Fine structural alterations in the aging rat pineal gland

The pineal glands of 1 mo to 28 mo old male and female rats were examined by electron microscopy. With increasing age the following observations were made: (1) the capsule thickness increases; (2) there is an increase in collagen infiltration; (3) increased amounts of granular deposits are seen between cells; (4) there is a greater variability in the number of light pinealocytes; (5) pinealocytes with nuclear invaginations and pinealocytes with nuclear inclusions increase in number; (6) more cytoplasmic dense bodies are seen in pinealocytes and gliocytes; (7) the maximum diameter of pinealocyte lipid droplets tends to increase; (8) no definite change is observed in granular endoplasmic reticulum; (9) occasional cells are found to contain reticulated mitochondria, and a few cell processes have an appearance similar to neuroaxonal dystrophy. Besides illustrating age-related changes, the present study proves the existence of pinealocyte nuclear inclusions, suggests the possibility of pineal concretions in the rat, and morphometrically or semi-morphometrically analyzes several structural features not previously quantified.     

Fine structural alterations in the aging rat pineal gland

The pineal glands of 1 mo to 28 mo old male and female rats were examined by electron microscopy. With increasing age the following observations were made: (1) the capsule thickness increases; (2) there is an increase in collagen infiltration; (3) increased amounts of granular deposits are seen between cells; (4) there is a greater variability in the number of light pinealocytes; (5) pinealocytes with nuclear invaginations and pinealocytes with nuclear inclusions increase in number; (6) more cytoplasmic dense bodies are seen in pinealocytes and gliocytes; (7) the maximum diameter of pinealocyte lipid droplets tends to increase; (8) no definite change is observed in granular endoplasmic reticulum; (9) occasional cells are found to contain reticulated mitochondria, and a few cell processes have an appearance similar to neuroaxonal dystrophy. Besides illustrating age-rated changes, the present study proves the existence of pinealocyte nuclear inclusions, suggests the possibility of pineal concretions in the rat, and morphometrically or semi-morphometrically analyzes several structural features not previously quantified.     

Effects of Long and Short Photoperiod on the Ultrastructure of Pinealocytes of the Cotton Rat (Sigmodon hispidus)

The ultrastructure of the pinealocytes of wild-captured cotton rats (Sigmodon hispidus) housed in either long or short photoperiod was examined. Quantitative comparison of selected pinealocyte organelles revealed larger relative volumes of mitochondria, granular endoplasmic reticulum and ribosomes, Golgi apparatus, and inclusion bodies, as well as a higher number of dense-core vesicles in the animals kept in short photoperiod (LD 8:16) as compared to those in animals kept in long photoperiod (LD 16:8). These observations suggest that restricting the amount of light to which animals are exposed activates pinealocytes of the cotton rat.     

Comparative study on the endocrine cells in the pancreas of Mauremys caspica (chelonia) in summer and winter

Four endocrine cell types were identified using peroxidase-antiperoxidase (PAP) technique and ultrastructurally characterized in the pancreas of Mauremys caspica in both winter and summer. In winter, insulin-immunoreactive cells were more abundant and the cell groups larger in the splenic than in the duodenal region, whereas in summer, medium or small cell groups were evenly distributed. Glucagon- and somatostatin-immunoreactive cells were found throughout the gland; they were more numerous in the splenic than in the duodenal region. Polypeptide pancreatic (PP)-immunoreactive cells were found only in the duodenal region. Somatostatin-immunoreactive cells were mainly isolated in winter and grouped in summer. Glucagon- and PP-immunoreactive cells had a similar arrangement in both seasons. Somatostatin- and PP-containing cells showed cytoplasmic processes and could be found next to the pancreatic ducts; the latter were also observed near insulin-immunoreactive cells. Some large secretory granules and numerous, isolated and long rough endoplasmic reticulum (RER) cisternae were seen in winter B cells; in summer B cells numerous lysosomes and few, dilated RER cisternae were found. Summer A cells showed well-developed, dilated RER cisternae and numerous vacuoles; secretory granules were more numerous in winter A cells. In winter B cells and summer A cells some nuclear filamentous inclusions were observed. Few RER cisternae were observed in winter D cells and many in summer D cells; secretory granules were found, the shape and electron density of which differed with the season. PP cells were characterized by their small secretory granules, which were less numerous in winter than in summer, being clustered at the cell pole or dispersed in the cytoplasm, respectively; in winter, the well-developed RER cisternae were dilated and irregularly distributed.     

