Search PubMed⌕ Search

Biomedical subjects

G Durand

Publications and source records attributed to G Durand.

At least 127 records · Page 7Linked to original sources
PubMed1994

Comparison of enhanced chemiluminescence and colorimetric techniques for the immuno-detection of alpha 1-antitrypsin.

In order to detect, characterize and quantify blotted proteins, such as human alpha 1-antitrypsin (AAT), there is a need for a specific, extremely sensitive, non-radioactive and uniform revelation system applicable to diluted biological fluids and to culture supernatants of cells isolated from such fluids. We compared two immunochemical revelation systems, enhanced chemiluminescence (ECL) and colorimetric procedures, applied to human ATT, after determining their optimal conditions of performance. ECL was the most sensitive method (down to 50 pg blotted AAT), but could not be used to quantify AAT. In contrast, the colorimetric method enables quantification of blotted AAT, either simply dotted or transferred after SDS-polyacrylamide gel electrophoresis, but is not as sensitive as ECL. Using these two complementary procedures, we have been able to detect AAT in the culture supernatant of a monocytic cell line (THP-1), to characterize the different forms of AAT present in the culture supernatant of blood monocytes and to quantify both.

Cell Line↗
PubMed1994

Effect of fish oil diet on fatty acid composition of phospholipids of brain membranes and on kinetic properties of Na+,K(+)-ATPase isoenzymes of weaned and adult rats.

The influence of dietary (n-3) fatty acids (such as eicosapentaenoic and docosahexaenoic acids) as found in fish oil on Na+ sensitivity and ouabain affinity of Na+,K(+)-ATPase isoenzymes (alpha 1, alpha 2, alpha 3) was studied in whole brain membranes from weaned and adult rats fed diets for two generations. The long chain (n-3) fatty acids supplied by fish oil decreased the fatty acids of the (n-6) series compared with the standard diet, resulting in a decrease in the (n-6)/(n-3) molar ratio in both 21- and 60-day-old rats. On the basis of ouabain titration, three inhibitory processes with markedly different affinities were associated with isoenzymes, i.e., low affinity (alpha 1), high affinity (alpha 2), and very high affinity (alpha 3). It appears that the fish oil diet, in part via the modification of membrane fatty acid composition, altered the proportion and ouabain affinity of isoenzymes. Na+ sensitivity is the best criterion of physiologic change induced by fish oil diet. We calculated the Na+ activation for each isoenzyme and found one Na+ sensitivity and two Na+ sensitivities per isoenzyme in weanling and adult rats fed different diets, respectively. In contrast to alpha 2 and alpha 3, alpha 1 appears insensitive to membrane change induced by fish oil diet. Fish oil diet, which is known to confer cardioprotection, induced significant modulation of Na+,K(+)-ATPase isoenzymes at the brain level.

Aging↗
PubMed1994

n-3 fatty acid deficiency increases brain protein synthesis in the free-moving adult rat.

The autoradiographic method with L-[35S]methionine was used to determine the effects of an n-3 fatty acid deficiency on brain protein synthesis. Brain protein synthesis was significantly increased (from 50 to 150%) in 45 of the 52 brain structures studied in n-3 fatty acid-deficient rats as compared with control animals. Biochemical analysis confirmed the increase in overall rate of protein synthesis in brain as a whole.

Animals↗
PubMed1994

Chronic dietary alpha-linolenic acid deficiency alters dopaminergic and serotoninergic neurotransmission in rats.

This study examined the effects of dietary alpha-linolenic acid [18:3(n-3)] deficiency on dopaminergic serotoninergic neurotransmission systems in 60-d-old male rats. Rats were fed semipurified diets containing either peanut oil [the (n-3)-deficient group] or peanut plus rapeseed oil (control group). We measured the densities of the serotonin-2 (5-HT2) receptors and the dopamine-2 (D2) receptors by autoradiography and membrane-binding assays in relation to the fatty acid composition and levels of endogenous monoamines in three cerebral regions: the frontal cortex, the striatum and the cerebellum. Long-term feeding of the (n-3)-deficient diet induced a significantly higher 5-HT2 receptor density in the frontal cortex compared with the control rats without any difference in the endogenous serotonin concentrations. The results also showed some modification of dopaminergic neurotransmission specifically in the frontal cortex in the rats deficient in alpha-linolenic acid, with a significantly lower density of D2 receptors and a significantly lower concentration of endogenous dopamine than in control animals. Moreover, there were lower levels of (n-3) fatty acids in all the regions studied in the deficient rats, balanced by greater levels of (n-6) fatty acids. These results suggest that chronic consumption of an alpha-linolenic acid-deficient diet could induce modifications of the neurotransmission pathways; this might induce the behavioral disturbances previously described in this fatty acid-deficient animal model.

