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Decision making in obstetrics is based on accurate knowledge of fetal gestational age. Menstrual dating based on the last menstrual period is an accurate method for estimating gestational age. Other reliable indicators are fundal height, quickening, the date that the fundus reaches the umbilicus and the date that fetal heart tones are first auscultated. Combinations of these data approach the reliability of menstrual dating. Biochemical assays are useful in early pregnancy. Ultrasound is indispensable when the clinical situation is questionable.

Testosterone 19-O-carboxymethyl ether (T19C) and 19-hemisuccinate (T19H) derivatives were synthesised, and coupled to bovine serum albumin (BSA) or porcine thyroglobulin (PT) for immunogens or to iodohistamine for radioligands. The immunogenicity of these conjugates in mice was compared with those of testosterone 3-O-carboxymethyloxime and 15 beta-thioethyl conjugates. Of 10 immunogens studied, those linked to PT gave the highest antiserum titres and more sensitive standard curves. The site of conjugation (19 or 3 position) had little effect on immunogenicity. Cross-reactivity with 5 alpha-dihydrotestosterone (DHT) was in the range 22-100%, for the 19-linked immunogens. Antisera to T19C and T19H conjugated to PT were then raised in rabbits and characterised with 4 radioligands. Homologous assay systems in which the chemical bridge was identical in immunogen and 125I-radioligand gave the highest antiserum titres but the poorest assay sensitivity while those heterologous with respect to bridge or site gave the most sensitive standard curves. Rabbit antisera to both T19C and T19H immunogens showed good specificities with respect to DHT (range of cross reactions 0.78-21.1%), androstenedione, AN (range 0.45-2.3%) and progesterone, Po (range 0.05-1.4%) with all radioligands. The best assay system employed an antiserum to the T19H-PT immunogen with heterologous radioligand [125I]T19C. It had a detection limit of 15pg/tube and low cross-reactivity with DHT (0.78%), Po (0.3%) and AN (0.43%). We conclude that 19-linked derivatives of testosterone conjugated to PT are good immunogens and the antisera when combined with [125I]testosterone radioligands which are heterologous with respect to the chemical bridge, provide highly specific assays for testosterone with potential for clinical application.

The effect of a synthetic peptide consisting of Arg-Gly-Asp-Ser (RGDS), the amino acid sequence representing the fibroblast attachment site in fibronectin (FN), was tested on migrating newt epidermal cells. In one approach, skin explants were placed on the bottom of plastic dishes coated with human FN, human fibrinogen (FGN), human serum spreading factor (SF), or bovine type I collagen. The explants were then incubated overnight in serum-free medium with or without RGDS. In these experiments exposure to 50 micrograms ml-1 of RGDS reduced migration over FN, FGN and SF to 2-7% of control levels. Two peptides structurally dissimilar to RGDS (Val-Gly-Ser-Glu and Thr-Pro-Arg-Lys), and two that are structurally similar (Lys-Gly-Asp-Ser and Arg-Gly-Glu-Ser), had no effect on explant migration even when used at concentrations higher than 50 micrograms ml-1. Upon removal of the RGDS peptide, inhibited explants quickly recovered. In collagen-coated dishes 50 micrograms ml-1 of RGDS was much less effective than in dishes coated with the other substrates. Raising the RGDS concentration in collagen-coated dishes tenfold did not greatly increase the RGDS effect. When added to the medium bathing wounded limbs, 50 micrograms ml-1 of RGDS only moderately inhibited wound closure. This concentration of peptide, however, severely inhibited migration from skin explants in newt-plasma-coated-dishes and migration over pieces of newt-plasma-coated plastic placed under one edge of a skin wound. Increasing the RGDS concentration to 500 micrograms ml-1 resulted in almost total suppression of wound closure. Wounds exposed to this same concentration of Lys-Gly-Asp-Ser closed normally. These results indicate that newt epidermal cells possess RGDS receptors and that these receptors are involved in epidermal wound closure in vivo and in migration from skin explants onto plastic coated with FN, FGN, SF and collagen. The relative RGDS-insensitivity of wound closure in vivo and in migration from explants onto collagen may reflect in these instances the presence of a relatively high density of RGDS receptor binding sites on the substrate; the presence of RGDS receptor binding sites of relatively high affinity; or the participation of receptors other than those involved in migration over plastic coated with FN, FGN or SF.

We describe the development and validation of an assay for cortisol 17-butyrate in blood in which there is no significant cross reaction with endogenous corticosteroids at levels encountered normally in man. Preliminary data on blood levels of the drug in absorption studies are presented.

Type XI collagen (1 alpha 2 alpha 3 alpha) extracted from bovine articular cartilage by pepsin digestion binds strongly to heparin immobilized on agarose. The collagens from cartilage will bind to heparin-agarose in 0.1 M NaCl/2 M urea/0.01 M Tris-HCl and can be eluted with a linear gradient of NaCl. Type XI begins to elute at NaCl concentrations higher than 0.28 M and is totally eluted at 0.40 M NaCl. The peak of elution occurs at 0.37 M NaCl. The other collagens of cartilage bind more weakly and are fully eluted when the NaCl concentration reaches 0.25 M. Collagen types I, III, and V are also bound to the column at low salt concentrations but are fully eluted before type XI begins to elute. All of the type XI preparation binds to heparin-agarose, suggesting that there is at least one binding site per molecule. Denatured 1 alpha and 2 alpha chains bind strongly, suggesting that at least one binding site exists on both of these chains. These data confirm that the interaction between polyanions and type XI collagen is stronger than that with other known collagens and provide a method for purification of type XI without any type II contamination.

The disposition of ethanol and its proximate metabolite, acetaldehyde, was determined in seven conscious instrumented pregnant ewes (127 to 132 days of gestation; term, 147 days) for intravenous infusion of four dosages of 0.5 gm ethanol/kg maternal body weight, administered over 5 hours to the mother. The maternal and fetal blood had ethanol concentrations that were maximal at 5 hours and were virtually identical during the 24-hour study. There was delayed transfer of ethanol into the amniotic and allantoic fluids during the dosing period, followed by higher ethanol concentrations in these fluids during the elimination phase compared with fetal blood. The ethanol elimination rate was similar for the four biologic fluids. Acetaldehyde concentrations in the four fluids were a thousandfold less than the respective ethanol concentrations. The maternal blood acetaldehyde concentration was greater than that in fetal blood. The data indicate that for a binge-type drinking episode during near-term pregnancy, there is unimpeded bidirectional placental transfer of ethanol between the mother and the fetus; the amniotic fluid surrounding the fetus is a reservoir for ethanol in utero; elimination of ethanol from the maternal-fetal unit is regulated by maternal hepatic biotransformation of ethanol; and there is appreciable acetaldehyde-oxidizing capacity in the maternal liver and at extrahepatic sites.

1. [1-(14)C]Stearic acid, [9-(14)C]stearic acid, [9-(14)C]palmitic acid and [9-(14)C]decanoic acid were fed to lactating rabbits, and the fatty acids of the mammary gland were separated and partially degraded. 2. Most of the (14)C recovered was located in the acids fed. Stearic acid was least efficiently absorbed; decanoic acid was the most extensively metabolized. 3. Resynthesis after degradation to C(2) units led to uniform alternate labelling in the C(2)-C(10) acids, whereas C(12)-C(18) acids had excess of (14)C at the carboxyl end. 4. Acids formed by beta-oxidation down to C(12), but not below, were also present in the mammary-gland lipids. Desaturation of the administered acids was a very minor reaction.