900 



SPERM, OVA, AND PREGNANCY 



comparable with the epithelia of the proxi- 

 mal convoluted tubule of the kidney and of 

 the small intestine than with the pulmonary 

 alveolar lining or the glomerular mem- 

 brane. 



Degenerative age changes that occur in 

 the human placenta have been variously 

 described. Tenny ( 1936a, b) and Tenny and 

 Parker (1940) reported hyaline degenera- 

 tion of the syncytium clothing the terminal 

 villi of aging placentas, a change which ac- 

 cording to them occurs to a greater degree, 

 as well as prematurely, in toxemia, pre- 

 eclampsia, and eclampsia. Wislocki and 

 Dempsey (1946a) examined the placentas 

 from two cases diagnosed respectively as 

 severe preeclampsia and eclampsia. Both 

 cases were atypical, because in each the 

 condition was present at 4.5 months of ges- 

 tation. Thinning of the syncytium with 

 some nuclear deterioration was observed, 

 as well as a premature decrease in baso- 

 philia associated with early accumulation 

 of alkaline and acid phosphatases and an in- 

 creased acidophilia. Some of the smallest 

 villi showed hyaline necrosis of both syn- 



cytium and stroma. These changes were 

 ascribed to premature aging of the chori- 

 onic villi. Subsequently, however, in a fur- 

 ther series of placentas from cases of toxemia 

 in the last trimester of gestation (unpub- 

 lished data ) , changes from normal, based on 

 loss of basophilia and an increase in phos- 

 phatases, were not apparent. 



Tenney and Parker (1940) observed that 

 a variable number of the terminal placental 

 villi undergo hyaline degeneration in both 

 normal and toxemic pregnancies. Wislocki 

 and Dempsey ( 1948) noticed that the 

 stroma of degenerating villi develops in- 

 tense metachromasia (Figs. 15.51 and 

 15.57), in contrast to the ground substance 

 of normal villi, which does not exhibit met- 

 achromatic staining, except as noted above 

 in the basement membrane at the growing 

 tips of secondary villi. The metachromatic 

 transformation of the stroma of fibrous, 

 degenerating villi is probably attributable 

 to the formation and accumulation of an 

 acid mucopolysaccharide. This develop- 

 ment, it seems probable, is the equivalent 

 of, or allied to, changes described in some 



Plate 15. VI 



Fig. 15.24. Human placental villus at full term. Frozen section stained by Baker's acid 

 hematein method for phospholipids following fi.xation in formalin-calcium-chloride. Observe 

 the positive reaction in the syncytium covering tlie villus. The reaction coincides with the 

 presence of mitochondria revealed in similar distribution by appropriate methods (Wislocki 

 and Bennett, 1943, Fig. 19). X 10 ocular; X 60 objective. 



Fig. 15.25. Cells of the basal plate (cytotrophoblastic shell) of a human placenta of 3'/2 

 months gestation. Frozen section stained by Baker's acid hematein method for phospho- 

 lipids. Observe the cytotrophoblasts which contain variable amounts of reactive material; 

 the latter coincides with mitochondria demonstrable by other methods. X 10 ocular; X 60 

 objective. 



Fig. 15.26. A portion of a human placental villus at 3'/2 months of gestation. Frozen sec- 

 tion stained by Baker's acid hematein method for phospholipids. Notice the dense concen- 

 tration of reactive material in the cytoplasm of the syncytial trophoblast. The distribution 

 corresponds to similarly abundant mitochondria demonstrable by other means (Wislocki 

 and Bennett, 1943, Figs. 15.13 and 15.14). Observe also the positive Baker reaction in the 

 cytoplasm of the Langhans cells beneath the syncytium as well as in a group of Hofbauer 

 cells in the stroma of the villus. X 10 ocular; X 60 objective. 



Fig. 15.27. The junction of the trophoblastic shell (upper half) and the decidua (lower 

 half) in the placenta of a monkey of 4 weeks gestation. Section stained by Pap's method for 

 reticulum. Bodian's fixative No. 2. Observe that the reticular fibers of the decidually trans- 

 formed endometrium cease abruptly at the border of the trophoblastic shell. As a result of 

 this, the boundary between the decidua and the trophoblastic shell is sharply demarcated. 

 The metachromatic ground substance of the decidua (c/. Fig. 15.58) also ceases abruptly at 

 the line of junction between the decidua and the fetal elements. X 800. (Wislocki and Ben- 

 nett, 1943.) 



Fig. 15.28. A chorionic fold of the placenta of a pig (fetal crown to rump length, 64 mm.), 

 illustrating two sinusoidal fetal capillaries (surrounded by black-stained reticular fibers), 

 penetrating the chorionic epithelium and creating thin epithelial surface plate (arrows). 

 Compare with Figures 15.23 and 15.64 which illustrate collectively the thinness of the pla- 

 cental barrier in the pig's epitheliochorial placenta. Pap's stain for reticulum; Bouin's fixa- 

 tive. X 10 ocular; X 90 objective. (Wislocki and Dempsey, 1946b.) 