Animals↗
PubMed1994

Effects of dietary fats on nucleoside triphosphatase activity and nuclear membrane fatty acid composition of rats during development.

The effect of various dietary fats on the nucleoside triphosphatase (NTPase) activity and nuclear membrane lipid composition of rat liver during development was assessed. Rats fed a fat-free diet exhibited higher specific activity of NTPase at all ages, compared with control animals. In rats fed a sunflower oil diet, the specific activity of NTPase was also found to be highest at all ages than was observed in the control group. In contrast, animals fed the fish oil diet or peanut-rapeseed oil diet showed a decrease in NTPase activity in comparison with the control group. The specific activity of NTPase was correlated positively with dietary sigma PUFA n-6 (r = 0.03, p < 0.05) and negatively with the dietary sigma PUFA n-3 (r = -0.87; p < 0.05). The fatty acid composition of liver nuclear membranes of rats fed a fat-free diet revealed high levels of 16:1 n-9, 18:1 n-9, and 20:3 n-9 acids. A dramatic decrease in 18:2 n-6, 20:4 n-6, and 22:6 n-3 acids was observed. Animals fed a sunflower oil diet showed high levels of n-6 fatty acids, particularly 22:4 n-6 and 22:5 n-6, and low levels of monounsaturated fatty acids. However, when rats were fed a fish oil diet, the liver nuclear membranes were highly enriched in 20:5 n-3, and 22:6 n-3 acids, and there was a simultaneous decrease in arachidonic acid. From these observations it is concluded that dietary fats induce changes not only in the fatty acid composition of the nuclear membrane lipids but also in the specific activity of NTPase involved in nuclear function.

Adenosine Triphosphatases↗
PubMed1994

[Neuropathies of septic syndrome with multiple organ failure in burnt patients: 2 cases with review of the literature].

We report two cases of axonal sensori-motor polyneuropathies complicating sepsis and multiple organ failure (MOF) among severely burned patients (total burned surface area of 35 to 40 per cent) in which no other cause of neuropathy was retrospectively identified. No steroids or neuromuscular blocking agents had been given. The date of onset was not established but the diagnosis was late, between the 30th and 45th day, at the recovery of consciousness. Regression was incomplete, with severe sequellae especially in one patient who was unable to walk 10 months after the injury. Burned patients can present with many kinds of peripheral neuropathies. Postburn polyneuropathies with nerve conduction slowing were described by Henderson. Mononeuropathies can result from nerve compression complicating unfavorable postures in comatose patients or from nerve entrapment in ischemic limbs. Polyneuropathy in postburn sepsis with MOF does not appear to have been previously reported. Postburn sepsis usually occurs in young patients, without other cause of MOF; and therefore represents a relatively "pure" sepsis syndrome.

Axons↗
PubMed1994

[Magnetic resonance imaging of pulmonary coin lesion and bronchopulmonary cancer].

Magnetic resonance imagery (MRI) is less sensitive than computed tomography (CT) for the detection of pulmonary masses and cannot detect calcifications within such masses. MRI performed during the work-up for bronchial cancers has often been compared with CT scans: neither T nor N can be evaluated with more precision. Nevertheless, there are certain specific indications such as the exploration of proximal tumours with suspected extension into the mediastinum including cardiac and vascular invasion, tumours of the aorto-pulmonary window, the Pancoast-tobias syndromes, and tumours situated near the thoracic wall or the spine.

Humans↗
PubMed1994

Comparison of liver microsome enzyme and fatty acid composition recovery in adult and old rats deficient in 18:3n-3 refed a diet containing 18:3n-3.

