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Biomedical subjects

M Postaire

Publications and source records attributed to M Postaire.

At least 19 recordsLinked to original sources
PubMed1992

[Determination of mannitol and lactulose in urine by capillary gas chromatography].

Gas capillary chromatography (GCC) determination of mannitol and lactulose in urine after oral intake is a method for assessing the intestinal permeability in various bowel diseases. The method proposed, using gas capillary chromatography with flame ionization detection after silylation of urine residue, gives good results: coefficients of variation varied from 6 to 8.7% for mannitol and 7.5 to 13.7% for lactulose. Detection limit was 5 mg/l for both compounds.

Flame Ionization↗
PubMed1991

[Intrinsic chemical stability of resins for removable dentures].

This article begins by recalling the notions of biocompatibility and bio-material, in order to define the general context of the research on the intrinsic chemical inertia of resins used for removable prostheses. The materials (10 resins), equipment and operating conditions set up to obtain the extraction liquids which are analysed according to three procedures are then treated: molecular absorption spectrophotometry under ultra-violet rays, gas phase chromatography, coupled with mass spectrometry and atomic absorption spectrometry. Gas phase chromatography coupled with mass spectrometry showed that only one resin released diethyl phthalate after an immersion duration of 8 weeks. Various propositions are discussed in order to try to explain these various behaviours. In conclusion, it appears at the end of this investigation that the resins tested (except for one) show good intrinsic chemical stability when they are used according to precise and rigorous procedures.

Biocompatible Materials↗
PubMed1991

[Complete removable dentures and prognathism].

Further to some reminders concerning terminology and resorption, this article presents the full denture prosthetic treatment for two patients with total edentation and a prognathic malocclusion. The first case presents a tridimensional symptomatology, described by: a progeny; a voluminous mandibular terrain; a concave profile; a rather closed mandibular angle; a mandible ridge which circumscribes the upper jaw; The particularities of the prosthetic treatment in this case are: a lowering of the posterior occlusal plane; a mounting of the teeth in a limited external position, that is to say, the maxillary lingual cuspids and the mandibular mesio-distal groove on the inter-crest line; the mandibular incisors and cuspids placed with a lingual inclination to obtain an edge-to-edge occlusal contact. The second case is of vertical symptomatology type, described by: a macrogeny; a moderate concavity of the profile; a very marked increase of the vertical dimension; an open mandibular angle; a short ramus; a long mandibule; a very marked overjet between the anterior crests. The particularities of the prosthetic treatment for this case are: a posterior teeth placement, avoiding cross-bite position, taken into account the strong convergence of the intercrest lines; a strong lingual inclination of the mandibular incisors and cuspids, in order to obtain an edge-to-edge occlusal contact. In the light of these two specific cases, emphasis is placed on the particularities of the treatment and on the teeth placement proposed in order to avoid any cross-bite teeth mounting.

Adult↗
PubMed1991

[Determination of fluorides and fluorophosphates in drugs, toothpastes and mineral waters by gas liquid chromatography].

Fluorides and monofluorophosphates present in drugs, toothpastes and mineral waters are converted into an organic compound by trimethylchlorosilane at acidic pH. The trimethylfluorosilane formed is determined with isopentane as internal standard by gas liquid chromatography with flame ionization detection. Some drugs containing fluoride at therapeutic or physiologic concentrations also some toothpastes and mineral waters were analyzed easily by this method. No interferences due to excipients or to other active substances present in drugs or toothpastes were observed with this method. Because of its sensitivity (0.01 ppm), its accuracy (CV: 0.7 à 2%) and its simplicity, the chromatographic method proposed is suitable for the routine controls of fluorides in drugs, toothpastes and mineral waters.

Chromatography, Gas↗
PubMed1991

[Elastomers and peripheral seal in complete maxillary dentures].