Synaptic Junctions Between the Adrenergic Axon Varicosity and the Pinealocyte in the Rat

Intercellular relationships of sympathetic nerve fibers and cells in pineal glands of Long-Evans rats and yellow-bellied country rats (Rattus losea Swinhoe) were studied with conventional electron microscopy. Typical synapses were found between adrenergic axon varicosities and pinealocytes. The synaptic cleft was 20-30 nm thick and contained granular or filamentous material of moderate electron density. Some small granulated vesicles attached to, or fused with, the presynaptic axolemma, a feature suggesting an exocytotic release of the vesicle content. The occurrence of membranous cisternae or tubules in the synaptic nerve ending may connote the phenomenon of synaptic vesicle recycling. Beneath the postsynaptic pinealocyte plasmalemma there was a dense plaque corresponding to the postsynaptic density of neurons. Possible origins and functional significance of the synapse-making nerve fibers are also discussed.     

Ultrastructural localization of bronchial antileukoprotease in central and peripheral human airways by a gold-labeling technique using monoclonal antibodies

The present report describes the ultrastructural localization of bronchial antileukoprotease (ALP) in human central and peripheral airways by using polyclonal as well as monoclonal ALP-specific antibodies in a two-step gold-labeling procedure. In the serous cells of bronchial glands, ALP could be demonstrated in secretory granules. These granules, among which 4 phenotypes could be distinguished morphologically in ultrathin sections, showed the following labeling patterns: phenotype I, which had an electron lucent, fine granular content, and phenotype II, which was homogeneously electron dense, both showed gold label over their entire area. The granules expressing zonal differences in electron density (phenotype III) showed only label in their electron-dense cores and the electron-lucent granules (phenotype IV) showed a minimal labeling. Sometimes gold particles could be observed in the rough endoplasmic reticulum and nuclear envelope, suggesting that ALP is present in these cell organelles. In the bronchiolar epithelium, ALP could be localized only in the secretory granules of Clara cells and goblet cells. These findings indicate that ALP is also synthesized in bronchioli. To our knowledge this is the first time that a well-defined protein has been described that is produced and secreted by human Clara cells.     

A Light and Electron Microscopic Study of the Pineal Gland of the Viscacha (Lagostomus maximus maximus)

The pineal of viscacha (Lagostomus maximus maximus) is formed by two main cellular populations of pinealocytes and interstitial cells. A connective capsule surrounds the gland sending numerous septa containing blood vessels and nerves. In the specimens collected during summer the pinealocyte displays a defined contour and a clear cytoplasm with abundant ribosomes and numerous cisternae of endoplasmic reticulum. The pinealocytes observed during winter have cytological characteristics of active cells with dense and elongated mitochondria, dense bodies, and a developed Golgi complex. These seasonal glandular changes could be related to the environmental condition and mainly to the summer photoperiod. The presence of abundant nerve terminals in the perivascular spaces suggests a neural control on the blood vessels.     