The effect of dietary n-3 deficiency on liver microsome enzymes activities and fatty acid composition was studied in adult (3 months old) and old rats (18 months old). At these two ages, deficient animals were refed with 18:3n-3 diet for 1 or 2 months and the recovery of these parameters was investigated. Cytochrome P 450 level was decreased by n-3 PUFA (Polyunsaturated fatty acid) deficiency. After refeeding, it returned to control values after 1 month. NADH-cytochrome b5 reductase activity was decreased, the activities of NADPH cytochrome c reductase, aminopyrine demethylase, aniline hydroxylase were also decreased, but in old rats they were increased by refeeding. N-3 PUFA deficiency caused a decrease of 18:2n-6 and 22:6n-3 and an increase in 20:4n-6, 22:5n-6 and 18:1n-9. After refeeding, in adult rats, the PUFA level remained lower; in old rats, the MUFA (Monounsaturated fatty acid) and PUFA levels returned to control values. Liver microsomal enzyme activities depend on the degree of unsaturation of fatty acids rather than the specific species of polyunsaturated fatty acids.

Aging↗
PubMed1993

Oligosaccharide specificity of normal human hepatocyte alpha 1-3 fucosyltransferase.

A purified alpha 1-3 fucosyltransferase (alpha 1-3 FT) was recovered in the Golgi fraction of isolated hepatocytes from normal human liver tissue. The efficiency of purification was controlled by measurement of fucose transfer to asialotransferrin (for alpha 1-3 FT), to phenyl-beta-D-galactose (for alpha 1-2 FT) and to 2' fucosyl lactose (for alpha 1-3/4 FT). The initial hepatocyte isolation step got rid of 97% and 94% of alpha 1-2 and alpha 1-3/4 total liver FT, respectively. After Golgi enrichment (26-fold purification and a yield of 7.6%), alpha 1-3 FT extract expressed a specific activity of 2 pM/min per mg protein. When incubated in optimized conditions with type 1, 2 or 6 oligosaccharide acceptors (10 mM), hepatocellular alpha 1-3 FT efficiently transferred fucose to N-acetyllactosamine and its 3' sialylated derivative, but poorly to lactose. When incubated with neutral or sialylated biantennary N-glycans, the enzyme expressed the highest affinity (Km = 0.38 mM) for the 3'bisialylated derivative. This suggests that hepatocellular alpha 1-3 FT is involved in the synthesis of sialosyl Le(x) determinants on cirrhotic alpha 1AGP.

Carbohydrate Sequence↗
PubMed1993

Effect of dietary alpha-linolenic acid on functional characteristic of Na+/K(+)-ATPase isoenzymes in whole brain membranes of weaned rats.

The influence of dietary fatty acids on Na+ sensitivity and ouabain affinity of Na+/K(+)-ATPase isoenzymes of whole brain membranes were studied in weaned rats fed for two generations with diets either devoid of alpha-linolenic acid (sunflower oil diet) or rich in alpha-linolenic acid (soya oil diet). The (n--3) deficiency induced by the sunflower oil diet led to an increase in the (n--6)/(n--3) molar ratio in whole brain membranes. Na+/K(+)-ATPase isoenzymes were discriminated on the basis of their differential affinities for ouabain. In rats fed sunflower oil diet, the ouabain titration displayed three inhibitory processes with markedly different affinities: low affinity (alpha 1); high affinity (alpha 2); and very high affinity (alpha 3). Membranes of rats fed soya oil diet exhibited only two inhibitory processes, i.e., low affinity (likely alpha 1+ alpha 2) and high affinity (likely alpha 2+ alpha 3) with the low affinity form intermediate between the sunflower alpha 1 and alpha 2 forms, and the high affinity form intermediate between the sunflower alpha 2 and alpha 3 forms. In fact, the Na+ response shows that the three isoenzymes have different Na+ sensitivities. Regardless of the diet, alpha 1 has a similar Na+ sensitivity (less than 1 mM), whilst alpha 2 and alpha 3 are more sensitive in soya oil membranes compared to sunflower oil membranes (5.1 vs. 7.2 mM and about 11 vs. 22.5 mM, respectively). Thus, sodium appears to be a better criterion of heterogeneity than ouabain.

Animals↗
PubMed1993

Impairment of consciousness induced by valproate treatment following neurosurgical operation.

