bluuebunny/crossref_metadata_2025_split huggingface dataset:
Electron microscopic analysis of the effect of progesterone upon the hormone‐sensitive solitary cilia and centriolar complexes in the luminal epithelial cells of the uterus of the ovariectomized‐adrenalectomized rat
Authors: Tachi Sumie 
Published: February 2005

AbstractThe time course of the hormonally controlled deciliation cycles of the centriolar complexes in the cells of the luminal epithelium of the uterus of the ovariectomized and adrenalectomized rat was analyzed at ultrastructural levels. The results were expressed quantitatively. The half‐life of the solitary cilia after progesterone administration in the cell population was 14.6 hr, longer approximately by 1 hr than that previously reported for the estrogen‐induced deciliation of the same cells.The time course of the progesterone‐induced loss of solitary cilia strongly suggested that the phenomenon is biphasic. After the initial loss of 50%, the process progressed slowly. Twenty‐four hours after the injection of the hormone, 35% of the cilia remained; after 60 hours, 4% were still present. This is in striking contrast to the effect of estrogen, which causes almost complete deciliation within 24 hr after the injection of the hormone. Prolonged exposure of the deciliated luminal epithelial cells to progesterone leads to disarrangement of the diplosome relationship. The phenomenon might be causally correlated with the block of estrogen‐induced mitoses by this hormone; this view, however, needs further experimental corroboration.
A quantitative study of pituitary colloid in the batMyotis lucifugus lucifugusin relation to age, sex, and season
Authors: Anthony Edythe L. P. , Gustafson Alvar W. 
Published: February 2005

AbstractExtracellular colloid accumulations were examined in pituitary glands of adult and juvenile, male and female, little brown bats,Myotis lucifugus lucifugus(Chiroptera: Vespertilionidae), collected at various times during the annual reproductive cycle. Round or ovoid periodic acid‐Schiffreactive accumulations of colloid were scattered throughout the pars distalis, pars intermedia, and pars tuberalis. These accumulations were surrounded by processes of agranular “follicular” cells. The proportion of the volume of the pars distalis occupied by colloid (volume fraction) exhibited considerable variation among animals, ranging from 0.00 to 3.18% in the total sample of bats. Pituitaries of juvenile males, yearling males, and nonparous females contained significantly less colloid than those of parous females and adult males. The mean volume fraction for each of these groups suggested that colloid content increased progressively from birth through sexual maturity in this animal. In addition, the frequency distribution of colloid content measurements made in parous females and adult males provided indirect evidence that colloid continues to accumulate throughout life. No sexual dimorphism in colloid content was observed before or after sexual maturity, and colloid content did not fluctuate in relation to the annual reproductive cycle of either males or females.
The fine structure of the placenta and chorionic vesicles of the bush baby, Galago crassicaudata
Authors: King Barry F. 
Published: February 2005

AbstractThe fine structure of the placental villi and the chorionic vesicles of the bush baby, Galago crassicaudata, were examined. The placenta was of the diffuse epitheliochorial type. The trophoblastic epithelium of the placental villi consisted of cells joined by tight junctions and desmosomes. The apical borders of these cells interdigitated with corresponding processes on the uterine epithelial cells. The fetal capillaries indented the trophoblastic cells later in gestation, and the trophoblast over the capillaries was correspondingly thinner with advancing gestation. The trophoblast of the villi was characterized by numerous lipid droplets and moderate amounts of granular endoplasmic reticulum (ER). The apical cytoplasm often had many mitochondria as well as small electron‐dense vesicles and tubules. Uterine epithelial cells contained agranular ER and a well‐developed Golgi apparatus. The apical cytoplasm contained numerous granules often with an electron‐dense content. The uterine epithelial cells appeared to be secretory, contributing to the electron‐dense material found between the fetal and maternal cells. Fetal capillaries were of the continuous type, whereas occasional fenestrae were observed in maternal capillaries. Recesses in the trophoblastic epithelium occurred at the tips, sides, and bases of the villi. These areas had taller trophoblastic cells that appeared to be more active in phagocytosing uterine content. The chorionic vesicles are invaginations of the chorion opposite the mouths of uterine glands. A layer of columnar trophoblastic cells covered the villi of the vesicles. These cells had abundant vacuoles and coated pits and vesicles. The mesodermal component of the chorionic vesicles included a capillary network and a layer of smooth muscle cells in the wall of the vesicle. It was concluded that the trophoblast of the placental villi is engaged in both hemotrophic and histotrophic nourishment of the embryo. The specialized chorionic vesicles are particularly important in providing histotrophic nutrients to the embryo, especially the secretions of the uterine glands. The similarity of the chorionic vesicles to the areolae of other species suggests they may be the pathway by which iron is transported from mother to fetus, perhaps by receptor‐mediated endocytosis of macromolecules derived from uterine gland secretions.
The effects of insulin replacement and withdrawal on hepatic ultrastructure and biochemistry
Authors: Garfield Sanford A. , Mohamed Shadia A. , Cardell Robert R. 
Published: February 2005

