Effect Of Phosphorylcholine Research Articles

Chitosan derivatives for gene transfer: effect of phosphorylcholine and diethylaminoethyl grafts on the in vitro transfection efficiency

The purpose of this work was to improve the functional properties of chitosan for gene transfer by inserting phosphorylcholine (PC) and diethylaminoethyl (DEAE) groups into the main chain. A series of derivatives containing increasing contents of DEAE and a fixed content of PC groups were synthesized and characterized, aiming to evaluate the effect of these groups on the nanoparticles’ properties and the in vitro transfection efficiency. The derivatives were soluble at physiological pH levels and all derivatives were less cytotoxic than the control, the lipid lipofectamine. The obtained derivatives complexed pDNA into nanoparticles with smaller sizes and higher zeta potentials than plain chitosan. The in vitro transfection was performed with nanoparticles prepared at pH 6.3 and 7.4 and the results showed that nanoparticles prepared with derivatives containing 20% of PC groups (PC18-CH) and high degrees of substitution by DEAE (PC20-CH-DEAE100, CH-DEAE80, CH-DEAE100) displayed the better transfection efficiencies in HeLa cells, reaching relative values comparable to lipofectamine. The most effective derivative, PC18CH, was selected for complexation with siRNA and its complexes demonstrated an in vitro knockdown efficiency highly dependent on the N/P ratio. Our combined results indicated that, by means of controlled modifications, the limitations of chitosan can be overcome to obtain more effective carriers based on chitosan, and the derivatives here studied hold potential for in vivo studies.

Evaluation of the effects of phosphorylcholine coated membrane oxygenators on renal functions in cardiac surgery patients

Objectives: Acute and chronic renal injury has an important effect on the surgical outcome of cardiovascular diseases in terms of morbidity and mortality. The coating techniques which have been significantly improved in the recent years aim to decrease the contact of blood with foreign surfaces in the cardiopulmonary bypass. The aim of this study is to research the effects of phosphorylcholine coating in the membrane oxygenators of cardiopulmonary bypass on renal functions in patients undergoing cardiac surgery. Materials and Methods: Thirty patients undergoing cardiac surgery were included to the study. Phosphor- ylcholine coated membrane oxygenator was used in one group (group 1) (n=15) and membrane oxygenator without coating with phosphorylcholine (group 2) (n=15) was used in the other group of patients. Preoper- ative and postoperative blood and urine analysis were obtained and data between the two groups were com- pared in order to evaluate the alterations in renal function. Results: Although plasma sodium and potassium as well as urine creatinine and microalbumin levels showed statistically significant difference within the groups, these values were not statistically different between the study groups. In both groups, creatinine clearance levels did not differ significantly. When the data within the groups are evaluated, creatinine clearance had a decrease in the early postoperative period whereas it increased over the preoperative levels in the third day after the operation. This situation did not show any sta- tistical significance in the group 2 but the group 1. In our study groups, urine microalbumin analysis showed an increase in the early postoperative period, but then a steep decline was observed in the postoperative third day, which still has a value more than the preoperative one. Conclusions: Postoperative renal dysfunction is a multi-factorial entity with a wide spectrum of clinical pre- sentations. The applied cardiac surgical procedure has a definitive role on the fate of renal failure. Although blood urea nitrogen and serum creatinine levels did not show statistically different variation, creatinine clear- ance was even increased in the study group.

Effects of Phosphoryl Choline Grafted Water Soluble Carbon Nanotubes Examined by Different Cytotoxicity Methods in 16-HEB Cells

The widespread explored application of water soluble carbon nanotubes makes it important to understand their potential toxic effects on health. This study investigates the effects of phosphoryl choline grafted water soluble multi-walled carbon nanotubes (MWCNTs-PC) on human bronchial epithelial (16-HBE) cells by different cytotoxicity methods in vitro. Various concentrations of MWCNTs-PC were incubated with 16-HBE cells, the effects of cell proliferation, cell apoptosis, cell cycle and DNA damage were detected by methyl thiazolyl tetrazolium (MTT) assay, flow cytometry, single cell gel electrophoresis assay (SCGE) and micronuclear assay, respectively. Compared with the control group, there were no significant differences in the changes of cell proliferation, cell apoptosis, cell cycle and DNA damage. Within the experimental concentrations of MWCNTs-PC, no obviously cytotoxicity and DNA damage was observed on 16-HBE cells in this study.

In vitro evaluation of PHISIO-coated sets for pediatric cardiac surgery

Objectives. Phosphorylcholine coated cardiopulmonary bypass (CPB) circuits for children have been available for some years, but conflicting results regarding the inflammatory response have been reported. Accordingly, we aimed to investigate the effect of phosphorylcholine coating on the inflammatory response. Design. Ten coated and nine uncoated pediatric CPB sets were tested in an in vitro CPB circuit model. The inflammatory response was assessed by serial assays of hemoglobin, hematocrit, leukocyte counts, platelet counts, activation of the complement system, activation of platelets measured as β-thromboglobulin, activation of neutrophils measured as myeloperoxidase, activation of coagulation measured as prothrombin fragments 1+2, assessment of hemolysis measured as lactate dehydrogenase, and a panel of seven cytokines. Samples were obtained at baseline and after 15, 30, 60 and 120 minutes. Results. There were no significant differences between the phosphorylcholine coated circuits and the uncoated circuits for any of the parameters during the observation period, although a potentially beneficial effect on platelets could not be ruled out. Conclusions. Phosphorylcholine coating of CPB equipment did not exert any beneficial effect on the inflammatory markers monitored.

