RESUMO
Acanthopanax senticosus (AS) is a well-known, highly effective traditional Chinese herbal medicine. Polysaccharides extracted from AS (ASPS) have multiple pharmacologic and biological activities with potential use as additives in broiler chicken feed. This trial evaluated the effects of dietary ASPS on growth performance, immune function, antioxidation, and ileal microbial populations in broiler chickens. A total of 240 1-day-old Arbor Acres male broiler chicks were randomly divided into 4 groups, with 10 replicates of 6 chicks and fed a corn- and soybean-based diet supplemented with 0, 1, 2, or 4 g/kg ASPS. Compared with the control group, supplementation with 1 g/kg ASPS increased ADG and ADFI in the finisher and overall periods and decreased the feed conversion ratio in the finisher period (both P < 0.05). Serum IgA and IgM were significantly increased by supplementation with 1 and 2 g/kg of ASPS (P < 0.05). Superoxide dismutase and glutathione peroxidase activities were increased and malondialdehyde concentration was decreased in birds fed ASPS-supplemented diets compared with those in the control group (P < 0.05). Polysaccharides extracted from AS supplementation increased Lactobacillus and decreased Escherichia coli and Salmonella counts in the ileal contents compared with the control diet (both P < 0.05). The results show that dietary ASPS improved growth performance, immune status, and antioxidant capacity and stimulated the growth of beneficial gut bacteria in broiler chickens. In conclusion, ASPS was effective as a natural additive in broiler chicken feed; 1 g/kg can be considered as the optimum dosage.
Assuntos
Galinhas , Eleutherococcus , Ração Animal/análise , Fenômenos Fisiológicos da Nutrição Animal , Animais , Antioxidantes , Dieta/veterinária , Suplementos Nutricionais , Imunidade , Masculino , Extratos Vegetais/farmacologia , Polissacarídeos/farmacologiaRESUMO
A novel electrolysis-integrated horizontal subsurface-flow constructed wetland system (E-HFCWs) was developed for intensified removal of nitrogen and phosphorus contaminated water. The dynamics of nitrogen and phosphorus removal and that of main water qualities of inflow and outflow were also evaluated. The hydraulic retention time (HRT) greatly enhanced nitrate removal when the electrolysis current intensity was stabilized at 0.07 mA/cm2. When the HRT ranged from 2 h to 12 h, the removal rate of nitrate increased from 20% to 84%. Phosphorus (P) removal was also greatly enhanced-exceeding 90% when the HRT was longer than 4 h in the electrolysis-integrated HFCWs. This improved P removal is due to the in-situ formation of ferric ions by anodizing of sacrificial iron anodes, causing chemical precipitation, physical adsorption and flocculation of phosphorus. Thus, electrolysis plays an important role in nitrate and phosphorus removal. The diversity and communities of bacteria in the biofilm of substrate was established by the analysis of 16S rDNA gene sequences, and the biofilm was abundant with Comamonadaceae and Xanthomonadaceae bacteria in E-HFCWs. Test results illustrated that the electrolysis integrated with horizontal subsurface-flow constructed wetland is a feasible and effective technology for intensified nitrogen and phosphorus removal.
Assuntos
Fósforo , Áreas Alagadas , Eletrólise , Nitratos , Nitrogênio , Eliminação de Resíduos LíquidosRESUMO
A novel electrolysis-integrated biofilter system was developed in this study to evaluate the intensified removal of nitrogen and phosphorus from contaminated water. Two laboratory-scale biofilter systems were established, one with electrolysis (E-BF) and one without electrolysis (BF) as control. The dynamics of intensified nitrogen and phosphorus removal and the changes of inflow and outflow water qualities were also evaluated. The total nitrogen (TN) removal rate was 94.4% in our newly developed E-BF, but only 74.7% in the control BF. Ammonium removal rate was up to 95% in biofilters with or without electrolysis integration with an influent ammonium concentration of 40 mg/L, and the accumulation of nitrate and nitrite was much lower in the effluent of E-BF than that of BF. Thus electrolysis plays an important role in TN removal especially the nitrate and nitrite removal. Phosphorus removal was significantly enhanced, exceeding 90% in E-BF by chemical precipitation, physical adsorption, and flocculation of phosphorus because of the in situ formation of ferric ions by the anodizing of sacrificial iron anodes. Results from this study indicate that the electrolysis integrated biofilter is a promising solution for intensified nitrogen and phosphorus removal.
