Search PubMed⌕ Search

Biomedical subjects

H H Floch

Publications and source records attributed to H H Floch.

At least 37 records · Page 2Linked to original sources
PubMed1991

The effects of chronic ethanol administration on rat liver and erythrocyte lipid composition: modulatory role of 'evening primrose oil'.

The effects of chronic administration of ethanol on the lipid composition of erythrocytes and liver of rats were investigated. Ethanol was chronically administered alone or in combination with Evening Primrose Oil (containing 10% v/v gamma-linolenic acid) in a nutritionally balanced milk diet. Chronic administration of ethanol alone significantly decreased the content of arachidonic acid in erythrocyte membranes, whereas the concomitant administration of Evening Primrose Oil reversed this effect. The triacylglycerol content was significantly increased in the microsomal fraction of the liver after chronic ethanol administration. Ethanol also significantly increased the ratio of cholesterol:cholesteryl esters in the microsomal fraction. The arachidonic acid content of the whole liver fraction was significantly reduced after chronic administration of ethanol, whereas concomitant administration of Evening Primrose Oil did not reverse this effect. The administration of Evening Primrose Oil during chronic ethanol intake may have beneficial effects, as it reverses some of the effects of ethanol on erythrocyte and hepatocyte membrane lipids which may be detrimental to health.

Animals↗
PubMed1991

Changes in whole brain membranes of rats following pre- and post-natal exposure to ethanol.

The chronic effects of ethanol on the fatty acid composition of rats that have been exposed to ethanol in utero were examined. Ten female Wistar rats were fed a nutritionally adequate liquid diet for 3 weeks before mating, throughout gestation and until the offspring reached the 10th or 20th post-natal day. Whole brain lipid changes were examined at these 2 time points. On day 10, a decrease in 18:1 lipid content was found, indicating tolerance development. However, by day 20 an increase in polyunsaturated fatty acid content (20:4) was detected, indicating that ethanol may be causing an increase in membrane fluidity. Although these results are contrary to those found in adult rats following chronic ethanol administration, it seems likely that, in the immature animal, the brain is still undergoing rapid development and therefore may be affected differentially by ethanol.

Animals↗
PubMed1990

Unusually high rates of metabolism of DHT in cytosols of the quail uropygial gland.

The metabolism of DHT in the cytosol of the quail uropygial gland was found to be so high that the steroid was almost completely inactivated within 2 hours of incubation at 0 C. In these conditions, DHT cannot be used for the characterization of androgen receptors. By contrast, R 1881 and mibolerone, which are not metabolized, can be used as alternative ligands. Moreover, the extremely high metabolism of DHT questions the physiologic role of this steroid in the quail uropygial gland.

Animals↗
PubMed1990

Ethanol-inducible cytochrome P-450: assessment of substrates' specific chemical probes in rat liver microsomes.

The capacity of liver microsomes to oxidize various substrates known to be specific of alcohol-inducible cytochrome P-450 was studied in rats treated with different xenobiotics such as 3-methylcholanthrene, phenobarbital, acetone, and ethanol. Analysis of results showed a significantly marked increase following ethanol and acetone treatments of the p-nitrophenol hydroxylation (283 +/- 19% and 304 +/- 21%), N-nitrosodimethylamine (NDMA) demethylation (280 +/- 105% and 228 +/- 95%), benzene hydroxylation (258 +/- 60% and 236 +/- 61%), butanol oxidation (173 +/- 34% and 154 +/- 32%), aniline hydroxylation (147 +/- 22% and 95 +/- 8%), and ether de-ethylation (95 +/- 17% and 83 +/- 17%) and a not significant increase of N-nitrosodiethylamine (NDEA) de-ethylation (34 +/- 11% and 9 +/- 8%) in rat microsomes, respectively, versus control animals (mean +/- SD, values expressed as nmol/min/nmole P-450). All of these activities significantly decreased after 3-MC treatment, except for the p-nitrophenol hydroxylation. PB treatment markedly enhanced NDEA de-ethylation, p-nitrophenol, and benzene hydroxylations (106 +/- 38%, 109 +/- 14%, and 153 +/- 62%, respectively) versus controls. These results suggest that NDMA and especially 1-butanol are the most specific and useful probes of alcohol-inducible cytochrome P-450 in crude liver microsomes.

Acetone↗
PubMed1989

Metabolism of androgens in human hyperplastic prostate: evidence for a differential localization of the enzymes involved in the metabolism.

