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McLone, David G.; Bondareff, William
doi: 10.1002/aja.1001420302pmid: 1119412
Development of pia‐arachnoidal membranes in the mouse occurs in four stages: the first (prenatal days 10–13) follows closure of the neural tube and is a period of initial vascularization of the developing telencephalon; the second (prenatal days 14–16) is a period of delineation during which the limits of the subarachnoid space are defined; the third (prenatal day 17 to birth) is a period of ensheathment of pia‐arachnoidal blood vessels, and the fourth (birth to postnatal day 21) includes addition of smooth muscle to larger vessels, the appearance of macrophages in the subarachnoid space, and a general increase in extracellular collagenous and elastic fibers.
doi: 10.1002/aja.1001420303pmid: 1119413
The permeability of ovarian capillaries and follicles in prepubertal and sexually mature (proestrus and metestrus) randomly bred Swiss Albino female mice (SCH:ARS HA ICR strain) was studied by intravenous injection of either ferritin or horseradish peroxidase (HRP), followed by examination with light and electron microscopes. The study revealed that capillaries in the interstitial and perifollicular regions were provided with a continuous endothelium that had constant permeability characteristics irrespective of sexual maturity or phase of the estrous cycle. Horseradish peroxidase left the capillaries primarily through interendothelial cell junctions and was present in all follicles within 30 seconds after administration of the tracer. Ferritin, on the other hand, was absent from endothelial cell junctions, and left the capillaries, at a slower rate than HRP, via cytoplasmic vesicular transport. Both tracers were found in the granulosa cells but rarely in the oocytes. The tracers reached the oocyte through the intercellular spaces between granulosa cells.
doi: 10.1002/aja.1001420304pmid: 1054534
The ultrastructure of bone marrow of RF mice having an acute myelogenous leukemia induced by inoculation with leukemic cells was investigated. In several respects sinuses of leukemic marrow are similar to normal marrow. Sinuses are present in numbers approximating that of the normal; the lining cells of the sinus wall have organelles similar in distribution and number to those of normal lining cells; the sinus wall is continuous, having openings only in conjunction with blood cells that are migrating through it (migration pores); migration pores occur within and not between lining cells. Abnormalities observed in leukemic marrow are the occurrence of virus‐like particles in leukemic cells, the presence of numerous particles 300 to 500 Å in diameter in the extracellular space, reduction in the number of adventitial cells of the sinus wall and an increase in the thickness and distribution of extracellular material located near the basal surface of lining cells.
doi: 10.1002/aja.1001420305pmid: 1168017
The fine structure of the endometrial epithelium of the pseudopregnant rabbit from the day of induced ovulation (day 0) to the 13th day is here correlated with previously defined light microscopic phases. In Phase 1 (0–1 day), in which there is a presumed “priming” of the endometrium by ovarian steroidal hormones, no changes were observed. In Phase 2 (1–3 days), in addition to mitotic activity, the epithelium showed a disappearance of the mucification and lymphocytic migration typical of Phase 1 and also of the nonpregnant or “estrous” phase, and showed other nuclear and cytoplasmic changes which probably reflect endogenous growth and protein synthesis. In Phase 3 (4–6 days), two distinct populations of reacting cells were present: (1) surface and cryptal cells investing the now folded mucosal surface, and (2) glandular cells. The first group showed characteristic dome‐like protrusions of the cytoplasm into the lumen, and also showed distinct cytoplasmic and nuclear changes which appear to be a prelude to the succeeding phase of fusion but are not necessarily secretory in type. The glandular cells, in contrast, showed cytoplasmic changes which appear to reflect active secretory activity (hypertrophy of the Golgi area, cytoplasmic vacuoles containing electron‐opaque material, etc.). This phase coincides with the maximal secretion of uterine‐specific proteins, and electron‐opaque material is abundant within the endometrial lumen. In Phase 4 (6–8 days), the surface and cryptal epithelium undergoes a transformation into multinucleated cells, the result of a process of lysis of intervening plasma membranes, the precise mechanism of which (i.e., with or without initial membrane fusion) was not determined. Cell fusion proceeded earlier and more actively mesometrially than antimesometrially. The glandular cells showed evidence of reduced secretory activity, but did not at any stage undergo multinucleate‐cell transformation. In Phase 5 (8–13 days) there was progressive fusion, and the number of nuclei per cytoplasmic sac appeared increased, presumably due to the continued action of progesterone which is maximal during this phase. Glandular cells showed further reduced secretory activity but remained columnar. Ciliation of the epithelium was sporadic in the pre‐secretory phases and rare or absent in the secretory and fusion phases; it became widespread during the phase of decline after day 14, a period which will not be included in this study. The fine structure of the ciliated cells was the same at all stages; there was no evidence for their origin from a reserve population; it is possible that they arise by modification of the multinucleated cells. Cytoplasmic crystals and intramitochondrial densities or lamellae were observed during the secretory and fusion stages, the former only in the glands, the latter in the surface and cryptal epithelium. They appear to be associated with rising or maximal progesterone secretion.
doi: 10.1002/aja.1001420306pmid: 804242
This paper embodies a comparative study of the hyoid apparatus in six species of primates. There is a direct correlation between a predominantly herbivorous diet and an increase in the relative size of the basihyal (the body) of the hyoid bone.
doi: 10.1002/aja.1001420307pmid: 1119414
Satellite cells covering the axon hillock region and initial axon process of the neurons of rat and mouse trigeminal ganglia contained numerous parallel microtubules and microfilaments. These were oriented circumferentially to axonal neurofilaments and neurotubules. The latter were sometimes grouped in fascicles. The results suggest a specialized role for the supporting cell in this region and that fascicles of neurotubules are not related to action potential initiation.
Fischer, Theodore V.; Fisher, Don Lowell
doi: 10.1002/aja.1001420308pmid: 1119415
The present study is an analysis of the effects of super‐ovulatory doses of gonadotropins on the rate and time of ovulation and ovarian histology in immature gerbils. Groups were treated with various combinations of pregnant mare serum gonadotropin (PMSG) and human chorionic gonadotropin (HCG). The maximum superovulatory response followed treatment with 10 IU PMSG and 20 IU HCG. High dosages of PMSG inhibited superovulation, as did some combinations involving the highest dose of HCG. Entrapment of ova within corpora lutea was common in groups receiving high doses of either gonadotropin. Luteal regression, appearing by day 3, occurred often in groups receiving high doses of HCG. A dose of 10 IU PMSG and 5 IU HCG resulted in both a near maximal superovulatory response and the least abnormal ovarian alteration.
Pelletier, Georges; Leclerc, Rachel; Dube, Donald; Labrie, Fernand; Puviani, Romano; Arimura, Akira; Schally, Andrew V.
doi: 10.1002/aja.1001420309pmid: 47223
Utilizing an immunoperoxidase technique at the light microscope level, growth hormone‐release‐inhibiting hormone (somatostatin) was localized in the external zone of the median eminence, the subcommissural organ, the organum vasculosum of the lamina terminal is and the pineal gland. No positive reaction was detected in any other brain area.
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