Molecular characterization and evolution of the resident population of some alfalfa mosaic virus (AMV) isolates in Egypt.

BACKGROUND: Alfalfa mosaic virus (AMV) is an important virus affecting many vegetable crops in Egypt. In this study, virus isolates were collected from naturally infected potato, tomato, alfalfa and clover plants that showed suspected symptoms of AMV in different locations of Beheira and Alexandria governorates during the 2019-2020 growing season. The relative incidence of the virus ranged from 11-25% based on visual observations of symptoms and ELISA testing. A total of 41 samples were tested by ELISA using polyclonal antisera for AMV. Four AMV isolates collected from different host plants, named AM1 from potato, AM2 from tomato, AM3 from alfalfa and AM4 from alfalfa, were maintained on Nicotiana glutinosa plants for further characterization of AMV. RESULTS: Electron micrographs of the purified viral preparation showed spheroidal particles with a diameter of 18 nm and three bacilliform particles with lengths of roughly 55, 68, and 110 nm and diameters identical to those of the spheroidal particles. The CP gene sequence comparisons of four AMV isolates (AM1, AM2, AM3 and AM4) showed the highest nucleotide identity of 99.7% with the Gomchi isolate from South Korea infecting Gomchi (Ligularia fischeri) plants. Phylogenetic analysis showed that the present isolates were grouped together into a distinct separate clade (GPI) along with the Gomchi isolate from South Korea. Similarly, the deduced amino acid sequence comparisons of Egyptian AMV isolates revealed that amino acids Q29, S30, T34, V92 and V175 were conserved among the Egyptian isolates in GPI. CONCLUSION: The present study found strong evolutionary evidence for the genetic diversity of AMV isolates by the identification of potential recombination events involving parents from GPI and GPII lineages. Additionally, the study found that Egyptian AMV isolates are genetically stable with low nucleotide diversity. Genetic analysis of the AMV population suggested that the AMV populations differ geographically, and AMV CP gene is under mild purifying selection. Furthermore, the study proposed that the Egyptian AMV population had common evolutionary ancestors with the Asian AMV population. Antioxidant enzymes activity was assessed on N. glutinosa plants in response to infection with each AMV isolate studied, and the results revealed that the enzyme activity varied.

Schwannome endonasal à localisation turbinale inférieure. A propos d'un cas

Introduction : Le schwannome est une tumeur bénigne développée aux dépens des cellules de Schwann des nerfs périphériques. La localisation endonasale en particulier au niveau des cornets est rare. Observation : Nous rapportons le cas d'une femme de 23 ans reçue dans notre structure pour une masse de la fosse nasale droite localisée au niveau du cornet inférieur, obstruant totalement la lumière nasale, sans envahissement local. Après un bilan endoscopique et radiologique, l'exérèse a été effectuée par voie endoscopique endonasale. L'analyse de la pièce opératoire avait mis en évidence un schwannome. Avec un recul de 24 mois nous n'avons pas noté de récidive. Conclusion : Le schwannome à point de départ turbinal inférieur constitue une entité rare. Il doit être considéré dans le diagnostic différentiel d'une tumeur bénigne unilatérale des cavités naso-sinusiennes

[Role of dietary fibers in the nutritional management of chronic renal failure]. / Place des fibres alimentaires dans la prise en charge nutritionnelle de l'insuffisance rénale chronique.

During the past few decades, considerable attention has been given to the impact of nutrition on kidney disease. Although most dietary attempts to treat chronic renal failure (CRF) and to decrease uremia recommend a protein restriction, another dietetic approach, based on dietary fibers (DF), can lead to the same urea-lowering effect by increasing urea-nitrogen (N) excretion in stool with a concomitant decrease of the total N quantity excreted in urine. In fact, feeding DF results in a greater rate of urea N transfer from blood to large bowel, where it will be hydrolyzed by bacterial ureases before subsequent microflora metabolism and proliferation. Because elevated concentration of serum urea N have been associated with adverse clinical symptoms of CRF, these results suggested a possible usefulness of combining DF with a low protein diet to increase N excretion via the fecal route. These results have been shown in animal models of experimental renal failure and in CRF patients. Further investigations in this population of patients are currently in progress to study whether DF may be beneficial on CRF progression and on CRF terminal stage tolerance. A part of this work is financed by the French Society of Nephrology.

