bluuebunny/crossref_metadata_2025_split huggingface dataset:
The surface topography of the colonic crypt in rabbit and monkey
Authors: Specian Robert D. , Neutra Marian R. 
Published: February 2005

AbstractScanning electron microscopy (SEM) was used to investigate the epithelial topography of the surface and crypt in rabbit and monkey colon. Crypt openings in monkey colon are arranged in a hexagonal pattern, in sharp contrast to rabbit colon where they are randomly arrayed and frequently hidden by epithelial folds. Crypt lumens were exposed by freezing ethanol‐dehydrated tissue in liquid nitrogen and fracturing the tissue with a razor blade. The resulting overview of crypt‐cell luminal surfaces showed that as columnar cells mature and migrate up the crypt and onto the colonic surface, their microvilli become progressively more abundant. Goblet cells were readily identified in the cross‐fractured crypt epithelium; their luminal surfaces are characterized by short, sparse microvilli. The changing appearance of the luminal surface of goblet cells was visualized by SEM during the exocytosis of single mucous granules from unstimulated crypt goblet cells, and during the compound exocytosis of multiple granules in response to acetylcholine.
Bone marrow cells associated with heightened eosinophilopoiesis: An electron microscope study of murine bone marrow stimulated by Ascaris suum
Authors: Sakai Nobuhiko , Johnstone Colin , Weiss Leon 
Published: February 2005

AbstractAn acute eosinophilopoiesis occurs in mice secondarily exposed to Ascaris suum, the marrow eosinophils increasing from approximately 5% to 45%, and blood levels from 50/ml3 to more than 1000/ml3, within 14 days. Eosinophilopoiesis occurs in hematopoietic compartments of the bone marrow and is associated with four other cell types: branched stromal cells, macrophages, lymphocytes, and reticular cells adventitial to venous sinuses. Branched stromal cells, a newly recognized cell type, are presented in intensified hematopoiesis of at least several blood‐cell types. They are characterized by extensive branches surrounding contiguous hematopoietic cells, dense cytoplasm, and multiple communications between nuclear cisternae and an extensive, dilated endoplasmic reticulum. These cells, moreover, have a capacity to coalesce to form an extensive, branching, multinucleate giant‐cell system. They are neither phagocytic nor fibroblastic, and attend every phase of eosinophilic hematopoiesis. Macrophages lie among eosinophils, and they possess many processes which extend among eosinophils. The may constitute, with the eosinophils, islets similar to erythroblastic islets; or they may lie among eosinophils in sheets. Macrophages also lie against the outside surfaces of vascular sinuses and extend transmural processes into the lumina. Lymphocytes of a type not yet known are regularly present among developing eosinophils. Adventitial cells of vascular sinuses, fibroblastic cells, extend processes deep into perivascular hematopoietic spaces, and thereby envelop eosinophils and other maturing blood cells. While adventitial cells can be dense, they were typically quite lucent and had microfilaments clustered beneath their plasmalemmae. With the large‐scale blood‐cell delivery characteristic of this model, marked changes occurred in the walls of the vascular sinuses. Adventitial cells moved away from the vascular wall, permitting blood cells direct access to the basal surface and reducing their cover from more than 65% to less than 20%. Both adventitial and endothelial cells may be compact and dark, or expanded and quite lucent. Heterolysomes occur in moderate‐to‐large numbers in both adventitial and endothelial cells, and large gaps filled with blood cells in transit occur in endothelium. The hematopoietic‐associated cells and the vasculature described here would appear to provide the cellular microenvironment which regulates hematopoiesis.
The ultrastructure of the thin limbs of henle in kidneys of the desert heteromyid (Perognathus penicillatus)
Authors: Nagle Ray B. , Altschuler E. M. , Dobyan Dennis C. , Dong S. , Bulger Ruth Ellen 
Published: February 2005

