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Biomedical subjects

J C Darbord

Publications and source records attributed to J C Darbord.

At least 19 recordsLinked to original sources

Importance of cleaning for reprocessing endoscopes and thermolabile sterile medical devices: French use and regulations.

In France, endoscope maintenance regulations present some particularities in terms of the definitions and texts referring to the disinfection and sterilization of medical devices, with respect to the prion risk. The main measures specified are a double cleaning prior to disinfection, with some stipulations concerning the procedure itself, such as time limits, duration and rinsing. The use of aldehydes in cleaning products is prohibited and it is recommended that peracetic acid, or any chlorinated product, be used at the disinfection phase. For machines, the recycling of detergents or disinfectants is prohibited, and traceability procedures are mandatory. The French Agency for Safety of Health Products (AFSSAPS) is committed to providing standards that prevent any undesirable consequences for the patient, the operator or the equipment. All these measures will be described in a 'user's guide' intended for medical care units, to be released by the National Technical Committee on Nosocomial Infections (CTIN).

Cross Infection↗

Flourescence-assay on traces of protein on re-usable medical devices: cleaning efficiency.

The cleaning of re-usable medical devices before disinfection or sterilization is recognized as being an essential phase. Detection of residual proteins can be used to validate the process, provided a sufficiently sensitive method is employed. A fluorescent method is presented, using orthophtalaldehyde (OPA) bound to N,N dimethyl-2-mercaptoethylammonium, to demonstrate the presence of amino acids on a medical device following cleaning. The sensitivity of this method (10-5 g/l) was assessed and the applicability of this detection technique is verified, using three types of carriers (steel blades, glass tubes or ceramic penicylinders), three types of contaminants (yeast extract, bovine albumin with native sheep's blood and formaldehyde fixed fibrin). In this context, studies involving formaldehyde-fixed fibrin are more sensitive and are to be recommended.

Disinfection↗

Inactivation of prions in daily medical practice.

The danger of transmission of non conventional agents such as prions constitutes a risk that is difficult to evaluate as the actual understanding of the infectious mechanism is minimal. The efficacy of each procedure is evaluated via submitting infectious particles mixed with cellular products to inactivating treatments, and then by inoculating animals with fractions of the preparation. With these protocols, some ineffective treatments can be identified (for example, soaking in aldehyde), and three reference treatments are recommended by the WHO: soaking in 1 N sodium hydroxide (1 h, 20 degrees C), soaking in 12.5% bleach (1 h, 20 degrees C) and steam sterilization in autoclave (134 degrees C-138 degrees C, 18 min). Universal precautions of asepsis and hygiene must be applied, especially in anatomo-pathological laboratories and for the re-use of medical devices in neurosurgery or in ophthalmology.

Animals↗

[Disinfection and sterilization of reusable devices].

Official of quality assurance requirements for the disinfection and sterilization of reusable medical devices in health care facilities has been reminded recently. These requirements concern good manufacturing practices, essential to avoid adverse events. Identification of non critical and invasive devices, protocols for pre-disinfection, cleaning, high level disinfection and sterilization for thermosensitive materials must be evaluated. Monitoring and process control of these operations are defined by French regulations and European standards, and every health professional has to become aware of these limits.

Cross Infection↗

Investigation of an outbreak of wound infections due to Alcaligenes xylosoxidans transmitted by chlorhexidine in a burns unit.

Alcaligenes xylosoxidans, an environmental gram-negative bacillus, was isolated within a 1-month period from six patients in a pediatric burns unit. Twelve isolates were studied, one from each of the six patients (five from wound cultures and one from a blood culture) and one from each of six contaminated atomizers containing chlorhexidine diluted to 600 mg/l. The biochemical and susceptibility patterns of all the isolates were similar, and their DNA enzyme restriction patterns were identical. The epidemic strain of Alcaligenes xylosoxidans was probably introduced into the atomizers during handling of the diluted solution, which failed to eliminate it.

Adolescent↗

Evidence of bacterial biofilm in tubing from hydraulic pathway of hemodialysis system.

