American Journal of Anatomy

doi: 10.1002/aja.1001710401pmid: N/A

Dombrowski, Teresa A.; McNulty, John A.

doi: 10.1002/aja.1001710402pmid: 6517036

Morphometric analysis of the superficial pineal gland of intact and blinded golden hamsters was conducted at both the light and electron microscopic level. The volume of the superficial gland was estimated to be 151 × 106 μm3, comprising 90–94% of the total pineal parenchymal tissue. Analysis of structural rhythms in animals maintained under a 14:10 L:D cycle showed significant 24‐hr variations in values for pinealocyte nuclei, nucleoli, rough and smooth endoplasmic reticulum, Golgi bodies, dense bodies, and dense‐cored vesicles. Peak values for these structures generally occurred at the light:dark interface. These results provide morphological correlates for known rhythmic variations in the synthesis of pineal‐gland products. Superficial pineals examined 8 weeks following optic enucleation exhibited a decrease in the volume of pinealocyte nuclei and cytoplasm, while nucleolar size and the amounts of smooth and rough endoplasmic reticulum, Golgi bodies, dense bodies and dense‐cored vesicles were enhanced. The latter changes are interpreted as indications of increased synthetic activity by the superficial pineal gland in response to light deprivation.

Dombrowski, Teresa A.; McNulty, John A.

doi: 10.1002/aja.1001710403pmid: 6517037

The deep pineal gland of golden hamsters was morphometrically analyzed and quantitatively compared with the superficial pineal under a 14:10 lighting regime and following blinding. The deep pineal comprised 6–10% of the total pineal parenchymal tissue. Pinealocytes of the deep gland were smaller than the cells of the superficial pineal and showed a greater percent volume of Golgi bodies, rough endoplasmic reticulum, and dense‐cored vesicles. Twenty‐four‐hour rhythms in nucleoli and Golgi bodies were found in deep pinealocytes. These rhythms were out of phase with comparable rhythms in the superficial pineal gland, suggesting that distinct subpopulations of pinealocytes are present within the respective parts. Blinding resulted in decreased nuclear and nucleolar volume, while the amount of smooth endoplasmic reticulum, Golgi bodies, dense bodies, and dense‐cored vesicles increased significantly. Marginal increases were seen in mitochondria and lipid droplets. The greater abundance of those organelles involved in synthesis and secretion suggests enhanced cellular activity after blinding. Many of the morphological responses are similar to alterations in the pinealocytes of the superficial pineal following optic enucleation.

Scheuermann, D. W.; De Groodt‐Lasseel, M. H. A.; Stilman, C.

doi: 10.1002/aja.1001710404pmid: 6517038

In the lung of the red‐eared turtle, large numbers of intramural ganglia located in the intraparenchymal connective tissue are demonstrated. Numerous cells in close proximity to the principal ganglionic neurons displayed a bright blue‐white formaldehyde‐induced fluorescence. Microspectrofluorometric analysis revealed the presence of dopamine (DA) in all cells measured. Subsequent light histochemcial staining of the fluorescent sections showed the DA‐containing cells to display argentaffinity. Electron microscopy of serial sections revealed cells characterized by dense‐cored vesicles corresponding to the intensely formaldehyde‐induced fluorescent cells. The argentaffin technique performed directly on ultrathin sections selectively stained the dense‐cored vesicles. After fixation with glutaraldehyde followed by dichromate, x‐ray microanalysis showed the chromium to be incorporated into the dense granules. Cholinergic‐type nerve endings formed axosomatic synaptic contacts with the DA‐containing cells, which can therefore be considered as intrinsic postganglionic elements. No efferent synapses from the granule containing cells to the principal ganglionic neurons could be observed. The granule‐containing cells occurred solitarily and in clusters, partially invested with satellite cells, and usually located near fenestrated capillaries; they displayed cytoplasmic processes and indicated emiocytotic granule release. Adjacent granule‐containing cells were separated by spaces about 20 nm wide, gradually widening to form intercellular channels with apically projecting microvilli and primary cilia. It is concluded that the intrapulmonary granule‐containing cells of the red‐eared turtle belong to the APUD system. Furthermore, morphologically these cells appeared to possess a special sensory apparatus which designates them as paraneurons. The possible physiological significance of these intrapulmonary granule‐containing cells is discussed.

Crissman, Robert S.; Guilford, William

doi: 10.1002/aja.1001710405pmid: 6517039

The architectural arrangement of the elastic‐fiber network in the wall of canine hepatic portal veins was observed with the scanning electron microscope (SEM). Selective NaOH sonication digestion and autoclaving were used to expose and isolate the networks of elastic fibers from six selected regions of the hepatic portal vessels from seven healthy dogs. Elastic stains of adjacent segments prepared for light microscopy demonstrated that the elastic fibers were concentrated in two areas within the intact portal wall. The innermost area corresponded to the internal elastic lamina (IEL) of the tunica intima, the internal muscular layer, and the connective tissue layer of the tunica media. The second area was in the tunica adventitia. SEM specimens revealed two sleeves of elastic fiber networks which corresponded to the above regions. Small scattered bundles of radially oriented elastic fibers spanned the gap between the two sleeves. Each tunica had a different architectural arrangement of elastic fibers. The IEL had circumferentially oriented fibers which branched and anastomosed to form a continuous network on the innermost surface. The architecture of the IEL was the most variable between the different regions. The network of the IEL was the most “open” in the caudal region (splenic vein) and became “denser” toward the liver. The large elastic fibers inthe tunica media were oriented at approximately right angles to the primary fibers of the IEL. These longitudinally oriented fibers anastomosed with adjacent longitudinal fibers to form a continuous network. In the tunica adventitia, thick, longitudinally oriented fibers of the continuous network fused together to form incomplete layers of fibers. The architecture of the elastic‐fiber network in the canine hepatic portal vein was compared to that previously described in the systemic canine saphenous vein.

