Depot medroxyprogesterone acetate (Depo-Provera) and levonorgestrel (Norplant) use in adolescents among clinicians in Northern Europe and the United States.

PURPOSE: To compare attitudes and practices related to clinicians' use of depot medroxyprogesterone acetate [Depo-Provera (DMPA)] and levonorgestrel implants in adolescents in three northern European countries and the United States. METHODS: Between the fall of 1993 and the winter of 1995, surveys eliciting clinician attitudes and practices with the two contraceptive methods were collected from practitioners who provide contraceptive care to teens in Sweden (n = 282), The Netherlands (n = 197), Great Britain (n = 108), and the United States (n = 548). RESULTS: Clinicians in Great Britain and the United States reported prescribing of DMPA, selected DMPA in their top three choices for contraception in teens, and had patients ask about DMPA more frequently than clinicians in Sweden or The Netherlands (p < 0.0001). U.S. clinicians were more likely to report prescribing of the implants, list them as a top choice, and have patients ask for it more frequently than were providers in the other three countries (p < 0.0001). Noncompliance with previous contraceptives was the most common indication for use of either method in this age group. "Worst fears" with DMPA use included infertility, particularly among Swedish clinicians (p < 0.0001), as was pregnancy and loss to follow-up, particularly among British clinicians (p < 0.0001). Condom nonuse was a concern associated with both methods. Breakthrough uterine bleeding was a concern related to implant use, particularly among Swedish practitioners (p < 0.0001). CONCLUSION: Clinicians in the United States and Great Britain display more enthusiasm toward the use of the long-term progestins in adolescents than do clinicians in Sweden or The Netherlands. Continuing education programs could be designed to educate clinicians to allay their concerns about these contraceptives in countries where teen pregnancy is considered a problem.

Myocardial capillaries: increase in number by splitting of existing vessels.

To study myocardial vascular development, stereological parameters were estimated in 24 Wistar rat hearts of six different age groups, from newborn to adult. The vascular surface density showed a sharp increase in the first 2 weeks, a peak around the age of 2 weeks, and then a steady decrease until it flattened in adulthood. In contrast, the vascular volume percentage, when plotted against age, decreased continuously with the greatest change in the first week, after which the curve flattened. These findings are compatible with an increase in the number of capillaries with a concomitant decrease of their diameters. Qualitative scrutiny of the histology did indeed support the idea that vessels become thinner. Reconstructions of the histological sections showed the same change three dimensionally. The reconstructions also demonstrated very small holes that seemed to go through the capillaries in the younger stages. Corrosion casts of the blood vessels were made using a casting resin. This was injected into the umbilical artery of rat embryos from 15 days gestation to birth. In postnatal rats of six age groups methacrylate was injected directly into the left ventricle. These casts supported the stereological data by showing an increase in number and decrease in diameter of capillaries, while during pre- and postnatal development, the intervascular spaces lengthened from small, irregular spaces to long, rectangular ones. Small holes, the probable precursors of such spaces, were clearly visible in the wider vessels of the youngest stages. All data point to an interesting mode of capillary growth, i.e. growth by division of existing vessels.