The cytology and developmental attributes of 18 deficiency mutations in the 3A1-3C6 region of the salivary gland X chromosome of Drosophila melanogaster have been investigated. The cytological limits of several older deficiencies have been revised and clarified and several new deficiencies are characterized. The deficiency mutants, withone possible exception, show a lethal phase in the late emb...

QUESTION I have a patient planning pregnancy who has resistant rheumatoid arthritis that will require treatment with some of the "new" medications. Which ones are safe to use during pregnancy, and which ones do we know enough about to tell whether they are safe or not? ANSWER For most new disease-modifying biologic medications, we have few data on safety. More and more reassuring data are acc...

A simple method is described for growing rat embryos in vitro for 48 hr from head-fold to early limb-bud stages at rates of development and protein synthesis indistinguishable from those in vivo. Culture of the embryos can be continued for longer periods but at a reduced growth rate. Preheating the culture serum to 56 degrees C for 30 min improves embryonic development, but raising the culture ...