Diagnosis of progressive multifocal leucoencephalopathy by PCR detection of JC virus from CSF.
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Biomedical subjects
Publications and source records attributed to C Bollet.
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Two ELISA tests (IgG and IgM) for the serodiagnosis of tuberculosis, both based on antigen 60 (A60) of M. bovis BCG, were applied to 1,644 controls and patients to analyse the immune response in different forms of this infectious disease. Out of 200 healthy individuals, 148 being tuberculin--positive BCG-vaccinated adults, only 10 contacts--nurses of the pneumology department and laboratory technicians of the mycobacterial laboratory--were found positive for anti-A60 IgG. One quarter of hospitalized patients affected by non-tuberculous pneumopathies (194 in total) were found weakly positive for anti-A60 IgG. We suppose that these positive cases have suffered from inapperant infections and are in a "persistent state". Out of 344 cases of primary pulmonary tuberculosis, 88% were positive for anti-A60 IgG and 75% for the corresponding IgM. Among 97 cases of primary extra-pulmonary tuberculosis, 94% were found IgG positive and 33% IgM positive. The difference between active and inactive post-primary (chronic) tuberculosis was striking: about 100% of both pulmonary and extra-pulmonary cases (367 altogether) had high titers of anti-A60 IgG but IgM positivity was observed in only 15% of the cases, whereas in inactive and quiescent noncavitary tuberculosis (442 cases), 57% of the patients were weakly positive for anti-A60 IgG and none were positive for IgM. Kinetics of synthesis of anti-A60 IgG and IgM were analysed in primary and post-primary (chronic) active tuberculosis. The IgM tracing immune response to A60 was shorter and lower during primary tuberculosis as compared to post-primary tuberculosis. Our findings point to the high prognostic value of the A60- ELISA test for tuberculosis. Anti-A60 IgM mark initial stages of the disease or reactivation processes whereas anti-A60 IgG last longer than IgM and provide an evaluation of the intensity of the infectious process. Repeated serological tests allow monitoring of the course of the infection and the efficacy of therapy. The test is negative in healthy BCG-vaccinated persons (tuberculin-positive) and healed tuberculous infection cases. The combined use of both IgG and IgM tests helps in the correct diagnosis of "false positive" cases.
"Chelex 100" chelating resin has been previously proposed for the rapid extraction of human DNA for polymerase chain reaction. Protocols are given for the rapid extraction of bacterial and viral DNA from cultures or clinical samples. The DNA samples obtained were suitable for use in polymerase chain reaction.
We evaluated an alkaline phosphatase-labeled oligonucleotide probe for the rapid identification of Mycobacterium tuberculosis and mycobacteria belonging to the M avium and M intracellulare complex (MAIS). Sixty-two strains of mycobacteria and eight strains belonging to related genera were studied. All M tuberculosis strains hybridized with the tuberculosis probe. All M avium and M intracellulare gave a strong signal with their probes. However the 3 M xenopi strains tested hybridized with all probes for MAIS complex.
Activity of the new fluoroquinolone sparfloxacin against 30 strains of M. avium complex and 25 strains of M. xenopi was tested in vitro. Sparfloxacin was used alone (determination of MICs and MBCs) and in combination with ethambutol and rifabutin. Synergy studies with determination of the FIC and FBC indices showed that the sparfloxacin-ethambutol combination was synergistic against 10 M. avium complex strains and 12 M. xenopi strains. With the three-drug combination (sparfloxacin-ethambutol-rifabutin), synergy was found against 12 M. avium and 14 M. xenopi strains. Studies of intracellular bacteria showed that the decrease in viable bacteria with the three-drug combination was 1 log for M. avium and 2 log for M. xenopi.