IgM lambda globular cytoplasmic inclusions in chronic lymphocytic leukaemia resembling immunocytoma

In a 64-year-old female with chronic lymphocytic leukaemia, nearly 50% of the lymphocytes presented one or several globular intracytoplasmic inclusions resembling Russell bodies which were characterized by immunofluorescence as IgM lambda. On electron microscopy, the inclusions looked like cisternae of the rough endoplasmic reticulum. Surface membrane Ig was not detected and the serum IgM was low. The histology of a lymph node showed a lymphocytic proliferation with evidence of Ig synthesis, compatible with immunocytoma. The aggressive course of the disease necessitated polychemotherapy. This case represents an unusual ill-defined lymphoproliferative disorder, lying between the B-CLL and a non-secretory macroglobulinaemia.     

Bone Marrow Culture and Autoradiography of IgA Myeloma Plasmocytes with Intranuclear Inclusion Bodies

Two cases of IgA myeloma, characterized by intranuclear inclusion bodies, stained positively with anti-IgA fluorescent conjugate and only faintly by the PAS method. Electron micrographs showed distension of the endoplasmic reticulum with accumulation of amorphous material of low electron density. The intranuclear inclusion bodies consisted of the same material, encircled by a single sheeted membrane, identical and sometimes continuous with the internal layer of the perinuclear membrane. Autoradiography of the bone marrow cells after incubation for different periods with ¹⁴C-leucine showed the appearance of the radioactive label, first in the cytoplasm, then on the perinuclear membrane, and finally in the inclusion bodies themselves. Bone marrow cultures showed progressive swelling of the inclusions resulting in the disruption of the cells. These findings confirm the opinion that intranuclear inclusion bodies originate from distension of the perinuclear cistern by accumulated immunoglobulin with subsequent invagination into the nucleus. The cases displayed a different clinical course despite the structural similarity of the intranuclear bodies.     

Effect of superior cervical ganglionectomy on the ultrastructure of the pinealocyte in the cotton rat (Sigmodon hispidus)

The ultrastructure of pinealocytes was examined morphometrically in superior cervical ganglionectomized and sham-operated cotton rats. Following denervation, the pinealocytes decreased in size. Reduced areas of the nucleoli, Golgi apparatus, granular endoplasmic reticulum, mitochondria, and vacuoles containing a flocculent material as well as a decreased number of dense-core vesicles were noted. In contrast, the numbers of “synaptic” ribbons and ribbon fields increased. The nature of ultrastructural changes observed in the cotton rat pinealocyte after sympathectomy may indicate a diminution of the presumptive secretory processes of this cell. The presence of a small number of myelinated and unmyelinated axons in the pineal gland of the cotton rat following superior cervical ganglionectomy suggests that the sympathetic nerve fibers from the superior cervical ganglia do not comprise the only source of innervation to the pineal. Additionally, the presence of striated muscle fibers has been observed in the present study in the pineal gland of the cotton rat which heretofore has not been reported in this species.     

Comparison of nonciliated tracheal epithelial cells in six mammalian species: ultrastructure and population densities

