Presence Of PS Research Articles

A comparison of phospholipid and platelets in the activation of human factor VIII by thrombin and factor Xa, and in the activation of factor X

Two aspects of the activation of factor X by the intrinsic clotting pathway have been studied in purified human systems, in the presence of either purified phosphatidylserine:phosphatidylcholine vesicles (PS:PC) or platelets activated with ionophore A23187: (1) the activation of factor VIII by factor Xa and by thrombin, and (2) the activation of factor X by the factor IXa/VIIIa complex. Factor VIII activation by thrombin was unaffected in either rate or extent by the presence of PS:PC or activated platelets. In contrast, factor VIII activation by factor Xa required either PS:PC or platelets. The products of optimal factor VIII activation by the two enzymes, designated factor VIIIa(T) and factor VIIIa(Xa), are kinetically different in the activation of factor X by factor IXa, factor VIIIa(T) being approximately twice as active (in factor X activation) as factor VIIIa(Xa) in the presence of PS:PC or platelets. Factor VIIIa(Xa) can be converted to the more active VIIIa(T) by thrombin treatment, but the activity of factor VIIIa(T) is unchanged by factor Xa treatment. Factor X activation was also studied with optimally activated factor VIIIa(T), in the presence of PS:PC or activated platelets, as a function of factor IXa concentration in order to determine the apparent dissociation constant for the factor IXa-VIIIa interaction in the two cases. Activated platelets increased the apparent affinity more than fivefold.

A Comparison of Phospholipid and Platelets in the Activation of Human Factor VIII by Thrombin and Factor Xa, and in the Activation of Factor X

Two aspects of the activation of factor X by the intrinsic clotting pathway have been studied in purified human systems, in the presence of either purified phosphatidylserine:phosphatidylcholine vesicles (PS:PC) or platelets activated with ionophore A23187: (1) the activation of factor VIII by factor Xa and by thrombin, and (2) the activation of factor X by the factor IXa/VIIIa complex. Factor VIII activation by thrombin was unaffected in either rate or extent by the presence of PS:PC or activated platelets. In contrast, factor VIII activation by factor Xa required either PS:PC or platelets. The products of optimal factor VIII activation by the two enzymes, designated factor VIIIa(T) and factor VIIIa(Xa), are kinetically different in the activation of factor X by factor IXa, factor VIIIa(T) being approximately twice as active (in factor X activation) as factor VIIIa(Xa) in the presence of PS:PC or platelets. Factor VIIIa(Xa) can be converted to the more active VIIIa(T) by thrombin treatment, but the activity of factor VIIIa(T) is unchanged by factor Xa treatment. Factor X activation was also studied with optimally activated factor VIIIa(T), in the presence of PS:PC or activated platelets, as a function of factor IXa concentration in order to determine the apparent dissociation constant for the factor IXa-VIIIa interaction in the two cases. Activated platelets increased the apparent affinity more than fivefold.

In vitro immune mechanisms associated with clearance of microfilariae of Dirofilaria immitis.

An in vitro system has been developed to elucidate potential immune mechanisms associated with clearance of microfilariae (Mf) from the bloodstream in canine Dirofilaria immitis infection. Granulocytes as well as mononuclear cells adhere to Mf of Dirofilaria immitis in the presence of immune serum. Only granulocytes, however, were capable of killing Mf, whereas PBMC attach to but do not effectively kill Mf. In the presence of granulocytes 1% +/- 1, 10% +/- 2, and 12% +/- 3 of Mf were killed by heated normal (NDS), patent (PS), and occult serum (OS), respectively, after an 18-hr incubation. With the addition of fresh NDS there was an increase in killing to 5% +/- 1 (p less than 0.025) with heat-inactivated NDS, to 12% +/- 3 in the presence of PS and to 77% +/- 12 (p less than 0.005) in the presence of OS. On further purification of granulocyte cell populations with metrizamide gradients, neutrophils were found to be the predominant effector cells with 73% +/- 18 killing with neutrophils and 18% +/- 6 with eosinophils (p less than 0.0005). Only with neutrophils was a significant increase in killing of Mf observed when fresh NDS was added to delta OS. Fractionation of OS by gel filtration suggested that IgM was the opsonizing antibody in the occult serum. In addition, immunofluorescent studies showed only IgM bound to the surface on Mf on incubation in OS. The involvement of complement in the fresh serum enhancement of killing was supported by the finding, by immunofluorescence, of surface C3 on Mf after incubation in fresh OS.

