organ function. A double-blind study was therefore designed to assess the possible improvement in metabolism and haemodynamic stability in brain-dead organ donors treated with T3 and cortisone.

Prion diseases in man.

Human spongiform encephalopathies (HSE) are uncommon neurodegenerative diseases of unknown etiology. Whilst numerous observations provide arguments for an infectious disorder mediated by an unconventional agent of the so-called prion-type, the recent discovery of predisposing allelic variants suggests that HSE might be considered as genetically linked diseases.

Mechanism of sucrose retrieval along the phloem path - a kinetic approach.

In contrast to hexoses (fructose, glucose, 3-oxymethylglucose) sucrose is preferentially taken up by isolated conducting tissue ofCyclamen persicum Mill. Sucrose absorption follows a biphasic kinetic, with a saturable component (Km=5.2 mM; Vmax = 4.

Role of the conserved amino acids of the 'SDN' loop (Ser130, Asp131 and Asn132) in a class A beta-lactamase studied by site-directed mutagenesis.

Ser130, Asp131 and Asn132 ('SDN') are highly conserved residues in class A beta-lactamases forming one wall of the active-site cavity. All three residues of the SDN loop in Streptomyces albus G beta-lactamase were modified by site-directed mutagenesis. The mutant proteins were expressed in Streptomyces lividans, purified from culture supernatants and their kinetic parameters were determined for several substrates.

Engineering a novel beta-lactamase by a single point mutation.

beta-Lactamases are widespread and efficient bacterial enzymes which play a major role in bacterial resistance to penicillins and cephalosporins. In order to elucidate the role of the residues lying in a conserved loop of the enzymatic cavity of the active-site serine Streptomyces albus G beta-lactamase, modified proteins were produced by oligo-directed mutagenesis. Mutation of Asn116, which lies on one side of the active site cavity pointing to the substrate-binding site, into a serine residue resulted in spectacular modifications of the specificity profile of the enzyme.

Cloning, partial sequence, expression, and antigenic analysis of the filamentous hemagglutinin gene of Bordetella pertussis.

The gene coding for the filamentous hemagglutinin (FHA), one of the main factors involved in mediating adherence of Bordetella pertussis to ciliated host cells, was cloned in Escherichia coli, and the 3,500-base-pair nucleotide sequence encoding the amino-terminal region was determined. Molecular cloning, together with the characterization of recombinant FHA-related proteins produced in E. coli, revealed that the primary translation product is a protein of about 370 kilodaltons (kDa).

Evidence for mitotic recombination in Wei/+ heterozygous mice.

A number of alleles at coat color loci of the house mouse give rise to areas of wild-type pigmentation on the coats of otherwise mutant animals. Such unstable alleles include both recessive and dominant mutations. Among the latter are several alleles at the W locus.

An immortalized osteogenic cell line derived from mouse teratocarcinoma is able to mineralize in vivo and in vitro.

The hybrid plasmid pK4 containing the early genes of the simian virus SV-40, under the control of the adenovirus type 5 E1a promoter, was introduced into the multipotent embryonal carcinoma (EC) 1003. Expression of the SV-40 oncogenes was observed at the EC cell stage, and this allowed the derivation of immortalized cells corresponding to early stages of differentiation. Among the immortalized mesodermal derivatives obtained, one clone, C1, is committed to the osteogenic pathway.

Could Borrelia burgdorferi be a causal agent of sarcoidosis?

Sarcoidosis is a multisystem granulomatous disorder of unknown etiology, most commonly affecting young adults presenting most frequently with bilateral hilar lymphadenopathy, pulmonary infiltrations, skin or eye lesions (1). Borrelia burgdorferi, the causal agent of Lyme disease, could also be responsible for sarcoidosis. Domestic animals may play a major role in transmitting the disease to humans.

A monoclonal anti-double-stranded DNA autoantibody binds to a 94-kDa cell-surface protein on various cell types via nucleosomes or a DNA-histone complex.

A crude supernatant of hybridoma secreting a monoclonal anti-double-stranded (ds)DNA antibody (PME77 mAb), used to stain fibroblasts (CVI cells) in immunofluorescence, gives a punctuated staining of variable intensity. We had suggested that anti-DNA antibodies bind to cell-surface protein(s) of several cells. When the mAb of this crude supernatant was purified on a dsDNA-cellulose column and a histone-Trisacryl column, the mAb no longer bound to the cell surface.

Pattern of expression of ecotropic murine leukemia virus in gonads of inoculated SWR/J mice.

An ecotropic murine leukemia virus (MuLV) isolate has recently been shown to be able to infect the germ line or the early embryo or both when inoculated at birth to SWR/J females (J. J. Panthier, H.

Inoculation of newborn SWR/J females with an ecotropic murine leukemia virus can produce transgenic mice.

Endogenous ecotropic murine leukemia proviruses that were not present in the parental stock are acquired by the progeny of some SWR/J X RF/J hybrid females. We have made a stock of an ecotropic murine leukemia virus produced by such a hybrid female and inoculated newborn SWR/J females with it. We show that upon crossing of the inoculated females to SWR/J males, some of their progeny acquire ecotropic proviruses.

[Measurement of cardiac output by thoracic electrical bioimpedance or thermodilution].

The present study was designed to assess a new non invasive method for measuring cardiac output. The thoracic electrical bioimpedance method was compared with the reference one, thermodilution. The measurements were made simultaneously with NCCOM3 (bioimpedance) using the freeze data mode, and with a Swan-Ganz catheter and a haemodynamic computer (thermodilution).

Nucleotide sequence and evolution of ETn elements.

The ETn (for "early transposon") family of long repeated sequences in abundantly transcribed in early mouse embryos from retroviral-like long terminal repeats. Nucleotide sequencing of two elements does not reveal any long open reading frame nor significant homology to retroviral proteins. The genetic polymorphism, monitored by Southern blotting within and across mouse species, reflects a concerted mode of evolution for the ETn sequences.

Presence of antibodies against a cell-surface protein, cross-reactive with DNA, in systemic lupus erythematosus: a marker of the disease.

Antibodies against a cell-surface protein, cross-reactive with double-stranded DNA, were detected in the serum of 25 patients with active human systemic lupus erythematosus (SLE), defined on the basis of the revised American Rheumatism Association classification. Among these sera, two did not display anti-DNA antibodies, as shown by Farr assay, solid-phase radioimmunoassay, and Crithidia luciliae test. Five other SLE patients were consecutively studied in active and remission states.