The risk of pelvic inflammatory disease (PID) associated with use of an intrauterine device (IUD) has been an important concern that has dominated decisions on its use throughout the world, especially in the USA. Early research that suggested such an association led to both a dramatic decline in use of the method and its withdrawal from the US market by two manufacturers. However, factors other than use of an IUD are now thought to be major determinants of PID risk. To address these concerns, we have reviewed the World Health Organisation's IUD clinical trial data to explore the incidence and patterns of PID risk with use of an IUD. The overall rate of PID among 22,908 IUD insertions and during 51,399 woman-years of follow-up was 1.6 cases per 1000 woman-years of use. After adjustment for confounding factors, PID risk was more than six times higher during the 20 days after insertion than during later times (unadjusted rates, 9.7 vs 1.4 per 1000 woman-years, respectively); the risk was low and constant for up to eight years of follow-up. Rates varied according to geographical area (highest in Africa and lowest in China) and were inversely associated with age. PID rates were lower among women who had IUDs inserted more recently. Our findings indicate that PID among IUD users is most strongly related to the insertion process and to background risk of sexually transmissible disease. PID is an infrequent event beyond the first 20 days after insertion. Because of this increased risk with insertion, IUDs should be left in place up to their maximum lifespan and should not routinely be replaced earlier, provided there are no contraindications to continued use and the woman wishes to continue with the device.

The molecular basis of cancer is now understood to involve activation of dominant oncogenes and inactivation of tumour suppressor genes, and these genetic events may represent novel targets for cancer therapy. This review focuses on the potential use and ethical implications of gene transfer to alter the behaviour of somatic cells in cancer patients. Antisense nucleic acids and ribozymes represent informational drugs that may be used to modulate the expression of selected genes and suppress malignant behaviour in cancer cells. Genetic immunomodulation by introducing genes for cytokines into cancer cells or lymphocytes can stimulate a cytotoxic immune response against the tumour. Gene transfer techniques can be applied to target prodrug activation specifically to tumour cells and also to protect normal tissues against toxic chemotherapy. Gene replacement therapy could even be used to restore the function of defective tumour suppressor genes.

Pregnancy is rare among breastfeeding women with lactational amenorrhoea. The lactational amenorrhoea method (LAM) is the informed use of breastfeeding as a contraceptive method by a woman who is still amenorrhoeic, and who is not feeding her baby with supplements, for up to 6 months after delivery. Under these three conditions, LAM users are thought to have 98% protection from pregnancy. It can be difficult, however, to determine when supplementation of the baby's diet begins. We have analysed data from nine studies of the recovery of fertility in breastfeeding women to assess the effectiveness of lactational amenorrhoea alone, irrespective of whether supplements have been introduced, as a fertility regulation method post partum. Cumulative probabilities of ovulation during lactational amenorrhoea were 30.9 and 67.3 per 100 women at 6 and 12 months, respectively, compared with 27.2 at 6 months when all three criteria of the LAM were met. Cumulative pregnancy rates during lactational amenorrhoea were 2.9 and 5.9 per 100 women at 6 and 12 months, compared with 0.7 at 6 months for the LAM. The probability of pregnancy during lactational amenorrhoea calculated from these studies is similar to that of other modern contraceptive methods, and it seems reasonable for a woman to rely on lactational amenorrhoea without regard to whether she is fully or partly breastfeeding. So that amenorrhoea and fertility suppression can be maintained, counselling about good breastfeeding and weaning practices remains important.

In a worldwide collaboration, information was sought and centrally checked on mortality and recurrence for each woman in any randomised trial that began before 1985 of any aspect of systemic adjuvant therapy for early breast cancer. Checked data were available for 75,000 women (about 90% of those ever randomised), of whom 32% had died and another 10% had experienced recurrence. The parts now reviewed include 30,000 women in tamoxifen trials, 3000 in ovarian ablation trials, 11,000 in polychemotherapy trials, 15,000 in other chemotherapy comparisons, and 6000 in immunotherapy trials. Highly significant reductions in the annual rates both of recurrence and of death are produced by tamoxifen (25% SD 2 recurrence and 17% SD 2 mortality: 2p less than 0.00001), by ablation below age 50 (26% SD 6 recurrence and 25% SD 7 mortality: 2p = 0.0004), and by polychemotherapy (28% SD 3 recurrence and 16% SD 3 mortality: 2p less than 0.00001), but not by ablation at older ages or by immunotherapy. (Tamoxifen also reduced the risk of development of contralateral breast cancer by 39% SD 9: 1p less than 0.00001). For tamoxifen and for polychemotherapy the avoidance of recurrence is chiefly during years 0-4 (this difference being maintained but not increased afterwards), but the avoidance of mortality is highly significant both during and after years 0-4, so the cumulative differences in survival produced by these relatively brief treatments (median: 2 years tamoxifen, 1 year polychemotherapy) are larger at 10 than at 5 years. There is little information beyond year 10 (except for ovarian ablation, which produces separately significant mortality reductions both during and after years 0-9). Both direct and indirect randomised comparisons show long-term polychemotherapy (eg, 12 months) to be no better than shorter (eg, 6 months) regimens, but do show polychemotherapy to be significantly better than single-agent chemotherapy. Indirect randomised comparisons do not reveal significant differences between different forms of polychemotherapy, or differences between different tamoxifen doses, but do show that long-term tamoxifen (eg, 2 years, or even 5 years) is significantly more effective than shorter tamoxifen regimens. In old age (70+) tamoxifen is of demonstrated efficacy, but chemotherapy has not been evaluated. Between ages 50 and 69 direct comparisons show that chemotherapy plus tamoxifen is better (1p less than 0.00001) than chemotherapy alone both for recurrence and for mortality, and better (1p less than 0.00001) than tamoxifen alone for recurrence.(ABSTRACT TRUNCATED AT 400 WORDS)

Use of chiral molecules in clinical practice may cause problems because different chiral forms of a drug (enantiomers) may have different biological activities--yet clinicians have little awareness of these risks. After discussion of the chemical conventions used to describe chirality, examples of the influence of chirality on the efficacy and toxicity of antirheumatic drugs are given. It is recommended that single enantiomers should be used in biological experiments and clinical trials.

Immunological self-tolerance is guaranteed by several complementary mechanisms arranged in a fail-safe hierarchy--namely, clonal deletion, inactivation, and suppression. Only failure of all these self-tolerance-preserving systems allows autoimmune disease to develop. The notion of such a fail-safe organisation of the immune system is compatible with several features of autoimmune disease: its multicausal nature, its slowly progressive and relapsing course, and the diverse range of interventions available to restore autotolerance. This hypothesis has practical implications for the understanding of both the pathogenesis of iatrogenic autoimmune disease and the design of strategies to re-establish self-tolerance.