The rDNA of C. elegans: sequence and structure.

We have sequenced one complete rDNA tandem repeat from the nematode C. elegans. By comparative analysis we derive secondary structures for the 18s, 5.8s, and 26s rRNA molecules, and comment on other important features of the sequence. We also present the sequence of a junction between the rDNA and non-ribosomal DNA. Finally, we use our data to quantify the evolutionary relationships among several organisms currently studied in developmental biology.     

The menopause: stressors and facilitators.

Between about ages 40 and 55 years, women experience a transition known as the menopause, which marks the end of their childbearing years. Although the most striking feature of the menopause is the cessation of menstruation, other biologic and psychosocial events occur and can be classified as stressors and "facilitators". For a predisposed group of women the stressors are likely to cause psychiatric disorders. At the same time, the facilitators are opportunities for personal growth and development. Physicians who understand both types of events during this phase of life and who are sensitive to the overall effects of ageing on marital partners can provide comprehensive care to the menopausal patient rather than automatically pursuing drug therapy (substitution hormonal therapy) alone.