Possible effects of positronium negative ion on 0.511 MeV ?-ray line in astrophysical sources

The astrophysical importance of the negative positronium ion, detected recently in the laboratory, has been pointed out. It is found that the presence of Ps− ions will contribute additionally to the width of 0.511 ψ-ray line formed by pair annihilation. The formation of Ps− ion from an aggregate of electrons, positrons and positronium results in a variable positron population in the 0.511 MeV ψ-ray line source.

Determination of Polysorbate 60 in Salad Dressings by Colorimetric and Thin Layer Chromatographic Techniques

Abstract Methods are described for the quantitation and verification of polysorbate 60 (PS 60) in salad dressing. The sample is partitioned between methylene chloride and water. The methylene chloride extract is further treated by silica gel column chromatography. The isolated PS 60 is complexed with ammonium cobaltothiocyanate and determined spectrophotometrically at 620 nm. Additional evidence indicating the presence of PS 60 is obtained from thin layer chromatographic analysis using the modified Dragendorff reagent for visualization of spots.

Degradation of the Mucoid Polysaccharide of Pseudomonas aeruginosa by Beneckea pelagia

The alginase formed by Beneckea pelagia in sodium alginate medium is weakly active on the mucoid polysaccharide of Pseudomonas aeruginosa. Supernatants of broth cultures of B. pelagia grown in the presence of Ps. aeruginosa mucoid material had a greater enzymic action on this material than did those grown in alginate broth. A mucoid strain of Ps. aeruginosa, when grown on nutrient agar to which a dilution of such a supernatant had been added, gave non‐mucoid colonies from which smooth suspensions suitable for agglutination tests could be prepared.

Bacteraemia.

‘Septic shock ’ is produced most commonly by Gram-negative bacilli derived from pre-existing infections in various parts of the body. Anaerobic bacteraemic states are most frequently due to Bacteroides fragilis and are usually derived from sepsis in the gastrointestinal or female genital tracts, or from aspiration pneumonia. Among aerobic bacilli, Pseudomonas aeruginosa has emerged as an increasingly frequent cause of septic shock, especially in leukaemic patients. For the treatment of septic shock of unknown cause gentamicin is the drug of first choice; if anaerobes are thought to be implicated metronidazole should be added. The possible presence of Ps. aeruginosa or streptococci requires the addition of carbenicillin or benzylpenicillin respectively.

Degradation of polymer mixtures. VII. Blends of poly(vinyl acetate) with polystyrene

AbstractThe degradation of films containing both PVA and PS has been investigated for comparison with the behavior already reported for PVC/PS blends. The presence of PS had little, if any, effect on the behavior of PVA, but PVA had an effect similar to that of PVC on the degradation of PS. Styrene production was retarded in the blend, compared to PS alone, and an increase in the rate of chain scission was observed for a high molecular weight sample. The molecular weight effect, however, was much smaller than in corresponding experiments with PVC/PS blends. Interference with intermolecular transfer in PS is again advanced as the probable explanation of the stabilization of PS.

日本稲と外国稲との交雑による育種の基礎的研究 : VIII. 二 三の花青素分布遺伝子ならびにそれらの抑制遺伝子について

Anthocyanin coloration in stigma and stem internode of the rice plant was considered by Nagao (1951) to be due to the two basic genes responsible for the production of the pigment, C and A. Takahashi (1958) has, however, confirmed in variety that coloration in stigma i-s controlled by a gene, Ps, Ivhich distributes the piglnent produced by C and A to the site. Although he had found the Ps-gene, he stated that sometimes stigma coloration could occur without its presence. If the genotype for the basic gene is either CBA or CBpA in the presence of the dominant P-gene, colored stigma is dis played. The results of the present experiment has, however, shown that Ps is indispensable for colored stigma and another gene, Pin, for colored stem internode. It has also been proved that even a weak basic gene constitution, CBrA, presents colored stigma in the presence of Ps, which is determined as colorless by Takahashi (1958) .

