To examine the effect of oxidized low density lipoprotein (oxLDL) on prostacyclin (PGI
2) generation by rat aorta in vitro and whether high density lipoprotein (HDL) has any protective effect against ...the inhibition of PGI
2 generation induced by oxLDL is the objective of this study. Preincubation of aortas with oxLDL resulted in significant inhibition of PGI
2 generation compared to preincubation with normal low density lipoprotein (nLDL) or buffer only. The inhibitory effect of oxLDL resided in its lipid moiety while the lipid fraction of nLDL showed no effect. Aortas preincubated with 10
μg/ml of lyso phosphatidycholine (lyso PC) also showed 30% inhibition of PGI
2 generation, indicating that lyso PC was among the lipid components of oxLDL which inhibited PGI
2 generation. Preincubation of aortas with a mixture of HDL and oxLDL at a ratio of 10:1 showed a significant recovery of PGI
2 generation compared to aortas preincubated with only oxLDL, indicating a protective role for HDL. When HDL was incubated with oxLDL the transfer of lyso PC from oxLDL to HDL suggested that HDL trapped lyso PC from oxLDL thus preventing it from acting on the aorta. However, when a mixture of HDL and oxLDL at a ratio of 3:1 was preincubated with aortas, no protective effect of HDL was observed. Preincubation of aortas with a mixture of HDL plus oxLDL at a ratio of 8:1, which was incubated for 1
h at 37
°C, produced significantly less PGI
2 than aortas preincubated only with oxLDL, indicating that HDL under these conditions was not protective but even enhanced the inhibitory effect of oxLDL. Similarly, aortas preincubated with HDL plus whole oxLDL (at a ratio of 10:1); containing all the small molecular weight oxidation products and characterized by high levels of thiobarbituric acid reactive substance (TBARS) and lipid hydroperoxides; produced significantly less PGI
2 than aortas preincubated with whole oxLDL. These results were evaluated in light of possible modification of HDL by oxLDL and its lipid oxidation products such as aldehydes and lipid peroxides. The modified HDL can add more lipid peroxides and increase the effectiveness of lipid peroxides originally present in oxLDL.
Our study was designed to determine whether hydrogenated fat high in trans monoenes concentration affected prostaglandin synthesis. Corn oil (CO), butter (B), hydrogenated vegetable oil (HF) and ...coating fat (CF) were used in this study. These fats were fed to rats for 10 wk at 10 g/100 g diet. The phospholipid (PL) fatty acid content of platelets, aorta and heart was determined by gas liquid chromatography, and the in vitro aorta production of prostacyclin (PGI2) from exogenous or endogenous arachidonic acid (AA) was measured using the radioimmuno-assay (RIA) method. Serum thromboxane B2 (TXB2) released by platelets as thromboxane A2 (TXA2) during incubation of whole blood was also measured by this method. In the group fed CF, AA was significantly lower in the PL of aorta, platelet and heart, and the ratio 20:3(n-9)/20:4(n-6) was greater than in the groups fed CO, B or HF, indicating that the group fed CF was essential fatty acid (EFA) deficient. Although AA was significantly lower in the aorta and platelet PL of the group fed HF compared to the group fed CO, that difference did not affect the amounts of PGI2 or TXB2 produced in these groups. The group fed CF had significantly less PGI2 and TXB2 released by aorta and platelets than the other groups. This was the result of the reduced level of AA and the presence of higher amounts of 20:3(n-9) acid in the PL, which might act as a competitive inhibitor for cyclooxygenase. The aortic production of PGI2 from exogenous AA did not differ among the groups indicating that prostaglandin synthetase was not affected by the dietary fat. We conclude that the consumption of hydrogenated fats high in trans 18:1 acids with adequate amount of linoleic acid had no effect on the amount of thromboxane or prostacyclin produced by platelet or aorta in vitro.
Estimation of forest variables using remote sensing and GIS: Case study of Nabag Forest-South Kordofan, Sudan Mohamedain, M.S. (Remote Sensing for Forest Management- Sudan University of Science and Technology (Sudan). Coll. of Forestry and Range Science); Csaplovics, E. (Technische Uinversitat Dresden (Germany). Remote Sensing and Applied Geoinformatic-Chair of Remote Sensing); Mohamed, A.A. (Sudan Univ. of Science and Technology (Sudan). Coll. of Forestry and Range Science) ...
