Validación de la capacidad predictiva de resultado de parto del índice de Bishop y Burnett modificado por paridad / Predictive validity of Bishop and Burnett Scores for vaginal deliverymodified by parity

Fundamento: Validar la capacidad predictiva del resultado de parto de los índices Bishop (BS) y Burnett (BRS) frente a versiones modificadas en las que se incorpora la paridad (BSM y BRSM). Método: Cohortes históricas sobre un total de 728 inducciones realizadas durante los años 2011-2013 en el Hospital «La Mancha-Centro» (HLMC) de Alcázar de San Juan. Se evaluaron las características predictivas (análisis de validez interna) mediante áreas bajo la curva (ABC) ROC de cada parámetro de los BS y BRS y de la paridad, así como de cada uno de los 4 índices. Resultados: La paridad y todos los parámetros del BS y BRS, a excepción de la estación fetal y la posición del cuello, se asociaron con el resultado de parto. Se definieron dos nuevas escalas modificadas a partir del BS y BRS, previa eliminación del parámetro de la estación fetal, por ser el que menor capacidad discriminativa mostraba: BSM y BRSM. Se asignó un valor de 0 en las nulíparas y, en el caso de las multíparas, 3 puntos a BSM y 2 a BRSM. Los índices modificados mostraron una capacidad predictiva (ABC) de parto vaginal superior a la de los índices originales, tanto para BS (0,70 vs. 0,62) como para BRS (0,69 vs. 0,62). Conclusión: Los índices modificados BSM y BRSM, donde se sustituye el parámetro altura de la presentación por la paridad, presentan mejor capacidad predictiva respecto de los índices originales BS y BRS para determinar el resultado de parto (AU)

Background: Validating the predictive capacity on the outcome of labour of the Bishop Score (BS) and the simplified Burnett Score (BRS) compared to their modified versions, in which parity is incorporated. Methods: Historical cohorts out of a total of 728 inductions during the years 2012-2013 in the «La Mancha-Centro» Hospital of Alcázar de San Juan. We evaluated the predictive characteristics by areas under the (AUC) ROC curve for each parameter of BS and BRS and for parity, as well as for each of the 4 indices. Results: Parity and all the parameters of BS and BRS, except for foetal station and cervical position, were associated with the outcome of labour. Two modified scales were defined on the basis of BS and BRS, following removal of the "foetal station" parameter due to its low discriminative capacity: BSM and BRSM. Nulliparity was given a value of 0 points, and multiparity a value of 3 points for BSM, and 2 for BRSM. Modified indices showed a higher predictive ability (AUC) for vaginal delivery than the original indices, for both BS (0.70 vs. 0.62) and for BRS (0.69 vs. 0.62). Conclusion: Replacing the «foetal station» parameter with parity in BS and BRS, improves predictive capacity with regard to the original indices in order to determine the outcome of labour (AU)

[Predictive validity of Bishop and Burnett Scores for vaginal delivery modified by parity]. / Validación de la capacidad predictiva de resultado de parto del índice de Bishop y Burnett modificado por paridad.

BACKGROUND: Validating the predictive capacity on the outcome of labour of the Bishop Score (BS) and the simplified Burnett Score (BRS) compared to their modified versions, in which parity is incorporated. METHODS: Historical cohorts out of a total of 728 inductions during the years 2012-2013 in the "La Mancha-Centro" Hospital of Alcázar de San Juan. We evaluated the predictive characteristics by areas under the (AUC) ROC curve for each parameter of BS and BRS and for parity, as well as for each of the 4 indices. RESULTS: Parity and all the parameters of BS and BRS, except for foetal station and cervical position, were associated with the outcome of labour. Two modified scales were defined on the basis of BS and BRS, following removal of the "foetal station" parameter due to its low discriminative capacity: BSM and BRSM. Nulliparity was given a value of 0 points, and multiparity a value of 3 points for BSM, and 2 for BRSM. Modified indices showed a higher predictive ability (AUC) for vaginal delivery than the original indices, for both BS (0.70 vs. 0.62) and for BRS (0.69 vs. 0.62). CONCLUSION: Replacing the "foetal station" parameter with parity in BS and BRS, improves predictive capacity with regard to the original indices in order to determine the outcome of labour. Key Words. Bishop Score. Induction of labour. Outcome of labour. Parity. Predictive model.