Assuntos
Nitrogênio/química , Fósforo/química , Poluentes Químicos da Água/química , Purificação da Água/métodos , Compostos de Amônio/química , Eletrólise , Filtração , Floculação , Nitratos/química , Nitritos/química , Purificação da Água/instrumentação , Qualidade da ÁguaRESUMO
In the hope of identifying agents of therapeutic value in glomerulonephritis from Chinese herbs, we found that methanolic extracts of Polygonum hypoleucum Ohwi (P. hypoleucum Ohwi) inhibit human mesangial cells proliferation activated with interleukin-1beta (IL-1beta) and interleukin-6 (IL-6) previously. This study was designed to identify bioactive components from P. hypoleucum Ohwi and elucidate their action mechanisms. We tested four anthraquinones emodin, emodin 1-O-beta-D-glucoside (49A), physcion (62A), and physcion 1-O-beta-D-glucoside (50A) purified from P. hypoleucum Ohwi for their effects on human mesangial cell proliferation and cytokines production in vitro. On a percentage basis, emodin had the highest suppressing activity on the human mesangial cells proliferation activated by IL-1beta and IL-6. The IC50 of emodin on human mesangial cells proliferation were 17.9+/-1.2 microM. In contrast to 49A, 50A, and 62A, emodin also decreased IL-1beta, IL-6 and tumor necrosis factor-alpha (TNF-alpha) production in human mesangial cells activated with IL-1beta and IL-6. The IC50 of emodin on IL-1beta, IL-6 and TNF-alpha production in activated human mesangial cells were 16.6+/-1.8 microM, 8.2+/-1.3 microM, and 9.5+/-1.6 microM, respectively. Moreover, IL-1beta and TNF-alpha mRNA expression in activated human mesangial cells was impaired by emodin. The intracellular free Ca2+ concentration ([Ca2+]i) in IL-1beta and IL-6 activated human mesangial cells was decreased by emodin. It is unlikely that cytotoxicity was involved because no cell deaths were observable. We hypothesize that the inhibitory mechanisms of emodin on activated human mesangial cells proliferation may be related to the impairments of gene expression and production of cytokines and [Ca2+]i in the cells.
Assuntos
Medicamentos de Ervas Chinesas , Emodina/farmacologia , Mesângio Glomerular/imunologia , Extratos Vegetais/farmacologia , Plantas Medicinais/química , Cálcio/metabolismo , Divisão Celular/efeitos dos fármacos , Sobrevivência Celular , Emodina/isolamento & purificação , Mesângio Glomerular/citologia , Mesângio Glomerular/efeitos dos fármacos , Humanos , Interleucina-1/biossíntese , Interleucina-1/genética , Interleucina-6/biossíntese , RNA Mensageiro/análise , Fator de Necrose Tumoral alfa/biossíntese , Fator de Necrose Tumoral alfa/genéticaRESUMO
Cordyceps sinensis (CS) is a traditional Chinese medicine with immunomodulatory effect and is effective in improving the survival of lupus mice. In the present study we isolated a pure compound (H1-A) from CS and investigated its effect on inhibiting autoimmune disease progression in MRL Ipr/Ipr mice. Our results demonstrated that MRL Ipr/Ipr mice treated daily with H1-A (40 microg/kg/d orally) for 8 weeks had a progressive reduction in anti-ds-DNA production (optical density value decreased from 0.172 +/- 0.009 to 0.112 +/- 0.015) when compared with the control group (optical density value increased from 0.141 +/- 0.036 to 0.198 +/- 0.047). In clinical presentation, the treated group had a reduction in lymphadenopathy, a delayed progression of proteinuria, and an improvement in kidney function. Histologic analysis of kidney tissue indicated that H 1-A could inhibit the mesangial proliferation that was evident in lupus nephritis. However, there was no significant change in immune complex deposition. The studies reveal that the pure compound (H1-A) may be potentially useful for treating systemic lupus erythematosus in human patients, and they provide some questions for further investigation of the pathogenesis of systemic lupus erythematosus and lupus nephritis.
