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Défontaines AD, Prost J. Critical points in layered systems. PHYSICAL REVIEW. E, STATISTICAL PHYSICS, PLASMAS, FLUIDS, AND RELATED INTERDISCIPLINARY TOPICS 1993; 47:1184-1198. [PMID: 9960121 DOI: 10.1103/physreve.47.1184] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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Mohamed-Benkada K, Belleville J, Prost J. Comparative changes between pancreas and pancreatic juice digestive enzyme contents during nutritional rehabilitation following severe protein malnutrition in the rat. Br J Nutr 1993; 69:83-96. [PMID: 7681321 DOI: 10.1079/bjn19930011] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The relationship between digestive enzyme activities in the pancreas and pancreatic juice was studied in post-weaning rats fed on a low-protein diet (30 g cereal protein/kg) for 1 month and a refeeding balanced diet (235 g mixed protein/kg) for the following 3 months. A control group was fed on the balanced diet for 4 months. At the end of malnutrition and at various times of refeeding, activities of amylase (EC 3.2.1.1), trypsin (EC 3.4.21.4), chymotrypsin (EC 3.4.21.1), lipase (EC 3.1.1.3), phospholipase A2 (EC 3.1.1.4) and cholesterolesterase (EC 3.1.1.13) in pancreas and pancreatic juice were measured. Recovery of body and pancreas weights was obtained after 3 months of refeeding. Pancreas offered a higher resistance to the low-protein diet; a quicker recovery than that of the whole organism was observed during refeeding. Protein and RNA contents of pancreatic cells were depressed by protein depletion. At the end of refeeding, pancreatic and cell RNA contents were still depressed. In pancreas and pancreatic juice, protein depletion produced a decrease in enzyme activities, with the exception of phospholipase A2 and cholesterolesterase. During refeeding, activities were increased to various levels in pancreatic juice and pancreas. In pancreatic juice, a deficit in enzyme activities still prevailed at the end of refeeding. The retention thresholds (total activity in pancreas v. activity per h in pancreatic juice) of hydrolases were increased by malnutrition. They were all decreased by refeeding at various rates, but after 3 months of refeeding the thresholds were still markedly increased for all enzymes studied. After malnutrition and during refeeding, the dissociated enzyme activities in pancreas and pancreatic juice could be the expression of an alteration at different stages: synthesis, intracellular transport, storage mechanisms and secretion.
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Bouziane M, Prost J, Belleville J. Changes in serum and lipoprotein fatty acids of growing rats fed protein-deficient diets with low or adequate linolenic acid concentrations. J Nutr 1992; 122:2037-46. [PMID: 1527644 DOI: 10.1093/jn/122.10.2037] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The effects of a protein-deficient diet associated with sunflower oil [adequate in 18:2(n-6), poor in 18:3(n-3)] or soybean oil [adequate in both 18:2(n-6) and 18:3(n-3)] on lipid serum and lipoprotein compositions were studied in growing rats. Four groups of rats were fed different diets: SFC (20% casein + 5% sunflower oil); SFd (2% casein + 5% sunflower oil); SC (20% casein + 5% soybean oil); Sd (2% casein + 5% soybean oil). After 28 d, both protein-deficient groups exhibited low concentrations of protein, phospholipid, triacylglycerol and total cholesterol in serum and VLDL. Compared with rats fed 20% casein diets, those fed low protein diets had lower 18:2(n-6) and 20:4(n-6) in phospholipids of serum, VLDL and HDL2-3, and the 20:4(n-6)/18:2(n-6) ratio was twofold higher in triacylglycerols of serum and VLDL. In the SFd-fed group, 22:5(n-6) was higher than in the SFC-fed group for both triacylglycerols and phospholipids in overall lipoprotein fractions studied. In addition, the 20:3(n-9)/20:4(n-6) ratio was 0.1 in HDL2-3 phospholipids of the SFd-fed group. Sunflower oil-fed rats compared with soybean oil-fed rats had greater monounsaturated fatty acids and lower total (n-3) fatty acids in both triacylglycerols and phospholipids of serum, VLDL and HDL2-3, as well as lower total (n-6) fatty acids in serum and VLDL triacylglycerols. Apolipoproteins (apo) of VLDL were drastically depressed in rats fed protein-deficient diets, whereas apo-AI of HDL2-3 showed a particular resistance. Likewise, sunflower oil-fed rats had enhanced apo-B48 of VLDL and apo-C, apo-AII and apo-AIV of HDL2-3. The present findings show that some effects of protein malnutrition were enhanced by alpha-linolenic acid deficiency, in particular reduced (n-6) and (n-3) fatty acid bioavailability.