Biofilms consist of microorganisms immobilized at a substratum surface embedded in an organic polymer matrix of bacterial origin. Tubing drawn from the fluid pathways within dialysis machines of various models were investigated for biofilm. Scanning electron microscopy (SEM), performed on approximately 2 cm2 samples of the tubing inner surfaces revealed that the inner surfaces of the tubing were covered with biofilms consisting of numerous deposits and glycocalix at different stages of formation with components containing bacteria and algae. Evaluations of biomass were performed from tubing sections of various lengths and inner diameters put in tubes containing water for injection and immersed in an ultrasound washtub for 1 h to ensure sloughing of the biofilm. Living bacteria were identified by plating on nutrient agar media and incubation for 48 h at 37 degrees C. Epifluorescent stains were used for the total bacteria count. Lipopolysaccharide levels were determined by the endotoxin activity measurements. Polyoside contents were determined by the colometric method, and the chemical oxygen demand was measured to evaluate the amount of organic substance. Biofilms detached from tubing samples drawn from the water path, bicarbonate path, and fresh dialysate path within dialysis machines contained approximately 1.10(3)-1.10(6) total bacteria/cm2, yet only some living bacteria were found. Endotoxin levels ranged from 1 to 12 EU/cm2. In contrast in the dialysate fluid, no bacteria were found, and the endotoxin content was under the detection level of the method. The polyoside content and chemical oxygen demand of the biomass ranged from 11 to 83 microg/cm2 and from 53 to 234 mg/cm2, respectively. It is concluded that a germ- and endotoxin-free dialysate does not exclude the risks and hazards of bacteria and endotoxin discharge from biofilm developed on the fluid pathway tubing, acting as a reservoir for continuous contamination, and efforts in the optimization of cleaning and disinfection procedures used for hemodialysis systems should aim to detach and neutralize biofilm when necessary.

Bacillus↗

Study protocol: stability of morphine injected without preservative, delivered with a disposable infusion device.

BACKGROUND AND OBJECTIVE: Morphine hydrochloride, a major analgesic drug, is being increasingly administered using portable disposable infusion devices. The objective of this study was to investigate the stability of morphine in such a system at two concentrations (2.50 and 5.00 mg/ ml) over a 30-day period. METHOD: High-performance liquid chromatography of stored morphine solutions. RESULTS: The best stability was observed with disposable infusion devices filled with a morphine solution containing sodium metabisulphite as a preservative. No breakdown products were detected after 1 month of storage at room temperature, in light or darkness. On the other hand, 2.50 and 5.00 mg/ml morphine solutions without sodium metabisulphite, stored in the infusion device led to the formation of 0.205% and 0.235% of pseudomorphine, respectively, after 6 days of storage in the light, and 1.50% and 0.94% after 30 days storage. CONCLUSION: Morphine hydrochloride solutions stored in disposable infusion devices degraded very slowly, particularly when preserved with sodium metabisulphite. The solutions are stable over 5 days, the maximum period of storage normally required when using disposable infusers.

Analgesics, Opioid↗

Planetary protection program for Mars 94/96 mission.

Mars surface in-situ exploration started in 1975 with the American VIKING mission. Two probes landed on the northern hemisphere and provided, for the first time, detailed information on the martian terrain, atmosphere and meteorology. The current goal is to undertake larger surface investigations and many projects are being planned by the major Space Agencies with this objective. Among these projects, the Mars 94/96 mission will make a major contributor toward generating significant information about the martian surface on a large scale. Since the beginning of the Solar System exploration, planets where life could exist have been subject to planetary protection requirements. Those requirements accord with the COSPAR Policy and have two main goals: the protection of the planetary environment from influence or contamination by terrestrial microorganisms, the protection of life science, and particularly of life detection experiments searching extra-terrestrial life, and not life carried by probes and spacecrafts. As the conditions for life and survival for terrestrial microorganisms in the Mars environment became known, COSPAR recommendations were updated. This paper will describe the decontamination requirements which will be applied for the MARS 94/96 mission, the techniques and the procedures which are and will be used to realize and control the decontamination of probes and spacecrafts.

Containment of Biohazards↗

Bactericidal activity of beta-lactams and amikacin against Haemophilus influenzae: effect on endotoxin release.

Ampicillin or cefotaxime, alone or in combination with amikacin, were tested at levels achievable in CSF for bactericidal activity against eight clinical isolates of Haemophilus influenzae serotype b. Endotoxin release was determined by the limulus amoebocyte lysate test and by macrophage tumour necrosis factor production for each beta-lactam antibiotic, alone and in combination with amikacin. Accelerated killing was observed when amikacin was added to ampicillin or cefotaxime; however, the additional antibiotic-induced bacterial lysis observed after the addition of amikacin to beta-lactam antibiotics was not associated with an increase in endotoxin release.

Amikacin↗

l-Methionine, a Precursor of Trace Methane in Some Proteolytic Clostridia.