Assuntos
Medicamentos de Ervas Chinesas/farmacologia , Hypocreales/química , Imunossupressores/farmacologia , Lúpus Eritematoso Sistêmico/tratamento farmacológico , Animais , Anticorpos Antinucleares/biossíntese , Modelos Animais de Doenças , Avaliação Pré-Clínica de Medicamentos , Medicamentos de Ervas Chinesas/química , Medicamentos de Ervas Chinesas/isolamento & purificação , Feminino , Humanos , Imunossupressores/química , Imunossupressores/isolamento & purificação , Técnicas In Vitro , Interleucina-2/biossíntese , Lúpus Eritematoso Sistêmico/etiologia , Lúpus Eritematoso Sistêmico/fisiopatologia , Nefrite Lúpica/patologia , Nefrite Lúpica/fisiopatologia , Nefrite Lúpica/prevenção & controle , Doenças Linfáticas/tratamento farmacológico , Masculino , Camundongos , Camundongos Endogâmicos MRL lpr , Proteinúria/tratamento farmacológicoRESUMO
BACKGROUND: We have previously shown that preincubation of whole blood clots with recombinants tissue factor pathway inhibitor (rTFPI) attenuates clot-associated procoagulant activity assessed ex vivo. This study was undertaken to determine whether a single local application of rTFPI induces similar attenuation of the procoagulant activity on preclotted Dacron grafts implanted in an artery in vivo. METHODS: Dacron grafts (4 mm x 4 cm long) were preclotted in porcine blood and incubated with either rTFPI (5 mg/ml) or arginine-phosphate buffer for 15 minutes. Grafts were implanted end-to-end in the femoral arteries of 10 pigs, with one rTFPI-treated and one buffer-treated graft implanted in each animal. Animals did not undergo anticoagulation either before or after graft implantation. Radiolabeled porcine fibrinogen was injected intravenously, and the grafts underwent perfusion for 1 hour. A subgroup of animals (n = 7) also had infusion of radiolabeled autologous platelets at the time of administration of radiolabeled fibrinogen. RESULTS: Fibrin(ogen) deposition was decreased in rTFPI-treated grafts by 36% +/- 7% (mean +/- SEM) compared with buffer-treated grafts (p = 0.001). Platelet deposition was also reduced in the rTFPI-treated grafts by 31% +/- 15%, although the reduction did not reach statistical significance (p = 0.10). The extent of rTFPI-mediated attenuation of fibrin(ogen) versus platelet deposition varied independently among animals. CONCLUSIONS: Clot-directed anticoagulant effects of rTFPI appear to be useful for substantially decreasing the thrombogenicity of Dacron grafts immediately after their implantation. Chronic studies to determine whether the decreases in thrombogenicity result in improved long-term graft patency appear warranted.