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Ajdari A, Prost J, Peliti L. Ajdari, Prost, and Peliti reply. PHYSICAL REVIEW LETTERS 1992; 69:861. [PMID: 10047052 DOI: 10.1103/physrevlett.69.861] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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Khalifa F, Bertrand V, Belleville J, Sarda L, Prost J. Short term effect of feeding raw or heated soya flour and casein meals on lipid intestinal digestion and absorption in rat. J Nutr Biochem 1992. [DOI: 10.1016/0955-2863(92)90044-j] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Ajdari A, Duplantier B, Hone D, Peliti L, Prost J. “Pseudo-Casimir” effect in liquid crystals. ACTA ACUST UNITED AC 1992. [DOI: 10.1051/jp2:1992145] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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Bertrand V, Prost J, Belleville J. Réhabilitation nutritionnelle du rat à la suite d'une malnutrition protéique sévère. Effets comparés de la réhabilitation par la farine de coton et de soja sur les protéines et le cholestérol plasmatiques. NUTR CLIN METAB 1992. [DOI: 10.1016/s0985-0562(05)80228-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Prost J, Belleville J. Age and protein restriction followed by balanced refeeding affect pancreatic digestive enzyme outputs and turnover times in rats. J Nutr 1991; 121:2044-54. [PMID: 1719168 DOI: 10.1093/jn/121.12.2044] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Outputs and turnover times of trypsinogen 2, chymotrypsinogen 1, lipase and amylase were determined in pancreatic juice of growing male Wistar rats at various times during protein restriction (5% protein) followed by balanced refeeding (20% protein). In control rats fed a 20% protein diet, trypsinogen 2, chymotrypsinogen 1 and amylase outputs increased progressively with age, those of lipase remained constant and the turnover times of the four hydrolases were shortened. With time, protein restriction induced the most rapid decrease in trypsinogen 2 output, followed by that of amylase, then by those of trypsinogen 1 and lipase. Compared with controls, protein restriction enhanced specific radioactivity in total proteins and each hydrolase and diminished the enzyme turnover times at the beginning of the experiment. Refeeding returned each hydrolase output to control values, but the turnover times remained shortened to the end of experiment. Pancreatic lobules were isolated from control and protein-depleted rat pancreata after 23 d of dietary treatment. After a pulse of [3H]leucine, lobules were incubated in Krebs-Ringer-bicarbonate-HEPES. Basal and stimulated (50 pmol cholecystokinin/L) secretions of total proteins, amylase and radioactive proteins were measured. Protein restriction resulted in a lower response of acinar cells to cholecystokinin. The reduced ability of cholecystokinin to stimulate secretion may be attributable to a lower number and/or to the reduced affinity of cholecystokinin receptors in acinar cells. Therefore, the observed output and turnover changes during protein restriction could be partly due to an impairment of cholecystokinin efficiency.
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Meghelli-Bouchenak M, Belleville J, Boquillon M, Prost J. Metabolism of serum VLDL-, LDL-, and HDL-apoproteins in rats on two different low protein diets. Nutr Res 1991. [DOI: 10.1016/s0271-5317(05)80348-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Ajdari A, Prost J. Free-flow electrophoresis with trapping by a transverse inhomogeneous field. Proc Natl Acad Sci U S A 1991; 88:4468-71. [PMID: 2034684 PMCID: PMC51681 DOI: 10.1073/pnas.88.10.4468] [Citation(s) in RCA: 64] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
We propose an electrophoretic technique combining the use of a series of dielectric traps controlled by an ac electric field and conventional continuous field free-flow electrophoresis. From the theoretical model that we describe, one can expect, for DNA electrophoresis, an improvement of one to two orders of magnitude in the selectivities or experimental durations.
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Abstract
The vast range of technological and industrial application of colloidal systems is largely a direct result of their diversity of structure on microscopic and mesoscopic scales. Recent progress in understanding these structures allows for greater control of the macroscopic properties, as well as providing new avenues of fundamental research in physics, chemistry and materials science.