AbstractThe thin limbs of both long‐ and short‐looped nephrons in Perognathus kidneys were studied with transmission and scanning electron microscopy. The superficial nephrons have a short thin limb located in the vascular bundles of the outer medulla and are characterized by a simple, low‐lying epithelium (0.4 ± 0.1 μ thickness). In contrast, the first descending part of the thin limb of the majority of midcortical and juxtamedullary nephrons has a relatively thick epithelium (1.7 ± 0.6 μ in thickness) with marked lateral and basal interdigitation and a dense surface covering of microvilli. The remaining part of the long descending thin limb is relatively simple with a low‐lying epithelium (0.6 ± 0.1 μ in thickness), decorated on its surface by sparse microplicae. The bend of the loop and the ascending limb are covered by a very simple low‐lying epithelium (0.6 ± 0.2 μ in thickness) with relatively little surface modification. The extreme urine‐concentrating ability of Perognathus does not appear to be due to the development of a unique thin loop epithelium but rather to the extensive length of the inner and outer medulla.
Localization of tritiated vitamin A in lymph nodes of the mouse: An autoradiographic study of vitamin A‐storing cells
Authors: Hirosawa Kazushige , Yamada Eichi 
Published: February 2005

AbstractLocalization of tritiated vitamin A in lymph nodes of the mouse was investigated by the use of light‐ and electron‐microscopic autoradiography. Young male mice were fed a diet containing 3H‐vitamin A acetate for a week. Lymph nodes were removed and prepared for autoradiography. Lipid droplets in fibroblast‐like cells showed high concentrations of radioactivity. These cells were distributed around lymphatic sinuses and blood vessels. The cells can, therefore, be classified as “vitamin A‐storing cells” according to criteria proposed earlier by Yamada and Hirosawa (1976). Control animals from the same litter were maintained on ordinary laboratory food for the same period and examined by electron microscopy. Lipid‐droplet‐containing cells were found in the same areas as in the experimental animals but in fewer numbers. This suggests that the increased number of vitamin A‐containing lipid droplets is due to hypervitaminosis A in the experimental animals. The presence of some cells containing these droplets in the control animals would imply that even under normal feeding conditions the animals ingested excess amounts of vitamin A, which was retained in lipid droplets. The stored vitamin A probably participates in metabolic processes such as the formation of glycoproteins in ground substance.
The ultrastructure of the atrioventricular junctional tissues in the newborn ferret heart
Authors: Marino Thomas A. , Biberstein Denise , Severdia Joseph B. 
Published: February 2005

AbstractIn this study the structure of the atrioventricular (AV) node and bundle in the newborn ferret heart was examined by light and electron microscopy. At the light microscopic level the AV node could be subdivided into deep and superficial portions. Electron microscopy revealed that both superficial and deep AV nodal cells were characterized by a paucity of myofibrils, desmosomes, fasciae adherentes and gap junctions. Deep AV nodal cells, however, had more surface specializations than did superficial AV nodal cells. In both subdivisions the constituent cells were ellipsoid with tapering end‐processes. In contrast to the nodal cells, the newborn AV bundle cells were round to ovoid. The AV bundle cells were organized into large fascicles, and there was a high frequency of anastomosing intercommunication between fascicles. These bundle cells had few myofibrils and a high incidence of apposed plasma membrane. The present morphological findings support the concept that there are significant postnatal morphological changes that occur in the region of the AV junction. These results are also consistent with findings in other species that AV nodal conduction time is similar in newborns and adults, while conduction through the AV bundle increases with age.
Functional organization of the oculomotor nucleus in the baboon
Authors: Augustine James R. , Deschamps Edgar G. , Ferguson James G. 
Published: February 2005