Assuntos
Prótese Vascular/efeitos adversos , Fibrinolíticos/uso terapêutico , Lipoproteínas/uso terapêutico , Polietilenotereftalatos/efeitos adversos , Trombose/prevenção & controle , Animais , Plaquetas/diagnóstico por imagem , Avaliação Pré-Clínica de Medicamentos , Artéria Femoral/cirurgia , Fibrinogênio/administração & dosagem , Radioisótopos de Índio , Transfusão de Plaquetas , Cintilografia , Proteínas Recombinantes/uso terapêutico , Suínos , Trombose/sangue , Trombose/etiologiaRESUMO
A detailed comparison of the structures of plasma very low density lipoprotein (VLDL) and liver triacylglycerols (TG) (Yang et al. 1995. J. Lipid Res. 36: 125-136) has demonstrated that a minimum of 60% of the secreted TG could have been derived from partial lipolysis and reesterification of stored TG and a maximum of 40% could have been derived from direct secretion of newly made TG. To investigate the processes involved in the transfer of TG to VLDL in vivo, we have determined the distribution of deuterium among the molecular species of the liver-TG and VLDL-TG during the infusion of perdeuterated ethanol along with fructose or glucose and during the provision of either glucose or fructose in the drinking water for 2 weeks. The deuterium labeling (percent excess and percent replacement) of the total fatty acids was determined by GC/MS of the methyl esters while the labeling of the glycerol and the glycerol plus fatty acids of the enantiomeric diacylglycerol moieties of TG was determined by LC/MS with on-line mass spectrometry. Supplementation of the diet for 2 weeks with either glucose and fructose stimulated the synthesis of TG containing new fatty acids and glycerol. The proportion of the newly made to preexisting TG differed in VLDL from that in the liver. The 2H % replacement in glycerol and in total fatty acids was greater in VLDL-TG than in the liver-TG. On the basis of the mass isotopomer distribution analysis it was estimated that a maximum of 30% of the VLDL-TG could have been derived directly from TG that was made de novo and did not equilibrate with the liver-TG stores. The transfer of the stored TG to VLDL was best accounted for by a degradation to 2-monoacylglycerols and resynthesis via the 2-monoacylglycerol pathway with addition of an excess of newly synthesized fatty acids to the resynthesized TG.
Assuntos
Etanol/metabolismo , Ácidos Graxos/biossíntese , Lipoproteínas VLDL/metabolismo , Triglicerídeos/metabolismo , Animais , Deutério , Frutose/farmacologia , Cromatografia Gasosa-Espectrometria de Massas , Glucose/farmacologia , Glicerol/metabolismo , Fígado/metabolismo , Masculino , Conformação Molecular , Ratos , Ratos Wistar , Estereoisomerismo , Triglicerídeos/químicaRESUMO
The lipid class, fatty acid and molecular species composition of the minor polar surface components of rat lymph chylomicrons were determined during absorption of menhaden oil and corn oil or of the corresponding fatty acid ethyl esters. In addition to the previously reported minor polar lipids (sphingomyelin, phosphatidylserine, phosphatidylinositol, phosphatidic acid and lysophosphatidylcholine), we identified phosphatidylglycerol, dimethylphosphatidylethanolamine, ceramide and cholesteryl sulfate in the chylomicrons from both oil and ester feeding. The dietary fatty acids were found to be incorporated to a variable extent into the different phospholipid classes, the proportions of which remained the same during both types of feeding. No evidence was obtained for the presence of the minor glycerophospholipids characteristic of the lysosomal membranes (e.g., bis-phosphatidic, lysobisphosphatidic and semilysobis-phosphatidic acids), although special efforts were made to identify them. These results indicate that the chylomicrons arising from the monoacylglycerol and phosphatidic acid pathways of triacylglycerol biosynthesis become enveloped in closely similar monolayers of phospholipids. Hence, all triacylglycerols may be secreted from the villus cells via a common mechanism as suggested by the previously demonstrated convergence (at the 2-monoacylglycerol stage) of the monoacylglycerol and the phosphatidic acid pathways of mucosal triacylglycerol formation [Yang, Y.L., and Kuksis, A. (1991) J. Lipid Res. 32, 1173-1186].
