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ABSTRACT: To determine whether DHA suppresses oxidative stress induced endothelial cell calcium influx by altering lipid composition and TRPC1 distribution in membrane rafts.
Endothelial cells (EC) were pretreated with DHA or stearic acid, then incubated for another 3h with media containing H(2)O(2). Membrane lipid rafts were isolated using the discontinuous sucrose density gradient ultracentrifugation method. Intracellular calcium was detected with laser scanning confocal microscope. TRPC1 protein in membrane fractions was detected by immunoblotting. Membrane fatty acids compositions were analyzed by gas chromatography; raft cholesterol level was assayed by an Amplex Red Cholesterol Assay kit, and DAG concentration was quantified by a DAG kinase assay.
DHA significantly reduced oxidative stress induced calcium influx; pretreated with DHA the n-3 PUFAs were significantly increased in raft fractions, as well as saturated myristic acid, palmitic acid content of membrane rafts in EC; while the stearic acid, monounsaturated oleic acid and cis-oleic acid were decreased. Incubation with DHA also significantly reduced the amount of SM and cholesterol levels in the raft. Interestingly, we fractioned plasma membrane subcellular compartments and discovered that certain amounts of TRPC1 existed in detergent-resistant plasma membrane fractions of EC. After DHA treatment, TRPC1 was partly displaced from lipid raft to detergent-soluble membrane fractions.
DHA significantly reduces oxidative stress induced endothelial calcium influx, this effect might be associated with, at least in part, altered raft lipid environment, and suppresses TRPC1-mediated calcium signaling pathway by partially displacing TRPC1 from membrane caveolar lipid rafts.
Prostaglandins Leukotrienes and Essential Fatty Acids 03/2010; 83(1):37-43. · 3.37 Impact Factor
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ABSTRACT: The objective of this study was to evaluate whether continuous enteral supplementation of L-arginine can stimulate intestinal adaptation in a rat model of short bowel syndrome (SBS). Male Sprague-Dawley rats were randomly divided into three groups of 10 each: Sham rats underwent bowel transaction and received continuous enteral nutrition (Control group, Con group), SBS rats underwent 75% small bowel resection and received continuous enteral nutrition (SB group), and SBS rats underwent 75% bowel resection and received continuous enteral nutrition supplemented with L-arginine (300 mg/Kg/d) (SB-Arg group). Fat absorbability, plasma free fatty acids, parameters of intestinal adaptation, enterocyte proliferation and apoptosis were determined on day 15 after operation. After massive small bowel resection, rats had significant bowel adaptation. Compared with SB untreated rats, SB rats supplemented with L-arginine demonstrated a significant increase in fat absorbability, plasma level of free fatty acids, ileal mucosal weight and DNA content, jejunal and ileal mucosal protein content, jejunal and ileal villus length, crypt depth and mucosal thickness. L-arginine supplementation increased enterocyte proliferation, while decreasing enterocyte apoptosis. We suggest that after massive small bowel resection, continuous enteral supplementation of L-arginine can stimulate intestinal adaptation. L-arginine may be a trophic factor to stimulate intestinal adaptation in rats of SBS.
Asia Pacific Journal of Clinical Nutrition 02/2007; 16(3):554-60. · 1.13 Impact Factor
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ABSTRACT: The aim of the present study was to evaluate the effect of short-term (7 days) glycyl-glutamine-supplemented total parenteral nutrition (TPN) on nutrition and intestinal absorptive function in a rat model. Thirty Wistar rats, weighting 140-180 g, were divided into three groups (n=10) randomly. The animals received isonitrogenous and isocaloric TPN solutions for 7 days. The nitrogen was supplied by glycyl-glutamine dipeptide-supplemented amino acid solution (group G), and two standard amino acid solutions (group V, group N), respectively. Body weight, plasma glutamine level, nitrogen balance, total tissue water and intestinal absorptive function, assessed by (15-N)-glycine absorption, were investigated. Body weight decreased in three groups at the end of TPN; there was no significant difference in relative body-weight changes. There was a significant improvement of cumulative nitrogen balance and nitrogen retention in group G compared to other groups (P<0.05). There was no significant difference in intestinal glycine absorption (P>0.05) among the three groups. Total tissue water of left thigh muscle was significantly higher in group V and group N than that in group G (P<0.05). The results indicated that short-term (7 days) TPN supplemented with glycyl-glutamine improved plasma glutamine level and nitrogen balance, decreased water content of muscle, but had no beneficial effect on absorptive function in a rat model.
Pediatric Surgery International 06/2006; 22(6):508-13. · 1.25 Impact Factor
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ABSTRACT: The presence of established intra-abdominal sepsis has been considered a contraindication to primary anastomoses. Our hypothesis was that fibrin glue (FG), growth hormone (rhGH), and combination of them synergistically improve intestinal primary anastomotic healing in a rat model of intestinal fistulae with peritonitis.
