Blunt-tipped versus sharp-tipped needles: wound morbidity

Blunt-tipped needles have previously been shown to reduce needle-stick injury but the issue of morbidity had not been addressed. As awareness of the need for universal precautions heightens, concerns have been raised about any possible morbidity brought about by their use. We present the results of a randomised, controlled study which investigated wound morbidity following caesarean section. Of the 204 women randomised to closure with sharp or blunt-tipped needles, none developed anything other than superficial infection and there were no significant differences between the two groups. We conclude that the use of blunt-tipped needles does not cause an increase in wound morbidity.

FLASHFLOOD: a 3D field-based similarity search and alignment method for flexible molecules

A three-dimensional field-based similarity search and alignment method for flexible molecules is introduced. The conformational space of a flexible molecule is represented in terms of fragments and torsional angles of allowed conformations. A user-definable property field is used to compute features of fragment pairs. Features are generalizations of CoMMA descriptors that characterize local regions of the property field by its local moments. The features are invariant under coordinate system transformations. Features taken from a query molecule are used to form alignments with fragment pairs in the database. An assembly algorithm is then used to merge the fragment pairs into full structures, aligned to the query. Key to the method is the use of a context adaptive descriptor scaling procedure as the basis for similarity. This allows the user to tune the weights of the various feature components based on examples relevant to the particular context under investigation. The property fields may range from simple, phenomenological fields, to fields derived from quantum mechanical calculations. We apply the method to the dihydrofolate/methotrexate benchmark system, and show that when one injects relevant contextual information into the descriptor scaling procedure, better results are obtained more efficiently. We also show how the method works and include computer times for a query from a database that represents approximately 23 million conformers of seventeen flexible molecules.

Molecular moment similarity between several nucleoside analogs of thymidine and thymidine. sil@watson.ibm.com

Molecular moment descriptors of the shape and charge distributions of twenty five nucleoside structures have been examined. The structures include thymidine as well as the difluorotoluene nucleoside analog which has been found to pair efficiently with adenine by polymerase catalysis. The remaining twenty three structures have been chosen to be as structurally similar to thymidine and to the difluorotoluene nucleoside analog as possible. The moment descriptors which include a description of the relationship of molecular charge to shape show the difluorotoluene nucleoside to be one of the most proximate molecules to thymidine in the space of the molecular moments. The calculations, therefore, suggest that polymerase specificity might be not only a consequence of molecular steric features alone but also of the molecular electrostatic environment and its registration with molecular shape.

Molecular moment similarity between clozapine and substituted [(4-phenylpiperazinyl)-methyl] benzamides: selective dopamine D4 agonists

Moment descriptors of the molecular charge and mass distributions are investigated within the context of molecular similarity. Euclidean distances in the moment descriptor space are shown to yield molecular proximities in accord with chemical intuition for a substituted [(4-phenylpiperazinyl)-methyl] benzamide series of dopamine D4 agonists. The proximity of the dopamine D4 antagonist clozapine to the molecules of this series is also examined in the moment space.

Simultaneous monitoring of head-to-cervix forces, intrauterine pressure and cervical dilatation during labour

In many westernized countries, the caesarean section role has now reached 15% or more, most commonly because of slow progress in labour. In order for labour to result in a vaginal delivery, the uterine cervix must dilate to allow the foetus to travel through the birth canal. This process is driven by uterine contractions, but the mechanisms by which the contractions result in cervical dilatation are still far from clear. The force exerted by the presenting part (foetal head) on the cervical tissue during contractions (head-to-cervix force, HCF) has been shown to be the variable with the best correlation with cervical dilatation. Unfortunately, the mechanism by which these two variables are related is still poorly understood. In order to investigate the relationship between head-to-cervix force, intrauterine pressure (IUP) and cervical dilatation, we have developed a system for their simultaneous and continuous monitoring during labour. The HCF is measured by using a novel intrauterine probe which is slipped alongside the foetal head so as to lie sandwiched between the latter and the cervix. The probe is fitted with six specially designed miniature force sensors, spaced 1.8 cm apart, which respond linearly and approximate the behaviour of load cells. They are interfaced with a PC by circuitry that allows auto-zeroing and drift compensation. The system enables simultaneous acquisition of intrauterine pressure and foetal heart rate (measured using a Sonicaid Meridian foetal monitor) via a serial link, together with continuous cervical dilatation measured by a caliper-like device applied to the cervix. Some preliminary data are presented, which suggest that the system can be used to investigate the role played by head-to-cervix force and intrauterine pressure in the cervix dilatation process.