AbstractThe functional organization of the oculomotor nucleus was investigated using horseradish peroxidase (HRP) histochemistry. In a series of baboons, injections of HRP were made into the skeletal muscles supplied by the oculomotor nerve (medial rectus, superior rectus, inferior rectus, inferior oblique, and the levator palpebrae superioris). After a 48‐hour survival time the animals were sacrificed via perfusion‐fixation and the brains treated according to the tetramethylbenzidine (TMB)‐HRP method of Mesulam (1978).The inferior oblique, inferior rectus, medial rectus, and levator palpebrae superioris muscles are supplied by cells located primarily in the homolateral oculomotor nucleus. Some fibers to the levator palpebrae superioris arise from cells in both caudal central nuclei. The superior rectus muscle receives fibers from cells in the contralateral oculomotor nucleus. The results were complied using a Lucite‐plate reconstruction method that permits visualization of the three‐dimensional configuration of the neuronal populations within the oculomotor nucleus.Oculomotor neurons are organized in a vertical column that may be anatomically divided into rostral, middle, and caudal thirds. A section through any of these levels may be further subdivided into dorsal, intermediate, and ventral zones. Each of the oculomotor skeletal muscles was found to have cells at almost all levels of the nucleus and in certain zones at each level. These functional cell groups intermingle with one another in the baboon and do not remain segregated into distinct subnuclei or subdivisions. Much overlap was evident between cells innervating the homolateral inferior rectus, homolateral inferior oblique, and the contralateral superior rectus muscles. There was also overlap between those cells supplying the homolateral levator palpebrae superioris and the homolateral medial rectus muscles.
Influences of age and vasopressin on the uptake capacity of fluorescent granular perithelial cells (FGP) of small cerebral vessels of the rat
Authors: Mato Masao , Ookawara Shigeo 
Published: February 2005

AbstractFluorescent granular perithelial cells (FGP) were found in the perivascular space around fine cerebral blood vessels. Their profiles and intracellular inclusions varied with the age of the animals. The FGP are able to take up exogenous substances administered intraventricularly.With light and electron microscopy, the relation between the uptake capacity of FGP and the aging of animals was studied using horseradish peroxidase (HRP). The effects of vasopressin on the uptake of HRP also were examined. The results can be summarized as follows: (1) The uptake capacity of FGP diminished with aging, that is, the reaction product of administered HRP was found abundantly in FGP in young rats, while it was sparse in the FGP of old rats; and (2) vasopressin increased the incorporation of HRP into the FGP of both young and old rats. The possible role of vasopressin in modulating the uptake capacity of FGP is considered, and the differences between FGP and other perivascular cells are discussed.
Nerve endings in human sympathetic ganglia
Authors: Helén Pauli , Hervonen Antti 
Published: February 2005

AbstractForty‐eight human sympathetic ganglia from 22 sympathectomies were examined ultrastructurally after one of three different fixations: (1) glutaraldehyde + osmium tetroxide, (2) glutaraldehyde + potassium dichromate + osmium tetroxide, or (3) potassium permanganate.Three different kinds of synapsing nerve ending could be identified after all fixation schedules. Type 1: “Cholinergic,” containing small, agranular vesicles 40–60 nm in diameter (75% of all vesicles) and some large granular vesicles (100 nm in diameter). The number of type 1 profiles decreased with increasing age. Type 2: “Adrenergic,” containing small granular vesicles 40–70 nm in diameter (over 90% of the vesicles). Type 3: “Nonadrenergic, noncholinergic,” characterized by large opaque vesicles 80–160 nm in diameter (over 50% of all vesicles). The frequencies of the types were counted after potassium permanganate fixation: type 1–71%, type 2–23%, and type 3–6%.In addition, at least two types of nerve profiles were observed which did not form synapses: (1) profiles entirely filled with mitochondria (mitochondrial accumulation), and (2) large nerve profiles full of different kinds of vesicles, myelin figures, and mitochondria (axonal dilatation).It is concluded that the sympathetic ganglion cells receive cholinergic and adrenergic innervation and also a third type of innervation, the possible peptidergic nature of which is discussed.
Morphological and histochemical observations on the duodenal glands of eight wild ungulate species native to North America
Authors: Krause W. J. 
Published: February 2005

