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Biomedical subjects

H H Floch

Publications and source records attributed to H H Floch.

12 recordsLinked to original sources
PubMed1979

[Release of diethyl-2-hexyl phthalate from stored blood on contact with polyvinyl chloride].

Softness and flexibility of PVC are due to the addition of plasticizers in high concentration; the most used of them for blood storage bags is DEHP. In this work, a method for labelling DEHP with 14C from 14C phtalic anhydrid is given. A piece of PVC from a commercial blood bag is labelled, in our laboratory, with 14C DEHP and used to follow the kinetics of DEHP leaching in blood during storage. It is also used to study the influence of some parameters such as lipids amount of blood, shaking, and plastic sterilisation on this leaching. DEHP leaching is a three steps phenomenon and the level is not correlated to lipids content of blood. Thermal treatment of PVC and shaking have an influence on leaching. DEHP is not metabolised during blood storage at 4 degrees C and can not be detected as free molecule; it is absorbed on plasmatic proteins.

Blood Preservation↗
PubMed1978

[Determination of plasma theophylline in the newborn by high resolution gas chromatography and specific detection (author's transl)].

The authors describe a micromethod for the determination of blood concentration of theophylline in premature newborn infants. The method includes the specificity of separation in gas phase chromatography on a glass capillary column, and the sensitivity of thermo-ionic detection. After addition of isobutyl-3-methyl-1-xanthine, which constitutes an internal standard, extraction is performed in acid pH, with the mixture dichloromethane-isopropanol. The derivation consists of an N-pentyl reaction. Analysis was carried out on a glass capillary column SE-30 measuring 75 m x 0.5 mm. The technic used is simple and rapid. Its application in pediatrics has been particularly studied; the limit of quantitative detection was 0.1 mg/l. The plasma sample may be 0.05 ml. The reproducibility is about 2% in usual therapeutic doses. The specificity of the method has been widely debated, in particular the stages of extraction, derivation, separation and detection. The authors are convinced that the analyses requiring systems of specific detection, more and more widely used, require a chromatographic apparatus with a high power of resolution; this is illustrated by an example.

Chromatography, Gas↗
PubMed1977

Analysis of C19O3 steroids by thin-layer and gas-liquid chromatography and mass spectrometry.

The separation of twenty-six saturated and two unsaturated C19O3 steroids has been studied by thin-layer chromatography on silica gel F254, with seven mobile phases, and by gas-liquid chromatography on packed columns with four stationary phases; combination of both techniques permitted separation of all the test compounds. The mass spectra of the steroids were obtained by gas chromatography-mass spectrometry and are presented. Fragmentation processes have been studied, and characteristic ions that may be used for multiple ion detection or lead to identification of biologically produced C19O3 steroids are discussed.

Androstanes↗
PubMed1977

Correlative study of the morphology and C19-steroid metabolism of benign and cancerous human prostatic tissue.

Perineal punch biopsy specimens of human prostate with benign hyperplasia (BPH), well- and poorly-differentiated adenocarcinoma and transitional-cell carcinoma were incubated with testosterone-1,2-3H and 5alpha-dihydrotestosterone-1,2-3H. Incubations were carried out using a single tissue-radiosubstrate ratio and time point. Resulting radiosteroid patterns were related to histologic and ultrastructural features of these tissues. Well differentiated neoplasms had ultrastructural characteristics closely resembling hyperplastic epithelia. Both in BPH and in well differentiated carcinomas the C19-steroids were mainly metabolized by the 17beta-hydroxysteroid pathway. In contrast, cells in poorly-differentiated adenocarcinoma and transitional-cell carcinoma lacked the cytoplasmic organelles responsible for secretion; formation of 5alpha-reduced 17beta-hydroxysteroids was decreased in these carcinomas, while conversion to 17-oxosteroid radiometabolites remained unchanged or was greatly increased. These results indicate that loss of prostatic differentiation is attended by a trend from reductive toward oxidative radiotestosterone metabolism. Even in NAPDH-supplemented preparations of the majority of poorly-differentiated tumors, there was diminished transformation to 5alpha-dihydrotestosterone, the key intracellular hormone in the expression of androgenic activity in the prostate. These findings may explain why poorly-differentiated prostatic neoplasms are frequently unresponsive to anti-androgenic therapy.

Androgens↗
PubMed1976

Gas chromatographic analysis of dialkylbarbituric acids.

A variety of procedures for the derivatization of barbituric acids for gas-liquid chromatography (GLC) are described and a convenient procedure for n-alkylation of barbiturates is reported. The gas chromatographic behavior of derivatives(methyl, ethyl, propyl, butyl, pentyl and hexyl) is discussed on the basis of the retention index. For the identification and quatitation of 23 barbiturates in biological fluids, use of the propyl derivatives allows a clear gas chromatogram to be obtained by using only one stationary phase. Alkylation with n-alkylating reagents gives only the N,N'-derivative, as confirmed by nuclear magnetic resonance (NMR) and infrared spectroscopy and gas chromatography-mass spectrometry (GC-MS). The fragmentation pattern by electron-impact mass spectrometry is discussed. Alkylation with branched alkylating reagents gives up to three peaks, the major peak being the N,N'-derivative; the other peaks identified by NMR and GC, correspond to the isomeric N,O-derivatives.

Alkylation↗
PubMed1976

[Diethylhexyl phthalate in plastic bags and glass bottles for blood preservation].

The amount of di-(-2 ethyl hexyl) phtalate (D.E.H.P.) is measured in the liquid contained in plastic bags or glass bottles for blood storage. Comparisons between the results show that D.E.H,P. has an equal level in plastic and glass container liquid except for one blood packs series. Particular attention has been paid to obtain solvents and glassware free from D.E.H.P., and to the specificity and the sensitivity of the detection method: a mass fragmentographic technic has been used.

Blood Preservation↗