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Hemophilia B is an X-chromosome-linked bleeding disorder resulting from lack of clotting factor IX activity and affects about 1 in 30,000 males. Current therapy involves injection of crude factor IX prepared from pooled human plasma. Treatment is complicated by viral contaminants in factor IX preparations, such as non A-non B hepatitis and the AIDS virus, and by the practical difficulties of chronic injections. An alternative therapy might include the insertion of a factor IX expression vector into the somatic cells of affected individuals to allow continued production of factor IX. Toward this end, we have constructed a retrovirus vector for transfer and expression of factor IX. Despite the fact that factor IX is normally synthesized in hepatocytes and requires extensive post-translational modification for activity, we have shown that fully active factor IX can be made by human skin-derived fibroblasts. These results open the way to testing the use of skin grafts for gene therapy of hemophilia B.

We describe the solubilization and purification of both the photoaffinity-labeled and unlabeled human placenta receptor for epidermal growth factor-urogastrone (EGF-URO). The photolabeled receptor can be purified 300- to 500-fold from membrane extracts by combined immunoaffinity and lectin-agarose affinity chromatography. This isolation approaches theoretical purity. Upon gel filtration and wheat germ agglutinin-Sepharose chromatography, the photolabeled receptor and the EGF-URO binding activity co-migrate, as measured by a newly developed lectin-agarose immobilization assay of receptor binding. Sequential ion exchange, Cibacron blue-Sepharose, wheat germ agglutinin-Sepharose, and gel filtration chromatography yield a 110-fold purification of the EGF-URO binding activity; this purified fraction contains protein constituents that exhibit electrophoretic mobilities parallel to those of the photolabeled receptor constituents, that have apparent molecular weights of 180,000 and 160,000. This molecular weight range is consistent with a measured apparent Stokes radius for both the photolabeled and unlabeled receptor of 5.1 nm (Sephacryl S-200 gel filtration), although an apparent radius of 4.3 nm is estimated by gel filtration on Sepharose-6B. The apparent molecular weight of the photolabeled receptor is unaffected by 2-mercaptoethanol. This work provides a basis for further detailed studies of this growth factor receptor.

The objective of management in the pregnant diabetic patient is to achieve physiologic glucose homeostasis through the use of diet and insulin. As outlined, the numerous ancillary tests developed during the past 15 years to assist the clinician in determining impending fetal death have left much to be desired, especially where metabolic homeostasis has not been achieved prior to the thirty-sixth week of gestation. The statistics from this institution indicate that the maintenance of the plasma glucose concentration below 100 mg. per cent throughout gestation, regardless of the severity of the diabetes, all but removes the risk of maternal-fetal complications due to diabetes. The management is uniform for all patients exhibiting an abnormality of carbohydrate metabolism, and, although it is rather difficult to accept, there have been minimal neonatal complications when the protocol outlined in this presentation has been followed.

Patients with certain genetic disorders can be cured by bone marrow transplantation. However, as prospective donors do not exist for most patients with potentially curable genetic abnormalities, an alternative treatment for such patients involves the transfer of cloned genes into the patient's haematopoietic stem cells followed by re-infusion of the treated cells. Retroviral vectors provide an efficient means for transferring genes into mammalian cells and have been used to transfer genes into mouse haematopoietic cells. We have now produced amphotropic retroviral vectors containing either the bacterial gene for neomycin resistance or a mutant dihydrofolate reductase gene that confers resistance to methotrexate and have used these vectors to infect and confer drug resistance to human haematopoietic progenitor cells in vitro. Transfer could be demonstrated in the absence of helper virus by using an amphotropic retrovirus packaging cell line, PA12 (ref. 9). These studies are an important step towards the eventual application of retrovirus-mediated gene transfer to human gene therapy and for molecular approaches to the study of human haematopoiesis.

The evaluation of a behavior and development training program that was integrated into a general pediatric training residency is reported. Thirty-two residents who participated in the program were evaluated over one year on measures designed to assess residents' opinions about the relevance of behavior and development concepts, residents' perceptions of their own competence in behavior and development knowledge and skills, supervisors' ratings of residents' general clinical performance, and residents' attitudes about 10 specific illnesses. Results suggest that residents perceive a high relevance for psychosocial concepts and an increasing competence with these concepts after training. Establishing rapport with patients emerged as an important variable in supervisors' ratings of resident performance and in residents' self-ratings of competence. Attitudes were initially negative toward the more behavioral and psychophysiological disease entities but showed some positive change over the year. These results and their implications are discussed.