We propose a rapid two-step PCR to amplify a 767-bp sequence present in the gene coding for the 65-kD antigen of mycobacteria. The high G+C content (80%) permitted annealing to occur at 70 degrees C, enhancing the specificity. The amplified fragment contains a restriction site for differentiation between M. tuberculosis, M. bovis/BCG, and M. avium. Complete diagnosis can be achieved in less than four hours without labelled probe or nucleic acid transfer.
Bacillus licheniformis has been found to be one of the dominant nosocomial species of Bacillus: laboratories dealing with nosocomial infections must be able to identify Bacillus up to the species level. To date, no DNA probes have been isolated for B. licheniformis although there is a clear need for a direct detection by polymerase chain reaction. The isolation of a B. licheniformis-specific DNA probe, as described in this paper, represents the first step toward accomplishing this goal.
Efficacy of various antibiotics: amikacin, rifampicin, rifabutin, ciprofloxacin, temafloxacin, erythromycin and clarithromycin was evaluated against pigmented and unpigmented variants of Mycobacterium avium complex isolated from patients with acquired immunodeficiency syndrome. The minimal inhibitory concentrations of antibiotics against unpigmented variants were multiplied by 2 to 16 compared to those of pigmented variants. Observations with intracellularly growing bacteria showed that unpigmented variants were more resistant to antibiotics than variants with a difference of approximately 0.25 a 0.3 log 10 in decrease of viable or bacterial counts. The combinations of temafloxacin or ciprofloxacin with rifabutin and amikacin were most effective against unpigmented variants.
Fourteen strains of Mycobacterium marinum were isolated from patients with granulomatous skin lesion. All the strains were resistant to isoniazid and pyrazinamid and five resistant to rifampicin. The following antibiotics are used alone or in combination: ethambutol, rifabutin, ciprofloxacin, temafloxacin, erythromycin, clarithromycin, minocyclin. Minimal inhibitory concentrations are evaluated using agar dilution method. After what, activity of antibiotics against Mycobacterium marinum strains within human macrophages in investigated. After treating the monolayers at 24 and 96 h, a bactericidal effect is observed with rifabutin, ciprofloxacin, temafloxacin, clarithromycin and minocyclin. Combinations of ciprofloxacin, temafloxacin or clarithromycin with ethambutol and rifabutin produced synergistic effect.
High-performance liquid chromatography is used for identification and quantitation of impurities which may be encountered in a new antalgic, benorilate (or Salipran), an ester of aspirin with paracetamol. Gradient elution is carried out using a stationary phase consisting of porous 10-micron silica beads bonded to alkylnitrile (Micropak CN), and a mixture of hexane-methylenechloride-methanol-acetic acid with varying methanol percentage as mobile phase. The following impurities were separated from benorilate: acetylsalicylic anhydride, aspirin, acetylsalicylsalicylic acid, salophene, amino-4-phenylacetoxy-2-benzoate, paracetamol, p-aminophenol. The repeatability of the quantitative analysis is good with a standard variation of 0.54% for benorilate (7 injections). Detection is by UV absorption at 254 nm, and detectability is between 2-10(-9) moles for p-aminophenol and 4-10(-11) moles for salophene.
Penimocycline is an antibiotic obtained by Mannich reaction between tetracycline and ampicilline. Separation of penimocycline from tetracyclines and other impurities has been studied by high-performance liquid chromatography. The most effective method is liquid-liquid partition on a Micropak CH column (non-polar hydrocarbon bonded on porous silica microparticles) and gradient elution with water-methanol, 0.02 M phosphate buffer (pH 7.6) and 1 mM EDTA. Some results on hydrolysis of penimocycline are given.
The separation by high-performance liquid chromatography of seventeen phenylthiohydantoin derivatives of amino acids released after Edman degradation of proteins is described. Sixteen phenylthiohydantoin derivatives of amino acids are differentiated within 40 min by liquid-liquid partition on a column packed with Micropak CN (moderately polar alkyl nitrile phase bonded on 10mum porous silica microparticles) and gradient elution with hexane=methylene chloride-isopropanol mixtures.