Three types of nonciliated epithelial cells in mammalian conducting respiratory airways are thought to be secretory: mucous (goblet) cells, serous epithelial cells, and Clara cells. Mucous and serous cells are considered to be the secretory cells of the trachea. Clara cells are considered to be the secretory cells of the most distal conducting airways or bronchioles. To ascertain if mucous and serous epithelial cells are common to the tracheal epithelium of mammalian species, we characterized the ultrastructure and population densities of tracheal epithelial cells in six species: hamster (H), rat (Rt), rabbit (Rb), cat (C), Bonnet monkey (M. radiata) (B), and sheep (S). Following fixation by airway infusion with glutaraldehyde/paraformaldehyde, tracheal tissue was processed for light and electron microscopy (EM) by a selective embedding technique. Tracheal epithelium over cartilage was quantitated by light microscopy and characterized by transmission EM. Mucous cells were defined by abundant large nonhomogeneous granules, numerous Golgi complexes, basally located nuclei and granular endoplasmic reticulum (GER). The percentage of mucous cells in the tracheal epithelium was: H (0%), Rt (0.5%), Rb (1.3%), C (20.2%), B (8%), S (5.1%). Serous cells had homogeneous, electron-dense granules and extensive GER. Serous cells were present only in rats (39.2%). Clara cells had homogeneous electron-dense granules, abundant agranular endoplasmic reticulum (AER) and basal GER. Clara cells were found in hamsters (41.4%) and rabbits (17.6%). In sheep trachea, 35.9% of the epithelial cells had small electron-lucent granules, abundant AER and numerous Golgi complexes. In Bonnet monkey trachea, 16% of the epithelial cells had small electron-lucent granules, numerous polyribosomes, perinuclear Golgi apparatus and moderate GER. In cat trachea, 5.4% of the epithelial cells lacked granules, and had moderate numbers of mitochondria, moderate amounts of polyribosomes, a central nucleus, and long luminal microvilli. The percentage of the tracheal epithelial population occupied by basal, ciliated and nonciliated cells was: H (5.6%, 47.5%, 46.7%), Rt (13.4%, 40.6%, 45.9%), Rb (28.2%, 43.0%, 28.3%), C (37.3%, 36.1%, 26.7%), B (31%, 41%, 28%), S (28.5%, 30.6%, 41%). We conclude: 1) mucous and serous cells are not common to the tracheal epithelial lining of all mammalian species; 2) there is significant interspecies heterogeneity in the abundance, distribution and ultrastructure of tracheal secretory cells; 3) potential differences in the roles of nonciliated cells in tracheal function exists within tracheal epithelial populations and between species.     

The Structure and Composition of Rat Reticulocytes: I. The Ultrastructure of Reticulocytes

1. Fixed, sectioned rat reticulocytes, embedded in araldite, have a regularouter limiting margin like that of erythrocytes; however, unlike erythrocytesthey contain cytoplasmic organelles similar to those in erythroblasts and othermammalian cells. These include mitochondria, ribosomes and a sparse endoplasmic reticulum consisting of rounded vesicles and occasional small cisternae. The endoplasmic reticulum appears to consist wholly of "rough-surfaced" elements.

2. Many mitochondria have disorientated cristae or ruptured outer membranes. The possible origin of these alterations is discussed.

3. Ribosomes appear as electron-opaque granules 10-20 mµ in diameterin sections of whole cells. Most of them occur free in the cytoplasm while afew appear to be attached to the surface of vesicles and cisternae of theendoplasmic reticulum. They can be isolated from ruptured cells by highspeed centrifugation and have a similar chemical composition to ribosomesfrom other mammalian tissues.

Submitted on March 30, 1962 Accepted on July 4, 1962     

Unusual Configurations of Endoplasmic Reticulum in Pinealocytes of the Djungarian Hamster (Phodopus sungorus)

Ultrastructural observations of the pineal gland of Phodopus sungorus revealed different morphological forms of endoplasmic reticulum. These included crystalloids composed of 200A-wide tubules with an intervening space of 200A and connected at right angles to form a rectangular lattice; complexes of undulating 500A-wide tubules in an electron-dense cytoplasmic matrix; and stacks of flattened cisternae covered with granular electron-dense material. All these structures are continuous with the surrounding endoplasmic reticulum. Frequently one structure is directly connected with another. The exact function of these structures derived from the endoplasmic reticulum is still unclear, but they can be assumed to be morphological features of augmented secretory activity.     