Mechanism of heparin and serum lipoprotein interaction: Effects of calcium, phosphorylcholine, and a serum fraction

The mechanism of formation of an insoluble complex between heparin and rat serum lipoprotein has been studied. Optical density changes during the reaction, counting of the fatty acid labelled lipoproteins in the precipitates, and complexing of [14C]palmitate-labelled lipoprotein with heparin-CNBr-Sepharose were used to quantitatively determine the formation of insoluble complexes. The maximal heparin--lipoprotein complex formation requires 25--30 mM of Ca2+, but with micromolar amounts of phosphorylcholine, the reaction was saturated at only 10 mM of Ca2+. The effect of phosphorylcholine in promoting the reaction was lost when purified chylomicrons or very low density lipoproteins were used. The effect of phosphorylcholine in promoting the interaction between heparin and pure chylomicrons or very low density lipoproteins was regained when a crude serum protein factor of unwashed chylomicrons was added to the system, suggesting that rat serum contains a protein factor(s) which normally inhibits the heparin--lipoprotein interaction by raising the requirement of Ca2+. Phosphorylcholine counteracted the effect of this protein, thereby favouring the precipitation reaction in the presence of much lower concentration of Ca2+. The results have been discussed with special reference to the possibility of a relationship between mucopolysaccharides, Ca2+, lipoproteins, and arterial phospholipids in the pathogenesis of atherosclerosis.

A Novel Stimulatory Action of Phosphorylcholine Plus Cytidine 5'-Triphosphate on Protein Synthesis in a Cell-free System

Abstract In rat liver slices, phosphorylcholine stimulates incorporation of radioactive leucine into the proteins recovered from microsomes and medium. In a cell-free microsomal system, prepared from rat liver, additions of phosphorylcholine plus cytidine 5'-triphosphate increased dramatically the incorporation of radioactive leucine or phenylalanine into hot trichloracetic acid-insoluble proteins. Such increased protein synthesis was evident even when the usual requirements of ATP, guanidine 5'-triphosphate, or pH 5 enzyme for protein synthesis were considerably reduced. Phosphorylcholine plus CTP did not stimulate radioactive leucine incorporation into leucyl-tRNA as measured by subtracting the radioactivity incorporated into heated trichloracetic acid-insoluble proteins from corresponding unheated samples. Incorporation of labeled phenylalanine from phenylalanyl-tRNA into microsomal proteins was increased by phosphorylcholine plus CTP. Cycloheximide and puromycin, at a concentration of 10-4 m, abolished the activation effect of phosphorylcholine plus CTP on protein synthesis. Microsomal proteins were solubilized at the end of incubation by sodium deoxycholate treatment or by ultrasonic oscillation. The stimulatory effect of phosphorylcholine plus CTP on the specific activity of the soluble proteins was 2-fold higher than on that of the insoluble proteins of the pellet. Incubation in the presence of phospholipase C, brief ultrasonic oscillation of microsomes prior to incubation, and aging of microsomes in frozen storage caused a partial reduction or complete inhibition of the effect of phosphorylcholine plus CTP on protein synthesis. Incorporation of a tracer dose of phosphoryl[1,2-14C]choline, in the presence of phosphorylcholine, CTP, or CTP plus phosphorylcholine, into the lecithin fraction was extremely rapid in the incubation system normally used for studying protein synthesis. In stimulating protein synthesis, CTP could be replaced by uridine 5'-triphosphate, cytidine 5'-diphosphate, and cytidine 5'-phosphate, and these nucleotides, except UTP, also activated phosphorylcholine incorporation into lecithin. The different effect of UTP on phosphorylcholine incorporation into lecithin and on protein synthesis argues against a simple causal relationship between lecithin and protein synthesis. However, the results presented raise the possibility of a relationship between phosphorylcholine metabolism and protein synthesis.

Stimulation of glycoprotein synthesis by phosphorylcholine in vivo and in liver slices

A stimulation of plasma glycoprotein synthesis and a reduction of liver triglycerides in 2-days choline deficient rats were observed within 2 hr of phosphorylcholine administration. Similar treatment with choline had no such effects. The effect of phosphorylcholine, in contrast to choline, was found to be more striking in liver slices on the incorporation of glucosaminel- 14C into medium proteins. The effect of phosphorylcholine is dependent on the dose used and the temperature and pH of the medium.

UTILIZATION OFL-α-GLYCEROPHOSPHORYLCHOLINE BY A LECITHIN-DEFICIENT STRAIN OF NEUROSPORA CRASSA

The growth response of a lecithin-deficient strain of Neurospora crassa to equimolar supplements of either choline or glycerophosphorylcholine is essentially the same. This is in contrast to the negligible stimulatory effect of phos-phorylcholine on growth of the same organism. The results of enzymatic and growth-response studies with Neurospora suggest that glycerophosphorylcholine is available to the organism without prior hydrolysis by enzymes released into the culture medium.