ON THE ROLE OF SOIL BACTERIA IN PLANT NUTRITION

1. Soil microorganisms play an important role in plant nutrition. Many species of microbes, especially those that abundantly develop in the rhizosphere, exert a direct influence on plant nutrition. These microbes synthesize various biologically very active organic compounds and transmit them to the plants. The latter absorb through their roots the microbial metabolites and use them as sources of additional nourishment.2. The present paper shows that some bacteria aid in the accumulation of amino acids in plant tissues. In the presence of certain species of activating bacteria the amount of amino acids in the plant tissues increases 50-100 per cent or more. In leguminous plants more amino acids are accumulated under the influence of active nodule bacteria. As a rule, the more nodules on the roots, the more free amino acids in the tissues. Greater concentration of amino acids is also observed under the influence of certain non-nodule bacteria-Bacterium sp., Ps. fluorescens, etc.. A particularly high increase in amino acids in leguminous plants is observed when they grow in the presence of Ps. fluorescens.3. A similar effect is produced by certain activating bacteria on non-leguminous plants. The tissues of cereals (maize, wheat, barley, etc.) also show an increased accumulation of free amino acids in the presence of bacteria although to a lesser extent than those of the leguminous plants.4. Certain activating bacteria influence the acumulation of phosphorus containing organic compounds in plant tissues. These compounds are in some extent synthesized by bacteria and are transmitted to the plants through the roots. This was shown in the experiments with tracer phosphorus P32 with the simultaneous use of the method of paper chromatography.

An epidemiological study on pseudomonas aeruginosa (Bacillus pyocyaneus) in premature infants in the presence and absence of infection

A systematic investigation on the presence of Ps. aeruginosa in the nasopharynx, throat, feces, and on the skin of 143 premature infants was carried out and the following observations were made. 1.Ps. aeruginosa was isolated from the skin in 25 per cent of these patients, from the feces in 51 per cent, from the nasopharynx in 27 per cent, and from the throat in 40 per cent. 2.Ps. aeruginosa was found in only one individual on the day of admission in the feces, though not in the throat, nasopharynx, or on the skin; from 16 per cent to 47 per cent (depending upon the specimen) of the infants harbored this microorganism on the third or fourth day after admission, indicating that this microorganism was acquired readily within a few days after admission to the nursery. 3.Of thirty-five premature infants more than half carried this microorganism in the feces and throat for two weeks; the carrier state of the skin tended to be more transient. 4.Ps. aeruginosa was present in large numbers on the skin of 6 per cent of the infants, in the feces in 17 per cent, in the nasopharynx in 16 per cent, and in the throat in 21 per cent. 5.In the majority of these premature infants the presence of this microorganism was not associated with clinical infection. Systemic infection, however, occurred in five patients, four of whom died. A brief résumé of these cases is presented. 6.ACTH was administered to twenty infants for the treatment of retrolental fibroplasia, sixteen of whom also received antibiotics. Systemic infection with Ps. aeruginosa followed ACTH therapy in three instances. 7.The “outbreak” of the Ps. aeruginosa carrier state terminated without special measures, and this microorganism has been encountered in premature infants during the ensuing two years only occasionally. 8.The significance of these findings, with particular reference to the Ps. aeruginosa carrier state and the potential pathogenicity of this bacterial species, is discussed. A systematic investigation on the presence of Ps. aeruginosa in the nasopharynx, throat, feces, and on the skin of 143 premature infants was carried out and the following observations were made. 1.Ps. aeruginosa was isolated from the skin in 25 per cent of these patients, from the feces in 51 per cent, from the nasopharynx in 27 per cent, and from the throat in 40 per cent. 2.Ps. aeruginosa was found in only one individual on the day of admission in the feces, though not in the throat, nasopharynx, or on the skin; from 16 per cent to 47 per cent (depending upon the specimen) of the infants harbored this microorganism on the third or fourth day after admission, indicating that this microorganism was acquired readily within a few days after admission to the nursery. 3.Of thirty-five premature infants more than half carried this microorganism in the feces and throat for two weeks; the carrier state of the skin tended to be more transient. 4.Ps. aeruginosa was present in large numbers on the skin of 6 per cent of the infants, in the feces in 17 per cent, in the nasopharynx in 16 per cent, and in the throat in 21 per cent. 5.In the majority of these premature infants the presence of this microorganism was not associated with clinical infection. Systemic infection, however, occurred in five patients, four of whom died. A brief résumé of these cases is presented. 6.ACTH was administered to twenty infants for the treatment of retrolental fibroplasia, sixteen of whom also received antibiotics. Systemic infection with Ps. aeruginosa followed ACTH therapy in three instances. 7.The “outbreak” of the Ps. aeruginosa carrier state terminated without special measures, and this microorganism has been encountered in premature infants during the ensuing two years only occasionally. 8.The significance of these findings, with particular reference to the Ps. aeruginosa carrier state and the potential pathogenicity of this bacterial species, is discussed.