American Journal of Anatomy

doi: 10.1002/aja.1001440101pmid: N/A

Morison, R. S.; Clark, S. L.

doi: 10.1002/aja.1001440102pmid: 1101676

Jollie, William P.; Haar, Jack L.; Craig, Shirley S.

doi: 10.1002/aja.1001440103pmid: 810016

Hemopoietic sinuses in the chorionic trabeculae of marmoset placenta were examined electron microscopically at several stages of pregnancy. Tissues were prepared both by standard technique and following injection of exogenous peroxidase into the maternal circulation prior to autopsy, and subsequent cytochemical localization of its reaction product in the fetal placenta. Aside from their dilated size and cellular content, the sinuses resembled the allantoic capillaries of the peripheral umbilical circulation in this species; and, in early and midgestational placentas, sinusal endothelium, like that of capillaries, looked mesenchymal. Within the sinusal lumina, differentiating elements in the erythroid line were present in placentas at all stages. Such cells appeared to arise both by a process of proliferation of undifferentiated progenitors from the sinusal lining and by mitosis of pre‐existing erythroid cells. Only the latter process was observed in the mature placenta near term. Granulopoiesis was not observed at any stage; on the other hand, cells in the thromboid line were identified in placentas believed to be near midgestation; and large intrasinusal phagocytes were present in both midgestational and late placentas. In the latter, they were seen to have endocytosed peroxidase, and, by tenuous, dendriform processes, to be related anatomically to large numbers of erythroid cells. Early in gestation, the developing erythroid elements were closely related by areas of contact, both to each other and to the delimiting endothelium of the sinuses.

Chang, W. W. L.; Nadler, N. J.

doi: 10.1002/aja.1001440104pmid: 170817

Proliferation and migration of cells in the vacuolated‐columnar and mucous cell lines were studied in the descending colon of adult female mice given a single injection or a continuous infusion of 3H‐thymidine and killed at various intervals from one hour to 12 days. This investigation was carried out using one μm‐thick Epon sections which were radioautographed after staining with the periodic acid‐Schiff technique and iron‐hematoxylin.

Brawer, James R.; Sonnenschein, Carlos

doi: 10.1002/aja.1001440105pmid: 170818

Large subcutaneous doses (2 mg/21 days) of estradiol valerate (EV) given over several months will induce a prolactin and growth hormone‐secreting pituitary tumor in female rats. The medial basal hypothalami (MBHs) of such EV‐treated animals were examined at different time intervals with light and electron microscopes to determine whether EV affects the MBH and to relate any observed effects to the process of tumorigenesis.

Pelliniemi, Lauri J.

doi: 10.1002/aja.1001440106pmid: 1172651

Pig embryos aged 26–27 days were used for an ultrastructural study of the early ovary and testis. Sex was identified by both chromosomal analysis and gonadal histology, with consistent results.

Snook, Theodore

doi: 10.1002/aja.1001440107pmid: 1166852

The major arteries which supply the follicular capillaries in the human spleen do not arise as they do in most mammals as lateral or radial branches from the central artery but come from penicillar arteries which penetrate the marginal zone and enter the follicle at various points around its circumference. Such arteries may have a very short course through the red pulp or they may pursue very long courses.

Kubota, Kimo; Malloy, John J.; Low, Frank N.

doi: 10.1002/aja.1001440108pmid: 1166853

The connective tissue cells of the dentinal pulp of unerupted dog teeth possess occasional cilia. Internally there are 4 to 8 peripheral doublets and one central doublet. Nine peripheral doublets are observed only close to or near the basal body.