Synthesis, characterization and in vitro degradation of a biodegradable elastomer.

An elastomer was prepared from biodegradable components as a potential biomaterial for drug delivery and tissue engineering applications. The elastomer was synthesized in two steps. First, a star copolymer (SCP) was manufactured via ring opening polymerization of -caprolactone (epsilon-CL) with D,L-lactide using glycerol as initiator and stannous 2-ethylhexanoate as catalyst. This living SCP was further reacted with different ratios of a crosslinking monomer, 2,2-bis(epsilon-CL-4-yl)-propane in the presence of epsilon-CL as a solvent and co-monomer. The elastomers had very low glass transitions (-32 degrees C), sol contents ranging from 17% to 37%, and were soft and weak with physical properties similar to those of natural elastomers such as elastin. The physical properties decreased in a logarithmic fashion with time when degraded in phosphate buffered saline, indicative of first-order degradation kinetics. The elastomers degraded relatively slowly, with degradation being incomplete after 12 weeks.

Epithelial cells infected with Chlamydophila pneumoniae (Chlamydia pneumoniae) are resistant to apoptosis.

The obligate intracellular pathogen Chlamydophila pneumoniae (Chlamydia pneumoniae) initiates infections in humans via the mucosal epithelia of the respiratory tract. Here, we report that epithelial cells infected with C. pneumoniae are resistant to apoptosis induced by treatment with drugs or by death receptor ligation. The induction of protection from apoptosis depended on the infection conditions since only cells containing large inclusions were protected. The underlying mechanism of infection-induced apoptosis resistance probably involves mitochondria, the major integrators of apoptotic signaling. In the infected cells, mitochondria did not respond to apoptotic stimuli by the release of apoptogenic factors required for the activation of caspases. Consequently, active caspase-3 was absent in infected cells. Our data suggest a direct modulation of apoptotic pathways in epithelial cells by C. pneumoniae.

Effects of two fermentable carbohydrates (inulin and resistant starch) and their combination on calcium and magnesium balance in rats.

Resistant starch and inulin are complex carbohydrates that are fermented by the microflora and known to increase colonic absorption of minerals in animals. The fermentation of these substrates in the large bowel to short-chain fatty acids is the main reason for this increase in mineral absorption. The purpose of the present study was to examine the potential synergistic effect of a combination of these two fermentable carbohydrates. For this purpose, thirty-two adult male Wistar rats weighing 200 g were used in the present study. The rats were distributed into four groups, and fed for 21 d a fibre-free basal purified diet or diet containing 100 g inulin, or 150 g resistant starch (raw potato starch)/kg diet or a blend of 50 g inulin and 75 g resistant starch/kg diet. After an adaptation period of 14 d, the rats were then transferred to metabolic cages and dietary intake, faeces and urine were monitored for 5 d. The animals were then anaesthetized and caecal Ca and Mg absorption were measured. Finally, the rats were killed and blood, caecum and tissues were sampled. Ca and Mg levels were assessed in diets, faeces, urine, caecum and plasma by atomic absorption spectrometry. Our results confirmed that inulin and resistant starch ingestion led to considerable caecal fermentation in the three experimental groups compared with the control group diet. Moreover, both carbohydrates significantly increased the intestinal absorption and balance of Ca and Mg, without altering the plasma level of these two minerals. Interestingly, the combination of the studied carbohydrates increased significantly the caecal soluble Ca and Mg concentrations, the apparent intestinal absorption and balance of Ca, and non-significantly the plasma Mg level. In conclusion, a combination of different carbohydrates showed synergistic effects on intestinal Ca absorption and balance in rats. Further studies with other types of carbohydrate combinations should be carried out to extend these findings.