Assuntos
Quilomícrons/química , Gorduras na Dieta/farmacologia , Ácidos Graxos/farmacologia , Fosfolipídeos/análise , Animais , Cromatografia em Camada Fina , Óleo de Milho/farmacologia , Ácidos Graxos/metabolismo , Óleos de Peixe/farmacologia , Metabolismo dos Lipídeos , Lipídeos/análise , Masculino , Ácidos Fosfatídicos/análise , Fosfolipídeos/metabolismo , Ratos , Espectrometria de Massas de Bombardeamento Rápido de Átomos , Triglicerídeos/metabolismoRESUMO
This study tests the hypothesis that the rat chylomicrons are assembled and released into lymph similarly regardless of the site (rough or smooth endoplasmic reticulum) or pathway (phosphatidic acid or monoacylglycerol) of triacylglycerol biosynthesis. For this purpose we determined the lipid class, fatty acid and molecular species composition of the choline, ethanolamine, inositol and serine phospholipids of lymph chylomicrons during absorption of menhaden, mustard-seed and corn oil (monoacylglycerol pathway) or the corresponding fatty acid methyl or ethyl esters (phosphatidic acid pathway). The dietary fatty acids were found to be incorporated to various extents into different phospholipid classes, the proportions of which were not affected by the nature of the dietary fat. The chylomicron phospholipids contained 80-82% choline, 8% ethanolamine and 2.5% inositol glycerophospholipids, and much smaller amounts of serine and other minor phospholipids. Administration of a meal of each dietary fat resulted in a retention of approximately 50% endogenous fatty acids in the major glycerophospholipids of the chylomicrons. A minimum of 50% of the molecular species of the choline and ethanolamine glycerophospholipids contained at least one exogenous fatty acid. No significant discrepancies were found in the fatty acid and molecular species composition of the glycerophospholipids between chylomicrons from the oil and corresponding ester feeding. It is concluded that the chylomicrons arising from the monoacylglycerol (oil feeding) and the phosphatidic acid (ester feeding) pathways of triacylglycerol biosynthesis become enveloped in surfactant monolayers containing qualitatively and quantitatively identical classes and molecular species of phospholipids.
Assuntos
Quilomícrons/metabolismo , Gorduras na Dieta/metabolismo , Linfa/metabolismo , Éteres Fosfolipídicos/metabolismo , Animais , Cromatografia Gasosa , Quilomícrons/química , Óleo de Milho/metabolismo , Ácidos Graxos/análise , Ácidos Graxos/metabolismo , Óleos de Peixe/metabolismo , Linfa/química , Mostardeira , Fosfatidilcolinas/química , Fosfatidilcolinas/metabolismo , Fosfatidiletanolaminas/química , Fosfatidiletanolaminas/metabolismo , Fosfatidilinositóis/química , Fosfatidilinositóis/metabolismo , Fosfatidilserinas/química , Fosfatidilserinas/metabolismo , Éteres Fosfolipídicos/química , Extratos Vegetais/metabolismo , Óleos de Plantas , RatosRESUMO
The relative cellular uptake and incorporation into prechylomicrons and chylomicrons was investigated for the menhaden and rapeseed oil fatty acids, when given by stomach tube as the original oils or the corresponding methyl and ethyl esters. The intermediates and final products of cellular acylation were determined by chromatographic methods at various times over a period of 1-24 h. There was little selectivity in the uptake among the oligo- and poly-unsaturated fatty acids of menhaden oil, when either oil or esters were fed. In contrast, the long-chain saturated and monounsaturated fatty acids of rapeseed oil were discriminated against during both cellular uptake and reacylation (60% overall reduction in utilization). Also, there was detectable discrimination against the long-chain polyunsaturated monoacylglycerols of menhaden oil and against the long-chain saturated and monounsatured monoacylglycerols of rapeseed oil during both cellular uptake and reacylation (30% overall reduction in utilization). Evidence was obtained for an indiscriminate cellular uptake of variable amounts (4-22%) of intact dietary methyl and ethyl esters of fatty acids, which, however, appeared in the chylomicrons only to a very limited extent (0.1-1.0% of total lipid). During peak absorption the cellular and lymphatic appearance of fatty acids from the digestion and absorption of the alkyl esters was nearly 50% lower than that from the corresponding triacylglycerols. The slower absorption of the fatty acids from the alkyl ester feeding is hypothetically attributed to a lower efficiency of the phosphatidic acid pathway, which is required in the absence of dietary 2-monoacylglycerols, but other mechanisms cannot be excluded.
