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Biomedical subjects

Y Henry

Publications and source records attributed to Y Henry.

At least 73 records · Page 4Linked to original sources
PubMed1992

Effects of dietary level of lysine and of level and source of protein on feed intake, growth performance, and plasma amino acid pattern in the finishing pig.

The effects of dietary level of lysine and of level and source of CP on voluntary feed intake, growth performance, plasma free amino acids, and carcass characteristics were investigated in a study involving 60 female and 60 castrated male Large White finishing pigs (from 42 to 101 kg live weight) with ad libitum access to feed. Six treatments were compared according to a 2 x 3 factorial plan, with two levels of lysine (.55 and .65% selected below the recommended levels for both sexes) and three types of CP (N x 6.25) supply: a 13% CP diet based on wheat, peanut meal and soybean meal; a 15.6% CP diet providing the same amino acid pattern as that of the basal diet; and a 15.2% CP diet containing the same levels of essential amino acids as the 13% CP diet, with the addition of glutamic acid as a source of nonessential amino acids. By maintaining a constant amino acid pattern separate changes in dietary lysine and CP levels resulted in a relative independency of their effects on feed intake, growth performance, and body composition. Muscle gain increased with supplementary lysine, with a lower response at the lower CP level (13%). At the same level of lysine (.55 or .65%), increasing protein content from 13 to 15.6% did not affect feed intake, but growth rate was lower and feed/gain was increased, partly because of an additional energy cost resulting from catabolism of excess protein.(ABSTRACT TRUNCATED AT 250 WORDS)

Adipose Tissue↗
PubMed1992

Interactive effects of dietary levels of tryptophan and protein on voluntary feed intake and growth performance in pigs, in relation to plasma free amino acids and hypothalamic serotonin.

The effects of dietary level of tryptophan (TRP) and CP content and composition on voluntary feed intake, growth performance, and carcass characteristics in finishing pigs were studied in two experiments, with an equal number of females and castrated males. In Exp. 1, involving 120 Large White pigs from 44 to 99 kg BW with ad libitum access to feed, six treatments were compared according to a 2 x 3 factorial arrangement: 1) two levels of TRP (.09 and .13%), suboptimal and optimal for growth, respectively, 2) three types of CP supply (a 12.5% CP diet based on corn-soybean meal, and adequately balanced for essential amino acids [EAA] other than TRP; 15.7% CP diet with additional protein from corn gluten meal; 16.2% CP diet with additional nonessential amino acids [NEAA, in the form of L-glutamic acid.HCl and glycine], and the same levels of EAA as in the 12.5% CP diet. In Exp. 2, including four of the six previous factorial combinations (.09 and .13% TRP, 12.3 and 15.8% CP with additional protein), 32 pigs of 50-kg initial BW were used during 21 d, and further observations on meat quality characteristics, plasma free amino acid levels, and serotonin concentrations in the posterior hypothalamus were made. The major observed effects were interactions of different magnitude according to sex between TRP level and the amount and the composition of additional CP. At the suboptimal level of .09% TRP, the increase in protein content severely decreased daily feed intake and growth compared with the .13% level, especially in females. Conversely, the addition of NEAA at both TRP levels had little effect on daily feed intake and growth. Deficiency of TRP exerted a significant increase of pH in adductor femoris and semimembranosus muscles measured 45 min and 24 h postmortem, but only in females. Voluntary feed intake, as affected by dietary TRP and CP levels, was linearly related with concomitant changes in TRP to large neutral amino acids (TRP:LNAA) ratio both in feed and in plasma, which in turn was directly associated to hypothalamic serotonin concentration. It was concluded that an overly low concentration of serotonin in the hypothalamus, especially in females, as a result of TRP:LNAA imbalance, could be involved in the reduction of voluntary feed intake.

Adipose Tissue↗
PubMed1992

Multiple enzymatic pathways involved in the metabolism of glyceryl trinitrate in Phanerochaete chrysosporium.

A study of glyceryl trinitrate metabolism by a filamentous fungus, Phanerochaete chrysosporium, carried out with the 14C-labeled substrate, provides evidence for a multienzymatic system leading to di- and mononitrate derivatives. At least two independent enzymatic activities were detected in the cytosolic fraction: an aerobic glutathione S-transferase activity and an anaerobic NADPH-dependent soluble cytochrome P450-like activity. Other hemoproteins with enzymatic activities dependent upon the presence of NADPH or ferrous ions were also detected in the microsomal fraction. Electron paramagnetic resonance spectra characteristic of an interaction between a hemoprotein and nitric oxide appeared in these two subcellular fractions during the anaerobic metabolism of glyceryl trinitrate.