[Smoking and atheromatous stenosis of the renal arteries]. / Tabac et sténoses athéromateuses des artères rénales.

UNLABELLED: Renal vascular pathologies are important causes of the chronic renal failure progression. In these pathologies, the role of smoking in so far as factor of risk was discussed. This work aims to evaluate the effect of smoking exposure on renal arteries of patients with both renal failure and hypertension. 67 patients more than 50 years old, having both renal failure and hypertension, have been explored by arteriography. The active smoking was required among all patients. Patients were classified in 2 groups: group (I) of 45 patients with one or more atheromatous stenoses of renal arteries considered to be significant and group (II) of 22 patients without significant atheromatous stenoses of renal arteries. [table: see text] 80.5% of patients of group (I) have smoked against only 44.4% in group (II). The fact that the presence of atheromatous stenoses of renal arteries was connected to the number of cigarettes and the exposure time, and not to the current comportment of patients towards smoking, this suggested a cumulative effect of smoking. CONCLUSION: This work shown a relation between the consumption of smoking and the existence of atheromatous stenoses of renal arteries, a reason moreover to fight against smoking. The prevention of smoking intoxication appears important to decrease the incidence of the renal vascular pathologies.

Fermentable carbohydrate and digestive nitrogen excretion.

BACKGROUND: Interventions that restrict protein intake lower plasma urea concentration and may slow the progression of renal failure. The question arises whether the effect of a dietary protein restriction could be reinforced by enrichment of the diet with fermentable carbohydrate because these carbohydrates may stimulate the extra-renal route of nitrogen (N) excretion through the digestive route. METHODS: The influence of fermentable carbohydrate and moderate protein restriction on N metabolism was investigated in a rat model of renal failure with ablation of 70% of renal mass compared with control rats with intact kidneys. Animals were adapted to diets varying with respect to nondigestible fermentable carbohydrate (0% or 10% fructooligosaccharide [FOS]) and with respect to protein content (10% or 18% casein). RESULTS: Feeding FOS led to a considerable enlargement of the cecum (increase in contents, wall thickness, and blood flow). These changes resulted in a concomitant enhancement of urea N uptake into the cecum and a decrease in plasma urea concentration (-30%). The extent of urea uptake by the cecum was influenced by plasma urea level that was determined by the dietary protein level and by the renal function. Thus, compared with control rats, the rate of urea uptake by the cecum and the total N excreted by the uremic rats was greater under all nutritional conditions. It is noteworthy that, when expressed as a percentage of total N excretion, fecal N excretion nearly doubled in rats adapted to the low-protein diets containing FOS. These effects occurred in both control rats and in uremic rats, in which a 22% decrease in urinary N was recorded as a result of FOS in addition to the low-protein diet. Globally, decreasing the amount of protein in the diet and adding a fermentable carbohydrate led to a decrease in urinary N excretion of more than 65% in uremic rats. CONCLUSION: These results suggest a possible usefulness for combining fermentable carbohydrate, such as FOS, with a low-protein diet to increase N excretion through the digestive route in detriment of the renal route. This may represent an efficient preventive measure to relieve the renal function in case of renal failure.

Low iron availability modulates the course of Chlamydia pneumoniae infection.

Chlamydiae are obligate intracellular bacteria residing exclusively in host cell vesicles termed inclusions. We have investigated the effects of deferoxamine mesylate (DAM)-induced iron deficiency on the growth of Chlamydia pneumoniae and Chlamydia trachomatis serovar L2. In epithelial cells subjected to iron starvation and infected with either C. pneumoniae or C. trachomatis L2, small inclusions were formed, and the infectivity of chlamydial progeny was impaired. Moreover, for C. trachomatis L2, we observed a delay in homotypic fusion of inclusions. The inhibitory effects of DAM were reversed by adding exogenous iron-saturated transferrin, which restored the production of infectious chlamydiae. Electron microscopy examination of iron-deprived specimens revealed that the small inclusions contained reduced numbers of C. pneumoniae that were mostly reticulate bodies. We have previously reported specific accumulation of transferrin receptors (TfRs) around C. pneumoniae inclusions within cells grown under normal conditions. Using confocal and electron microscopy, we show here a remarkable increase in the amount of TfRs surrounding the inclusions in iron-starved cultures. It has been shown that iron is an essential factor in the growth and survival of C. trachomatis. Here, we postulate that, for C. pneumoniae also, iron is an indispensable element and that Chlamydia may use iron transport pathways of the host by attracting TfR to the phagosome.