Male Wistar rats, induced intestinal fistulae with peritonitis after 24 h, were performed an enterectomy and intestinal anastomoses. Group A, rats (n = 60) had a complete anastomoses (end-to-end single layer anastomoses using 12 inverted interrupted 6-0 sutures) without peritonitis, group B, rats (n = 60) had a complete anastomoses after 24 h of peritonitis, group C rats had an incomplete anastomoses (four inverted interrupted sutures), groups D, E, F rats (n = 60) received FG, rhGH, or both of them, respectively. rhGH was given daily for 5 days. Anastomoses indicated the anastomotic bursting pressure (ABP), tensile strength, and hydroxyproline content, were determined.
On POD 1, ABP of group C and group D was significantly lower than that of other groups (P < 0.01); On POD 3, ABP could not be determined because of intestinal dehiscence in groups C and E, ABP was significantly higher in groups D and F than that of groups A and B (P < 0.01); the ABP increased after 5 days of operation in groups A, B, and F. At the same time, that of group D decreased (P < 0.01). On POD 5, the tensile strength was significantly higher in groups A, D, and F than that in groups C, and E. On POD 5, hydroxyproline content was higher in groups D and F compared to that in group C (P < 0.05).
These data suggested that FG improve intestinal primary anastomotic healing within post-operative 5 days in a rat model of intestinal fistulae with peritonitis. RhGH alone fails to improve intestinal anastomotic healing, and the combination of FG and rhGH have no synergistic effect to improves intestinal anastomotic healing.
Journal of Surgical Research 03/2006; 131(1):111-7. · 2.25 Impact Factor
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ABSTRACT: Recent studies have shown that polyunsaturated fatty acids (PUFA) regulated the functions of membrane receptors in T cells and suppressed T cell -mediated immune responses. But the molecular mechanisms of immune regulation are not yet elucidated. Lipid rafts are plasma membrane microdomains, in which many receptors localized. The purpose of this study was to investigate the effect of DHA on IL-2R signaling pathway in lipid rafts. We isolated lipid rafts by discontinuous sucrose density gradient ultracentrifugation, and found that DHA could change the composition of lipid rafts and alter the distribution of key molecules of IL-2R signaling pathway, which transferred from lipid rafts to detergent-soluble membrane fractions. These results revealed that DHA treatment increased the proportion of polyunsaturated fatty acids especially n-3 polyunsaturated fatty acids in lipid rafts and changed the lipid environment of membrane microdomains in T cells. Compared with controls, DHA changed the localization of IL-2R, STAT5a and STAT5b in lipid rafts and suppressed the expression of JAK1, JAK3 and tyrosine phosphotyrosine in soluble membrane fractions. Summarily, this study concluded the effects of DHA on IL-2R signaling pathway in lipid rafts and explained the regulation of PUFAs in T cell-mediated immune responses.
Science in China Series C Life Sciences 03/2006; 49(1):63-72. · 1.61 Impact Factor
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ABSTRACT: Short-chain fatty acids are organic acids with 1 - 6 carbon atoms. Their physiological functions and clinical applications have attracted considerable attention. Their high polarity, low ultraviolet (UV) absorbance, low contents in biological samples, high volatility, good water-solubility and easy adsorption on metal and glass surfaces result in some difficulties in their separation and determination. This review focuses on the methods for extraction of short-chain fatty acids in biological samples such as feces, urine, blood and culture solutions by distillation, high speed centrifugation, liquid-solid extraction, solid phase microextration, supercritical fluid extraction and liquid phase microextraction and determination by gas chromatography, high performance liquid chromatography and capillary electrophoresis. Sixty-three references are cited.
Se pu = Chinese journal of chromatography / Zhongguo hua xue hui 02/2006; 24(1):81-7.
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Journal of Liquid Chromatography & Related Technologies 01/2006; 29(1):45-53. · 0.71 Impact Factor
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ABSTRACT: Polyunsaturated fatty acids, including docosahexaenoic acid (DHA, 22:6n-3), modulate immune responses and exert beneficial immunosuppressive effects, but the molecular mechanisms inhibiting T-cell activation are not yet elucidated. Lipid rafts have been shown to play an important role in the compartmentalization and modulation of cell signaling. We investigated the role of DHA in modulating the lipid composition in lipid rafts and membrane subdomain distribution of interleukin-2 (IL-2) receptor signaling molecules. We found that DHA altered lipid components of rafts and modified the IL-2-induced Janus kinase-signal transducer and activator of transcription (STAT) signaling pathway by partially displacing IL-2 receptors from lipid rafts. We fractionated plasma membrane subcellular compartments and discovered that certain amounts of STAT5a and STAT5b existed in detergent-resistant plasma membrane fractions of T-cells. After DHA treatment, STAT5a and STAT5b were not detected in lipid raft fractions and were located in detergent-soluble fractions. These data demonstrate for the first time that DHA alters the lipid composition of membrane microdomains and suppresses IL-2 receptor signaling in T-cells. Thus, our data provide evidence for a functional modification in lipid rafts by DHA treatment and explain PUFA-mediated immunosuppressive effects.
