Clinical outcomes from a prospective study evaluating the role of ambulation during medical termination of pregnancy.

Background: Although induced abortion is one of the most commonly performed gynecological procedures in Great Britain and medical termination of pregnancy is being used more frequently, very little is known about the role of ambulation during the procedure. We sought to compare ambulatory and non-ambulatory groups of patients undergoing medical termination in the hospital setting and determine whether ambulation impacted clinical outcomes.

Study Design: This was a prospective patient-preference study carried out among 130 women with pregnancies up to 63 days of gestation fulfilling the requirements of the 1967 Abortion Act and undergoing medical termination of pregnancy.

Noncomplementary DNA double-strand-break rejoining in bacterial and human cells.

We examined the rejoining of noncomplementary restriction enzyme-produced DNA double-strand breaks in Escherichia coli and in cultured human cells. The enzymes used in this study, ClaI, BamHI and SalI, produce double-strand breaks with 5 protruding single strands. The joining of a ClaI-produced DNA end to a BamHI-produced end or to a SalI-produced end was examined at the DNA sequence level.

Restriction enzyme-induced DNA double-strand breaks as a model system for cellular responses to DNA damage.

To learn more about cellular responses to DNA double-strand breakage, we used three methods to assay cellular damage after treatment with a restriction enzyme that causes DNA double-strand breaks by cleaving at specific recognition sites in the DNA. Chinese hamster ovary cells were treated with increasing doses of Pvu II and studied for double-strand breakage, chromosomal aberration yield, and cell survival. The yield of DNA double-strand breaks, as measured by pulsed-field gel electrophoresis, increased at concentrations up to 500 units and saturated thereafter.

Chromosomal aberration induction in CHO cells by combined exposure to restriction enzymes and X-rays.

The potential interaction between restriction enzyme-induced double-strand breaks (dsb) and X-ray-induced lesions in the formation of chromosomal aberrations was investigated in Chinese hamster ovary cells. Either Alu I, which induces blunt-end dsb, or Sau 3AI, which induces cohesive-end dsb, was electroporated into cells, which were irradiated with 2 Gy of X-rays immediately or 15, 30, 60, 120, or 180 min after electroporation. A significant increase in Alu I-induced chromosomal aberrations was observed when cells were irradiated with 0, 15, 30, or 60 min after enzyme exposure, but only additive effects were found when cells were irradiated 120 or 180 min after enzyme exposure.

Induction of chromosome damage by restriction enzymes during mitosis.

Once electroporated into the nucleus of eukaryotic cells, restriction enzymes will bind at specific DNA sequences and cleave DNA to make double-strand breaks. These induced breaks can lead to chromosome aberrations and consequently offer one approach to determining the mechanism(s) of aberration formation. Because the higher-order structure of DNA in eukaryotic cells might influence the ability of restriction enzymes to locate their recognition sequence, bind, and cleave DNA, we have investigated whether enzymes will cut DNA during metaphase when the chromosomes are most condensed.