The subcellular distribution of 5 alpha-reductase, 17 beta-hydroxy steroid dehydrogenase, 3 alpha- and 3 beta-hydroxysteroid dehydrogenase activities was studied in human hyperplastic prostate. 5 alpha-reductase and 17 beta-hydroxysteroid dehydrogenase activities are located in the nuclear envelope. 3 alpha-hydroxysteroid dehydrogenase activity was almost equally distributed between cytosol and membranes, 3 beta-hydroxysteroid dehydrogenase activity was linked to all membranes. Direct testosterone metabolism (transformation into its active metabolite 5 alpha-DHT and into androstenedione, an inactive androgen) takes place only in the nucleus whereas indirect metabolism takes place mainly in the cytoplasm. These findings add new evidence for the mechanism of action of testosterone in prostatic tissue. Testosterone diffuses into the cell, migrates toward the nucleus and is transformed at the nuclear envelope level into two metabolites, DHT and androstenedione. After transformation into its active form, the hormone enters the nucleus whereas the inactive form is released into the cytoplasm. This metabolism could be seen as a control of the amount of active hormone entering the nucleus and being able to bind the androgen receptor.

17-Hydroxysteroid Dehydrogenases↗
PubMed1988

Testosterone metabolism and its testosterone-dependent activation in the uropygial gland of quail.

The in vitro metabolism in the uropygial gland of the male quail results into large yields of 5 beta-reduced and/or 17 alpha-hydroxylated metabolites. This metabolism was studied in glands of sexually quiescent quails five days after a single intra-muscular injection of testosterone to the birds. This treatment led to an increased production of inactive metabolites (epitestosterone and its 5 beta-reduced metabolites) and to a decrease of unmetabolized testosterone. Thus testosterone controls its own metabolism and by this way means to modulate its action in the uropygial gland of quail.

Animals↗
PubMed1988

Acetaldehyde adducts with haemoglobin: determination of acetaldehyde released from haemoglobin by acid hydrolysis.

Acetaldehyde, the first metabolite of ethanol, reacts with haemoglobin in vitro to produce acetaldehyde-haemoglobin adducts. Some clinical studies on the minor haemoglobins have suggested that these adducts may be formed in people abusing alcohol. Under hydrolysis of haemoglobin, with oxalic acid at 100 degrees C in sealed vials, some acetaldehyde was released and then specifically determined by HPLC. The kinetics of hydrolysis were studied using haemoglobin previously labelled with 14[C] acetaldehyde. The maximum liberation of 14 [C] acetaldehyde was obtained after 3 hr 30 min hydrolysis and this time factor was then utilized in the analysis of alcoholic and control haemoglobin. Thus, we have confirmed the formation of acetaldehyde haemoglobin adducts in vivo. It must be noted that the released acetaldehyde corresponds only to an index of the stable adducts. The levels were higher in alcoholics than in controls (1.417 +/- 0.171 and 1.295 +/- 0.139 nmol/mg Hb, respectively, P less than 0.001). In conclusion, this marker is not a convenient tool for the monitoring of alcohol exposure levels because of the low differences between alcoholic and control haemoglobins.

Acetaldehyde↗
PubMed1987

Improved HPLC determination of urinary neopterin.

In order to improve the urinary neopterin measurement, the reversed-phase HPLC method has been reevaluated. The parameters which influence the chromatographic behavior of 12 pteridines were studied: nature of buffer, pH, ionic strength, addition of organic modifier to the mobile phase. Accordingly, an isocratic HPLC method is described which offers a good compromise between specificity and analysis time. This method is well-suited to automation in routine clinical laboratory use. Using this HPLC method, urinary neopterin related to creatinine was determined in lung diseases (neoplasm, sarcoïdosis and bronchial asthma) and in kidney allografts. This method was shown to be useful in the diagnosis and in the monitoring of treatment of rejection episodes.

Asthma↗
PubMed1986

Determination of free acetaldehyde in blood as the dinitrophenylhydrazone derivative by high-performance liquid chromatography.