[Factors associated with blood loss during precipitate labor]. / Factores asociados a la pérdida sanguínea en partos precipitados.

BACKGROUND: Precipitate labour is related to the appearance of postpartum haemorrhage due to posterior uterine atony. However, preventive measures that may be effective in reducing blood loss in this type of delivery are still unknown. Therefore, the objective of this study was to determine the risk factors associated with blood loss produced in precipitate labour. METHODS: This was an observational, analytical retrospective cohort study based on a total sample of 742 women with vaginal delivery whose duration was less than 180 minutes, during the period 2010-2014. Dead foetus antepartum gestations, twin gestations and labour induction were excluded from the analysis. The main outcome variable was intrapartum blood loss. RESULTS: By making use of multivariate analysis, the risk factors independently associated with higher blood loss (g/dL) during precipitate labour were nulliparity (0.38; p<0.001), higher antepartum haemoglobin levels (0.23; p<0.001), higher gestational age (0.06; p<0.001), manual removal of the placenta (0.92; p=0.004) and the use of episiotomy (0.34; p<0.001). Performing active management emerges as a protective factor against increased blood loss (-0.23; p<0.001). The average loss of haemoglobin was 1.0 g/dL (standard deviation =0.92). CONCLUSION: The restriction in the practice of episiotomy and the use of active management can therefore be established as key measures that professionals can modify in order to reduce blood loss during precipitate labour and to improve these mothers' postpartum period. Key words. Haemoglobin. Precipitate labour.

Factores asociados a la pérdida sanguínea en partos precipitados / Factors associated with blood loss during precipitate labour

Fundamento: El parto precipitado se relaciona con la aparición de hemorragia postparto por atonía uterina posterior. Sin embargo, las medidas preventivas que pueden resultar efectivas para lograr reducir las pérdidas sanguíneas en este tipo de parto son aún desconocidas. Por ello, el objetivo de este estudio fue conocer los factores relacionados con la pérdida sanguínea en los partos precipitados. Material y método: Se realizó un estudio observacional y analítico de cohortes retrospectivo sobre una muestra total de 742 mujeres con parto vaginal cuya duración fue inferior a 180 minutos durante el periodo 2010-2014. Las gestaciones con feto muerto anteparto, gemelares e inducciones de parto fueron excluidos del análisis. La variable resultado principal fue la pérdida hemática intraparto. Resultados: Mediante el empleo de análisis multivariante, los factores de riesgo asociados de manera independiente a mayores pérdidas sanguíneas (g/dL) en partos precipitados fueron la nuliparidad (0,38; p<0,001), niveles de hemoglobina preparto elevados (0,23; p<0,001), mayor edad gestacional (0,06; p<0,001), realización de alumbramiento manual (0,92; p=0,004) y empleo de episiotomía (0,34; p<0,001). La realización de alumbramiento dirigido surge como factor protector frente a mayores pérdidas sanguíneas (-0,23; p<0,001). La pérdida de hemoglobina promedio se situó en un 1,0 g/dL (desviación típica =0,92). Conclusiones: La estricción de la práctica de la episotomía y el empleo del alumbramiento dirigido se establece como medidas clave modificables por los profesinales para reducir las pérdidas sanguíneas en partos precipitados y mejorar el estado materno postparto (AU)

Background: Precipitate labour is related to the appearance of postpartum haemorrhage due to posterior uterine atony. However, preventive measures that may be effective in reducing blood loss in this type of delivery are still unknown. Therefore, the objective of this study was to determine the risk factors associated with blood loss produced in precipitate labour. Methods: This was an observational, analytical retrospective cohort study based on a total sample of 742 women with vaginal delivery whose duration was less than 180 minutes, during the period 2010-2014. Dead foetus antepartum gestations, twin gestations and labour induction were excluded from the analysis. The main outcome variable was intrapartum blood loss. Results: By making use of multivariate analysis, the risk factors independently associated with higher blood loss (g/dL) during precipitate labour were nulliparity (0.38; p<0.001), higher antepartum haemoglobin levels (0.23; p<0.001), higher gestational age (0.06; p<0.001), manual removal of the placenta (0.92; p=0.004) and the use of episiotomy (0.34; p<0.001). Performing active management emerges as a protective factor against increased blood loss (-0.23; p<0.001). The average loss of haemoglobin was 1.0 g/dL (standard deviation =0.92). Conclusion: The restriction in the practice of episiotomy and the use of active management can therefore be established as key measures that professionals can modify in order to reduce blood loss during precipitate labour and to improve these mothers' postpartum period (AU)

Determination and applications of the molar absorptivity of phenolic adducts with captopril and mesna.