Pathological characteristics of gastric leiomyoblastoma

AIM: To determine the pathological characteristics of gastric leiomyoblastoma. METHODS: All tissues were obtained during surgery or gastroscopy. Tissue specimens for examination by light microscope were 1 cm x 1 cm x 1 cm in size, fixed in 40 g/L neutral buffered formaldehyde, embedded in paraffin, and stained with hematoxylin and eosin. The fresh tissues obtained for electron microscopy were 1 mm x 1 mm x 1 mm in size, and fixed in phosphate buffered 30 g/L glutaraldehyde, postfixed in 10 g/L osmium tetroxide and dehydrated in graded alcohol, embebbed in Epon 812. Ultrathin sections of 50 nm were stained with uranyl acetate and lead citrate and examined under a JEM-2000 EX transmission electron microscope. RESULTS: The most important histopathological feature of leiomyoblastoma was the predominance of large, rounded or polygonal cells with characteristic perinuclear clear zone in cytoplasms. The tumor cells arranged in patch, cell junction or junctional complex could be found occasionally between cells under electron microscope. Most of the neoplastic cytoplasms were filled with myofilaments, dense bodies, and dense patches. Rough endoplasmic reticulum dilatated as lakes, and large quantities of protein secretions of intermediate electron density were found in the dilated cisternae. Intracisternal segregation could also be found. The nuclei were round or oval, and anomalous nuclei were found in part of cells. CONCLUSION: The diagnosis of gastric leiomyoblastoma can be confirmed by electron microscopy. The clear appearance of tumor cells is due to the dilation of rough endoplasmic reticulum, not fat droplets, glycogens or mucus in cytoplasm.     

Granular cell tumor of the esophagus

A case of granular cell tumor of the esophagus in a 50-year-old man is reported. Gastrointestinal endoscopy revealed a round, sessile, non-ulcerated white-yellow elevated tumor at the lower third of the esophagus. Biopsy revealed a granular cell tumor. Immunohistochemical staining demonstrated that granules in the cytoplasm of tumor cells were positive for S-100 protein and negative for carcinoembryonic antigen. An electron microscopic study revealed that tumor cells were closely packed in clusters, surrounded by basal lamina and collagen fibers. Most cells contained dark cytoplasm filled with electron-dense granules. These granules resembled lysosomes and phagosomes. In a few cells with clear cytoplasm, some mitochondria and poorly developed endoplasmic reticulums were seen. Fibrillar internal materials, myelin-like figures and a premature angulate body were observed in the clear cytoplasm. The lesion has remained unchanged in gross appearance and in size for twenty-three months without any treatment.     

Modifications of pars intermedia cells of ovariectomized rats by oestrogen and progesterone

The effects of the ovarian steroids, oestradiol benzoate (EB), and progesterone (P) on the cells of pars intermedia (PI) from chronically ovariectomized rats (CHR-OVX) were analyzed by qualitative and quantitative electron microscopy (EM) at different intervals after steroid injection. The PI cells of CHR-OVX are rich in secretory granules but poor in organelles related to hormonal synthesis. Twenty-four h after EB administration the cells exhibited cytological features indicative of an increased synthetic activity. These included hypertrophy of rough endoplasmic reticulum, cisternae, a moderately developed Golgi complex, and newly formed granules. These features were also observed in PI cells 48 h after EB administration. Thirty-two and 56 h after the treatment, the PI cells showed signs of both increased synthetic and secretory activity. Thus, it was possible to observe a well-developed rough endoplasmic reticulum, and Golgi apparatus, numerous electron-lucent vesicles, and secretory granules in contact with the cell membrane. However, no exocytotic figures were observed. Progesterone administration resulted in considerable modifications of the ultrastructural features of PI cells also indicative of increased synthetic and secretory activity. The greatest modifications were observed in the mornings with changes that were 12 h out of phase with respect to those observed with EB. Quantitative estimations of the variation in the content of secretory granules of PI cells fully confirmed the qualitative observations described above. The serum alpha-MSH concentrations in ovariectomized rats was found to be increased 24 h after administration of a single dose of EB and thereafter serum MSH exhibited high levels in the afternoon, whereas the values in the morning were lower.     