The in vivo formation of methane and of several S-methyl volatile compounds from the terminal S-methyl group of l-methionine is reported for growing cultures of four Clostridium strains (C. hastiforme, C. histolyticum, C. subterminale, and Clostridium sp. strain DSM 1786). After growth in 5 ml of unamended medium, C. hastiforme formed the highest amount of methane (408 nmol per tube in the headspace). When the culture medium was amended with 100 mM l-[S-methyl-H(3)]methionine, the four strains formed [H(3)]methane (proportion in the methane peak, >85%) as well as methanethiol, dimethyl disulfide, dimethyl trisulfide, and S-methyl thioacetate labeled on the methyl moiety. Methanethiol is also a precursor of methane for Clostridium sp. strain DSM 1786. The trace methane formation observed for these four proteolytic, nonglucidolytic Clostridium strains can be of ecological interest, particularly in aquatic sediments and in the gastrointestinal tract of humans and animals. It can explain in part the trace methane formation which cannot be ascribed to methanogens sensu stricto.

Journal Article↗

[Comparative study of 3 methods of evaluation of antiseptic products and disinfectants in quality control].

For choosing a protocol of determination of bactericidal activity of antiseptic and disinfectant products, we have compared a method using an MS2 Abbott system and the classic methods: membrane filtration and dilution-method by transfer loops. The bactericidal-activity of 12 antiseptic solutions are determined. The results shown that there was no significative difference between the automated system and AFNOR specifications. The dilution-method by transfer loops gave higher bactericidal concentrations than the two other methods.

Anti-Infective Agents, Local↗

Susceptibility of Torulopsis glabrata in the presence of six antifungal agents determined by comparison of growth at several pHs.

We describe a method using an automated system whereby fungistatic activities can be determined in several conditions. The process was adapted to Torulopsis glabrata, and it showed that benzalkonium chloride, chlorhexidine gluconate, and thimerosal preserve fungistatic activities in acidic medium, whereas acidification reduces the activity of povidone iodine and poloxamer.

Antifungal Agents↗

[Use of the MS2 automated system in the determination of the activity of 5 antiseptic drugs: quality control].

The study of growth curves of Klebsiella pneumoniae and Staphylococcus aureus in presence of five antiseptics, established using a MS2 Abbott system is presented. From our results, the advantages of automation after the adaptation of the method for the determination of bactericidal properties are examined. This technique may be proposed for the quality control of such drugs.

Anti-Infective Agents, Local↗

Headspace gas chromatographic-mass spectrometric analysis of light hydrocarbons and volatile organosulphur compounds in reduced-pressure cultures of Clostridium.

A static headspace gas chromatographic method for the simultaneous separation of trace light hydrocarbons and volatile organosulphur compounds in gases of nineteen Clostridium cultures at reduced pressure is described. The separation was achieved on n-octane-Porasil C after sampling of the gaseous compounds in a PTFE loop without any pretreatment. Most peaks were identified by gas chromatography-mass spectrometry. The presence of methane and ethylene sulphide among Clostridium volatiles is confirmed and 3-methyl-1-butene, 2-methyl-2-butene, dimethyl trisulphide and S-methyl thioacetate are reported for the first time in the Clostridium group.

Clostridium↗

[Artificial nutrition in hospitals: general principles of quality control].

Sterile pharmaceutical preparations must be supplied to clinical wards; their high degree of safety is given by hospital pharmacists who are responsible for quality control of these preparations. Various considerations on the choice of protocol are suggested. Good manufacturing practice is to carry out quality controls at every stage of production of total parenteral nutrition fluids. However, these controls are made difficult by the poor equipment of hospital pharmacies and by the absence of specific pharmaceutical monographs. The selected protocol involves: preliminary controls, which determine the practicability of the suggested formulation, as well as its expiration date: amino acid determinations using liquid chromatography, electrolyte analysis and concentration, pH, evolution of particle size in fat emulsion according to storage conditions, choice of plastic container; microbiological controls: every two months and every time the pharmaceutical staff changes; moreover, a search for bacterial endotoxins using a chromogenic substrate (LAL technique) with "microstrips" is suggested; a sample from each admixture is kept under refrigeration for 15 days; controls during fabrication to check, at the end of the process, if good manufacturing practices have been realized: microbiological sampling of the working area and elaboration of a written procedure; control after fabrication of each nutrient admixture: determination of various elements such as sodium, potassium and dextrose in a 5 ml sample. These assays enable the checking of high standards of fabrication. Hospital pharmacies, despite their reduced equipment, can answer by these procedures to the physicians' needs and supply sterile TPN meeting pharmaceutical standards.

Electrolytes↗