Jack Davies

Placental transfer of mercuric nitrate and methyl mercury in the rat.

Abstract Inorganic mercury tracer, 197 Hg(NO 3 ) 2 , and organic mercury tracer, CH 3 , 203 HgCl, were given to 15- and 20-day pregnant rats. The tissues investigated from 16 pregnant rats were decidua, yolk sac, placenta, and fetus. Tissues were taken as soon as 5 minutes after an intravenous maternal injection, as late as 120 hours for the 15-day-pregnant rats and as late as 24 hours for the 20-day-pregnant rats. The two mercury tracers were given simultaneously, and the percentages of the injected doses in the tissues were determined by gamma counting. Fetal uptake of methyl mercury was greater than that of mercuric nitrate at both 15 and 20 days gestation. Decidual tissue showed a comparatively low and constant uptake of both mercury tracers, while the percentage uptake of inorganic mercury by the yolk sac was higher than for methyl mercury.

Observation on the fine structure of the sheep placenta

Authors’ addresses: Prof. Dr. Jack Davies, Department of Anatomy, Vanderbilt University School of Medicine, Nashville, Term. 37203 and Dr. W. A. Wimsatt, Department of Zoology, Cornell University Ithaca, N.Y. (USA) Histological and histochemical studies by many authors (Assheton [1906], Jenkinson [1906], Bonnet [1888], Wimsatt [1950, 1951], Amoroso [1958]) have established the principal morphological features of the sheep placenta. As in the placentae of other ruminants, controversy has centered upon the fetal or maternal origin of the cryptal lining in the area of the so-called placentomes and the cellular versus the syncytial character of this epithelium. The characteristic binucleate giant cells or diplokaryocytes found in all ruminant placentae have been intensively studied in the sheep by Wimsatt [1951], Specialized chorionic areas have also been described in detail by Wimsatt [1950] in the sheep, especially the so-called “ areolae” overlying the mouths of the uterine glands, and the areas of extravasation of blood and ery-throphagocytosis by the chorionic epithelium at the bases of the villi in the placentomes. Electron microscopic studies on the sheep placenta showing the interlocking of the microvilli of the cryptal and chorionic epithelia were made by Ludwíg [1962] who concluded that the cryptal epithelium was of maternal origin. A similar conclusion was reached by Björkman [1954, 1964] and by Björkman and Bloom [1957] in the cow, by Hamilton et al. [1960] in the deer, based on combined light and electron microscopic studies. These authors also described the fine structure of the binucleate giant cells and gave evidence of their migration into the cryptal lining without making, however, any permanent contribution to this lining. No published accounts have been found on the fine structure of the important and extensive intercotyle-donary zone of the ruminant placenta. The electron microscopic observations in this paper have been concerned more with a depiction of the areas of the sheep placenta presumed to be of importance in the transfer of materials between the mother and the fetus than with the problem of the precise origin of the cryptal epithelium. However, the syncytial nature of the latter has been clearly established and evidence has been obtained favouring its origin from the binucleate giant cells of the trophoblast. The fine structure of the latter has also been described. Some observations on the allantois are included. 1 Grant acknowledgements: This investigation was supported by Public Health Service Research Grant, No.HD00971 and National Science Foundation Grants, Nos. GB 1639, G-2188 and G24043. Davies and Wimsatt 183 Materials and methods

The presence of androgen-binding protein in the guinea-pig testis, epididymis and epididymal fluid

Androgen-binding protein (ABP) is present in the guinea-pig testis, epididymis and epididymal fluid. Guinea-pig ABP sediments as an approx. 4.6S species on sucrose gradients containing 0.01 M KCl. Electrophoresis on non-denaturing polyacrylamide gels indicated that specific androgen binding was present in epididymal cytosol, but not in plasma. Time-course studies indicated that binding equilibrium is approached in about 2.5 h; the dissociation half-time of [3H]5 alpha-DHT from guinea-pig ABP is 5.64 +/- 0.62 h (n = 6) at 4 degrees C. The relative affinities of some steroids for guinea-pig ABP in relation to 5 alpha-DHT = 1 are: testosterone = 0.55 +/- 0.13 (n = 4), estradiol = 0.14 +/- 0.03 (n = 4), the anti-androgen cyproterone acetate = 0.0025 +/- 0.0002 (n = 3). Guinea-pig ABP exhibited an equilibrium dissociation constant of 6.34 +/- 0.52 nM (n = 3) at 4 degrees C and there were 3.43 +/- 0.78 (n = 3) pmoles of binding sites per mg of protein when homogenates of the whole epididymis were assayed. The concentration of ABP was lowest in the caput-corpus region of the epididymis, highest in the proximal cauda, and intermediate in the distal cauda. Essentially all of the ABP present in the distal cauda was intraluminal, as evidenced by the fact that flushing of the duct eliminated most of the [3H]5 alpha-DHT binding activity.

Light and electron microscopic observations on a human placenta 2 weeks after fetal death

Abstract Morphologic evidence for the viability of the placenta 2 weeks after fetal death at the twenty-seventh week of gestation was obtained using light and electron microscopy. The syncytial trophoblast appeared normal for this stage of gestation. There was an abundance of cytotrophoblastic elements, which showed many intermediate stages in cytoplasmic complexity from simple cells with little endoplasmic reticulum and an abundance of ribosomal and glycogen granules to cells with the cytoplasmic characteristics of syncytial trophoblast. The fetal mesenchyme was devascularized and showed a marked de position of collagen and basement membrane-like material. Follicles in the ovary showed evidence of luteinizing influence. The single corpus luteum appeared nonfunctional as judged by light and electron microscopic criteria.

Unique variant of partial anomalous pulmonary venous connection with intact atrial septum.

SummaryPartial anomalous pulmonary venous connections (PAPVCs) are rare in association with an intact atrial septum. However, the diagnosis should be considered in patients with otherwise unexplained findings of left-to-right shunt and right heart enlargement. An unusual variant is presented, which we considered unsuitable for operative repair, based on findings at catheterization. Developmental, hemodynamic, and surgical considerations are discussed.

Delayed Effects of Prenatal or Postnatal Exposure to Diethylstilbestrol in the Adult Female Guinea Pig

Of 25 mature female guinea pigs exposed transplacentally to diethylstilbestrol (DES) for more than 20 days before term, 8 showed abnormal changes in the genital tract (stimulation of the epithelium and stroma, cystic glandular hyperplasia of the endometrial glands near the junction of the upper endocervix and endometrium) and 9 showed severe changes (cystic glandular hyperplasia of the endometrial glands throughout the corpus uteri and cornua, squamous metaplasia). Hyperkeratosis of the vulvar and nipple skin was also observed. No neoplastic changes were observed with one exception at 14 months in one ovary. Prenatal exposure to DES for less than 15 days before term or after birth for 3 days failed to result in abnormal changes in the adults. Prenatal exposure to estradiol for more than 20 days also was without effect in the adult, despite the higher tolerated doses given to the mothers. Cycling activity as judged by vaginal opening was abnormal in all experimental groups, suggesting a derangement of the pituitary-hypothalamic function not specifically related to DES exposure. It was concluded that there is a critical period of exposure of the Müllerian duct- and sinus-derived tissues with respect to the delayed effects of prenatal exposure to DES, which is estimated on the basis of embryological studies to range from the 28th to about the 45th day of gestation.