Ultramorphological features of an experimental hamster sarcoma

Summary Cells from an experimental sarcoma produced by inoculation of BHK 21 cells clone 13 cells in hamsters showed many similar ultrastructural features with the original cultured cells. Clear and dark cells, probably representing different metabolic stages of the same tumor cell, were noted. In both tumor and culture cells, type R or H virus-like particles could be detected. The high number of R or H particles observed in tumor cells suggests their participation in the oncogenesis of this neoplasm. The tumor cells contained several dilated endoplasmic reticulum cisternae with round and filamentous R type virus particles. Many tumor cells presented nuclear bodies of the filamentous and granular types.

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Ultrastruktur eines experimentellen Sarkoms des Hamsters

Zusammenfassung Zellen eines experimentellen Sarkoms, verursacht im Hamster durch Inoculation von BHK 21 Klon- 13 Zellen, wiesen zahlreiche ultrastrukturelle Eigenschaften auf, die mit den Stamm-Kulturzellen vergleichbar sind. Es wurden klare und dunkle Zellen beobachtet, die möglicherweise aus verschiedenen Stufen des Metabolismus derselben Geschwulstzelle entstanden sind. Sowohl in den Geschwulstzellen wie auch in den Kulturzellen sind R oder H Virus-ähnliche Partikeln festzustellen. Die hohe Anzahl der R oder H Partikel in den Geschwulstzellen läßt vermuten, daß diese an der Onkogenese der Neoplasie beteiligt sind. Die Geschwulstzellen enthielten einige erweiterte Cystomen des endoplasmatischen Reticulums, in denen runde und filamentöse Virus-Partikel des R-Typs festzustellen sind. Viele Geschwulstzellen zeigten Kernkörperchen des filamentösen oder granulären Typs.

     

Morphological changes in pancreatic B-cells after intravenous administration of forskolin

Summary The morphological changes in rat pancreatic islets were studied after intravenous injection of forskolin (1.5 mg/kg), an activator of adenylate cyclase, to male Wistar rats. A high amount of insulin containing granules was observed on PAP immunostained paraffin sections. Ultrastructural study of islet B-cells demonstrated enlarged perinuclear space, dilated cisternae of rough endoplasmic reticulum and activated Golgi complex with numerous vesicles. The results suggest that intravenous administration of forskolin produces a modest increase of B-cell synthetic activity in the pancreatic islets of rats. It is assumed that forskolin affects pancreatic B-cells via increased cAMP.     

Fine structural effects of hypophysectomy on the aging rat pineal gland

A study was undertaken to examine the effects of pituitary removal on age-related changes in the female rat pineal. Three 9-month-old controls, three 23-month-old controls and three rats hypophysectomized at 19 months and sacrificed at 23 months of age were utilized. Electron microscopic evaluation indicated that following hypophysectomy there was a significant loss of lipid droplets, no change in the frequency of light and dark pinealocytes or cytoplasmic dense bodies (probably lipofuscin), a trend towards increased granular deposits between cells, no change in the number of pinealocytes with nuclear invaginations and decreased numbers of cells with nuclear inclusions. The results indicate that while some tissues (kidney) may show reduced aging indices following hypophysectomy other tissues such as the pineal may be detrimentally affected.     

Localization of neurophysin within organelles associated with protein synthesis and packaging in the hypothalamoneurohypophysial system: an immunocytochemical study.

Electron microscopic immunocytochemical localization of neurophysin in the hypothalamo-neurohypophysial system of mice has been studied by using the pre-embedding staining approach to the unlabeled antibody-enzyme technique of Sternberger. In supraoptic cell bodies, peroxidase-antiperoxidase reaction product was localized within cisternae of the nuclear envelope, rough endoplasmic reticulum, and Golgi saccules but not in GERL (Golgi-associated smooth endoplasmic reticulum from which lysosomes arise). Reaction product was also present in secondary lysosomes. Secretory granules in supraoptic perikarya and posterior pituitary Herring bodies were likewise immunoreactive. These findings with the unlabeled antibody-enzyme technique provide conclusive evidence for the localization of an antigen within cellular organelles associated with protein synthesis and packaging.