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doi: 10.1002/aja.1001180102pmid: 5915032
The nucleus preopticus (NPO) of the normal goldfish examined at intervals of three hours for a complete day exhibits marked variation in their affinity for aldehyde fuchsin (AF). Some times in this nucleus the cells of the pars magno‐cellularis were deeply stained while those of the pars parvocellularis were lightly stained, which suggests a functional difference. Both NPO and the nucleus lateralis tuberis (NLT) are AF‐positive in the goldfish. In the neurohypophysis three tinctorial types of Herring bodies were seen; the AF‐positive bodies can be traced back to the NPO but the origin of the fast green and acid fuchsin bodies is uncertain. In the hypophysectomized specimens without regenerating neurosecretory axons the NPO exhibited degenerative changes. However, if regeneration of the pituitary stalk occurred, forming a neurohypophysis‐like organ the NPO was apparently normal. Prominent AF‐positive granules were not obvious in the NLT of hypophysectomized specimens.
doi: 10.1002/aja.1001180103pmid: 5915030
Methods of stripping did not demonstrate a significant spiral course of fibers within longitudinal muscle coats of the jejuno‐ileum of the dog, cat, hog or man.
doi: 10.1002/aja.1001180104pmid: 5950307
In an attempt to elucidate some of the mechanisms utilized in the placental transfer of large molecules morphological changes in the visceral yolk sac have been studied in relation to the disposition of ferritin molecules at different stages of gestation.
doi: 10.1002/aja.1001180105pmid: 5915036
The objectives of this study were to observe with the electron micro scope (a) the epithelial cell types found in the neck and isthmus of the gastric fundic gland of the rat, and (b) the effects of hypophysectomy on the gland. The following cell types were distinguished in the neck of the fundic gland of the rat: nondifferentiated cell, immature surface cell, mucous neck cell, and neck parietal cell. In the normal gland, these cell types resembled each other in the possession of a ground cytoplasm and nucleoplasm of low density, a poorly developed endoplasmic reticulum, few mitochondria and numerous free ribosomes. The most important structural difference between mucous neck and immature surface cells was the contrasting density of the secretory granules; both cell types differed from the nondifferentiated cell primarily in the presence of their characteristic secretory granules. The neck parietal cell appeared to be a developmental form between the immature surface cell and the mature parietal cell. No changes were observed in these cells to result from hypophysectomy.
doi: 10.1002/aja.1001180106pmid: 5915037
Seven of 24 newborn hamsters developing maxillary molars which were transplanted to the femur for 28 days showed growth and development of crowns and roots. Enamel, dentin, pulp, cementum, periodontal ligament and alveolar bone proper developed in their normal locations just as they had done previously in molars transplanted into subcutaneous connective tissues. Several relationships were observed between alveolar bone proper, developed in the foreign body environment and under the inductive influence of the tooth root, and femoral bone. Femoral bone was continuous with alvolar bone and supported the tooth socket. In some areas near transplanted molar roots, femoral bone was built out to join and support alveolar bone. In other areas, femoral bone was resorbed by the development of a molar root or the molar root was diverted from its normal direction of development. Despite the effort to orient transplanted molars for eruption, the orientation was altered and no evidence for tooth eruption was observed.
Felts, William J. L.; Spurrell, Francis A.
doi: 10.1002/aja.1001180107pmid: 5915029
Odontocete radii are short, flattened, longer than the humeri, and lacking in open medullary cavities. Their cross‐section is essentially a semi‐streamlined wedge. End‐on articulation at the elbow is a synchondrosis. In the streamlined, amuscular antebrachium, the radius sustains loadings predominantly in the mediallateral transverse plane as flipper movements (at the shoulder) counter body inertia and water resistance in controlling body attitude.
doi: 10.1002/aja.1001180108pmid: 5915031
Fat absorption and transport in rat intestinal epithelial cells were followed by electron microscopy and radioautography. Physiological fatty‐chyme, prepared from fat‐fed donor rats, was injected into ligated segments of the upper jejunum of fasting recipient animals. Samples of tissue were removed in a time sequence from 1 to 30 minutes. Oleic acid‐H3 was added to the chyme for light and electron microscopic radioautography. The results indicate that fat is absorbed and transported through the epithelium very rapidly. Within 1 minute, fat droplets can be seen in the endoplasmic reticulum and the Golgi apparatus. Fat is shown to be absorbed during, not prior to, experimentation by the radioautographic identification of labeling in the vicinity of fat droplets throughout the cell. Evidence of accumulation of fat within the Golgi apparatus appears between 1 and 2 minutes. Such accumulation may be indicative of a rate‐limiting step in absorption. It is suggested that phenomena occurring within the Golgi apparatus are in part responsible for the appearance of cellular saturation with fat, which is evident in 8 to 10 minutes. The sequential pattern can be followed in cells along the entire length of the villus.
McMasters, Robert E.; Weiss, Arthur H.; Carpenter, Malcolm B.
doi: 10.1002/aja.1001180109pmid: 4958201
In 35 monkeys attempts were made to produce localized unilateral lesions in individual vestibular nuclei in order to study vestibular projections to nuclei of the extraocular muscles. Portions of the medial, superior and inferior vestibular nuclei were destroyed selectively; lesions in Deiters' nucleus involved small portions of either the superior or inferior vestibular nuclei. Fiber degeneration was studied by the Nauta‐Gygax technic.
doi: 10.1002/aja.1001180110pmid: 4223795
Similar histological and histochemical changes occur in the uteri of pregnant and pseudopregnant ferrets. The pre‐implantation period is characterized by general growth of the tissue and moderate secretory activity. At the time of implantation, the luminal epithelium undergoes hypertrophy and hyperplasia and shows much secretory activity. This area of altered activity sweeps progressively toward the gland fundi and the epithelium behind it becomes greatly enlarged and forms symplasmic masses. Symplasma formation occurs in all regions of the uterus, in contrast to other carnivores where it occurs only next to trophoblast and in response to uterine trauma.
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