Journal of Agriculture and Social Sciences (Pakistan),
(Apr 2012), Volume:
8, Issue:
2
Journal Article
Peer reviewed
Acacia senegal (gum Arabic tree) is one of the most important economic species in the Sudan and constitutes a large part of the forest stand in the country specially in Kordofan state. The gum Arabic ...tree in study area was facing a lot of endanger factors such as desertification, domination by invader natural species, illicit falling and week management plans. Therefore, there was a need for reliable estimate and update of information and condition regarding the tree management in sustainable bases. This study used remote sensing and GIS techniques together with field inventory to estimate the gum tree volume parameter. The study used ASTER L1b satellite imagery band 1, 2 and 3n for the year 2007 together with forest inventory. The procedure for forest variables estimate began with acquisition of the mentioned satellite imagery then registered, enhanced and subset. Afterwards, the subset was clustered into several strata using unsupervised classification ISODATA algorithm of ERDAS Imagine 9.1 software; and after with the help of the spectral profile tests and Principal Component Analysis (PCA), the image was clustered in to three classes. Afterward, the sample plots were selected randomly from the strata for collection of field data (diameter & height). With regards to remote sensing, the study used the Normalized Difference Vegetation Index (NDVI) to estimate the forest volume. The results showed that the volume produced from the NDVI was not significantly different from that calculated from the field data and what has been found in the literature. The study concluded that remotely-sensed data together with the field data were useful and effective in estimation of forest volume parameter in the study area and the NDVI was a good index for forest variable estimate.
A recent task force of The American Society for Clinical Nutrition and American Society for Nutritional Sciences recommended in a position paper on trans fatty acids that models be developed to ...assess the effects of changes in fat intake on disease risk.
The objective was to investigate, using human arterial endothelial cells as a model, the influence of trans fatty acids and magnesium on cell membrane composition and on calcium influx into arterial cells, a hallmark of atherosclerosis.
Endothelial cells were cultured for 3 d in media with high (adequate) or low (inadequate) amounts of magnesium plus various concentrations of trans,trans linoelaidic; cis,cis linoleic; trans elaidic; oleic; or stearic acids. The cells were then harvested and the fatty acid composition and the amount of 45Ca2+ incorporated into the cell was determined.
The percentage of fatty acids incorporated into the endothelial cells was proportional to the amount added to the culture medium. Adequate magnesium was crucial in preventing calcium influx into endothelial cells. Without an adequate amount of magnesium in the culture medium, linoelaidic and elaidic acids, even at low concentrations, increased the incorporation of 45Ca2+ into the cells, whereas stearic acid and oleic acid did not (P < 0.05).
Our model indicated that a diet inadequate in magnesium combined with trans fat may increase the risk of calcification of endothelial cells.
Oxidation of low-density lipoprotein (LDL) by copper sulfate led to a significant increase in lysophosphatidylcholine (lyso PC) at the expense of phosphatidylcholine. Incubation of different ...concentrations of oxidized LDL (oxLDL) (32–650 μg protein/ml) with platelets for 1 h at 37°C increased lyso PC content. The increase was dependent on oxLDL concentration. Incubation of platelets with various concentrations of lyso PC in solution for 5 or 15 min showed that lyso PC percentage was increased in the platelet membrane and the increase was dose dependent. Platelets incubated with various concentrations of lyso PC (2–100 μM) for 5 or 15 min and then triggered with thrombin also showed a significant decrease of thromboxane A
2 (TXA
2) release as lyso PC concentration reached 10 μM or 6 μM, respectively. The decrease of TXA
2 release was more significant as lyso PC concentration was increased. The present study showed that this inhibition of TXA
2 release by lyso PC was due to 1) inhibition of phospholipase A
2 and the decrease of free arachidonic acid liberation from platelet phospholipid and 2) inhibition of cyclooxygenase. These inhibitory effects of lyso PC were discussed in relation to its effect on membrane fluidity. Lyso PC at concentrations of 30, 50, and 100 μM caused a sudden drop in TXA
2 release and a sudden increase of lactic dehydrogenase loss from the platelets due to their lysis and inhibition of cyclooxygenase enzyme. The present study shows that oxLDL contains high levels of lyso PC that are transferable to the platelets and can weaken their responsiveness to thrombin and decrease TXA
2 release. In our previous study, we found that oxLDL also contained high levels of oxysterols and thiobarbituric acid reactive substances (TBARS), which enhanced platelet reactivity to thrombin and increased TXA
2 release. We conclude that the net effect of oxLDL on platelets will depend on its degree of oxidation and the ratio between oxysterols plus TBARS/lyso PC. Variations in this ratio may explain some of the contradictions cited in the literature concerning the effect of oxLDL on platelet activation.