Assuntos
Gorduras Insaturadas na Dieta/metabolismo , Absorção Intestinal , Animais , Transporte Biológico Ativo , Quilomícrons/metabolismo , Ácidos Graxos/farmacocinética , Ácidos Graxos Monoinsaturados , Óleos de Peixe/farmacocinética , Metabolismo dos Lipídeos , Linfa/metabolismo , Masculino , Óleos de Plantas/farmacocinética , Óleo de Brassica napus , Ratos , Ratos Endogâmicos , Frações Subcelulares/metabolismoRESUMO
Simple alkyl (ethyl) esters of polyunsaturated fish oil fatty acids have been proposed as dietary supplements, but their relative efficiency of digestion and absorption have not been determined. Using stomach tubes, we gave rats menhaden or rapeseed oils, or the corresponding methyl and ethyl esters, and determined by chromatographic methods the lipid classes and molecular species recovered from the lumen of the jejunum during the first 1 to 2.5 h of digestion. Hydrolysis of menhaden oil resulted in a preferential retention of a high proportion of the polyunsaturated long chain acids in the sn-2-monoacylglycerols and in the residual triacyglycerols, while digestion of rapeseed oil led to a preferential release of free long chain monounsaturated fatty acids. In contrast, hydrolysis of the alkyl (methyl and ethyl) esters of the fatty acids of either menhaden or rapeseed oil resulted in a composition of free fatty acids which was much more representative of the original esters. It was therefore concluded that the differential lumenal liberation of the long chain and polyunsaturated (three or more double bonds) fatty acids from fish and rapeseed oil is largely due to their characteristic distribution between the primary and secondary positions in the glycerol molecule, and to a much lesser extent to a chain length discrimination by pancreatic lipase. This study also shows that the methyl and ethyl esters are hydrolyzed about 4 times more slowly than the corresponding triacylglycerols, which is sufficient to maintain a saturated micellar solution of fatty acids in the intestinal lumen during absorption.
Assuntos
Ácidos Graxos Insaturados/metabolismo , Óleos de Peixe/metabolismo , Óleos de Plantas/metabolismo , Animais , Brassica , Cromatografia Gasosa , Ésteres/metabolismo , Ácidos Graxos Monoinsaturados , Glicerídeos/análise , Hidrólise , Lipólise , Masculino , Micelas , Óleo de Brassica napus , Ratos , Ratos Endogâmicos , Triglicerídeos/metabolismoRESUMO
Male rats with thoracic duct cannulae were intubated with mustard-seed oil or the corresponding fatty acid methyl esters and the lymph was collected over 0-24 h. The chylomicron and very low density lipoprotein fractions were obtained by conventional ultracentrifugation. The triacylglycerols and glycerophospholipids were isolated and the positional distribution and molecular association of fatty acids were determined by stereospecific and chromatographic methods. The oleic, linoleic, and linolenic acids were recovered in the lymph in the proportion in which they occurred in the fat fed, while eicosenoic, erucic, and lignoceric acids were rejected to about the same extent by the two pathways of intestinal triacylglycerol biosynthesis. It is shown that the lymph triacylglycerols arising via the monoacylglycerol or the phosphatidic acid pathway possess structures that are closely similar to each other and to that of the original mustard-seed oil. It is proposed that this is a result of comparable fatty acid and positional specificity of the acyltransferases associated with the acylglycerol synthesis in the animal and plant tissues and the wide range of fatty acid chain lengths in the mustard-seed oil.
