RESUMEN
BACKGROUND: Lipiodol is an oil-based solution commonly used in hysterosalpingogram (HSG), but not hysterosalpingo contrast sonography (HyCoSy). In women with unexplained infertility, evidence suggests that tubal flushing with Lipiodol results in improved fertility post-procedure. We propose that Lipiodol can be visualised under ultrasound similar to commonly used saline, and hence utilised for HyCoSy, allowing the benefit of an oil-based tubal flushing to occur with HyCoSy. AIMS: To examine whether Lipiodol is visible sonographically, assess optimal agitated Lipiodol mix and ultrasound settings for visibility, and compare visibility to agitated saline, routinely used for HyCoSy. MATERIALS AND METHODS: Two separate sonographers with identical ultrasound machines and model pelvises recorded images with varying degrees of agitated Lipiodol and ultrasound settings, in addition to capturing images with no fluid and agitated saline. Each test was performed in quadruplicate and in random order. Images were read by 47 blinded reporters and visibility reported on a scale of one (not visible) to five (clearly visible). RESULTS: The mean visibility score for images captured where the Lipiodol sample was agitated five times prior to injection to allow the formation of air microbubbles, regardless of ultrasound setting, were higher than or not different from that for agitated saline (all P > 0.7 when not different, <0.001 when higher). CONCLUSIONS: Sonographic visualisation of agitated Lipiodol is similar or better than that of agitated saline. Lipiodol may therefore present a possibility for use with HyCoSy, with the added benefit of oil-based tubal flushing, avoiding the radiation exposure of HSG and concurrently providing pelvic soft-tissue evaluation.
Asunto(s)
Aceite Etiodizado , Medios de Contraste , Pruebas de Obstrucción de las Trompas Uterinas , Trompas Uterinas/diagnóstico por imagen , Femenino , Humanos , Histerosalpingografía , Infertilidad Femenina , UltrasonografíaRESUMEN
Using small-angle x-ray scattering, we have observed the cGMP-induced elongation of an active, cGMP-dependent, monomeric deletion mutant of cGMP-dependent protein kinase (Delta(1-52)PKG-I beta). On saturation with cGMP, the radius of gyration of Delta(1-52)PKG-I beta increases from 29.4 +/- 0.1 A to 40.1 +/- 0.7 A, and the maximum linear dimension increases from 90 A +/- 10% to 130 A +/- 10%. The elongation is due to a change in the interaction between structured regulatory (R) and catalytic (C) domains. A model of cGMP binding to Delta(1-52)PKG-I beta indicates that elongation of Delta(1-52)PKG-I beta requires binding of cGMP to the low-affinity binding site of the R domain. A comparison with cAMP-dependent protein kinase suggests that both elongation and activation require cGMP binding to both sites; cGMP binding to the low-affinity site therefore seems to be a necessary, but not sufficient, condition for both elongation and activation of Delta(1-52)PKG-I beta. We also predict that there is little or no cooperativity in cGMP binding to the two sites of Delta(1-52)PKG-I beta under the conditions used here. Results obtained by using the Delta(1-52)PKG-I beta monomer indicate that a previously observed elongation of PKG-I alpha is consistent with a pure change in the interaction between the R domain and the C domain, without alteration of the dimerization interaction. This study has revealed important features of molecular mechanisms in the biochemical network describing PKG-I beta activation by cGMP, yielding new insight into ligand activation of cyclic nucleotide-dependent protein kinases, a class of regulatory proteins that is key to many cellular processes.
Asunto(s)
Proteínas Quinasas Dependientes de GMP Cíclico/química , GMP Cíclico/metabolismo , Sitios de Unión , Fenómenos Biofísicos , Biofisica , Proteína Quinasa Dependiente de GMP Cíclico Tipo I , Proteínas Quinasas Dependientes de GMP Cíclico/metabolismo , ADN Complementario/metabolismo , Dimerización , Activación Enzimática , Humanos , Mutagénesis Sitio-Dirigida , Unión Proteica , Estructura Terciaria de Proteína , Dispersión de Radiación , Rayos XRESUMEN
Infrared (IR) spectroscopy of biological cells is a growing area of research, with many papers focusing on differences between the spectra of cancerous and noncancerous cells. Much of this research has been performed using a monolayer of dehydrated cells. We posit that the use of monolayers can introduce artefacts that lead to an apparent but inaccurate measurement of differences between cancerous and noncancerous cells. Additionally, the use of dried cells complicates the extraction of biochemical information from the IR spectra. We demonstrate that using suspensions of viable cells in aqueous suspension reduces measurement artefacts and facilitates determining the concentration of the major biochemical components via a linear least-squares fit of the component spectra to the spectrum of the cells.