Taki, Taki M.; Nickerson, Peter A.

doi: 10.1002/aja.1001710406pmid: 6393755

The average cell volume of rat adrenocortical zona fasciculata cells, determined using three different stains on semifine sections, was compared to that of dissociated, unfixed zona fasciculata cells. The maximum number of nuclei per area (NA) was obtained by counting nuclear profiles in semifine sections from nonosmicated adrenocortical tissue stained with toluidine blue. In osmicated adrenocortical tissue on the other hand, fewer nuclear profiles were seen and more of the small size classes were missing from the distribution of profiles. The skewness of the nuclear‐profile distribution was much greater in osmicated than in nonosmicated tissue, reflecting the missing small profiles. Although the average diameter of nuclei (D) in nonosmicated tissue was smaller than that for osmicated tissue, profiles were in all likelihood more readily identified because they stained quite intensely. Three different methods for correcting nuclear‐size profile distribution and determining nuclei per volume (NV) (Giger‐Riedwyl, Cruz‐Orive, and Weibel‐Gomez) were generally in agreement for nonsmicated tissue. Considerable shrinkage occurred during preparation for electron microscopy, with the greater change occurring in nonosmicated tissue. Cell volume in osmicated tissue corrected for shrinkage varied considerably among the different methods, producing significantly greater values for cell volume than those in nonosmicated tissue. The cell volume of nonosmicated tissue, corrected for shrinkage during processing and for missing small nuclear profiles, did not differ significantly from that of freshly dissociated zona fasciculata cells. The one exception was nonosmicated tissue stained by Feulgen‐methylene blue and corrected for missing small nuclear profiles by the method of Cruz‐Orive. Use of nonosmicated adrenocortical tissue in stereological studies with an appropriate correction for shrinkage for each experiment is recommended for determining cell volume, although osmicated tissue should also be included to facilitate identification of intracellular membranes when electron microscopy is required.

Price, Maureen G.; Sanger, Joseph W.

doi: 10.1002/aja.1001710407pmid: 6542748

Chicken skeletal muscle taken from embryos in ovo was examined by thin‐section electron microscopy. Measurements of filament diameters reveal three nonoverlapping groups of filaments: thin (actin myofibrillar) filaments with mean diameters of 5.3 ± 0.6 nm (S.D.), thick (myosin myofibrillar) filaments with mean diameters of 15 ± 1.4 nm, and intermediate filaments with mean diameters of 9.3 ± 0.9 nm. During muscle development these diameters do not change. By counting the number of filaments observed in the sarcoplasm at different stages, we find that the spatial density of intermediate filaments decreases during avian myogenesis in ovo, from 91 intermediate filaments/μm2 at 6 days to 43 intermediate filaments/μm2 at 17 days in ovo. Initially randomly arranged, some intermediate filaments become associated with Z discs, sarcoplasmic reticulum, nuclear membrane, and the sarcolemma between 6 and 10 days in ovo. These associated intermediate filaments course both parallel and transverse to myofibrils, forming lateral connections between myofibrillar Z discs and longitudinal connections from Z disc to Z disc within myofibrils. Intermediate filaments also appear to connect Z discs with the nuclear membrane. The intermediate filament associations persist through day 17 of development, after which the presence of cytoskeletal filaments is obscured by the densely packed myofibrils and membranes. Intermediate filament distribution becomes anisotropic during development. A greater proportion of intermediate filaments in the immediate perimyofibrillar area are oriented parallel to myofibrils than in other areas, so that the majority of the intermediate filaments nearest the myofibrils course parallel to them. The longitudinal intramyofibrillar intermediate filaments persist throughout development, as shown by their existence in KI‐extracted adult myofibrils.

Hollis, D. E.; Frith, P. A.; Vaughan, J. D.; Chapman, R. E.; Nancarrow, C. D.

doi: 10.1002/aja.1001710408pmid: 6542749

Isthmic and ampullary oviductal epithelia sampled from Merino ewes at days ‐1, 1, 3, and 10 of the estrous cycle (estrus = day 0) were studied by scanning and transmission electron microscopy after fixation by vascular perfusion. Secretory cells, ciliated cells, and lymphocytelike basal cells were observed in both isthmic and ampullary epithelium at all stages of the estrous cycle studied and their ultrastructural features were analyzed. Synthesis of lamellated secretory granules occurred in the ampullary secretory cells during the follicular and early luteal phases, and their contents were released by exocytosis into the oviductal lumen during the luteal phase. Granule release was associated with nucleated apical protrusion of these cells into the oviductal lumen. No such secretory activity was displayed by isthmic secretory cells even though a few cells contained nonlamellated granules. Apocrine release of apical vesicles and accompanying cytoplasmic material from apical protrusions of ciliated cells occurred in the isthmus around estrus but not in the ampulla. This unexpected feature has not previously been reported in any other mammal. Dendritic basal cells were distinguished in the lower part of the epithelium by their heterochromatic nuclei, electron‐lucent cytoplasm, and lack of attachment zones. No migration of basal cells was observed, and their ultrastructural features were similar in the ampulla and isthmus and at all stages of the estrous cycle examined. The function of these lymphocytelike cells in the epithelium is uncertain, but the presence of phagocytic bodies and lysosomes in 20% of them may indicate a phagocytic role.