A simple and sensitive method is proposed for the measurement of acetaldehyde in human blood. Venous blood samples were collected in EDTA Vacutainer tubes, and treated immediately with 0.6 M ice-cold perchloric acid in saline. After centrifugation at 4 degrees C, the supernatants were treated with dinitrophenylhydrazine reagent. After addition of the internal standard (crotonaldehyde dinitrophenylhydrazone) and 3 M sodium acetate, the derivatives were extracted and analysed by high-performance liquid chromatography (HPLC) using an Ultrasphere ODS column. The compounds were separated using acetonitrile--water as the mobile phase and detected at 356 nm. A blank determination was carried out for each analysis and subtracted from the results. The specificity of the method was tested by UV and mass spectrometry and the purity of the derivatives by capillary gas chromatography. The recovery of blood acetaldehyde was 98%. Interference from ethanol was minimized by using the tripotassium salt of EDTA as an anticoagulant. The sensitivity of the method can be increased dramatically using microbore HPLC. The level of acetaldehyde was found to be 0.41 +/- 0.13 microM (mean +/- S.D.) for eight fasting controls and 0.91 +/- 0.73 microM for fourteen alcoholics (p less than 0.05). At 30 min after oral administration of ethanol (0.8 g/kg), the ethanol levels were 16.3 +/- 2.8 and 17.7 +/- 2.5 mM and the acetaldehyde levels were 1.67 +/- 0.35 and 3.13 +/- 2.43 microM (p less than 0.05) for the controls and alcoholics, respectively.

Acetaldehyde↗
PubMed1986

Changes in neutral lipids in brain synaptosomes of rats after chronic administration of ethanol.

Rats were chronically treated with ethanol in a liquid milk diet for 21 days so that the animals consumed 10 +/- 1 g/kg ethanol daily. Following decapitation, the cortex and hippocampus were removed and a synaptosomal fraction prepared from the cortex. After chronic administration of ethanol, a significant decrease in the cholesterol esters:cholesterol ratio was found in the cortical synaptosomes and a decrease was found in the linoleate content of the cholesterol esters fraction. The composition of the pool of free fatty acids remained unchanged. These results are in agreement with those previously reported which show that following its chronic administration, ethanol decreases polyunsaturated fatty acid composition of phospholipids in the synaptosomal fraction and increases the saturated and monounsaturated fatty acids in cholesterol esters.

Alcoholism↗
PubMed1986

Determination of 5 alpha-androstane-3 alpha,17 beta-diol and 5 alpha-androstane-3 beta,17 beta-diol in human plasma by selected ion monitoring.

5 alpha-Androstane-3 alpha,17 beta-diol (3 alpha-diol) and 5 alpha-androstane-3 beta,17 beta-diol (3 beta-diol) were measured in human peripheral plasma by gas chromatography-selected ion monitoring as their t-butyl dimethylsilyl ethers. The purification of the plasma extract involved a Sep-Pak C18 cartridge and high-performance liquid chromatography. The concentrations (mean +/- SD) of the two diols in four normal males are: 213 +/- 111 pg/ml for the 3 alpha-diol and 246 +/- 133 pg/ml for the 3 beta-diol.

Androstane-3,17-diol↗
PubMed1986

Ultrastructural changes in the uropygial gland of the male Japanese quail, Coturnix coturnix, after testosterone treatment. Comparison with the sebaceous gland of the male rat.

The ultrastructure of the uropygial gland of the male quail was compared to that of the sebaceous gland of the male rat after castration and testosterone treatment of both species. In intact animals, the differentiating cells of these glands displayed almost the same pattern as regards their smooth endoplasmic reticulum, an organelle involved in lipogenesis in both cases. Castration reduced the volume of this organelle, while testosterone administration restored cell morphology to a normal or supranormal level. Finally, this study showed that at ultrastructural level, there is a close functional analogy between the uropygial gland of quail and the sebaceous glands of rats as regards their androgen dependency. Consequently, the uropygial gland might be an attractive model for study of action of androgens on sebaceous-like glands.

Animals↗
PubMed1986

Testosterone regulation of androgen receptor levels in the uropygial gland of quails (Coturnix coturnix): a further proof for the androgen dependency of the uropygial gland.

In castrated quails supplemented with testosterone by a chronically implanted silastic capsule, removal of the implant resulted in the gradual disappearance of the androgen receptors in both cloacal and uropygial glands. However, after a 7-day time span, the receptors reappeared in both glands but did not reach the original level of implanted birds. On the other hand, the photostimulation of intact birds induced an increase of the receptor content of their uropygial and cloacal glands when compared to sexually quiescent birds. These results show that, the concentration of the androgen receptors of the uropygial and cloacal glands of adult male quails is partly controlled by testosterone. By comparison with the mechanism of the action of testosterone in mammal target organs, our results add weight to the androgen dependency of quails uropygial glands (a sebaceous like organ).