AbstractThis study examines the early hepatic biochemical and ultra‐structural responses to insulin replacement in streptozotocin‐diabetic rats and insulin withdrawal from insulin‐maintained diabetic rats. Insulin administration rapidly lowered plasma glucose and the elevated glucose‐6‐phosphatase (G‐6‐Pase) specific activity of the diabetic rats. However, hepatic glycogen did not increase until after 3 hr of insulin treatment. Hepatic ultrastructure responded to insulin replacement after the decline in glucose and G‐6‐Pase. This was seen in periportal hepatocytes as a reduction in the close association between smooth endoplasmic reticulum (SER) and glycogen particles in the diabetic animals. The treated rats showed hepatic SER restricted to the periphery of glycogen masses, as is characteristic of these cells from normal rats, in many cells by 6 hr and all cells by 18 hr. Insulin withdrawal from insulin‐treated diabetic rats elicited nearly a total reversal of the above events. Plasma insulin declined to a value half that of the normal rats by 6 hr after withdrawal; concurrently, plasma glucose rose sharply to hyperglycemic values as hepatic glycogen content dropped. Following the rise in plasma glucose and fall in glycogen content, G‐6‐Pase specific activity increased and by 16 hr reached the high values characteristic of the diabetic animal. Hepatic ultra‐structure was also changed as evidenced by an intrusion of elements of the SER into the dense glycogen masses; the result was dispersed glycogen closely associated with SER as seen in the diabetic animal. It is concluded that the hepatic response to insulin replacement in diabetic animals and diabetic onset in insulin‐withdrawn animals is rapid and occurs through defined stages.
The transverse‐axial tubular system (tats) of mouse myocardium: Its morphology in the developing and adult animal
Authors: Forbes M. S. , Hawkey L. A. , Sperelakis N. 
Published: February 2005

AbstractInvaginations of the sarcolemma that generate the transverse‐axial tubular system (TATS) of the ventricular myocardial cells have begun to develop in the mouse by the time of birth. The formation of the TATS appears to be derived from the repetitive generation of caveolae, which forms “beaded tubules”. Beaded tubules are retained in the adult, in which they frequently present a spiraled topography. Development of the TATS progresses so rapidly that complex systems are already present in the cardiac muscle cells of young mice; by 10–14 days of age, the ultrastructure is essentially identical to that of the adult. The mouse myocardial TATS is composed of anastomosed elements that are directed transversely and axially (longitudinally). Many tubules have an oblique orientation, however, and most elements of the TATS are highly pleiomorphic. In this respect the TATS of the mouse heart is relatively primitive in appearance in comparison with the more ordered TATS latticeworks typical of the ventricular cells of other mammals. Stereological analysis of the mouse TATS indicates that the volume fraction (VV) and surface density (SV) are considerably greater than previously reported (3.24% and 0.5028 μm−1, respectively). The most complex ramifications of the TATS are embodied in the subsarcolemmal caveolar system and the deeper tubulovesicular “labyrinths”, both of which can be found in early postnatal and adult ventricular cells. In atrial cells, TATS development is initiated several days later than in the ventricular cells. The TATS of adult atrial myocardial cells is less prominent than the ventricular TATS and consists largely of axial elements; the incidence of the TATS, furthermore, is more pronounced in the left than in the right atrium.
The sensorineural apparatus of the human eyelid
Authors: Munger Bryce L. , Halata Zdenek 
Published: February 2005

AbstractThe present study describes a complex array of sensory nerve terminals in the human eyelid. In many respects this pattern of innervation resembles that previously described in the rhesus monkey, but in other respects it is unique to man. The most prominent nerve terminals are a complex array of lanceolate and circular Ruffini and free nerve endings that envelop the eyelashes. In addition, Merkel cells have not been conclusively identified to date in other nonhuman primate nonsinus hairs. The external root sheath collar contains Merkel cells, and dermal Merkel cells have also been identified close to the collar. The anterior cutaneous surface of the eyelid contains small vellus hairs with typical lanceolate, Ruffini, and free nerve endings resembling those of primate facial skin.Scattered Meissner and scant simple corpuscles as well as scattered free nerve endings (FNEs) can be identified on the occlusal surface of the eyelid. Intraepithelial as well as dermal FNEs were most easily identified in this region in areas lacking other corpuscular receptors. Corpuscular receptors are especially common at the occlusal/conjunctival angle.The inner or conjunctival surface of the eyelid appears to be a glandular epithelium, whereas in the rhesus monkey it is stratified squamous epithelium. This epithelium needs additional study.In summary, the present study confirms the unique sensory neural status of the human eyelid and verifies the presence of Ruffini nerve terminals by light and electron microscopy and of free nerve ending terminals at least by light microscopy, as well as a unique pattern of innervation of the human eyelash.
The microcirculation of cerebral arteries: A morphologic and morphometric examination of the major canine cerebral arteries
Authors: Liszczak Theodore M. , Mc Black Peter L. , Varsos Vassilios G. , Zervas Nicholas T. 
Published: February 2005

