Raw and processed data used in the simultaneous analysis of electrical characteristics and microstructure of crystallised PEDOT:PSS based OECTs under strain.

Here is presented raw and analysed data collected during study of the evolution, with uniaxial stretching, of the electrical and microcrystalline characteristics of polystyrene sulfonate doped poly(3,4-ethylenedioxythiophene) (PEDOT:PSS) organic electrochemical transistors (OECTs). X-ray diffraction data from GIWAXS measurements of the PEDOT:PSS material, performed at the SOLEIL light source are presented in raw and partially analysed forms. Current-voltage data, collected concurrently with the GIWAXS data, are also presented, and the evolution of the transconductance of the OECT devices with stretching is shown. GIWAXS data are only examined along the qz specular reflection ridge, and scans along this ridge are extracted and presented. However, the off-specular data may also be of interest to readers and is therefore made available here in its entirety.

Monitoring of cell layer coverage and differentiation with the organic electrochemical transistor.

Electrical, label-free monitoring of cells is a non-invasive method for dynamically assessing the integrity of cells for diagnostic purposes. The organic electrochemical transistor (OECT) is a device that has been demonstrated to be advantageous for interfacing with biological systems and had previously been shown to be capable of monitoring electrically tight, resistant, barrier type tissue. Herein, the OECT is demonstrated not only for monitoring of barrier tissue cells such as MDCK I, but also for other, non-barrier tissue adherent cells including HeLa cells and HEK epithelial cells. Transistor performance, expressed as transconductance (gm) is measured as a function of frequency; barrier tissue type cells are shown to have a more abrupt drop in transconductance compared to non-barrier tissue cells, however both tissue types are clearly distinguishable. Simple modelling of the cell layers on the transistor allows extraction of a resistance term (Rc). OECT monitoring shows that barrier tissue cells lose their barrier function in a standard calcium switch assay, but remain adhered to the surface. Re-addition of calcium results in recovery of barrier tissue function. The entire process is continuously followed both electronically and optically. Finally, high resolution fluorescence imaging of live cells labelled with a red fluorescent actin marker demonstrates the versatility of this method for tracking molecular events optically, with direct correlation to electronic readouts.

Response of Brucella suis 1330 and B. canis RM6/66 to growth at acid pH and induction of an adaptive acid tolerance response.

Acid pH is an environmental stress often encountered by Brucella during both the "environmental" and the "pathogenic" stages of its life. We have investigated the behaviour of B. suis biovar 1 and B. canis in acid conditions. Growth at suboptimal pH was characterized by a dramatic reduction in growth yield due to an early onset of stationary phase. B. suis was more resistant to low pH than B. canis, which lysed at pH 4.6. Viable counts measured after a 4-h acid shock at pH 3.2 showed that the relative survival of B. suis was 1,000-fold greater than that of B. canis. An adaptive acid tolerance response (ATR) was induced in both species by culture at pH 5.8; however, while the acid-sensitive B. canis had more than a 2,000-fold increase in survival following acid shock at pH 3.2, the increase in survival of B. suis was only around 50-fold. The kinetics of the induction of ATR were followed: for B. suis, 1-2 h (1 generation) at pH 5.8 were required to induce acid tolerance (50-fold protection), and these levels remained constant over 24 h. B. canis became relatively acid-resistant after only 30-min exposure to pH 5.8. Levels of acid tolerance continued to increase and were maximal at 24 h. Stationary phase pH 7.2 cultures of either species did not exhibit acid resistance, suggesting that, like Salmonella, Brucella does not have an rpoS-controlled stationary phase acid resistance.

In vitro immunosuppressive activity of gram-positive (Streptococcus pyogenes) peptidoglycan on mouse lymphocytes.