Animals↗
PubMed1986

Acetaldehyde adducts with serum proteins are not responsible for decreased drug binding in alcoholic patients.

Decreased plasma binding of phenytoin and diazepam has previously been described in patients with alcoholic liver diseases. It has been attributed to hypoalbuminemia, endogenous displacers and/or qualitative changes in albumin such as formation of adducts with acetaldehyde, a highly reactive metabolite of ethanol. In the present report this hypothesis was tested. After treating the sera with activated charcoal to remove the endogenous displacers and adjusting albumin concentration to a constant level, the binding parameters of both drugs, phenytoin and diazepam, were determined in 14 healthy men and 16 alcoholic patients by equilibrium dialysis. In these conditions, no significant difference in the number of binding sites nor in the affinity constant was observed, which suggests that acetaldehyde adducts with proteins do not contribute, to a major extent, to the defect of drug binding observed in alcoholic patients.

Acetaldehyde↗
PubMed1986

Acetaldehyde adducts with serum proteins: effect on diazepam and phenytoin binding.

The in vitro effects of acetaldehyde treatment on the binding of phenytoin and diazepam to human serum albumin (HSA) and human serum proteins (HSP) have been investigated. The incorporation of acetaldehyde into proteins following incubation with different concentrations of [1,2-14 C]-acetaldehyde (0.5, 25, 100 mmol/l) was carried out. The proteins were then dialyzed so that only the stable adduct was retained. Binding of phenytoin and diazepam was then studied. Scatchard plot analysis showed a slight decrease (p less than 0.01 for HSP and 25 mmol/l acetaldehyde) in the number of binding sites for phenytoin when the acetaldehyde/protein ratio was increased. The affinity constant was also increased (p less than 0.01) with 100 mmol/l acetaldehyde. No change could be demonstrated in the number of diazepam binding sites on HSA; an increase in the binding capacity of HSP was shown following incubation with 25 mmol/l acetaldehyde. The fraction of drug bound at therapeutic levels has been also calculated for both drugs. An increase for diazepam but no change for phenytoin can be observed before or after treatment of proteins with acetaldehyde.

Acetaldehyde↗
PubMed1986

Androgen regulation of the androgen receptor of the quail uropygial gland: application of a [3H]mibolerone exchange assay.

An exchange assay for androgen receptors in the quail uropygial gland using [3H]mibolerone was established. The most efficient exchange conditions were 3 days of incubation at 15 degrees C. Under these conditions, androgen receptors were stable in the presence of sodium molybdate, and the exchange of [3H]mibolerone with endogenous testosterone bound to cytosolic or nuclear androgen receptors was maximal. Less than 5% of [3H]mibolerone-binding sites occurred in the extracted nuclear pellets. Using this exchange technique, it was shown that androgen receptors in the uropygial gland of photostimulated male quail or castrated quail treated with testosterone were activated and that their concentrations in both cytosolic and nuclear fractions were increased. These results confirm the androgen dependency of the quail uropygial gland, and show that it is an organ which can be used as a model for the study of androgen action in sebaceous glands.

Animals↗
PubMed1985

Determination of 5 alpha-androstane-3 alpha, 17 beta-diol and 5 alpha-androstane-3 beta,17 beta-diol in human plasma by radioimmunoassay.

5 alpha-Androstane-3 alpha,17 beta-diol (3 alpha-diol) and 5 alpha-androstane-3 beta,17 beta-diol (3 beta-diol) were measured in human peripheral plasma by radioimmunoassay using celite microcolumn purification. The antisera used for the assay were obtained by immunization of rabbits with 3 alpha,17 beta-dihydroxy-5 alpha-androstane-6-(O-carboxymethyl) oxime: BSA for 3 alpha-diol and 3 beta,17 beta-dihydroxy-5 alpha-androstane-15 alpha-carboxymethyl: BSA for 3 beta-diol. The concentrations (pg/ml +/- SD) of the two diols in normal male and female plasma are respectively: 216 +/- 51 and 49 +/- 32 for 3 alpha-diol, 239 +/- 76 and 82 +/- 45 for 3 beta-diol. Comparison of these results with published ones shows that 3 beta diol concentrations were significantly lower. The high specificity of the assay is due to chromatography on celite microcolumns, allowing elimination of 5-androstene-3 beta,17 beta-diol from the plasma sample.

Adult↗