AbstractA morphologic and morphometric examination of the major cerebral blood vessels in the dog was carried out to determine whether there were vasa vasorum in these arteries and what features might be associated with them. True vasa vasorum confined to the media were not seen in any of the vessels examined. Microvessels confined to the adventitia, however, were found in the internal carotid and vertebral arteries but not in the basilar, middle cerebral, or anterior spinal arteries. Animal size, vessel size as determined by adventitial and medial area, and the number of smooth muscle cell lamellae were not associated with the presence of these adventitial vessels; they occurred only in arteries with both an intra‐ and extradural portion. It therefore appears that most canine cerebral arteries do not have vasa vasorum.
The organogenesis of murine striated muscle: A cytoarchitectural study
Authors: Ontell Marcia , Kozeka Kenneth 
Published: February 2005

AbstractThe ultrastructure and the three‐dimensional cytoarchitecture of the developing murine extensor digitorum longus muscle has been studied in spaced, serial, transverse and longitudinal ultrathin sections of the muscles of 12‐, 14‐, 16‐, and 18‐day in utero, newborn, and 5‐day‐old 129 ReJ mice. Despite the fact that in vivo myogenesis is asynchronous (i.e., during most of the fetal period, multiple stages of myogenesis can be seen in a single developing muscle mass), a distinct temporal pattern of development can be seen across the entire width and length of the developing muscle. At 12 days in utero, the developing extensor digitorum longus muscle consists of primary myotubes surrounded by a pleomorphic population of mononucleated cells devoid of myofilaments. At this stage, blood vessels and nerves are found peripheral to but not within the developing muscle mass. A delay of ≥ 2 days occurs between the time of formation of the primary and secondary myotubes. Clusters (consisting of one primary myotube and secondary myotubes), axon bundles, capillaries, and primitive motor endplates are found in the muscle by 16 days in utero. Evidence is presented consistent with the hypothesis that cluster formation and cluster dispersal occur simultaneously in the developing muscle, beginning as early as 16‐days in utero. By 18 days in utero, many of the primary myotubes of the cluster and the independent myotubes (i.e., single myotubes enclosed in their own basal lamina) have begun to acquire the polygonal shape, fascicular arrangement, and ultrastructure characteristic of more mature myofibers. At birth, clusters are infrequently encountered, and intramuscular axons have begun to undergo myelination. At this time, the only undifferentiated, mononucleated cells present in the muscle are myosatellite cells. The first week postnatal was characterized by further maturation of the myofibers.
Dynamic histology of the antral epithelium in the mouse stomach: I. Architecture of antral units
Authors: Lee E. R. , Leblond C. P. 
Published: February 2005

AbstractThe architecture of the pure mucous units of the pyloric antrum was investigated in 3‐ to 4‐month‐old CD1 mice. Units were serially cut in cross section and stained by a method combining the periodic acid‐Schiff sequence, a modified Grimelius's silver nitrate procedure, and Regaud's hematoxylin. A total of 195 units were then reconstructed. Of these, six were cast in polyester resin and 189 were two‐dimensionally reproduced on graph paper.The reconstructions showed antral units to be divided among three main classes. The first class, which contained 32% of the units, consisted of fingerlike tubules referred to as “singlets.” Three types of singlets were observed. The first or type A, which represented 76% of the singlets, was divisible into three successive portions: a pit (foveola) opening onto the mucosal surface and lined by mucous cells referred to as pit cells, and isthmus continuous with the pit and containing immature proliferative mucous cells, and a gland forming the blind end of the tubule and lined by mucous cells referred to as gland cells. Type B (14% of singlets) was similar to type A except that its gland was forked. Type C (10% of singlets) differed by the absence of a gland. The units of the second class, which contained 53% of the total number, were joined together along part of their length and were named “multiplets.” Most of them (90%) were organized into clusters of two, and 10% into clusters of three. In the joined portion, the epithelial cells of the adjacent units were in contact through junctional complexes and, therefore, were not separated by basement membranes. Otherwise the units showed the same component parts as in singlets. Also, as in singlets, the majority of the units were type A and a few were type B or C. The units of the third class, or “intermediates,” consisted of tubules which exhibited a branching process. This process was of variable length but could include gland, isthmus, and sometimes pit. Thus, the process duplicated a varying proportion of the unit.In conclusion, the pure mucous units of the antrum exhibit various patterns which have been designated singlet, multiplet, or intermediate. It is proposed that these three patterns are related and represent temporal differences in the duplication and production of new units. Based on this assumption, a model has been elaborated to depict the likely sequence in the proliferation of pure mucous units. It is proposed that this proliferation takes place in the antrum of young adult mice.
Dynamic histology of the antral epithelium in the mouse stomach: II. Ultrastructure and renewal of isthmal cells
Authors: Lee E. R. , Leblond C. P. 
Published: February 2005