Anaerobiosis↗
PubMed1991

Nitroglycerin metabolism by Phanerochaete chrysosporium: evidence for nitric oxide and nitrite formation.

We have demonstrated that a filamentous fungus Phanerochaete chrysosporium converts glyceryl trinitrate (GTN) into its di- and mononitrate derivatives concurrently with the formation of nitric oxide detected by electron paramagnetic resonance (EPR), and the formation of nitrite. The metabolisms of nitrite and nitrate by the fungus are evaluated and taken into account when considering GTN degradation. Lack of evidence for nitrate formation from GTN suggests that an esterase-type activity is not involved. Furthermore, the kinetics of appearance of the hemoprotein-NO and non-heme protein-NO (FeS-NO) complexes indicate that an enzymatic process producing NO directly from GTN may be involved concurrently with a glutathione transferase-like system.

Aerobiosis↗
PubMed1991

Generation of EPR-detectable nitrosyl-iron complexes in tumor target cells cocultured with activated macrophages.

After immunostimulation, murine macrophages oxidize L-arginine into nitric oxide (NO) which acts as an effector molecule. In this study, we attempted to establish whether activated macrophage-derived NO forms paramagnetic complexes in tumor target cells which do not express by themselves the L-arginine:NO pathway. Accordingly, murine L1210 leukemia cells were cocultivated with activated peritoneal macrophages from Bacillus-Calmette-Guérin-infected mice, or activated in vitro with interferon-gamma. In control experiments, macrophages were prevented from producing nitrogen oxides by incubation with NG-monomethyl-L-arginine, a specific inhibitor of the L-arginine:NO pathway. After coculture, L1210 cells were removed from adherent macrophage monolayers and analyzed by electron paramagnetic resonance at 77 K. In the L1210 cells cultured with activated macrophages, we detected a signal typical of nitrosyl-iron-sulfur complexes, with g values of 2.041 and 2.015. This signal was not present when L1210 cells were either cultured alone or cocultured with activated macrophages in the presence of NG-monomethyl-L-arginine. Mitochondria from activated macrophage-injured L1210 cells also exhibited the signal with g values of 2.041 and 2.015. These results show that when tumor target cells undergo cell-to-cell contact with activated macrophages during culture, the macrophages promote target cell nitrosylation in compartments like mitochondria.

Animals↗
PubMed1991

Nitric oxide, a biological effector. Electron paramagnetic resonance detection of nitrosyl-iron-protein complexes in whole cells.

Nitric oxide has been used for more than 20 years as an electron paramagnetic resonance probe of oxygen binding sites in oxygen-carriers and oxygen-metabolizing metalloenzymes. The high reactivity of NO with oxygen and the superoxide anion and its high affinity for metalloproteins led biochemists to consider NO as a highly toxic compound for a living cell. This assertion has recently been reconsidered following a number of discoveries of great significance: the finding of the activation of guanylate cyclase by NO, the recognition that NO is the precursor of nitrite and nitrate ions released in the activation of macrophages by endotoxin and cytokines, evidence that NO is an Endothelium-Derived Relaxing Factor, and the discovery of NO-biosynthesis from L-arginine, a pathway common in various biological cell-to-cell signalling processes. It is now admitted that NO plays a key bioregulatory role within mammalian cells, between cells of different types and in the host defence response. In the present review we have attempted to give a general picture of what is known of the chemical, physical, biochemical and biophysical properties of NO among the various nitrogen oxides. We have focussed on the structural information that can be obtained by electron paramagnetic resonance spectroscopy of nitrosyl-metalloprotein complexes. Finally we have shown how molecular targets of nitric oxide can be characterized, within whole cells, by electron paramagnetic resonance spectroscopy.

Animals↗
PubMed1991

Impact of dietary tryptophan and behavioral type on growth performance and plasma amino acids of young pigs.