Eight patients, who underwent neurosurgery for various supratentorial lesions presented unexplained impairment of consciousness during the first post-operative days. These states ranged from stupor to deep coma, and two patients had an emergency re-exploration. All these patients were receiving the usual dosage (1000 to 1500 mg per day) of Valproic acid (VPA). The treatment had been initiated either several weeks or months previously in 4 cases, and was thus well tolerated, or the day before surgery in the 4 other cases. EEG recordings displayed diffuse abnormalities, delta waves and/or high voltage triphasic complexes, that led to the diagnosis of VPA intolerance and drug withdrawal. Then full clinical recovery and EEG clearing occurred within 1 to 5 days. VPA intolerances are wellknown but remain exceptional, about 1 case per 100.000. In our neurosurgical population, however, the rate was higher, approximately 2%. Wide areas of blood brain barrier destruction may contribute to the higher frequency of this easily reversible cause of post-operative stupor or coma.

Adolescent↗
PubMed1993

Effect of age and alpha-linolenic acid deficiency on delta 6 desaturase activity and liver lipids in rats.

The combined effects of age and of diet deficient in n-3 fatty acids on delta 6 desaturation of linoleic acid and on lipid fatty acid composition were studied in the liver of the rat at 2, 6, 12, 18 and 24 mon of age. The profiles of delta 6 desaturase activity and fatty acid composition were studied in the deficient rats refed, at these different ages, either with 18:3n-3 (mixture of peanut and rapeseed oils) or with 20:5n-3 + 22:6n-3 (fish oil) diets for 2, 4, 8 or 12 wk. Results showed that the liver delta 6 desaturation activity in the control rats remained high at 2 and 6 mon, decreased by 30% from 6 to 12 mon, and then remained stable from 12 to 24 mon. In the deficient rats, this activity remained high during the entire period studied. Thus, the profile of liver delta 6 desaturase activity after puberty was not related to age only; it also depended on the polyunsaturated fatty acid (PUFA) n-6 and n-3 balance in the diet. In the controls, in parallel with the delta 6 desaturase activity, PUFA metabolism could be divided into three periods: a "young" period, and "old age" period, separated by a period of transition between 6 and 12 mon. Recovery from PUFA n-3 deficiency occurred at all ages but in a different manner depending on whether the rats were "young" or "old". Recovery was faster if long-chain n-3 PUFA rather than alpha-linolenic acid were supplied in the diet.

Aging↗
PubMed1993

Age-related changes in delta 6 and delta 5 desaturase activities in rat liver microsomes.

Age-related changes in delta 6 desaturation of [1-14C]alpha-linolenic acid and [1-14C]linoleic acid and in delta 5 desaturation of [2-14C]dihomo-gamma-linolenic acid were studied in liver microsomes from Wistar male rats at various ages ranging from 1.5 to 24 mon. Desaturase activities were expressed both as specific activity of liver microsomes and as the capacity of whole liver to desaturate by taking into account the total amount of liver microsomal protein. delta 6 Desaturation of alpha-linolenic acid increased from 1.5 to 3 mon and then decreased linearly up to 24 mon to reach the same desaturation capacity of liver measured at 1.5 mon. The capacity of liver to desaturate linoleic acid increased up to 6 mon and then remained constant, whereas microsomal specific activity was equal at 1.5 and 24 mon of age. The capacity of liver to convert dihomo-gamma-linolenic acid to arachidonic acid by delta 5 desaturation decreased markedly from 1.5 to 3 mon. It then increased to reach, at 24 mon, the same level as that observed at 1.5 mon. Age-related changes in the fatty acid composition of liver microsomal phospholipids at the seven time points studied and of erythrocyte lipids at 1.5 and 24 mon were consistent with the variations in desaturation capacity of liver. In particular, arachidonic acid content in old rats was slightly higher than in young rats whereas contents in linoleic and docosahexaenoic acids varied little throughout the life span.(ABSTRACT TRUNCATED AT 250 WORDS)

8,11,14-Eicosatrienoic Acid↗
PubMed1993

Function of dietary polyunsaturated fatty acids in the nervous system.

