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Biomedical subjects

E Postaire

Publications and source records attributed to E Postaire.

32 records · Page 2Linked to original sources
PubMed1988

Characterization and identification of substances isolated from dialyzer extracts.

The organic phase of dialyzer dried extracts obtained from Cuprophan hollow fiber and polyacrylonitrile AN 69 parallel-plate dialyzers, all sterilized by ethylene oxide, were submitted to light and polarized light microscopy, infrared (IR) spectrophotometry, and gas chromatography coupled with mass spectrometry. Colorless polygonal (approximately 5 X 20 micron) and needle-like (approximately 3 X 50 micron) crystals were found in great quantity on microscopy examination. IR spectrophotometry of the crystals embedded in potassium bromide disc showed specific spectra in the 1400-800 cm-1 wave number range and typical peaks on wave number assigned for hydroxy or amine (3420 cm-1), aromatic hydrogen (3060 cm-1), methyl, methylenic, or methenyl (2960-2860 cm-1), and carbonyl (1715 cm-1) groups can be demonstrated. Seven peaks were detected on gas chromatography of the organic solution containing crystals. Fatty acids and undefined compounds could originate from the dialyzer. Phtalates may leach from blood tubing, used in the rinsing procedure, and BHT is a stabilizer of ethyl ether used as solvent. These compounds could also originate from the dialyzer since phtalates are widely used as a plasticizer and BHT an antioxidant for various polymers.

Acrylic Resins↗
PubMed1987

Various techniques for the routine evaluation of the degradation of glucose in parenteral solutions--a critical study.

A practical approach is described for studying the influence of various physicochemical factors on the degradation of glucose in parenteral solutions sterilized by heating in an autoclave. Five routine analytical methods are discussed: pH determination; direct ultraviolet absorption measurement (BP) method; liquid chromatography of 5-HMF; thin-layer chromatography of sugars, carboxylic acids and carbonyl species; and enzymatic determination of glucose. The effects of various factors on the degradation of glucose were studied: glucose concentration (10%, 30%, 50%); pH of solution before sterilization (2-10); sterilization cycle (103 min at 110 degrees C, 20 min at 120 degrees C, 3 min at 134 degrees C; same Fo); time of heating at 120 degrees C (30, 40, 60 min); and the presence of salts (sodium acetate, sodium lactate, sodium chloride). The results demonstrate the importance of these factors in influencing the rate of glucose degradation during sterilization. In the presence of salts, 5-HMF is not the most important product of degradation and the BP assay is not suitable for evaluation of glucose breakdown. The authors propose two control procedures. For simple solutions of glucose, the BP method is suitable. In the presence of salts the glucose oxidase method should be used.

Journal Article↗
PubMed1986

[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↗
PubMedDate not supplied

Development of a standard, freeze-dried serum containing the drugs assayed most often in French hospitals.

A quality control program for the therapeutic drug monitoring methodology used to determine serum levels of the fourteen drugs assayed most frequently by French hospital laboratories is described. The program has been adopted by the Societé Française de Biologie Clinique (SFBC), which provides participating laboratories with a statistical analysis of the performance data. The control samples developed for the program are prepared by spiking calf serum with, in one case, phenobarbital, phenytoin, carbamazepine, sodium valproate, amikacin, lithium carbonate, digitoxin and hydroquinidine, and, in the other case, caffeine, quinidine, digoxin, isoniazid and gentamycin. After freeze-drying the spiked serum, the drugs were shown to be stable for at least a year when stored at -20 degrees, +4 degrees and +22 degrees; at the end of this time, the samples were pathogen free. For checking therapeutic drug monitoring methods, the freeze-dried serum is diluted with distilled water (10 ml); these solutions are chemically stable, and remain pathogen-free, when stored in stoppered glass tubes at -20 degrees or +4 degrees for 4 weeks.

Drug Contamination↗
PubMedDate not supplied

Plasma concentrations of beta-carotene, vitamin A and vitamin E after beta-carotene and vitamin E intake.

We have studied the metabolism (absorption) of beta-carotene and vitamin E by assigning eleven volunteers to receive daily two capsules of OENOBIOL, each containing 15 mg of beta-carotene and 15 mg of vitamin E, over 60 days. The beta-carotene, vitamin E and vitamin A plasma levels were then determined using new methods developed in our laboratory. After two months, the actively treated group's median beta-carotene and vitamin E levels were significantly higher than those of a control group. However, no significant change between treated and control groups in the mean of vitamin A (retinol) plasma levels were observed. Treatment with beta-carotene, a vitamin A precursor, does not significantly modify the vitamin A levels. This conclusion had already been observed and it is assumed that a plasma level of beta-carotene equal or higher than 0.3 mg/L reflects a nutritional intake of provitamins sufficient to support homeostasis of retinol (Brubacher et al., 1982).

Absorption↗
PubMedDate not supplied

Thermal desorption-gas chromatographic determination of ethane and pentane in breath as potential markers of lipid peroxidation.

Formation of free radicals and lipoperoxidation occur at the onset of cellular damage. These effects are produced during normal metabolism and in pathological states. The peroxidation of polyunsaturated fatty acids, i.e. linoleic acid and linolenic acid, which are both cellular membrane compounds, induces ethane and pentane formation in pulmonary air exhalation. These two volatile hydrocarbons can be considered as potential lipoperoxidation markers. Methodological difficulties limit the use of these gases for assessment of free oxygen radical activity but we have developed and validated a non-invasive technique. A study was performed with ten healthy volunteers.

Biomarkers↗