A peptidoglycan fraction prepared from group-A streptococcus was assayed for in vitro mitogenicity on mouse lymphocytes. This fraction reduced considerably the uptake of radioactive thymidine both on unstimulated cell suspensions and on suspensions stimulated by T(PHA)- or B(LPS)-mitogens. The immunosuppression was induced by relatively moderate doses of the fraction, and was dose-dependent. Several experiments ruled out the possibility that these results could be due to a cytotoxicity of the fraction, or to a non-specific interference with the uptake or metabolism of the radioactive precursor. These results are coherent with the observations made in vivo on the mouse and previously published. It is suggested that the mechanism of the immunosuppression could be in relation with the capacity of this fraction to stimulate the reticulo-macrophagic system.

Two cases of Mycobacterium haemophilum infection in a renal-dialysis unit.

Two cases of Mycobacterium haemophilum infection in renal-transplant patients occurred in the same hospital department. This raised the possibility that infection may have been acquired in hospital.

Mycobacterium haemophilum and mycobacterium xenopi associated infection in a renal transplant patient.

The case is presented of a renal-transplant patient in Europe with a Mycobacterium haemophilum infection in association with M. xenopi infection. Clinical signs suggested the diagnosis of mycobacteriosis, which was confirmed by a skin biopsy. Despite antitubercular treatment which rapidly eliminated M. xenopi, the patient's condition did not improve until M. haemophilum was identified. Minimal inhibitory concentrations of various antimicrobial compounds showed a lack of efficacy of isoniazid, and rifampin had no clinical effect. The patient recovered only after careful surgical drainage of the lesions and the administration of minocycline. The pathogenesis of such mycobacterioses is discussed, with focus on the immunodepressive status which in our patient may have been partially induced by a cytomegalovirus reinfection.

[Current role of ELISA methods in bacteriology and virology]. / Place actuelle des méthodes ELISA en bactériologie et virologie.

The use of fixed-phase immuno-enzymatic methods (ELISA) is becoming more widespread. In theory, these methods appear to be attractive because of their adaptability to various clinical situations. However, in practice problems remain to be solved. The detection of serum antibodies would seem to be easier, with the exception of tests for IgM, which are interfered with by rheumatoid factor. The detection of viral or bacterial antigens in pathological material would seem to be more difficult to achieve, but holds great promise for the future. Improvements have already been made, but progress remains to be made in the technique and in the clinical interpretation of the results.

[A genetic and molecular biological study of the pathogenicity factors in Brucella]. / Geneticheskoe i molekuliarno-biologicheskoe izuchenie faktorov patogennosti brutsell.

The use of gene engineering techniques made it possible to obtain strain GSE830, capable of a higher level of expression of the gene of 38-kD protein in immunoblotting with sheep and rabbit antibrucellar sera in comparison with the expression of this gene of other Escherichia coli strains, containing recombinant plasmids with this gene. Due to the presence of the gene of 38-kD protein, recombinant E.coli strains were capable of survival in macrophage-like cell line U937 3.6-6.3 times more effectively. The model of interaction of Brucella pathogenic and nonpathogenic species with HeLa cells was studied. The bank of insertion mutants of B.suis virulent strain 1330 was studied with the use of transposon TnblaM. Out of 380 insertion mutants, 7 clones expressing beta-lactamase and having decreased capacity for multiplication in HeLa cells 48 hours after inoculation were selected. Detailed analysis revealed that 3 of them had lower adhesive capacity, 1 of them had lower invasive capacity and 3 other mutants were less capable of intracellular multiplication in HeLa cells than the initial B.suis strain 1330. All these 7 mutants had different sites of TnblaM insertion into the chromosome of B.suis strain 1330.

[Perspectives and hopes in infectious pathology]. / Nouveautés et espoirs en pathologie infectieuse.

Over the last few decades, changes in socio-economic conditions and social practices as well as aggressive therapy of many diseases have led to the emergence of new infectious pathologies. These new pathologies are either associated with newly identified microbial species or the emergence of known microbes which have encountered new environments in which they are able to cause disease. Recent progress has allowed us to understand the mechanisms by which these pathogens express their virulence and will certainly allow us to diagnose and treat these infections more efficiently in the future.

Previously undescribed 6.6-kilobase R plasmid in penicillinase-producing Neisseria gonorrhoeae.