First the various physical factors involved in retention are discussed. Adhesion is designed by the Gibert formula: [formula: see text] bringing the notion of interfacial surface delimited by the fluid meniscus (epsilon) and the thickness of the salivary film at the site of formation of the meniscus (h). Atmospheric pressure plays a role by the formation of a periphery seal ensuring the creation of a depression of the interfacial fluid in order to oppose the forces of pulling. As a summary, it is important to achieve the formation of a salivary meniscus: with the smallest curvature; continuous despite the mobility of the mucosa; beyond the limit between the free mucosa and the attached mucosa and the "farthest" possible from this area. The purpose of recording the periphery borders is to obtain the highest and widest possible denture flanges without any over-extension or over-thickness. The authors then propose performing a comparative study of the various materials available for recording the periphery of maxillary full dentures, in order to determine which best responds to the criteria of quality mentioned. Several recording techniques are possible, depending on the material used: either a segmented border recording (widely described); or a recording of the periphery seal in one or several stages which is then illustrated by the use of Impregum. For each patient, recordings of the periphery was made according to a protocol always identical and precise; only the material used for this purpose (Kerr compound, regular Neo-Plex and Impregum) varied. The measure taken from these recordings showed that Impregum demonstrates the highest and thickness borders as opposed to Neo-Plex and Kerr compound which provided intermediary results. Thus, Impregum appears to be the material of choice for the optimal recording of the functional periphery seal in maxillary full dentures.(ABSTRACT TRUNCATED AT 400 WORDS)

Dental Impression Materials↗
PubMed1990

Home parenteral nutrition in children: 8 years of experience with 112 patients.

It is essential that children on prolonged parenteral nutrition for anatomical or functional loss of small bowel should enjoy a quality of life which is as normal as possible. Their return home is a major factor in this. Over the past 8 years, 112 children were able to remain at home on cyclic parenteral nutrition. Forty-nine of them are no longer on home parenteral nutrition (HPN), 45 are still on HPN, and 18 have died. Growth and quality of life were good in most cases. Most of the complications were from infection, 1 septicaemia per 594 days on HPN. In the light of these results, HPN seems to be the best option for children requiring prolonged parenteral nutrition, although it can only be considered within the framework of a specialized centre, which ensures patient follow-up, and provides the logistical support required for this high-technology treatment.

Journal Article↗
PubMed1990

[Influence of chemical composition and polymerization technic on the quality of removable denture resins].

With the new means of investigation, such as scan electron microscopy and gaseous phase chromatography combined with mass spectrometry, the authors have analyzed some of the variables involved in the preparation of resin bases for removable prostheses. Various polymerization methods were tested: --the pressed technique: standard and Acron MC systems; --the injection technique: SR-Ivocap and Unipress systems. They were thus able to demonstrate the effect of the chemical composition on the homogeneity of the microscopic surface structure of the resins. They also pointed out that some of the muffle systems induce visible strains on the macroscopic surface structure. Besides, they observed that the polymerization cycle does not modify the microscopic surface structure of the resin. In conclusion, they advocate the use of resins with a chemical composition fitted in systems inducing minimum tensions.

Acrylic Resins↗
PubMed1989

[Home parenteral nutrition in children. Evaluation after 8 years' activity with 88 patients].

In cases where an anatomic or functional amputation of the small bowel dictates that parenteral nutrition needs to be prolonged, it is essential to offer the child the best possible quality of life. In this regard, being in his home environment is an important component. Over a 8 year-period (1980-1988), 88 children went home with cyclic parenteral nutrition. In 34, parental nutrition was eventually discontinued: 40 are still parenteral nutrition-dependent and 14 died. In most cases, the growth and quality of life were satisfactory. Complications consisted essentially of infections, with 1 septicemia for 692 days of home parenteral nutrition (HPN). In the light of these results, HPN appears to be the best option for prolonged parenteral nutrition-dependent children. However, it cannot be set up without the help of a suitable center able to follow the children and to ensure the logistic support necessary for this highly technical and demanding type of care.

Adolescent↗
PubMed1989

[Study of blood cyclosporine after kidney or bone marrow transplantation. Comparison of immunofluorescence and radioimmunoassay].

The apparition of cyclosporine, immunodepressive drug, has largely improved the organ transplantations. However, the range of blood concentrations must be defined to allow the efficacity of cyclosporine therapy and to avoid toxic reactions, because there are very important variations for a same dosage according to the individuals and the diseases. Relative to the low concentrations to be determined (about one hundred ng/ml), the most useful methods for cyclosporine measurement are based on immunochemical assays. This work compare the two methods: radioimmunoassay (RIA) and fluorescence polarization immunoassay (FPIA) simultaneously performed on several hundred samples. A very significant correlation exists between the two techniques (r = 0,80). The advantages of immunofluorescent assay consists in rapidity, sensibility and facility to realize emergency analysis.

Bone Marrow Transplantation↗
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↗