The brain is the organ with the second greatest concentration of lipids; they are directly involved in the functioning of membranes. Brain development is genetically programmed; it is therefore necessary to ensure that nerve cells receive an adequate supply of lipids during their differentiation and multiplication. Indeed the effects of polyunsaturated fatty acid (PUFA) deficiency have been extensively studied; prolonged deficiency leads to death in animals. Linoleic acid (LA) is now universally recognized to be an essential nutrient. On the other hand, alpha-linolenic acid (ALNA) was considered non-essential until recently, and its role needs further studies. In our experiments, feeding animals with oils that have a low alpha-linolenic content results in all brain cells and organelles and various organs in reduced amounts of 22:6(n-3), compensated by an increase in 22:5(n-6). The speed of recuperation from these anomalies is extremely slow for brain cells, organelles and microvessels, in contrast with other organs. A decrease in alpha-linolenic series acids in the membranes results in a 40% reduction in the Na-K-ATPase of nerve terminals and a 20% reduction in 5'-nucleotidase. Some other enzymatic activities are not affected, although membrane fluidity is altered. A diet low in ALNA induces alterations in the electroretinogram which disappear with age: motor function and activity are little affected but learning behaviour is markedly altered. The presence of ALNA in the diet confers a greater resistance to certain neurotoxic agents, i.e. triethyl-lead. We have shown that during the period of cerebral development, there is a linear relationship between brain content of (n-3) acids and the (n-3) content of the diet up to the point where alpha-linolenic levels reach 200 mg for 100 g food intake. Beyond that level there is a plateau. For the other organs, such as the liver, the relationship is also linear up to 200 mg/100 g, but then there is merely an abrupt change in slope and not a plateau. By varying the dietary 18:2(n-6) content, it was noted that 20:4(n-6) optimum values were obtained at 150 mg/100 g for all nerve structures, at 300 mg for testicle and muscle, 800 mg for the kidney, and 1200 mg for the liver, lung and heart. A deficiency in ALNA or an excess of LA has the same main effect: an increase in 22:5(n-6) levels.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1993

Deficiency of (n-6) but not (n-3) polyunsaturated fatty acids inhibits the secretagogue effect of prolactin in lactating rat mammary epithelial cells.

The repercussions of various kinds of dietary polyunsaturated fatty acid (PUFA) deficiencies on the fatty acid composition of membranes and on the secretory activity of lactating female rat mammary epithelial cells were investigated. Primiparous female rats were fed different PUFA diets from weaning: adequate (n-6) and (n-3) PUFA supply; overall PUFA deficiency; specific (n-6) PUFA deficiency or specific (n-3) PUFA deficiency. Mammary gland phospholipids contained very low amount of (n-3) PUFA in control rats, and only 1% docosahexaenoic acid. The fatty acid composition of membrane phospholipids reflected the type of diet received by the animals, i.e., the diets deficient in the (n-3) or (n-6) PUFA series resulted in lower (n-3) or (n-6) PUFA, and the (n-3) + (n-6) deficient diet caused a true overall PUFA deficiency in the membranes. The morphology of cells from overall PUFA- or (n-6) PUFA-deficient rats showed an accumulation of secretory vesicles in the cytoplasm. Basal casein secretion was independent of the diet and of the composition of membrane phospholipids. However, prolactin did not have a secretagogue effect on cells from (n-6) PUFA- or overall PUFA-deficient rats but retained this effect on cells from (n-3)-deficient rats. These results emphasize the specific role of (n-6) PUFA in the functioning of the lactating mammary epithelial cell.

Analysis of Variance↗
PubMed1993

Dietary alpha-linolenic acid at 1.3 g/kg maintains maximal docosahexaenoic acid concentration in brain, heart and liver of adult rats.

We have previously determined the dietary alpha-linolenic requirement for membrane synthesis in the developing animal. This study measures the dietary requirement for maintaining normal membrane composition in adult rats, as determined by 22:6(n-3) (docosahexaenoic acid) concentration. Sixty-day-old rats, previously fed a diet containing both linoleic and alpha-linolenic acid, were divided into nine groups, each receiving different quantities of alpha-linolenic acid but the same amount of linoleic acid. They were killed 4 wk after initiation of the new diet to determine the minimum quantity of alpha-linolenic acid required in the diet for maintaining the 22:6(n-3) tissue concentration in brain (whole tissue, myelin and nerve endings), liver and heart. The minimal amount of dietary alpha-linolenic acid that maintained the maximal 22:6(n-3) level and minimal 22:5(n-6) level in tissues was considered to be the dietary requirement. The quantity was found to be 1.30 g/kg diet (0.26% of dietary energy). It was lower than that found for the developing animal (0.4% of energy). At lower quantities of dietary alpha-linolenic acid, 22:6(n-3) was replaced by 22:5(n-6) in the organs examined, except in nervous tissue, in which 22:6(n-3) was highly preserved.

Administration, Oral↗