Les fards rouges cosmétiques et rituels a base de cinabre et d'ocre de l'époque punique en Tunisie: analyse, identification et caractérisation.

Natural antique colorants include mainly red pigments such as cinnabar and ochre. These archeological pigments were used especially as funeral and cosmetic makeup and are a material proof of handicraft activities and exchanges. The identification and characterization of a group of punic colorants, corresponding to samples discovered during excavations at several Tunisian archeological sites (Cartage, Ksour Essef, Kerkouane, Bekalta, Makthar, Bou Arada), were conducted using the least destructive analysis techniques such us scanning electron microscopy coupled to X-ray fluorescence microprobe, direct current plasma emission spectroscopy, atomic absorption spectrometry, Fourier transform infrared spectrometry and X-ray diffraction. Eleven natural red colorants from punic period were subject to this investigation and were compared to contemporary substances. Five colorants were cinnabar and the other six were ochre.

Humoral response of Meriones libycus to experimental infection with Leishmania major.

The humoral responses of laboratory-reared jirds (Meriones libycus) to inoculation with various doses of Leishmania major were determined. The animals were inoculated intradermally with 10(2), 10(3), 10(5) or 10(7) promastigotes of a strain of L. major originally isolated from a Jordanian patient. The jirds were then bled at various intervals throughout the 26 weeks of the study, and the sera checked, by IFAT, for antibodies to homologous parasites. There were no detectable humoral responses in the animals inoculated with 10(2) promastigotes each or in parasite-free controls but a positive response was apparent in each of the other jirds. The animals given 10(3) promastigotes each required 3 months to become IFAT-positive whereas those given 10(5) and 10(7) parasites only needed 4 and 2 weeks, respectively. More than 50% of the animals inoculated with 10(3) parasites each developed strongly positive sera 2 months post-infection, whereas > 50% of the animals inoculated with 10(5) or 10(7) parasites each had strongly or very strongly positive sera 4 and 2 weeks post-inoculation, respectively. The data indicate that, in M. libycus inoculated with L. major, the time required for the humoral response to develop and its intensity are both dose-related.

Role of fermentable carbohydrate supplements with a low-protein diet in the course of chronic renal failure: experimental bases.

During the past few years, considerable attention has been given to the impact of nutrition on kidney disease. The question arises of whether the effect of a moderate dietary protein restriction could be reinforced by enrichment of the diet with fermentable carbohydrates. Feeding fermentable carbohydrates may stimulate the extrarenal route of nitrogen (N) excretion through the fecal route. Such an effect has been reported in several species, including healthy humans and patients with chronic renal failure (CRF). Furthermore, studies of these subjects show that the greater fecal N excretion during the fermentable carbohydrate supplementation period was accompanied by a significant decrease in plasma urea concentration. In animal models of experimental renal failure, the consumption of diets containing fermentable carbohydrates results in a greater rate of urea N transfer from blood to the cecal lumen, where it is hydrolyzed by bacterial urease before subsequent microflora metabolism and proliferation. Therefore, this results in a greater fecal N excretion, coupled with a reduction in urinary N excretion and plasma urea concentration. Because elevated concentrations of serum urea N have been associated with adverse clinical symptoms of CRF, these results suggest a possible usefulness of combining fermentable carbohydrates with a low-protein diet to increase N excretion through the fecal route. Further investigations in this population of patients of whether fermentable carbohydrates in the diet may be beneficial in delaying or treating the symptoms and chronic complications of CRF will certainly emerge in the future. This should be realized without adversely affecting nutritional status and, as far as possible, by optimizing protein intake for the patients without being detrimental to renal function.