A penicillin-resistant Neisseria gonorrhoeae strain was isolated. The resistance was due to the production of TEM-1 beta-lactamase encoded by a plasmid. This 6.6-kilobase plasmid was compared with the previously known 7.4- and 5.3-kilobase penicillin R plasmids of N. gonorrhoeae.

[Enzyme determination in vitro of inhibitor activity of beta-lactamase from tazobactam. Comparison with high performance liquid chromatography]. / Dosage enzymatique in vitro de l'activité inhibitrice de beta-lactamase du tazobactam. Comparaison à la chromatographic liquide à haute performance.

We developed an enzymatic method using nitrocefin to assay tazobactam in vitro. Tazobactam was incubated with TEM-1 beta-lactamase. Then, residual beta-lactamase activity was assayed by adding nitrocefin. This activity corresponded indirectly to the initial concentration of tazobactam. Within-assay, between-assay and accuracy coefficients of variation were below 15%. The correlation coefficients between enzymatic method and high performance liquid chromatography (the reference method)was 0.98. The enzymatic method is rapid, easy to perform and should be applied to daily clinical practice.

[Adherent cell and T lymphocyte cooperation for the "in vitro" production of Brucella-induced interferon by murine spleen cells (author's transl)]. / Coopération entre cellules adhérentes et lymphocytes T mutins pour la synthèse in vitro d'interféron Brucello-induit.

Although Brucella is a good in vivo inducer of interferon, in vitro infection of murine spleen cells by Brucella suis has not, to the present time, led to in vitro synthesis. In the present work we show that normal spleen cells can however synthetize interferon in vitro when cultured together with adherent cells obtained from the spleens of syngeneic mice 45 min after in vivo inoculation. Induction and synthesis are thus shown to be distinct phenomena. Moreover soluble factors are shown to be involved in the induction phenomenon and T cells to be essential for synthesis. This in vitro brucella-induced interferon differs from in vivo brucella-induced interferon: its acid lability and its antigenic properties are characteristic of type II "immune" interferon.

DNA polymorphisms in methicillin-susceptible and methicillin-resistant strains of Staphylococcus aureus.

Restriction fragment length polymorphisms in methicillin-susceptible and methicillin-resistant (MRSA) strains of Staphylococcus aureus isolated in the same hospital over a 4-month period were studied by using SmaI and ApaI digestion of genomic DNA and pulsed-field gel electrophoresis. Each of the 20 methicillin-susceptible strains had a unique SmaI pattern, but the 27 MRSA strains showed only seven SmaI patterns. More than half of the SmaI fragments in all of these seven patterns were identical, as were those in the patterns from two unrelated MRSA strains. Digestion with ApaI, which cuts staphylococcus DNA into at least twice as many fragments, confirmed the results obtained with SmaI. Lastly, the plasmid contents of MRSA strains showing identical SmaI and ApaI electrophoretic patterns were not identical. These results are interpreted as supporting the hypothesis that all MRSA strains arose from a single clone and emphasize the need to use several methods in epidemiological investigations of MRSA outbreaks.

DNA polymorphism in strains of Listeria monocytogenes.

DNA polymorphism in 35 Listeria monocytogenes strains belonging to serovars 1/2a, 1/2b, 1/2c, and 4b was studied by genomic DNA digestion. The restriction endonucleases ApaI and NotI, which cleave DNA at rare sequences, were used, and DNA fragments were analyzed by pulsed-field gel electrophoresis. Restriction fragment length polymorphism varied among different serovars and was used for epidemiological studies, but serovar 1/2c isolates could not be analyzed because their restriction patterns were indistinguishable. The genome sizes were calculated by addition of the sizes of the ApaI fragments and were found to be about 2,660 kb for serovar 1/2a strains, 2,640 kb for serovar 1/2b strains, and 2,710 kb for serovar 4b strains but only 2,340 kb for serovar 1/2c strains. This last group therefore appears to differ from the other serovar strains by the absence of restriction fragment length polymorphism and a chromosome that is 15% shorter, suggesting that strains of serovar 1/2c have quite recently emerged.