Engineering a soluble extracellular erythropoietin receptor (EPObp) in Pichia pastoris to eliminate microheterogeneity, and its complex with erythropoietin.

The extracellular ligand-binding domain (EPObp) of the human EPO receptor (EPOR) was expressed both in CHO (Chinese Hamster Ovary) cells and in Pichia pastoris. The CHO and yeast expressed receptors showed identical affinity for EPO binding. Expression levels in P. pastoris were significantly higher, favoring its use as an expression and scale-up production system. Incubation of EPO with a fourfold molar excess of receptor at high protein concentrations yielded stable EPO-EPObp complexes. Quantification of EPO and EPObp in the complex yielded a molar ratio of one EPO molecule to two receptor molecules. Residues that are responsible for EPOR glycosylation and isomerization in Pichia were identified and eliminated by site-specific mutagenesis. A thiol modification was identified and a method was developed to remove the modified species from EPObp. EPObp was complexed with erythropoietin (EPO) and purified. The complex crystallized in two crystal forms that diffracted to 2.8 and 1.9 A respectively. (Form 1 and form 2 crystals were independently obtained at AxyS Pharmaceuticals, Inc. and Amgen, Inc. respectively.) Both contained one complex per asymmetric unit with a stoichiometry of two EPObps to one EPO.

Contraceptive use for planned parenthood patients.

Three hundred consecutive new patients coming to Planned Parenthood clinics were reviewed. Of these patients, 68.3 percent were not using contraception and 67.8 percent had never used contraception. Also, 35.1 percent had experienced one or more pregnancies, and 52 percent had first coitus before 16 years of age.

PIP: 300 new patients attending 2 clinics of Planned Parenthood, Essex County, New Jersey were studied to evaluate contraceptive prevalence. 150 each came from an urban and a suburban clinic, respectively. 68.3% were not using contraception and 67.8% had never used it. 35.1% of nonusers had been pregnant once or more. Among the urban clinic patients 89.3% were nonusers, 67.1% had never used contraception, and 40.3% had been pregnant. Among suburban clinic patients 40.3% were nonusers, 69% had never used contraception, and 25.3% had been pregnant. 6000 of 25, 712 clinic visits in 1988 had been for pregnancy testing. 164 patients were 19 or younger: 78.6% were nonusers, 83.7% had never used contraception, and 22.5% had been pregnant. 133 patients were 20 or older: 51.8% were nonusers, 47.8% had never used contraception (despite the efforts of sex education), and 68% had been pregnant. 52% of the urban patients and 22% of suburban patients had 1st coitus before the age of 16. Urban patients had a higher rate of nonuse, younger age at 1st coitus, and a higher pregnancy rate. This finding calls for redoubled efforts at sex education to lower an alarmingly high pregnancy rate among those 19 and younger.

Pregnancy after jejunoileal bypass. A review and report of one case.

A case of pregnancy after jejunoileal bypass is presented. Fifty-six full-term pregnancies among 44 patients reported in the literature are reviewed. Pregnancy is not contraindicated after jejunoileal bypass, as it is accompanied by few more problems than those normally encountered in the obese woman. Somewhat smaller babies are born from these pregnancies and some minor disturbances of glucose, protein, and minerals may have to be adjusted during the pregnancy. A two-year interval is suggested after jejunoileal bypass before pregnancy is undertaken, to allow a weight-loss plateau to be established. The 7% incidence of severe congenital anomalies among these 57 pregnancies is higher than normal and suggests an added risk.