Characterization and intracellular trafficking pattern of vacuoles containing Chlamydia pneumoniae in human epithelial cells.

Chlamydiae are obligate intracellular pathogens that reside within a membrane-bound vacuole throughout their developmental cycle. In this study, the intraphagosomal pH of Chlamydia pneumoniae (Cpn) was qualitatively assessed, and the intracellular fate of the pathogen-containing vacuole and its interaction with endocytic organelles in human epithelial cells were analysed using conventional immunofluorescence and confocal microscopy. The pH-sensitive probes acridine orange (AO), LysoTracker (LyT) and DAMP did not accumulate in the bacterial inclusion. In addition, exposure of cells to bafilomycin A1(BafA1), a potent acidification inhibitor, did not inhibit or delay chlamydial growth. The chlamydial compartment was not accessible to the fluid-phase tracer Texas Red (TR)-dextran and did not exhibit any level of staining for the late endosomal marker cation-independent mannose-6-phosphate receptor (Ci-M6PR) or for the lysosomal-associated membrane proteins (LAMP-1 and -2) and CD63. In addition, transferrin receptor (TfR)-enriched vesicles were observed close to Cpn vacuoles, potentially indicating a specific translocation of these organelles through the cytoplasm to the vicinity of the vacuole. We conclude that Cpn, like other chlamydial spp., circumvents the host endocytic pathway and inhabits a non-acidic vacuole, which is dissociated from late endosomes and lysosomes, but selectively accumulates early endosomes.

Intestinal fermentation lessens the inhibitory effects of phytic acid on mineral utilization in rats.

The specific effects of phytic acid (PA) and resistant starch (RS) on mineral bioavailability, namely, Ca, Mg, Fe, Zn and Cu, were investigated in rats adapted to semipurified diets. The diets provided either 73 g/100 g digestible wheat starch (DS) alone, or 53 g/100 g DS plus 20 g/100 g crude potato starch (RS) and either 0 or 1.1 g/100 g PA. A period of 3 wk was first planned to adapt the rats to their respective diets. Compared with rats fed the DS diets, those fed the RS diets had significant cecal hypertrophy and an accumulation of short-chain fatty acids, together with greater cecal blood flow. RS enhanced the cecal absorption of Ca and Mg (from 0.15 to 0.55 micromol/min for Ca, and from 0.10 to 0.35 micromol/min for Mg). Mineral balance was enhanced significantly by RS (Ca, +46%; Mg +50%; Fe +20%; Zn, + 33% and Cu, +61%). PA had no significant effect on Ca or Mg solubility and absorption in the cecum, and it failed to alter significantly Ca or Mg balance. The apparent absorption of Fe, Zn and Cu was significantly lower in rats fed the DS + PA diet than in rats fed the DS diet (Fe, -35%; Zn, -28%; and Cu, -31%). In rats adapted to the RS diet, the inhibitory effects of PA were practically abolished and the mineral balance was restored to the control values. We conclude that the negative effects of PA on mineral balance are relatively minor compared with the stimulatory effect of RS.

Fermentable carbohydrate exerts a urea-lowering effect in normal and nephrectomized rats.