Captopril and mesna are molecules with a free thiol group, used as active ingredients due to their hypotensor and mucolytic properties, respectively. These compounds cross the hematoencephalic barrier and, due to the reactivity of their thiol group, can form adducts with the o-quinones formed during the oxidation of mono- and o-diphenols. Polyphenol oxidase from plants and fungi can be used as a tool for generating o-quinones in their action on o-diphenols and facilitate the formation of adducts in the presence of captopril or mesna. The spectrophotometric characterization of these adducts is useful from several points of view. Here, using the end-point method, which involves the exhaustion of oxygen in the medium, we determined the molar absorptivity of the adducts of different o-diphenols with captopril and mesna. Besides the analytical interest of this approach, we also use it to make a kinetic characterization of polyphenol oxidase as it acts on o-diphenolic substrates that produce unstable o-quinones.

Kinetic characterization of the enzymatic and chemical oxidation of the catechins in green tea.

The oxidation of green tea catechins by polyphenol oxidase/O2 and peroxidase/H2O2 gives rise to o-quinones and semiquinones, respectively, which inestability, until now, have hindered the kinetic characterization of enzymatic oxidation of the catechins. To overcome this problem, ascorbic acid (AH2) was used as a coupled reagent, either measuring the disappearance of AH2 or using a chronometric method in which the time necessary for a fixed quantity of AH2 to be consumed was measured. In this way, it was possible to determine the kinetic constants characterizing the action of polyphenol oxidase and peroxidase toward these substrates. From the results obtained, (-) epicatechin was seen to be the best substrate for both enzymes with the OH group of the C ring in the cis position with respect to the B ring. The next best was (+) catechin with the OH group of the C ring in the trans position with respect to the B ring. Epigallocatechin, which should be in first place because of the presence of three vecinal hydroxyls in its structure (B ring), is not because of the steric hindrance resulting from the hydroxyl in the cis position in the C ring. The epicatechin gallate and epigallocatechin gallate are very poor substrates due to the presence of sterified gallic acid in the OH group of the C ring. In addition, the production of H2O2 in the auto-oxidation of the catechins by O2 was seen to be very low for (-) epicatechin and (+) catechin. However, its production from the o-quinones generated by oxidation with periodate was greater, underlining the importance of the evolution of the o-quinones in this process. When the [substrate] 0/[IO4 (-)] 0 ratio = 1 or >>1, H2O2 formation increases in cases of (-) epicatechin and (+) catechin and practically is not affected in cases involving epicatechin gallate, epigallocatechin, or epigallocatechin gallate. Moreover, the antioxidant power is greater for the gallates of green tea, probably because of the greater number of hydroxyl groups in its structure capable of sequestering and neutralizing free radicals. Therefore, we kinetically characterized the action of polyphenol oxidase and peroxidase on green tea catechins. Furthermore, the formation of H2O2 during the auto-oxidation of these compounds and during the evolution of their o-quinones is studied.

Expressions for the fractional modification in different monocyclic enzyme cascade systems: analysis of their validity tested by numerical integration.

This paper presents the derivation, under a minimal set of assumptions, of a general expression for the steady-state fractional modification of an interconvertible protein involved in four different schemes of monocyclic enzyme cascade systems. From this general expression we derive, as particular cases, other, simpler expressions by applying additional assumptions and which have, therefore, a smaller range of validity. Some of these particular expressions coincide with those already obtained in previous contributions on individualised analyses. We discuss the relationships between the kinetic parameters and the concentrations needed for the fulfilment of the additional assumptions. The goodness of the analysis was tested by reference to the shape in the steady-state of the simulated time progress curves obtained by numerical integration.

Kinetic analysis of the general modifier mechanism of Botts and Morales involving a suicide substrate.

