890 



SPERM, OVA, AND PREGNANCY 



Furthermore, despite the fact that none 

 of the various reactions is specific for ke- 

 tosteroids, their occurrence in lipid drop- 

 lets of the adrenal cortex, gonads, and pla- 

 centa, and their variations under different 

 physiologic conditions of these organs sug- 

 gest that the methods are empirically use- 

 ful in identifying the probable sites of ke- 

 tosteroid hormone formation. Application of 

 the above procedures for the identification 

 of sites of steroid hormone production will 

 be found in the following papers: for the 

 adrenal cortex (Bennett, 1940; Deane and 

 Greep, 1946) , ovary (Dempsey and Bassett, 

 1943; Deane, 1952), testis (Pollock, 1942), 

 and placenta (Wislocki and Bennett, 1943; 

 Dempsey and Wislocki, 1944; Wislocki. 

 1952). 



D. ENZYMES 



Numerous histochemical methods have 

 been devised for preserving enzymes so that 

 they will retain activity toward either nat- 

 urally occurring or synthetic substrates. In 

 most of these procedures an insoluble pri- 

 mary reaction product is precipitated in 

 situ in frozen sections, and it is then visual- 

 ized by a color reaction which reveals the 

 location of the enzyme. The methods of Go- 

 mori (1941a, b) for acid and alkaline phos- 

 phatases, utilizing a variety of substrates, 

 were applied to the study of the placentas 

 of various animals (Dempsey and Wislocki, 



1947). Observations by Padykula (1958) 

 on fluctuations of phosphatase activity of 

 the rat placenta included changes in adeno- 

 sine triphosphatase, as well as acid and al- 

 kaline phosphatases. 



The presence of tlie cytochrome oxidase- 

 cytochrome c system has been demonstrated 

 by the indophenol blue oxidase reaction by 

 treating fresh spreads of placental villi with 

 the nadi reagents (paraphenylene-diamine 

 and a-naphthol (Dempsey and Wislocki, 

 1944). A series of oxidation-reduction indi- 

 cator dyes was applied similarly to deter- 

 mine the oxidation-reduction potential of 

 various placental elements. 



Succinic dehydrogenase activity of the 

 human placenta, as illustrated in this re- 

 view, was localized by the tetrazolium 

 method developed by Seligman and Ruten- 

 burg (1951) and modified by Padykula 

 (1952). The localization of this enzyme in 

 the rodent placenta was reported by Telkka 

 andLehto (1954), Reale and Pipino (1957), 

 and Padykula (1958). A comparative study 

 of the distribution of this oxidative enzyme 

 in various placental types was made by 

 Reale and Pipino (1959). 



Esterase activity was localized in the hu- 

 man placenta in this review according to 

 the procedures of Nachlas and Seligman 

 (1949) and Barrnett and Seligman (1952). 

 In the rat placenta, Padykula ( 1958) dem- 

 onstrated this enzymatic activity by the 



Plate 15. Ill 



Fig. 15.9. The trophoblast of a secondary chorionic villus of a 30-day human placenta 

 stained with Mallory's connective tissue stain. Observe the syncytium which contains small 

 nuclei and possesses a brush-border on its free surface facing the intervillous space. Notice 

 the large chromophobic Langhans cells which rest upon a deeply stained basement membrane 

 contiguous to a fetal capillary which contains several nucleated erythrocytes. X 1600. (Wis- 

 locki and Bennett, 1943.) 



Fig. 15.10. The localization of basophilic substances in a human villus of 13 weeks. Zenker 

 formol fixative. Methylene blue staining. Basophilia is intense in the inner layer of the syncy- 

 tial cytoplasm whereas the marginal zone and brush border are unstained. The cytoplasm of 

 the Langhans cells is also unstained. The basophilic staining of the sj^ncytial cytoplasm, but 

 not that of the nuclei, is prevented by prior exposure of sections to ribonuclease, a result 

 which indicates that the cytoplasmic basophilia is due to the presence of ribonucleoprotein. 

 X 10 ocular; X 60 objective. (Dempsey and Wislocki, 1945.) 



Fig. 15.11. Localization of basophilic substances in a cytotrophoblastic cell island from a 

 human placenta of 13 weeks. The cytotrophoblastic cells contain strongly basophilic material 

 in their cytoplasm, arranged in a fashion reminiscent of Nissl substance in neurons. In addi- 

 tion, the intercellular matrix is weakly basophilic. Zenker formol fixative. Methylene blue 

 staining. (Dempsey and Wislocki, 1945.) 



Fig. 15.12. The same region as in Figure 15.11, from a contiguous section, stained following 

 treatment with ribonuclease. The basophilia of nuclei and the intercellular matrix is un- 

 changed, whereas the cytoplasmic basophilia has been abolished. (Dempsey and Wislocki, 

 1945.) 