AbstractThe duodenal glands of the species examined (Alces alces, Ovis canadensis, Cervus canadensis, Oreamnos americanus, Bison bison, Antilocapra americana, Odocoileus virginianas, Odocoileus heminous) are confined primarily to the submucosa of the small intestine. In one species, the moose, a significant population of secretory tubules also is observed in the mucosa. The ducts of the duodenal glands pierce the overlying muscularis mucosae to empty most often independently into the intestinal lumen. Those of the bison, unlike the other species examined, drain into intestinal glands. The duodenal glands consist primarily of a simple columnar epithelium, the cells of which contain basally positioned round or oval nuclei. The lumina of scattered duodenal glands in the pronghorn and to some extent those of the moose, white‐tailed deer, and mule deer may be extremely dilated, and the surrounding epithelium thin and attenuated. Component cells of the duodenal glands of all the species examined show remarkably similar ultrastructural features. They exhibit scattered profiles of rough endoplasmic reticulum, dilated cisternae of which contain an electrondense, amorphous material. Numberous well‐developed Golgi complexes occupy the supranuclear region together with transport vesicles and forming secretory granules. Electron‐dense, membrane‐bound secretory granules generally are concentrated in the apical cytoplasm immediately subjacent to the cell membrane. The apical cell membrane exhibits short, scattered microvilli; and the basal cell membrane is smooth without apparent specialization.Histochemically, the duodenal glands of most species examined in this study consist of a heterogeneous population. The majority of the glands of the moose, elk, mountain goat, bison, pronghorn, and white‐tailed deer elaborate a neutral mucin, whereas scattered individual glands, tubules or cells also produce acid mucins. Cells near the terminations of the ducts of the bighorn sheep are the only elements to produce acid mucins in the duodenal glands of this species. The duodenal glands of the bison are unusual in that only the peripheral portions of individual glands produce acid mucins. The remainder of the glands elaborate neutral mucins. Morphological differences between the two regions were not observed. The duodenal glands of the mule deer secrete both acid and neutral mucins. The structural and histochemical observations appear unrelated to the diet of individual species.
The development of the lung in mammals: An analysis of concepts and findings
Authors: Ten Have‐Opbroek Antonia A. W. 
Published: February 2005

AbstractTo evaluate one model of mammalian‐lung development, i.e., division into periods, pre‐ and postnatal lung development in the CPB‐S mouse strain was divided into the currently distinguished periods: the pseudoglandular period, covering establishment of the air‐conducting portion; and the canalicular, terminal‐sac, and alveolar or postnatal periods, in which the respiratory portion develops. The last three periods would each cover the formation of a different component of the respiratory unit or pulmonary acinus (acinus pulmonaris) (nonalveolated respiratory bronchiole, nonalveolated duct and sac, and alveolar pouch). However, determination of the nature of the relevant structures on the basis of recent findings concerning the epithelia showed that these hypotheses are not tenable. Since the tubule with cuboidal epithelium (appearing in the pseudoglandular and following periods) is the basic structure in the genesis of the pulmonary acinus, the development of the respiratory portion must start in the pseudoglandular period. Likewise, since the definitive components of the acinus are derived from this acinar tubule, their establishment may not be restricted to one of the other periods.Because other postulated divisions of mammalian‐lung development were based on similar histological interpretations, they cannot reflect the course of mouse‐lung development either. Therefore, a developmental scheme based on the recent findings concerning the epithelia is given as well as a tentative scheme for the human lung.The respiratory portion proved to develop by budding of acinar tubules, the mode of budding being not restricted to any particular pattern.
Microcirculation of the rat adrenal gland: A scanning electron microscope study of vascular casts
Authors: Kikuta Akio , Murakami Takuro 
Published: February 2005

AbstractBlood vascular beds of the rat adrenal gland were filled with methacrylate resin and observed with a scanning electron microscope. The classical findings on mammalian adrenal glands of Flint (1900), Bennett and Kilham (1940), and Gersh and Grollman (1941) were confirmed. The cortical capillaries arise from the cortical arteries and converge at the corticomedullary junction into the peripheral venous radicles which flow into the tributaries of the central vein. The medullary capillaries originate from the medullary arteries and drain through the deep venous radicles into the tributaries of the central vein. No direct connection between the cortical and medullary capillaries was noted except for rare communications via the peripheral venous radicles. These findings show that most of the cortical blood, rich in glucocorticoids, flows in the medulla, not through the medullary capillary plexus but exclusively through the radicles of the central vein. Evidence for adrenal portal vessels could not be found.
Anatomy and innervation patterns of cat lateral gastrocnemius and plantaris muscles
Authors: English Arthur W. , Letbetter William D. 
Published: February 2005