Suicide substrates are widely used in enzymology for studying enzyme mechanisms and designing potential drugs. The presence of a reversible modifier decreases or increases the rate of substrate-induced inactivation, with evident physiological and experimental consequences. To date, only the action of a competitive or uncompetitive inhibitor of an enzyme system involving suicide substrate has been reported. In this paper, we analyse the kinetics of enzyme-catalysed reactions which evolve in accordance with the general modifier mechanisms of Botts and Morales in which enzyme inactivation is induced by suicide substrate. Rapid equilibrium of all of the reversible reaction steps involved is assumed and the time course equations for the residual enzyme activity, the inactive enzyme forms and the reaction product are derived. Partition ratios giving the relative weight of the product and inactive enzyme concentrations, and the relative contribution to the product formation of each of the unmodified and modified catalytic routes, are studied. New indices pointing to the conditions under which the modifier acts as inhibitor or as activator are suggested. The goodness of the analytical solutions is tested by comparison with the simulated curves obtained by numerical integration. An experimental design and kinetic data analysis to evaluate the kinetic parameters from the time progress curves of the product are proposed. From these results, those corresponding to several reaction mechanisms involving both a suicide substrate and a modifier, and which can be regarded as particular cases of the general case analysed here, can be directly and easily derived.

Linear mixed irreversible inhibition of the autocatalytic activation of zymogens. Kinetic analysis checked by simulated progress curves.

Autocatalytic zymogen activation is a phenomenon of great importance for understanding some fundamental physiological processes involved in the enzyme regulation of gastrointestinal-tract enzymes, blood coagulation, fibrinolysis and the complement system. Examples of such processes are the activation of prekallikrein, trypsinogen and pepsinogen, all of which are controlled by natural proteinase inhibitors. This work studies the kinetics of a general autocatalytic zymogen activation process overlapped by two two-step irreversible inhibitions, i.e. a linear mixed irreversible inhibition. The kinetic equations for the whole course of the reaction are derived for this mechanism. In addition, we determine the corresponding kinetics for a number of particular cases of the general model analyzed, i.e. for reversible and irreversible non-competitive, competitive and uncompetitive inhibition systems which are considered particular cases of the general mechanism studied. The kinetic behavior of the system is related to a parameter, a dimensionless quantity, which shows whether the inhibition or the activation route prevails, in a similar way to that which we have previously carried out for other mechanisms. Finally, based on the kinetic equations obtained, a procedure for discriminating between the different mechanisms considered is suggested. The results of this contribution can be directly applied to most physiological autocatalytic zymogen activations in the presence of an inhibitor, allowing their complete kinetic characterization and suggesting procedures for varying the relative weight of the catalytic and inhibition routes or for changing the predominant route.

Kinetic analysis of the opened bicyclic enzyme cascades.

A kinetic analysis of the opened bicyclic enzyme cascade is presented. It includes the time-dependence of the concentrations of the modified and unmodified forms of the interconvertible enzymes, as well as their fractional modifications, from the onset of the reaction to its completion. The transient phase equations obtained allow the definition of new regulatory properties. The expressions corresponding to the concentrations and fractional modification in the steady-state are derived as particular cases of the general transient phase equations. These steady-state expressions agree with those obtained by other authors.

Kinetic analysis of reversible closed bicyclic enzyme cascades covering the whole course of the reaction.

A kinetic analysis of the closed bicyclic enzyme cascades is presented. 1. It includes the dependence on time from the onset of the reaction, of the concentration of the modified and unmodified enzyme species involved and the time course equations of the modificational fractions of the interconvertible enzymes. 2. The transient phase equations obtained allow the definition of new regulatory modification properties. 3. The expressions for concentrations of the unmodified and modified forms of the interconvertible enzymes, as well as those of the fractional modifications in the steady state are derived as particular cases of the general equations. 4. These steady state expressions coincide with those obtained by other authors. 5. The analytical results obtained are discussed in relation to the Escherichia coli glutamine synthetase cascade.

Time course of the uridylylation and adenylylation states in the glutamine synthetase bicyclic cascade.

A kinetic analysis of the glutamine synthetase bicyclic cascade is presented. It includes the dependence on time from the onset of the reaction of both the uridylylation of Shapiro's regulatory protein and the adenylylation of the glutamine synthetase. The transient phase equations obtained allow an estimation of the time elapsed until the states of uridylylation and adenylylation reach their steady-states, and therefore an evaluation of the effective sensitivity of the system. The contribution of the uridylylation cycle to the adenylylation cycle has been studied, and an equation relating the state of adenylylation at any time to the state of uridylylation at the same instant has been derived.