Tryptophan (TRP) content in the protein of the weaning diet was varied from deficient (.70 g/16 g N) to adequate (1.15 g/16 g N) and excess (1.60 g/16 g N) in diets fed to 108 pigs from d 5 to d 26 after weaning (W) and in 72 pigs from d 26 after weaning to slaughter (100 kg live weight) to assess immediate and long-term effects of TRP on performance. Daily weight gain and feed efficiency were improved when dietary TRP was increased from deficient to adequate (+60 and +40%, respectively). Concurrently, daily feed intake was elevated moderately (+15%). No further improvement was observed with excess TRP. In the low TRP group, gain/feed was significantly poorer up to 25 kg live weight, but this effect did not continue later. Although no compensatory growth could be shown in the group fed the deficient diet, growth retardation was very small (1.5%; P greater than .10) at slaughter. Early changes in TRP supply did not affect either carcass or meat quality. Behavioral reactivity, as determined on day W + 5 in an "open-field" test, did not affect early performance, but growth rate during the growing-finishing stage (3.2%) or the whole period (2.5%) was greater by nonemotional than by emotional pigs. Plasma amino acid contents in blood samples, withdrawn on day W + 15 (fed state) and W + 17 (fasted state), were consistent with the effect of TRP on growth rates. However, in the fasted state, a diet x reactivity interaction suggested that TRP removal from the plasma was less rapid in nonemotional than in emotional pigs. Furthermore, increased plasma concentrations of essential amino acids and urea in the latter group suggested that protein and amino acid catabolism was more rapid in emotional than in nonemotional pigs. These data are discussed relative to the effect of the behavioral type of pig on its TRP requirement.

Amino Acids↗
PubMed1991

Impact of dietary tryptophan and behavioral type on behavior, plasma cortisol, and brain metabolites of young pigs.

The behavioral reactivity in an "open-field" test and plasma cortisol levels were studied in 72 pigs from 12 litters fed for 3 wk one of three diets with different levels of tryptophan: deficient (.14%), adequate (.23%), or excess (.32%). "Open-field" tests were performed three times: 5 d (day W + 5), 23 d (day W + 23) and 45 d (day W + 45) after weaning. The exploration time and the number of grunts provided an adequate measure of the individual emotional reactivity at day W + 5. Significant correlations were obtained between exploration time and the number of grunts at each time (r = -.83 at day W + 5; r = -.46 at day W + 23; r = -.71 at day W + 45). The distinction between animals remained (P less than .05) in terms of exploration time at both 23 and 45 d after weaning. At day W + 23, exploration time was lower in the group fed the adequate diet than in the two other groups. This effect was maintained subsequently after feeding all pigs the same adequate diet (day W + 45). In 36 pigs slaughtered at day W + 23, brain TRP concentration was higher with the excess dietary TRP than with deficient or adequate levels. Conversely, other plasma amino acids (particularly threonine) accumulated only in the brains of pigs fed the deficient diet. Plasma cortisol level assayed at weaning (W) and 2 wk later increased with age and was higher in 16-h fasted (day W + 15) than in 3-h fasted (day W + 17) pigs. Correlations were observed within litters in the fasting state, between the cortisol level and behavioral traits measured at day W + 23 (r = .70 for number of grunts, r = -.60 for exploration time). Dietary TRP did not affect the plasma cortisol level irrespective of the nutritional state after weaning. However, an interaction was noted between plasma cortisol and TRP status (P less than .05). Although dietary TRP induced large variations in brain amino acids and 5-hydroxyindole concentrations, changes in behavioral and cortisol responses were relatively minor.

Amino Acids↗
PubMed1991

The "Besançon smoke-free" programme. Concepts, measures and evaluation.

Three years ago the city of Besançon, France, launched a city-wide, multi-level and multi-disciplinary smoking prevention programme with the ambitious goal of reducing the number of smokers by 50%. This paper describes the philosophy and methodology behind the programme while reporting on its mid-term progress.

Adolescent↗
PubMed1990

ARS binding factor 1 binds adjacent to RAP1 at the UASs of the yeast glycolytic genes PGK and PYK1.

The UAS of the yeast gene encoding the glycolytic enzyme phosphoglycerate kinase (PGK) contains several different sequence elements involved in transcriptional activation. These elements include the activator core sequence, which is bound by the RAP1 protein, and three copies of the pentamer sequence 5' CTTCC 3'. Upstream of the activator core sequence is a region (Yfp), identified as the site of a strong DNA-protein interaction. The Yfp region contains the consensus binding site for the factor ABF1. We have purified the Y protein, which binds to the Yfp region, to homogeneity. The Y protein migrates as a doublet on SDS-polyacrylamide gel electrophoresis with an apparent molecular weight of 125 KDa. These properties are similar to those of ABF1. ABF1 synthesised in vitro bound strongly to the Yfp region and formed a gel retardation complex of identical mobility to the complex formed by the Y protein. UAS1 of the pyruvate kinase gene (PYK1) promoter contains a RAP1 binding site and single copy of the CTTCC sequence. We have now identified an ABF1 binding site close to the RAP1 binding site and CTTCC sequence in the PYK1 promoter. This site is strongly bound by ABF1 in vitro. The organisation of the PGK and PYK1 UASs is thus similar to each other and to the transcriptional silencer HMR(E) which also contains these sequences.