AbstractThe isthmus of typical mucous units of the pyloric antrum was investigated in 3‐ to 4‐month‐old CD1 mice using light and electron microscopy as well as 3H‐thymidine radioautography.On the average, the isthmus measured 25 μm in length and was composed of 36 isthmal cells and two enteroendocrine cells. Isthmal cells generally displayed features found in embryonic cells, such as many free ribosomes, scant organelles, and a large reticulated nucleolus, and were, therefore, at an immature stage of development. Isthmal cells could be devoid of secretory granules (“granule‐free cells,” 2%) or contain a few small, spherical, PA‐Schiffpositive, mucous granules in their apex. The granules in some of the cells had a variegated appearance and a diameter averaging 235 nm (“mottled granule cells,” 39%); in other cells, the granules had a large diameter, 278 nm, with a pale background and a dense core (“core granule cells,” 28%); while in still others they were homogeneously dark and measured 264 nm (“dense granule cells,” 12%). Finally, some cells included a mixture of core and dense granules (“mixed granule cells,” 14%). One hour after a single injection of 3H‐thymidine, 37% of the isthmal cells were labeled. Each of the five isthmal cell types could acquire label and, therefore, divide. After one or more days of continuous 3H‐thymidine infusion, all isthmal cells were labeled. Their turnover time was estimated to be 16.1 hr (t1/2 = 11.2 hr).The isthmus is thus composed of several cell types which are turning over rapidly. While all are relatively immature, the various types are thought to represent different developmental stages in the life history of an isthmal cell. A model devised on this basis proposes that the granule‐free cells are stem cells, from which mottled granule cells are derived. These in turn evolve into either the dense granule cells of the upper isthmus or the core granule cells of the lower isthmus, or into the mixed granule cells (which are believed to develop eventually into dense granule cells or core granule cells). Maintenance of a steady state requires that the rapid production of isthmal cells be associated with rapid emigration; the dense granule cells presumably going to the pit and the core granule cells to the gland. The turnover of isthmal cells is accordingly described as following a “bidirectional pattern” of renewal.
Dynamic histology of the antral epithelium in the mouse stomach: III. Ultrastructure and renewal of pit cells
Authors: Lee E. R. 
Published: February 2005

AbstractThe pit (foveola) of typical mucous units of the pyloric antrum was investigated in 3‐ to 4‐month‐old CD1 mice, using light and electron microscopy, sometimes combined with 3H‐thuymidine radioautography.Reconstruction of units from serial sections revealed that, on the average, the pit measured 151 μm in length and was lined by 184 mucus‐containing pit cells. Of these, 164 were located along the wall of the pit, whereas 20 surrounded its opening on the free surface. For ultrastructural examination the pit was divided into equal thirds. The proximal third, located next to the isthmus and referred to as pit base, was composed of cells showing electrondense mucous granules greater in number but similar in density and diameter to those of isthmal dense granule cells. Nucleoli were rather large, irregular, and reticulated; these and other features were indicative of partial differentiation. The appearance of the cells gradually changed with the distance from the isthmus. In the middle third or mid pit, cells had small, fairly rounded nucleoli, while mucous granules were more numerous than in the pit base but similar in appearance and size; these cells were considered to be mature. In the distal third or pit top‐surface, granules became elongated and nucleoli shrank, and lysosomes and vacuoles greatly increased in number, indicating that cells were at a terminal stage. Indeed, some of the cells were extruded into the stomach lumen while others were phagocytosed by adjacent cells. Following a single injection of 3H‐thymidine, labeling was found only in a small cohort of cells in the pit base. At the end of 1 day of continuous infusion, the cohort of labeled cells had reached the mid pit; by 2 days, the pit top; and by 3 days, the free surface, where cells were eventually lost. The renewal time of pit cells was assessed at 2.98 days (t1/2 = 1.8 days), giving a turnover rate of 33.5% per day.It is estimated that the divisions of pit base cells provide two‐thirds of the cells needed daily for pit‐cell renewal, while the other third is supplied by an influx of dense granule cells from the isthmus. These cells enter the pit and continuously migrate toward the gastric lumen, while differentiating in the pit base, maturing in the mid pit, and reaching a terminal stage at the pit topsurface. The progressive and orderly migration of pit cells is described as a “pipeline pattern” of renewal. It is completed in about 3 days when terminal cells are lost at the pit top‐surface.