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Ajdari A, Peliti L, Prost J. Fluctuation-induced long-range forces in liquid crystals. PHYSICAL REVIEW LETTERS 1991; 66:1481-1484. [PMID: 10043220 DOI: 10.1103/physrevlett.66.1481] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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Prost J, Pommier J, Rouillon JC, Marcerou JP, Barois P, Benzekri M, Babeau A, Nguyen HT. Critical behavior of the layer-compressional elastic modulus at a smectic-smectic isolated critical point. PHYSICAL REVIEW. B, CONDENSED MATTER 1990; 42:2521-2525. [PMID: 9995702 DOI: 10.1103/physrevb.42.2521] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Prost J, Belleville J, Valantin-Rollet C. Time course of changes in rat pancreatic synthesis rates and retention thresholds of four hydrolases during consumption of a low-protein followed by a balanced diet. Nutrition 1990; 6:247-53. [PMID: 1726507] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Synthesis rates of pancreatic amylase, trypsinogen 2 (Tg2), chymotrypsinogen 1 (Chtg1), and lipase, were measured in control rats fed a 20% protein diet for 46 days and in malnourished rats fed a 5% protein diet for 23 days (protein malnutrition) followed by refeeding a balanced diet for 23 days. In the control group, a progressive pancreatic maturation (namely an increase in hydrolase synthesis per gram of tissue) appeared with age. In the malnourished group, pancreas maturation of the four hydrolases was inhibited. Synthesis rates of the four hydrolases were reduced to a lesser extent from day 2 of protein malnutrition. With continued protein malnutrition, Tg2 synthesis rates remained steady, whereas the lipase synthesis rate continued to decrease and Chtg1 and amylase rates started to increase. As soon as refeeding was initiated, an important enhancement in synthesis was observed. The synthesis rates of Tg2, Chtg1, and amylase actually showed a rebound effect, then decreased with the refeeding time to reach control values, except for Chtg1, which remained higher than control values throughout the refeeding phase. Lipase synthesis rate rose more slowly and reached the control values only after 9 days of refeeding. The retention threshold (pancreas tissue versus pancreatic secretion) values showed that the storage levels were different from one hydrolase to the other and were variable with age in the control group, and with protein malnutrition and refeeding times in the malnourished group. In the control group, a preferential secretion of newly synthesized enzymes was observed in young rats, whereas with age, the proportion of newly synthesized hydrolases excreted decreased slowly.(ABSTRACT TRUNCATED AT 250 WORDS)
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Prost J, Lejek L. Pore opening in ferroelectric smectic-C free-standing films. PHYSICAL REVIEW. A, GENERAL PHYSICS 1989; 40:2672-2680. [PMID: 9902454 DOI: 10.1103/physreva.40.2672] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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Nallet F, Roux D, Prost J. Dynamic light scattering study of dilute lamellar phases. PHYSICAL REVIEW LETTERS 1989; 62:276-279. [PMID: 10040191 DOI: 10.1103/physrevlett.62.276] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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Nallet F, Roux D, Prost J. Hydrodynamics of lyotropic smectics : a dynamic light scattering study of dilute lamellar phases. ACTA ACUST UNITED AC 1989. [DOI: 10.1051/jphys:0198900500200314700] [Citation(s) in RCA: 110] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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Prost J, Belleville J, Valantin-Rollet C. Effects of age, and protein malnutrition followed by a balanced diet on the non-parallel change in digestive enzymes in the pancreas and their secretion in the rat. Br J Nutr 1988; 60:619-31. [PMID: 2464365 DOI: 10.1079/bjn19880132] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
1. Ninety male Wistar rats were divided into two groups. A control group (C) was fed on a balanced diet, containing 200 g protein/kg for 51 d. An experimental group (E) was fed on a low-protein diet containing 50 g protein/kg for 28 d (PM), and then on a balanced diet for 23 d (BR). At different days of PM and BR, the pancreas and the pancreatic juice were collected 40 min after injection of 0.1 mCi [3H]leucine. The amounts of amylase (EC 3.2.1.1), trypsinogen 2 (EC 3.4.21.4), chymotrypsinogen 1 (EC 3.4.21.1) and lipase (EC 3.1.1.3) were determined after separation by the isoelectric focussing technique. Incorporation of [3H]leucine into the four hydrolases of pancreatic juice and pancreas was also determined. 2. In control rats a progressive increase in the concentration of digestive enzymes and the amounts secreted were observed with age. Maturation was reached when the rats were 9 weeks old. In rats E, PM inhibited maturation of the pancreas. However, individual enzymes were not affected to the same extent and at the same time. As soon as re-feeding was initiated, pancreas maturation took place and a significant increase in these variables was observed. The increases varied according to the hydrolase and did not appear at the same time. 3. In control rats, a preferential secretion of newly synthesized enzymes was observed in young rats, whereas with age, the proportion of newly synthesized enzymes excreted decreased slowly. In group E rats, at the beginning of PM, the proportion of newly synthesized enzymes secreted was very low and increased with time. 4. In rats C and E, our results indicated a non-parallelism between pancreatic enzyme levels and amounts secreted. This non-parallelism was different in both groups, it was changed with age and pancreas maturation in group C, and according to nutritional state in group E.
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Helfrich W, Prost J. Intrinsic bending force in anisotropic membranes made of chiral molecules. PHYSICAL REVIEW. A, GENERAL PHYSICS 1988; 38:3065-3068. [PMID: 9900723 DOI: 10.1103/physreva.38.3065] [Citation(s) in RCA: 225] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Park Y, Lubensky TC, Barois P, Prost J. New critical point in smectic liquid crystals. PHYSICAL REVIEW. A, GENERAL PHYSICS 1988; 37:2197-2213. [PMID: 9899915 DOI: 10.1103/physreva.37.2197] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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Prost J, Toner J. Dislocation-loop melting theory of phase diagrams with nematic regions surrounded by smectic regions. PHYSICAL REVIEW. A, GENERAL PHYSICS 1987; 36:5008-5014. [PMID: 9898760 DOI: 10.1103/physreva.36.5008] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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Baumann C, Marcerou JP, Prost J, Rouillon JC. Frequency behavior of the second-sound damping in the smectic-A phase of octylcyanobiphenyl: Evidence for the divergence of viscosities. PHYSICAL REVIEW LETTERS 1985; 54:1268-1270. [PMID: 10030981 DOI: 10.1103/physrevlett.54.1268] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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