Base Sequence↗
PubMed1990

IFN-gamma-activated macrophages: detection by electron paramagnetic resonance of complexes between L-arginine-derived nitric oxide and non-heme iron proteins.

Interferon-gamma induces the L-Arginine-dependent pathway that leads to the formation of nitrogen oxides in murine macrophages with subsequent inhibition of mitochondrial non-heme iron-dependent enzymes. To evaluate a possible role of nitric oxide through binding to enzymes containing iron-prosthetic groups, we used Electron Paramagnetic Resonance spectroscopy. In IFN-gamma-activated macrophages, we observed the appearance of a signal in the g = 2.04 region which is consistent with that given by nitrosyl-iron-sulfur complexes. Appearance of this signal was dependent on the presence of L-Arginine in the culture medium. Furthermore, we detected a virtually identical signal in macrophages non stimulated by IFN-gamma, following exposure to nitric oxide (after addition of an excess of nitrite in the presence of ascorbate). These data suggest that L-Arginine-derived nitric oxide may alter the configuration of the catalytic site of certain mitochondrial enzymes by coordinating to iron at their iron-sulfur cluster(s).

Aconitate Hydratase↗
PubMed1990

Kinetic studies of four types of nitroheterocyclic radicals by pulse radiolysis. Correlation of pharmacological properties to decay rates.

The chemical properties of the nitro radical of four types of nitroheterocyclic compounds, nitrofurans, 2-nitroimidazoles, 4(5)-nitroimidazoles, 5-nitroimidazoles, having radiosensitizing and cytotoxic properties, have been studied by pulse radiolysis. The acid-base equilibria involving the nitro radical, the imidazole ring and some residues on the heterocycle have been determined. The pH-dependence of the rate of the disproportionation reaction of the nitro radical have been extensively studied. While the nitro radical derived from nitrofurans, 4- and 5-nitroimidazoles had a second-order decay, those of the 2-nitroimidazoles were found to decay through simultaneous first-order and second-order processes. Intrinsic second-order rate constants of the decay of the radical species in its various acidic and basic forms, could be determined. The intrinsic rate constants that determine the overall decay rates in the physiologically important 6 to 7.5 pH-range could be related to the one-electron redox potential E7(1). The implication of such chemical properties to enzyme-catalyzed reduction processes and to the mechanisms of radiosensitization and cytotoxicity of nitroheterocyclic compounds are briefly discussed. Pharmacological properties such as in vitro radiosensitization efficiency or metabolic reduction rates could be related to two of the nitro radical intrinsic disproportionation rates.

Chemical Phenomena↗
PubMed1989

Associative effects between two fibre sources on ileal and overall digestibilities of amino acids, energy and cell-wall components in growing pigs.

1. The associative effects of two fibre sources on ileal and overall digestibility of amino acids, energy and cell-wall components were studied by comparing wheat bran and soya-bean hulls in semi-purified diets given to growing pigs. 2. Castrated male pigs were prepared with ileo-rectal anastomosis to measure ileal digestibility, and overall digestibility was measured in pigs without anastomosis. 3. The three diets contained 190 g total fibre/kg dry matter (DM), derived from each fibre source or from a mixture of both fibre sources, so that each source provided half the amount of total fibre, and 170 g crude protein (nitrogen x 6.25)/kg DM by additions of casein. 4. The effects of fibre sources on the ileal digestibility of amino acids were additive for most amino acids; the only significant interactions were found for threonine, methionine and aspartic acid. In contrast with ileal digestibility, systematic negative interactions between fibre sources on overall digestibility of amino acids were noted. 5. There was no interaction between fibre sources in their effects on the digestibility of energy or of cell-wall components, irrespective of the site of digestion. The digestibility values were higher with soya-bean hulls than with wheat bran, especially at the faecal level. 6. It is concluded that ileal digestibility of amino acids provides a better estimate of amino acid availability, as ileal measurements allow a better discrimination between diets than faecal measurements when distinct fibre sources are used alone or in combination at the same total fibre content. In contrast, for energy, the measurement of digestibility at both faecal and ileal levels permits the estimation of the partition of available nutrients between the small and large intestines.

Amino Acids↗
PubMed1987

Radicals of nitroimidazole derivatives: pH dependence of rates of formation and decay related to acid-base equilibria.