AbstractThe anatomy, fiber architecture, and innervation patterns of cat lateral gastrocnemius (LG) and plantaris (P) muscles are described. The plantaris is a simple unipennate muscle arising from an aponeurosis in common with LG and inserting primarily into the tendon of m. flexor digitorum brevis, but with ligamentous connections to the calcaneus. The lateral gastrocnemius is more complex and contains three distinctly identifiable heads, each of which is a unipennate band of fibers coursing between a proximally attached aponeurosis of origin and a distal aponeurosis of insertion that gives rise to the tendocalcaneus. Following microdissection of the LG and P nerves, and using glycogen depletion of the primary muscle nerve branches, discrete motor subvolumes are demonstrated in both muscles. Despite large specific differences in fiber architecture between the LG and P muscles, their organization into compartments about primary muscle nerve branches is fundamentally similar. This principle of organization may be a basis for the observed functional and structural properties of other vertebrate muscles. It may thus constitute a unifying concept in the organization of motor control mechanisms.
Morphological studies on long‐term culture of marrow cells: Characterization of the adherent stromal cells and their interactions in maintaining the proliferation of hemopoietic stem cells
Authors: Tavassoli Mehdi , Takahashi Kiyoshi 
Published: February 2005

AbstractIn long‐term cultures of bone marrow, the adherent stromal cells provide support for the proliferation and maintenance of hemopoietic stem cells. These stromal cells and their interactions were characterized by means of scanning (SEM) and transmission (TEM) electron microscopy in correlation with functional studies. Cultures were initiated by establishing the adherent stromal layer as a “soil” which was then “seeded” after 3 weeks by the addition of another marrow‐cell suspension. Clonal assay of the supernatant demonstrated the continuous proliferation of the hemopoietic stem cell. The stroma essentially consisted of two cell types, macrophages and epithelioid cells. Macrophages were smaller, 10–15 μm, phagocytosed latex and carbon particles, and contained lysosomes. Their surface did not stain with polycationic ferritin (PCF). Epithelioid cells were much larger, more than 100 μm; contained numerous thin, elongated mitochondria; did not phagocytose latex particles; but did display strong surface staining with PCF. The appearance of epithelioid cells in TEM depended on their state of development and whether the section was parallel or perpendicular to the substratum. Epithelioid cells displayed a maturational spectrum, at two ends of which were synthetic and storage phases. In the synthetic phase, the cell contained numerous profiles of rough endoplasmic reticulum, and in the storage phase, numerous storage granules. These two phases were best appreciated in sections perpendicular to the substratum, demonstrating synthetic cells on top settling over the substratum upon maturation into the storage cells.Both macrophages and epithelioid cells contained fat globules which increased in number and size with the addition of hydrocortisone to the culture medium. A distinct fat‐cell type, as has been claimed, was not found in this study. Granulopoiesis was observed in the culture system in the absence of colony‐stimulating activity in the supernatant, suggesting direct cellular interaction or short‐range factors in the induction of granulopoiesis. Widespread cellular interactions were noted between macrophages and epithelioid cells, the latter often completely embracing the former and both extending cytoplasmic processes toward each other. This is reminiscent of the cooperative interaction of endoderm and meso‐derm in chick embryo hemopoiesis and may be necessary for the maintenance of stem cells in these cultures.
Quantitative autoradiography, electron microscopy, and granulometry of endocrine cells in the rabbit colon
Authors: Lefranc G. , Barriere P. , Chung Y. T. , Pradal G. 
Published: February 2005

AbstractA high‐resolution autoradiographic study was conducted on 268 thin sections of endocrine cells in the rabbit colon following injection of (3H) Ldopa. Using quantitative autoradiography, silver‐proteinate impregnation, granulometry, and statistical analysis of cell populations by the Falck procedure, three cell types were identified‐EC, L; and H‐as well as a single cell with distinct ultrastructural characteristics. For the first time, a fine quantitative estimation of the handling ability of amine precursor related to the cross‐sectional areas of each cell type was obtained, using a Kontron Digiplan image analyzer. All cells studied showed the ability to take up the precursor. Labeling indices were 6.63, 2.15, and 2.14 for EC, L, and H, respectively. These data and silver‐proteinate impregnations provide good criteria for differentiating EC from H cells despite morphological similarities. After critical analysis of granule diameters, L cells were considered to be pluripotential in secretory activity.