The Journal of Lipid Research 10/2005; 46(9):1904-13. · 5.56 Impact Factor
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ABSTRACT: A novel method for simultaneous determination of d- and l-lactic acids in plasma was presented by capillary electrophoresis with photodiode array detection at 195nm. The separation was performed in an uncoated fused-silica capillary. The parameters influencing the resolution and the migration time of lactic acids were optimized. When 150mM phosphate-Tris buffer (pH 7.0) consisting of 220mM 2-hydroxypropyl-beta-cyclodextrin and 0.2mM tetradecyltrimethylammonium bromide was utilized as the running buffer, highly effective chiral separation of d- and l-lactic acids was achieved at about 42min at an effective voltage of -25kV. The resolution of lactic acid enantiomers was >/=1.25. The limits of detection of d- and l-lactic acids in standard solution without any pretreatment were 80 and 50muM (S/N=3), respectively. Sample pretreatment was preceded by protein-removal procedure with acetonitrile. With a pre-concentration procedure by 10 times, the limits of detection of d- and l-lactic acids were 20 and 15muM (S/N=10), respectively. The satisfactory analytical performance of the proposed method was validated.
Journal of Chromatography B 02/2005; 814(2):393-8. · 2.89 Impact Factor
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ABSTRACT: A method for analysis of gamma-aminobutyric acid (GABA) and glutamate (Glu) in human gastric mucosa by high performance liquid chromatography (HPLC) was developed. A gradient elution was used for the separation and quantification of GABA and Glu after pre-column derivatization with phenylisothiocyanate (PITC). The column was Pico x Tag for free amino acids. GABA and Glu were determined with UV detector at 254 nm. Good linearities were observed within the ranges from 0.125 to 6.25 micromol/L for GABA and from 0.025 to 2.5 mmol/L for Glu. The average recoveries were 95.4% for GABA and 93.5% for Glu. The intra- and inter-precision values were within 3.56% and 7.47% for GABA, and 1.12% and 5.98% for Glu, respectively. The method is sensitive, specific and accurate. It can be used in the determination of GABA and Glu in human gastric mucosa tissue. The concentrations of GABA and Glu in cancer tissues are significantly higher than those in normal tissue.
Se pu = Chinese journal of chromatography / Zhongguo hua xue hui 04/2004; 22(2):131-3.
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ABSTRACT: This study was devised to investigate whether fibrin glue (FG) in combination with growth hormone (GH) could have a beneficial effect at a late period (14 days) after injury. Male Wistar rats, with abdominal sepsis induced by an incomplete anastomosis, were divided into three groups. In the control group, the rats got incomplete anastomoses sutured alone; in the FG and FG/GH groups, anastomoses protection was performed with application of FG alone or in combination with GH. The anastomotic bursting pressure (ABP) was significantly higher in the FG/GH group than that of the FG group on postoperative day (POD) 5 (p < .01), while it could not be measured from POD 7 to POD 14 because of intestinal dehiscence. There was no difference between FG and FG/GH group on POD 3 and POD 5 in anastomotic tensile strength, which was significantly higher in the FG/GH group than that of the FG group from POD 7 to POD 14 (p < .001). Hydroxyproline content of the FG/GH group was significantly higher than that of the control from POD 3 and that of the FG group from POD 5 (p < .05). Combination of FG with GH had a synergistic effect to improve intestinal anastomotic healing over a limited 14-day course of observation.
Journal of Investigative Surgery 20(5):301-6. · 1.09 Impact Factor
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ABSTRACT: Sixty patients with breast cancer were randomly assigned to oral glutamine or placebo pre-neoadjuvant chemotherapy (CEF regimen).
Oral glutamine supplementation was continued for at least 12 days. Patients kept a daily record of diarrhea and stomatitis. The plasma glutamine level, intestinal permeability (lactulose-mannitol test), and tumor size were analyzed. The expression of Ki-67 and PCNA antigens in breast carcinoma was assessed.
The plasma glutamine level was significantly higher in the glutamine group than in the placebo group (420.39 +/- 52.39 mmol/L vs 309.76 +/- 42.34 mmol/L, P < 0.05). After one cycle of chemotherapy, the lactulose-mannitol ratio was higher in the placebo group than in the glutamine group (0.0630 +/- 0.0091 vs 0.0471 +/- 0.0094, P < 0.05). No differences were observed in the grades of stomatitis and diarrhea, in the changes in tumor size, and in the expression of Ki-67 and PCNA antigens between the two groups.
Prophylactic oral glutamine could ameliorate the neoadjuvant chemotherapy-induced increase in intestinal permeability, but had no significant positive clinical effect on stomatitis and diarrhea and did not interfere with the antitumor effect of chemotherapy.
Tumori 92(5):396-401. · 0.86 Impact Factor
