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Biomedical subjects

B Connolly

Publications and source records attributed to B Connolly.

5 recordsLinked to original sources

The changing role of surgery in the management of rhabdomyosarcoma.

A retrospective analysis was performed of 56 patients presenting to Our Lady's Hospital for Sick Children, Crumlin, Dublin, Ireland, over a 25 year period with a diagnosis of rhabdomyosarcoma, in an effort to assess the changing role of surgery in the management of this disease. There were 38 males and 18 females; the age range at presentation was from birth to 13 years with a median of three years. Head and neck tumors occurred most frequently (23) followed by pelvic (14), paratesticular (6), extremities (6), gastrointestinal (4) and thoracic (3). Prior to 1971 there were no survivors while a doubling of survival has been observed within the past decade (31% to 63%). The minimum period of follow-up was four years. Surgical intervention ranged from total primary excision (20) to biopsy only (21) with total or subtotal resection performed electively in 15. Surgical evaluations, including examinations under anesthesia, staging laparotomy and second look laparotomy were also invaluable in assessing disease status. The incorporation of multiagent chemotherapy together with more selective use of radiotherapy has enabled a more conservative role to be adopted by the surgical oncologist thereby minimizing longterm sequelae.

Antineoplastic Combined Chemotherapy Protocols

Biological roles of the Escherichia coli RuvA, RuvB and RuvC proteins revealed.

In Escherichia coli, the ruvA, ruvB and ruvC gene products are required for genetic recombination and the recombinational repair of DNA damage. New studies suggest that these three proteins function late in recombination and process Holliday junctions made by RecA protein-mediated strand exchange. In vitro, RuvA protein binds a Holliday junction with high affinity and, together with RuvB (an ATPase), promotes ATP-dependent branch migration of the junction leading to the formation of heteroduplex DNA. The third protein, RuvC, which acts independently of RuvA and RuvB, resolves recombination intermediates by specific endonucleolytic cleavage of the Holliday junction.

Adenosine Triphosphate

Resolution of Holliday junctions in vitro requires the Escherichia coli ruvC gene product.

In previous studies, Holliday junctions generated during RecA-mediated strand-exchange reactions were resolved by fractionated Escherichia coli extracts. We now report the specific binding and cleavage of synthetic Holliday junctions (50 base pairs long) by a fraction purified by chromatography on DEAE-cellulose, phosphocellulose, and single-stranded DNA-cellulose. The cleavage reaction provided a sensitive assay with which to screen extracts prepared from recombination/repair-deficient mutants. Cells with mutations in ruvC lack the nuclease activity that cleaves synthetic Holliday junctions in vitro. This deficiency was restored by a multicopy plasmid carrying a ruvC+ gene that overexpressed junction-resolving activity. The UV sensitivity and deficiency in recombinational repair of DNA exhibited by ruv mutants lead us to suggest that RuvC resolves Holliday junctions in vivo.

Bacterial Proteins

Genetic recombination in Escherichia coli: Holliday junctions made by RecA protein are resolved by fractionated cell-free extracts.

Escherichia coli RecA protein catalyzes reciprocal strand-exchange reactions between duplex DNA molecules, provided that one contains a single-stranded gap or tail, to form recombination intermediates containing Holliday junctions. Recombination reactions are thought to occur within helical RecA-nucleoprotein filaments in which DNA molecules are interwound. Structures generated in vitro by RecA protein have been used to detect an activity from fractionated E. coli extracts that resolves the intermediates into heteroduplex recombinant products. Resolution occurs by specific endonucleolytic cleavage at the Holliday junction. The products of cleavage are characteristic of patch and splice recombinants.

Adenosine Triphosphate

Interdisciplinary early intervention program.

Developmental data were obtained on 40 children with Down's syndrome by an interdisciplinary team during an ongoing early intervention program. Interventive methods are described. Results are compared with available data on children with Down's syndrome who were not in early intervention programs. Comparisons of developmental progress are also made of children begun in the early intervention program before six months of age with those begun after six months of age. Conclusions from the study indicate that early intervention helps the child in earlier attainment of many developmental tasks and enhances functioning of the family unit.

Counseling