While generally mild in children, rubella infection during pregnancy can lead to miscarriage, foetal death or congenital rubella syndrome. Rubella vaccination is not yet available as a part of ...routine immunisation in Sudan, and the burden of infection is unknown. Using the clinical case definition adopted by the World Health Organisation, a total of 123 children suspected of having of measles were enrolled in this study during January-December 2017 in Gadarif Hospital, Eastern Sudan. Those cases whose sera were negative for measles IgM antibodies were tested for rubella IgM antibody. A confirmed rubella case was a person who tested positive for rubella IgM. Sera were analysed for IgM specific antibodies against measles virus and rubella virus using enzyme-linked immunosorbent assay. Among the total 123 children suspected to have measles, 92 (74.8%) children were positive for measles IgM antibodies. Of the 31 children who had measles IgM antibodies negative, 20 (16.3%) children were seropositive for rubella IgM antibodies. Implementation of a surveillance system will provide the improved estimates of rubella virus and estimated the burden of congenital rubella syndrome. Such information is necessary and it is an important step for future policy decisions for vaccine delivery strategies.
The objective of this study was to examine the effect of oxLDL on prostacyclin (PGI
2) generation by rat aortic segments and to see whether the lipid fraction of oxLDL or its components are ...responsible for that effect. We also tested if antioxidants have any protective role. LDL oxidized by copper was characterized by higher TBARS, conjugated diene, lysophosphatidylcholine (lyso PC), oxysterols and less polyunsaturated fatty acids (PUFA) than nLDL. Preincubation of aortas with oxLDL caused a significant inhibition of PGI
2 generation compared to aortas preincubated with nLDL or buffer only. The percent inhibition was dependent on the concentration of oxLDL. Most of the inhibitory effect of oxLDL resided in its lipid moiety while the lipid fraction of nLDL, as well as native LDL had no effect. Preincubation of aortas with 10 μg/ml of 7-ketocholesterol the major oxysterol in oxLDL reduced the amount of PGI
2 generated by aorta at all times tested; however that decrease did not reach a significant level. Aortas preincubated with 10 μg/ml of lyso PC showed a 21–36% inhibition of PGI
2 generation which was comparable to the inhibition produced by preincubating the aortas with 50 μg protein/ml of oxLDL (containing about 7.5 μg lyso PC). This indicated that most of the inhibitory effect of oxLDL was due to its lyso PC. The small molecular weight fraction (<10 kDa) with a high level of TBARS (TBARS solution) also significantly decreased the PGI
2 generation by aorta. Addition of superoxide dismutase (SOD) + catalase or vitamin E simultaneously with oxLDL or TBARS solution in the preincubation medium did not reverse their inhibitory effects. This indicated that oxygen free radicals are not a contributing factor to the inhibitory effect of oxLDL but lyso PC and the lipid peroxides and probably other components already present within oxLDL are the important inhibitors.
The effect of 2% and 10% dietary Tamarindus indica ripe fruit on Brown Hisex chicks was examined. There was a decrease in body weight gains and efficiency of feed utilization and soft faeces between ...days 21 and 35. Hepatonephropathy due to consumption of 10% T. indica food was confirmed by changes in serum enzyme activity and in total protein, cholesterol and uric acid concentrations. No haematological abnormality was observed in birds fed T. indica. The hepatocytes and the cells of the renal convoluted tubules had not completely reverted to normal at the end of a 2 week recovery period.
In this study, we compared the effects of normal LDL (nLDL) and oxidized LDL (oxLDL) on thromboxane (TXA2) release by platelets triggered by low concentration of thrombin, and we determined which ...component of oxLDL is responsible for that activation. After oxidation of LDL with copper sulfate, the small molecular weight fraction (< 10 kDa) which was high in TBARS was removed; using Amicon Centriprep-10 concentrator membrane. More than 67% of TBARS in the oxLDL preparation was found in solution while the remaining was covalently attached to the oxLDL particles. OxLDL contained significantly higher levels of oxysterols and TBARS than the nLDL. Platelets preincubated with low concentrations of oxLDL (33-132 micrograms protein/mL) produced significantly higher TXA2 than platelets preincubated with equivalent concentrations of nLDL when triggered with thrombin. Platelets treated with oxLDL also contained significantly higher levels of oxysterols than platelets treated with nLDL. Platelets preincubated with pure cholestanetriol (10 micrograms/mL) contained a high level of cholestanetriol in the membrane, and TXA2 release was significantly increased in these platelets compared to the control platelets. The TBARS in solution also was very potent in enhancing TXA2 release by thrombin-treated platelets. These results indicate that oxysterols and the free TBARS either in solution or covalently attached to the oxLDL particles are partly responsible for the stimulatory effect of oxLDL on TXA2 release by platelets. The present study also showed that this enhancement of TXA2 release was due to activation of phospholipase A2 and to the increase of arachidonic acid liberation from the platelet phospholipids.
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