Assuntos
Absorção Intestinal , Lipoproteínas VLDL/farmacocinética , Linfa/metabolismo , Extratos Vegetais/farmacocinética , Triglicerídeos/farmacocinética , Animais , Quilomícrons/metabolismo , Ácidos Graxos/farmacocinética , Cinética , Lipoproteínas VLDL/metabolismo , Conformação Molecular , Mostardeira , Óleos de Plantas , Ratos , Ratos Endogâmicos , Triglicerídeos/metabolismoRESUMO
Male rats with thoracic duct cannulae were intubated with corn oil or fatty acid methyl esters and the lymph was collected over the next 2-72 h. The apoprotein (apo) composition of the chylomicrons, isolated by conventional ultracentrifugation, was determined by sodium dodecyl sulfate - polyacrylamide - glycerol gel electrophoresis and isoelectric focusing. The lipid content and composition was assessed by gas--liquid chromatography. The particle size was obtained by calculation and confirmed by electron microscopy. The study demonstrates that both the monoacylglycerol (corn oil feeding) and the phosphatidic acid (methyl ester feeding) pathways of triacylglycerol biosynthesis yield chylomicrons with closely similar apoprotein profiles representing apo B-48, apo A-IV, apo E, apo A-I, and the apo C components. A protein band corresponding to apo B-100 was occasionally observed as a minor component of the chylomicrons from both groups of animals. The chylomicrons from corn oil feeding had about two times larger diameters than those from methyl ester feeding. There were no significant differences in the composition of the apoproteins, although the smaller particles had two times higher apoprotein/triacylglycerol ratios. It was calculated that the amount of apo B per lipid particle for the ester fed rats ranged from one to eight molecules and was closely correlated with the particle size. The corn oil fed rats yielded about three molecules apo B per lipid particle regardless of the particle size. It is concluded that the pathway of intestinal triacylglycerol biosynthesis has a significant effect on the apoprotein mass and to a lesser extent on the apoprotein and lipid composition of the chylomicrons. The phosphatidic acid pathway produces smaller particles and transfers to the bloodstream twice as much apoprotein per gram of fat than the monoacylglycerol pathway, which yields the larger particles. Possible variations in the site and rate of biosynthesis of the triacylglycerols could not be entirely excluded as contributing factors.
Assuntos
Quilomícrons/isolamento & purificação , Óleo de Milho , Linfa/análise , Óleos de Plantas , Animais , Apoproteínas/isolamento & purificação , Cromatografia Gasosa , Quilomícrons/biossíntese , Eletroforese em Gel de Poliacrilamida , Focalização Isoelétrica , Lipoproteínas/sangue , Lipoproteínas/isolamento & purificação , Masculino , Microscopia Eletrônica , Ratos , Ratos EndogâmicosRESUMO
The shape of the initial part of the dose-dependent response curve of LoVo cells, an established human colon carcinoma cell line, exposed for 1 hr to graded concentrations of 5-FU depended on the medium supplement, i.e., fetal calf serum (FCS), in which the cells were treated and subsequently incubated for colony-formation. At concentrations of 50--100 micrograms/ml (equivalent to peak plasma levels following an in vivo bolus dose of 15 mg/kg) cell kill was completely prevented by FCS. The serum did not contain thymidine (TdR) but had significant amounts of uridine (UR). When 5-FU was delivered in dialyzed FCS, concentrations of 50--100 micrograms/ml achieved only a modest 15% cell kill after 1 hour treatment. Regardless of medium supplement, the killing effect of 5-FU did not increase beyond concentrations greater than 2,000 micrograms/ml. Increasing the exposure interval dramatically increased the killing of LoVo cells by 5-FU, although the effects of medium supplement on the degree of cell survival persisted for about 12 hours. Virtually all of the incorporated 5-FU was transformed into 5-FUR, and a very small proportion eventually was incorporated into nucleic acids, suggesting that the killing effect of 5-FU on LoVo cells is mediated mostly by ribosidation and not by conversion into the deoxyribonucleoside. This conclusion is supported by the failure of 5-FUdR to kill LoVo cells after a treatment interval of one hour, even at concentrations of 5000 micrograms/ml; yet after the same exposure interval, 5-FUR effectively killed cells at concentrations of 50--100 micrograms/ml. TdR afforded no protection from cell kill by 5-FU. In contrast, UR was capable of protecting LoVo cells from the lethal effects of both 5-FU and 5-FUR even at concentrations as low as 10 micrograms/ml. Ftorafur exposed to LoVo cells for 1 hour had a slight killing effect (about 20--25%) at concentrations ranging up to 2000 micrograms/ml. Although the lethal effect of ftorafur was slightly increased after longer periods of incubation, it failed to reach 90% even after intervals of 48 hours. The results on cellular sensitivity that we obtained for LoVo cells treated with various fluorinated pyrimidines differ substantially from those of other investigators who used different methods to assess cell killing on nonhuman and noncolonic cell systems. The predictive relevance of these data as compared to those obtained in other systems is justified by the suboptimal results with these agents in clinical practice.