Programas de optimización de uso de antimicrobianos (PROA) en hospitales españoles: documento de consenso GEIH-SEIMC, SEFH y SEMPSPH / No disponible

Los antimicrobianos son fármacos distintos al resto. Su eficacia en términos de curación y reducción de mortalidad es muy superior a la de otros grupos de medicamentos,habiéndose demostrado que la indicación de antimicrobianosinadecuados en determinadas situaciones clínicas es un factorindependiente de aumento del riesgo de mortalidad. Por otra parte, son los únicos fármacos con efectos ecológicos, de manera que su administación afecta tanto al paciente que los recibe como al resto, dado que pueden contribuir a la aparicióny diseminación de resistencias microbianas. Finalmente, sonutilizados por médicos de prácticamente todas las especialidades.La complejidad actual motivada por los avances en el conocimiento del manejo de las nfermedades infecciosas y del aumento de las resistencias hace imprescindible el establecimiento de programas de optimización del uso de antimicrobianos en los hospitales (PROA). Este documento de consenso define los objetivos de losPROA (por este orden: mejorar los resultados clínicos de los pacientes con infecciones, minimizar los efectosadversos asociados a la utilización de antimicrobianos, incluyendo aquí la aparición y diseminación deresistencias, y garantizar la utilización de tratamientos coste-eficaces) y establece recomendaciones para suimplantación en los hospitales españoles. Las líneas maestras de las recomendaciones son las siguientes: eldiseño y desarrollo de los PROA debe basarse en la constituciónde un equipo multidisciplinar de antibióticos, dependiente de la Comisión de Infecciones. Para posibilitar su éxito, estos programas necesitan ser considerados comoparte de la propia institución sanitaria y formar parte de los objetivos de los centros donde se desarrollen (AU)

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Precipitation of fibrinogen, fibrinogen degradation products and fibrin monomer by histone H3.

Incubation of histone H3 with normal citrated plasma resulted in the formation of insoluble aggregates, as determined by turbidity measurements. The precipitate was subjected to sodium dodecyl sulfate polyacrylamide gel electrophoresis, confirming that fibrinogen was a major component. Purified fibrinogen precipitated rapidly as determined with turbidity experiments and experiments with radioiodinated protein. The amount of fibrinogen precipitation was strongly dependent on H3 concentration. Variation of ionic strength (0.2-0.84) and pH (5.3-7.4), however, had little or no effect on the reaction. Fibrinogen subjected to gelatin-Sepharose chromatography or dialysis against 3.3M urea reacted equivalently with H3. Precipitation of 125I-fibrinogen by H3 was strongly favored by increasing temperature (4 degrees-45 degrees C). Precipitation of fibrinogen by protamine was maximized by decreasing the temperature. In addition, formation of insoluble fibrinogen-protamine aggregates was highly dependent on ionic strength and pH, suggesting that different types of protein-interaction are involved in the two studied precipitation reactions. Of the fibrinogen degradation products, only fragment X precipitated significantly when incubated with H3. Radioiodinated fibrin monomer also precipitated when incubated with H3 in solutions of sufficient ionic strength to prevent spontaneous polymerization. The extent of precipitation was equivalent for fibrin monomer and fibrinogen. Fragment D inhibited the precipitation of fibrinogen by H3 or protamine. These studies indicate that the proteins termed "paracoagulants" are not all equivalent and that the hydrophobic domain of H3 plays a critical role in fibrinogen precipitation.

In vitro preparation of nonenzymatically glucosylated human transferrin, alpha 2-macroglobulin, and fibrinogen with preservation of function.

Human transferrin, alpha 2-macroglobulin, and fibrinogen were incubated with [3H]-glucose. After a 7-day, 37 degrees C incubation at 20 mM glucose, transferrin incorporated 1.1 mol of glucose/mol protein; alpha 2-macroglobulin, 10 mol of glucose/mol; and fibrinogen, 3.8 of glucose/mol, or approximately 14 mumol of glucose/g for each protein. These results were the same for glucose labeled in the 1 or 6 position. No radiolabel was incorporated into the proteins during incubations with glucose labeled in the 2 position. The rate and extent of iron binding were identical for both glucosylated and nonglucosylated transferrin. Glucosylated transferrin bound to Wil-2 human lymphoblast cells with a Kd = 33 nM and receptor number of 3.4 X 10(5) receptors/cell; nonglucosylated transferrin with a Kd = 31 nM and receptor number of 3.9 X 10(5) receptors/cell. Glucosylated and nonglucosylated alpha 2-macroglobulin showed the same conformational change as determined on native PAGE after reaction with trypsin, plasmin, or methylamine and had the same activity in the Ganrot assay after reaction with trypsin or plasmin. The clearance of 125I-labeled, methylamine-treated alpha 2-macroglobulin from the mouse circulation was identical for both glucosylated and nonglucosylated alpha 2-macroglobulin, t1/2 = 3 min. alpha 2-Macroglobulin that was first glucosylated then reacted with methylamine bound to mouse peritoneal macrophages with a Kd of 2.5 nM and receptor activity of 370 fmol/mg cell protein. alpha 2-Macroglobulin that was first reacted with methylamine and then glucosylated bound with a Kd of 3 nM and receptor activity of 320 fmol/mg cell protein. Glucosylated fibrinogen had the same clotting time as control fibrinogen.(ABSTRACT TRUNCATED AT 250 WORDS)

The role of ligand-ligand interactions in competition by fibrinogen and fibrin degradation products for fibrinogen binding to human platelets.