The influence of nondigestible carbohydrate on intestinal fermentations and on the route of nitrogen excretion has been investigated in normal rats and in unilaterally nephrectomized rats. Rats were adapted to 10% casein diets, either fiber free or containing different levels of two fermentable carbohydrates, inulin or crude potato starch. Ingestion of fermentable carbohydrate led to a considerable enlargement of the cecum because of hypertrophy of the cecal wall and an increase in cecal contents. Cecal digesta contained elevated concentrations of short-chain fatty acids, resulting in acidic pH. Diets containing fermentable carbohydrate enhanced fecal nitrogen excretion, which was more than doubled at the highest level of inulin or potato starch. In parallel, urinary nitrogen excretion was significantly decreased by fermentable carbohydrate. Although these changes were similar in all animals, there were quantitative differences in the response of nephrectomized animals to fermentable carbohydrate. In nephrectomized rats, plasma urea concentrations were more than 2.5 times higher than in normal rats (5.8 mM compared with 2.2 mM). Plasma urea concentrations were reduced by approximately 50% when normal rats were fed diets containing 7.5-15% inulin or 10-20% resistant starch. In nephrectomized animals fed the highest level of fermentable carbohydrate, plasma urea concentrations were also significantly decreased, but only by 30%. In nephrectomized rats, the concentration of nitrogen cycling in the cecum was greater (urea nitrogen transfer into the cecum was 50-60% greater and ammonia flux from the cecal lumen to the blood was two times higher than in normal rats), but fecal nitrogen excretion was equivalent in normal and nephrectomized animals. When expressed as a percentage of total nitrogen excretion, fecal nitrogen excretion was <20% in animals fed fiber-free diets, compared with 45-50% in normal animals and 40% in nephrectomized animals fed fermentable carbohydrate.

Effectiveness of resistant starch, compared to guar gum, in depressing plasma cholesterol and enhancing fecal steroid excretion.

Amylase-resistant starch (RS) represents a substrate that can be administered in substantial amounts in the diet, in contrast to gel-forming polysaccharides, such as guar gum (GG). The aim of this work was thus to compare the effects of GG and RS on cholesterol metabolism in rats adapted to 0.4% cholesterol diets, using dietary GG or RS levels (8 or 20%, respectively) that led to a similar development of fermentations, as assessed by the degree of enlargement of the cecum. The RS diet elicited a marked rise in the cecal pool of short-chain fatty acids, especially acetic and butyric acid, whereas the GG diet favored high-propionic acid fermentations. Both polysaccharides markedly altered the cholesterol excretion, from 50% of ingested cholesterol in controls, up to about 70% in rats adapted to the RS or GG diets. With these diets, the fecal excretion of bile acids was enhanced (67 and 144% with the RS and GG diets, respectively). RS and GG diets were effective in lowering plasma cholesterol (about -40%) and triglycerides (-36%). There was practically no effect of the diets on cholesterol in d > 1.040 lipoproteins (high density lipoproteins), whereas RS (and to a larger extent, GG) were very effective to depress cholesterol in d < 1.040 lipoproteins (especially in triglyceride-rich lipoproteins). Fermentable polysaccharides counteracted the accumulation of cholesterol in the liver, especially cholesterol esters. In parallel, liver acyl CoA:cholesterol acyltransferase was depressed in rats fed the RS or GG diets, whereas only the GG diet counteracted the downregulation of 3-hydroxy-3-methylglutaryl-CoA by cholesterol. These data suggest that RS may be practically as effective as a gel-forming gum, such as GG, on steroid excretion and on cholesterol metabolism.

Acidic fermentation in the caecum increases absorption of calcium and magnesium in the large intestine of the rat.

The effect of fermentation on colonic absorption of Ca and Mg was investigated in 8-week-old rats adapted to diets containing either digestible wheat starch (DS diets) or including resistant starch, i.e. 350 g raw potato starch/kg (RS diets). The dietary Ca level of the DS and RS diets was 2.5 or 7.5 g/kg. RS diets resulted in enlargements of the caecum together with hypertrophy of the caecal wall. Acidification of the caecal contents by microbial fermentation of RS was influenced by the dietary Ca level. Very acidic pH conditions and relatively low concentrations of short-chain fatty acids, in the presence of lactic acid fermentation, were observed with the 2.5 g Ca/kg level. Rats fed on RS diets had a higher percentage of soluble Ca (and inorganic phosphate) in the caecum, particularly of rats adapted to the high Ca level. As a result of the hypertrophy of the caecal wall and of an elevated concentration of soluble Ca, the caecal absorption of Ca was 5-6-fold higher in the RS groups than in the DS groups. The difference between dietary intake and faecal excretion (DI-FE) of Ca was higher in rats fed on RS diets than in those fed on DS diets, when the dietary Ca level was 2.5 g/kg. With the higher Ca intake the elevated rate of Ca absorption from the caecum in RS-fed rats was not paralleled by an enhanced DI-EE difference: this suggests a shift of the Ca absorption towards the large intestine. Feeding RS diets also enhanced Mg caecal absorption, resulting in a substantially higher DI-FE difference for Mg, especially with the 2.5 g Ca/kg diets, because a high Ca intake tends to inhibit Mg absorption. The present findings support the view that the large intestine may represent a major site of Ca (and Mg) absorption when acidic fermentations take place. This process could improve the digestive Ca balance when the dietary Ca supply is low; when the Ca supply is affluent, it rather shifts Ca absorption towards a more distal site of the digestive tract.