Three analogous 5-nitroimidazoles, having radiosensitizing and cytotoxic properties, have been studied by pulse-radiolysis in N2O-saturated aqueous formate solutions. Rates of formation of the radicals ImNO2-. are found to have little pH dependence. Decay of the radicals always follows second-order kinetics. The observed rates of decay decrease by three to four orders of magnitude over the pH range 0-12. A pK at 2.3 has been observed kinetically for metronidazole. The pK assigned to the radical couple (ImH)NO2H./(ImH)-NO2-., or alternatively (ImH2+)-NO2-./(ImH)-NO2-., varies from 4.7 to 6.1, depending on the substituents on the imidazole ring. Intrinsic second-order rate constants for decay of the acidic form of the radical, of the anionic form and of the mixed reactions were determined. While the anionic radical reacts slowly with itself, both the acidic radical self-reaction and the mixed reaction proceed at fast rates. The implications of these chemical properties to the mechanisms of radiosensitization and cytotoxicity of the nitroaryl compounds are briefly discussed.

Acid-Base Equilibrium↗
PubMed1987

Effect of protein and lysine levels in the diet on body gain composition and energy utilization in growing pigs.

Eight replicates of four Large White littermate female pigs were used to evaluate the effect of protein and lysine levels in the diet on the efficiency of protein and energy utilization. In each replicate, one pig was slaughtered at about 20 kg live weight and the others received three diets that contained (per Mcal digestible energy) 37.5 and 2.00 g (diet pl), 37.5 and 2.35 g (diet pL) or 45.0 and 2.35 g (diet PL) of digestible protein and lysine, respectively. Pigs were slaughtered after a 7-wk period. Tissue and chemical composition of the gain and energy and nitrogen gain were determined by using the comparative slaughter technique. Metabolizable energy (ME) intakes were similar in the treatments. Pigs fed the pl diet had a smaller body weight and muscle gain and retained less nitrogen and more lipids than pigs fed pL and PL diets. The decrease in the level of nonessential nitrogen in the diet (pL vs PL) did not affect body weight and muscle gain and the amount of nitrogen retained in muscle tissues. However, pigs given the PL diet had a higher total nitrogen retention and a lower fat deposition and exhibited a higher heat production. For each gram of additional protein catabolized for energy purposes (PL vs pL), heat production was increased by 1.8 kcal. The amount of lysine per unit of muscle gain (38 g/kg) or protein deposited (120 g/kg) was independent of protein and lysine levels in the diet. Estimates of energy (indirect calorimetry) and nitrogen (balance technique) retention were also obtained on the same animals; results were comparable with data obtained by direct measurements.

Animals↗
PubMed1987

Self-selection by growing pigs of diets differing in lysine content.

Two 42-d experiments were conducted with 60 and 100 Large White growing pigs, initially weighing 17.7 and 18.3 kg, respectively, to determine their ability to select between diets varying in lysine content. Dietary lysine levels ranged from .60 to 1.40%. A common basal diet (17% crude protein, 3.3 Mcal digestible energy/kg) based on corn, soybean meal and peanut meal was used in both experiments. When offered a choice between deficient (.60% lysine) and balanced (.85% lysine) diets, the pigs consumed a higher proportion of the balanced diet. However, they did not discriminate between diets deficient in lysine (.60%) or containing excess lysine (1.16 or 1.40%). There were differences in diet preference over time. Pigs offered the deficient diet (.60%) and balanced diet (.85% lysine) progressively chose a higher proportion of the balanced diet as the trial progressed, but pigs offered a marginally deficient diet (.72% lysine) and a diet with excess lysine (1.21%) consumed a higher proportion of the high lysine diet during the first 3 wk of the experiment, but not during the last 2 wk of the experiment. These differences could be explained by the fact that the preference for a higher lysine diet at a given age depends on its proximity to the optimal level for growth, but also on the range between self-selected lysine concentrations.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1985

Acid phosphatase localization in the digestive glands of Dionaea muscipula Ellis flytraps.

The intracellular localization of acid phosphatases in stimulated digestive glands of Dionaea flytraps has been studied to provide evidence for the route taken by this enzyme during secretion. Previous studies have either included or excluded a role for the dictyosomes in this pathway. Both p-nitrophenyl phosphate and beta-glycerophosphate were used as substrates, and both gave similar localization patterns. Unstimulated glands contained little phosphatase activity in the endomembrane system, whereas 24 and 48 hr after stimulation, heavy deposits of lead were located in the endoplasmic reticulum cisternae, including the nuclear envelope, the dictyosome cisternae, and secretory vesicles. Since dictyosome activation, as judged by the presence of secretory vesicles in the cytoplasm, also coincides with gland stimulation, we conclude that secretion of the hydrolase enzymes occurs via this route and not, as suggested elsewhere, via direct endoplasmic reticulum to plasma membrane connections.

Acid Phosphatase↗