Binding to human platelets of radioiodinated human fibrinogen and fragments X, Y, D, D1 dimer and E was studied to determine the domain of the fibrinogen molecule responsible for binding to the platelet receptor. Although the fragments did not bind, some were able to compete for the binding of fibrinogen to platelets. It was postulated that the fragments bound to fibrinogen and subsequently interfered with its binding to the receptor. Two approaches were developed to test this hypothesis. In the first technique, molecular exclusion on Sephacryl S-200 superfine was utilized to examine the interaction of radiolabeled fragments with fibrinogen. In the second series of studies, fibrinogen-Sepharose was prepared and the binding of degradation products directly determined. A spin dialysis apparatus was employed in each case to achieve rapid separation of bound and free radioligand. These studies demonstrated that fragments D and E bind to fibrinogen. Therefore, the mechanism by which degradation products interfere with fibrinogen binding to the platelet receptor is ligand-ligand interaction rather than binding of the fragments to the receptor. Since none of the radiolabeled degradation products bound to platelets, it appears that receptor recognition requires the intact molecule.

The clearance of human fibrinogen fragments X and Y in mice: a process mediated by the fragment D receptor.

The clearance of radiolabeled human fibrinogen fragments X and Y was studied in the mouse model. Fragment X cleared rapidly from the circulation with less than 10% of the ligand remaining in the circulation at 4 hr. The clearance of fragment Y was somewhat slower, but was identical to the rate of clearance of fragment D1. Competition studies indicated that fragments X, Y, D1 amd D1 dimer clear via the same, saturable pathway. Fragment E did not compete for the clearance of there ligands. Tissue distribution studies demonstrated that the liver was the principle site of clearance of all three ligands. The kidneys also cleared a fraction of each ligand in the order fragment D3 greater than D2 greater than D1 greater than Y greater than X. This pattern suggests that renal clearance is a passive phenomenon dependent on the size of the fibrinogen degradation product.

The clearance of human fibrinogen fragments D1, D2, D3 and fibrin fragment D1 dimer in mice.

The clearance of human fibrinogen fragments D1, D2, D3 and fibrin fragment D1 dimer were studied in the mouse model. Clearance of these fragments is a complex process involving clearance from blood into three other compartments. The overall clearance of fragment D1 and its dimer were essentially identical. Fragments D2 and D3 cleared at a progressively slower rate. Competition studies were performed between 125I-labeled fragment D1 and large molar excesses of unlabeled human fragments D1, D2, D3, D1 dimer, fragment E, fibrinogen, macroalbumin, mannan and asialoorosomucoid. Of these ligands only the fragment D variants competed for the clearance of 125I-labeled fragment D1. Cross-competition was observed when 125I-labeled fragment D1 dimer was cleared in the presence of a large molar excesses of fragment D1. Autopsies demonstrated that injected fragments D1, D2, D3 and D1 dimer cleared primarily in liver and kidneys. In some clearance studies, livers were perfused with tissue culture fluid, subjected to light microscopic autoradiography, and silver grain counts performed to localize cleared fragment D1. These experiments indicated that 80% of the liver uptake was in hepatocytes. However, when silver grain counts were normalized for the number of parenchymal and nonparenchymal cells, the distribution of silver grains was essentially identical (1.8 and 1.6 grains per cells, respectively). It is concluded that fragments D1, D2, D3 and D1 dimer are recognized by a similar clearance pathway. Since neither fibrinogen nor fragment E competed for the clearance of fragment D1, it is suggested that determinants present in the fragment D domain become exposed after plasmin attack on fibrinogen and are responsible for clearance.

A colorimetric assay for releasable plasminogen activator.

We describe an equilibrium assay for measuring release of plasminogen activator form blood-vessel walls and report data from 125 individuals free of overt thromboembolic disease. Excess human plasminogen is added to the euglobulin fraction of plasma obtained before and after venous occlusion at mean systolic pressure. To measure plasmin generation in these samples, we used the chromogenic plasmin substrate D-Val-Leu-Lys-p-nitroanilide, which liberates p-nitroaniline upon cleavage. Releasable plasminogen activator in 24 subjects was determined by this colorimetric assay and by the radiocasein assay previously reported by this laboratory (Am. J. Clin. Pathol. 76,403-409, 1981), and the results were compared. The correlation coefficient was 0.97. The colorimetric assay offers several advantages over the radiocasein assay: shorter incubation (6 vs 16 h) and no preparation or quantification of a radioactive substrate and its cleavage products.