Resistant starch is more effective than cholestyramine as a lipid-lowering agent in the rat.

Amylase-resistant starch (RS) represents a substrate for the bacterial flora of the colon, and the question arises as whether RS shares with soluble fibers common mechanisms for their lipid-lowering effects. It is uncertain whether a cholesterol-lowering effect depends basically on an enhanced rate of steroid excretion or whether colonic fermentations also play a role in this effect. In the present study, the effect of RS (25% raw potato starch), of a steroid sequestrant (0.8% cholestyramine), or both were compared on bile acid excretion and lipid metabolism in rats fed semipurified diets. RS diets led to a marked rise in cecal size and the cecal pool of short-chain fatty acids (SCFA), as well as SCFA absorption; cholestyramine did not noticeably affect cecal fermentation. Whereas cholestyramine was particularly effective at enhancing bile acid excretion, RS was more effective in lowering plasma cholesterol (-32%) and triglycerides (-29%). The activity of 3-hydroxy-3-methylglutaryl-CoA reductase was increased fivefold by cholestyramine and twofold by RS. This induction in rats fed RS diets was concomittant to a depressed fatty acid synthase activity. In rats fed the RS diet, there was a lower concentration of cholesterol in all lipoprotein fractions, especially the (d = 1.040-1.080) fraction high-density lipoprotein (HDL1), while those fed cholestyramine had only a significant reduction of HDL1 cholesterol. In contrast to cholestyramine, RS also depressed the concentration of triglycerides in the triglyceride-rich lipoprotein fraction.(ABSTRACT TRUNCATED AT 250 WORDS)

Fermentable fibers or oligosaccharides reduce urinary nitrogen excretion by increasing urea disposal in the rat cecum.

The availability of fermentable carbohydrates could influence the digestive degradation and disposal of blood urea. The effects of a poorly fermented cellulosic oat fiber, a soluble fermentable fiber (gum arabic) or one of two oligosaccharides (fructooligosaccharide or xylooligosaccharide) on nitrogen excretion were compared with a wheat starch-based control diet in male Wistar rats. The fibers and oligosaccharides were added to the semipurified diets at 7.5 g/100 g in place of wheat starch. The diets contained 13 g casein/100 g. Oat fiber did not cause an enlargement of the cecum. In contrast, gum arabic and the oligosaccharides elicited a 35-60% enlargement of the cecal wall and a 2 to 2.6-fold mean increase in the cecal pool of short chain fatty acids. Compared with rats fed the oat fiber-based diet, urea flux from blood to cecum was nearly 50% greater and more than 120% greater in those fed the gum arabic and oligosaccharide diets, respectively. In those groups, net nitrogen retention in the cecum more than doubled (nitrogen retention was calculated as the difference between net urea nitrogen flux into the cecum and ammonia nitrogen reabsorption). As a percentage of total excreted nitrogen, fecal nitrogen was 20% in the oat fiber group and 27-29% in the gum arabic and oligosaccharide groups, compared with only 10% in fiber-free controls. Results indicate that under these dietary conditions, the addition of oligosaccharides to the diet induced a 20 to 30% decrease in blood urea and renal and renal nitrogen excretion relative to the control, indicating a potential for oligosaccharide diet therapy in chronic renal disease.