Modern X-ray scattering studies of complex biological systems.

X-ray scattering is one of the most prominent structural characterization techniques in biology. The key advantage of X-ray scattering is its ability to penetrate and weakly interact with the bare studied materials. In addition, X-ray scattering does not require any tags, markers or modification to the sample under examination, and is not limited by the nature of the surrounding environment. The main handicapping limitation of X-ray scattering is the subject of particles polydispersity. However, the monodispersity in biological complexes and supra-molecular interactions makes them ideal for structural and interaction studies in particular when combined with higher (e.g. NMR) and/or lower resolution (e.g. optical microscopy) techniques. This review seeks to highlight some of the major recent achievements in the field of X-ray scattering as being implemented for complex biological systems.

Risk in the vaginal delivery of the large fetus.

The problem of the excessively weighted fetus was studied. For this purpose, over a period of 2 years, each delivery with fetal weight of 4,500 g or more was included in the study. The history and examination findings of the present pregnancy were reviewed following delivery. The postpartum outcome and later complications in both mothers and infants were investigated prospectively. A total of 82 deliveries of large babies were included in the study and the outcome was compared with that of parallel deliveries of babies within the normal weight range (2,500-4,000 g). Factors frequently associated with excessive fetal weight were identified. A relatively high perinatal mortality and morbidity relating to vaginal delivery were observed among the large infants. In all those cases who developed delay in the second stage of labour, Caesarean section is proposed when macrosomia is clinically suspected and confirmed by ultrasonic assessment. Moreover elective Caesarean section should be considered before labour, when macrosomia is associated with hyperglycaemia or other pathology.