Faculty Bibliography

A study was undertaken to determine whether pelvic inflammatory disease (PID) resulting from the insertion of an intrauterine device (IUD) could be eliminated by inserting the IUD during ovulation and administering prophylactic antibiotics to cover insertion. IUDs, 95% of which were Progestaserts, were inserted within two days of probable ovulation in 288 patients. These study patients were compared with a matched control group of 288 patients not using IUDs. None of the 288 IUD patients (totaling 619 woman-years of IUD use) developed PID after insertion, and only 0.5% per 100 woman-years developed PID later. The incidence of PID seen in these patients was less than that observed in the control group. It was also less than that in the general population or that following legal induced abortion. The expulsion rate of 1% per 100 woman-years in our patients is the lowest ever reported. It probably is related to the low motility of the uterus and expansion of the cervix during ovulation; the latter facilitates insertion during ovulation

A sensitive homologous recombination strand-transfer assay is described that employs short radiolabeled double-stranded DNA fragments from the lac/polylinker region of plasmid pUC18 and (+)viral M13mp18 single-stranded DNA as substrates. Substitution of a short radiolabeled double-stranded fragment for full-length linear M13 double-stranded DNA results in an assay whose sensitivity is improved greater than 8-fold. In addition, it is less sensitive to interference from nucleases or ligases than previous assays. The assay was used to partially purify an ATP-independent strand-transfer activity from a crude nuclear extract of Drosophila melanogaster embryos. We have also tested the efficiency with which various short double-stranded DNA segments are assembled into plectonemic joints by RecA protein with this assay and found 5- to 10-fold differences. These results are interpreted as evidence for DNA sequence-specific effects in RecA-mediated homologous pairing in vitro

The Broadbent-Bolton cephalostat produces intrinsically three-dimensional information about cranial form. Yet in the clinical setting, this information has been used primarily two dimensions at a time in the separate study of lateral or posteroanterior cephalograms. In this article we demonstrate an expedient use of existing cephalostat-based data sets to derive certain analyses of three-dimensional form. The technique is essentially the same as that of the Broadbent-Bolton 'Orientator,' an exploitation of the geometry of the cephalostat to simulate stereophotogrammetry. The three-dimensional method supports the usual biometrics of landmark locations, and takes advantage of a normative data base that is suited for semiautomatic analysis of syndromic data. The principal drawback of the method is its inability to represent curving form in three dimensions. However, in comparison with computed tomography (CT), it involves low radiation dose, is simpler to obtain, has an available normative data base, and is more practical for quantitative or long-term serial analysis