bluuebunny/crossref_metadata_2025_split huggingface dataset:
Histochemical study of estrogenic and antiestrogenic effects of clomiphene citrate on glycogen synthesis by myometrium and luminal epithelium of rat uterus
Authors: Poteat William L. , Bo Walter J. 
Published: February 2005

AbstractGlycogen localization in the myometrium and luminal epithelium of the rat uterus was studied by the periodic acid‐leucofuchsin technique after ovariectomized rats had been treated with various regimens of 1.0 μg estradiol dipropionate and 50.0 μg clomiphene citrate. Three regimens were used: (a) one or three dosages of clomiphene, alone or in combination with one or three dosages of estradiol; (b) a single dosage of clomiphene before a single dosage of estradiol; (c) a single dosage of clomiphene after a single dosage of estradiol.The estrogenic effect of clomiphene on the myometrium was less than that of estradiol. Clomiphene suppressed myometrial glycogen accumulation induced by estradiol when administered with estradiol, six hours before the hormone, or as long as 24 hours after estradiol. The luminal epithelium responded differently to estradiol and clomiphene: the number of luminal epithelial cells containing glycogen strikingly increased after clomiphene treatment but not after estradiol treatment. A few scattered cells contained glycogen 24 hours after one dosage of the drug. Forty‐eight hours after a single dosage or after three dosages of the drug administered one per day, every luminal epithelial cell contained glycogen. The effect of clomiphene on the luminal epithelium may be either a unique action of the drug or an abnormal response of the tissue, similar to that reported for high doses of estradiol. This effect of clomiphene on the luminal epithelium may possibly be a factor in the drug's ability to block blastocyst implantation in the rat.
The ultrastructure of the keratinizing epithelia of the incisor and molar gingivae of the albino rat: Similarities and differences
Authors: Martinez I. Ricardo 
Published: February 2005

AbstractUltrastructural differences suggest that the keratinizing epithelium of the incisor gingiva (IG) is more rigid and durable than that of the molar gingiva (MG). The more numerous and larger collagen fibrils of the lamina propria, the more dense and homogeneous basal lamina, the more numerous anchor filaments distributed along the basal lamina and the larger and more frequently occurring hemidesmosomes along the base of basal cells all provide the IG epithelium with a firmer base and stronger attachment than the MG. The presence of many and long filaments in the IG and their aggregation into bundles inserted into the attachment plaques of desmosomes also suggest that this epithelium is tougher than the MG. This is further emphasized by the larger size of the desmosomes and their more frequent occurrence along the plasma membrane of cells of the IG. The ultrastructure of membrane‐coating granules and their role in membrane modifications appear to be the same in both the IG and MG. As the irregularly shaped keratohyalin granules of the IG increase in size, the dense amorphous material spreads out over the bundles of tonofilaments. On the other hand, as the spherical keratohyalin granules of the MG grow in size, they maintain their spherical shape and do not appear to be associated with or spread out over the filaments. The flattened horny cells of the IG with smooth contours and joined together by closely spaced desmosomes appear to be more protective and less easily detached by the abrading stress of mastication than those of the MG, which are irregular in shape with convoluted cell membranes and widely spaced desmosomes.
Ultrastructure of hepatic sinusoids in sheep
Authors: Grubb Donald J. , Jones Albert L. 
Published: February 2005

AbstractThe fine structure of the sheep hepatic sinusoid has been examined. Unlike that of most previously studied mammals, the sheep sinusoid has a continuous endothelial lining and a distinct basal lamina. Another unusual feature of the sheep sinusoidal endothelium is the presence of fenestrae closed by thin, single‐layered diaphragms. Between the basal lamina and the hepatic parenchyma, processes of perivascular connective tissue cells are seen in unusual abundance. Particles consistent in size with very low density lipoproteins are found on both sides of the basal lamina, but the mechanism of transport of these particles across the endothelial barrier is unknown.
The connective tissue ground substance in the mouse uterine cervix: An electron microscopic histochemical study
Authors: Leppi T. John , Kinnison Patricia A. 
Published: February 2005

AbstractSections of uterine cervix from ovariectomized mice treated with relaxin (R) or estradiol benzoate (EB) alone or EB and R in combination were exposed to dialyzed iron solutions prior to epoxy embedding. Control mice were untreated or received the hormone vehicles. Prior to iron staining, some sections were exposed to: (1) 0.05% testicular hyaluronidase for four hours at 37°C; or (2) acidified methanol for four hours at 60°C. Ultrastructurally, the uterine cervical walls from control mice and those treated with R contained densely packed bundles of collagenous fibrils and cells that resembled fibrocytes with few organelles. Except for spurious intracellular iron deposits, there was no iron staining of extracellular components.Fibroblasts of cervices from mice treated with EB or EB and R were larger with highly developed endoplasmic reticulum and Golgi components. Small cytoplasmic vesicles were present close to the cell surface and each contained a thin inner rim of material. The stroma was characterized by widely dispersed bundles of collagenous fibrils in a greatly expanded cervical wall where there was extracellular iron staining that was prominent near cell surfaces and between individual fibrils within an amorphous material. Brief digestion with testicular hyaluronidase resulted in a reduction of extracellular iron staining, although deposits remained adjacent to cell surfaces, between fibrils and within cytoplasmic vesicles. Acidic methylation caused severe tissue damage so that an assessment of iron deposition in thin sections was impossible.
A new technique of measuring blood vessel volume in bone applied to the mandible and humerus of the rat
Authors: Brady J. M. , Cutright D. E. 
Published: February 2005

AbstractThis report describes a method developed to measure the blood volume and vascularity of bone. The technique utilized neutron‐activated silicone rubber perfusion material and was applied to normal rats from 1 to 18 months of age. By this means it was determined that blood vessel volume over the 18 month growth period measured increased from 8.41 to 15.45 μliters in the mandible and from 2.71 to 4.68 μliters in the humerus. Vascularity decreased from 2.91 to 1.18 μliters per mg × 10−2 of dry mandible and from 3.30 to 0.81 μliters per mg × 10−2 of dry humerus over the same period. Changes in volume and vascularity were greatest in the early months attaining a plateau at from four to six months of age, from 6 to 18 months of age, blood vessel volume increased gradually in the mandible while remaining constant in the humerus. Vascularity in these tissues paralleled changes in vascular volume.
Ultrastructural studies of the effects of reserpine on mouse abdominal sympathetic paraganglia
Authors: Mascorro Joe A. , Yates Robert D. 
Published: February 2005

AbstractMale and female A/Jax mice 10–18 days of age were given one, two, or three daily subcutaneous injections of Serpasil (Reserpine USP; 2.5 mg/kg) and sacrificed 24 hours after the last injection. Abdominal extra‐adrenal tissue was processed for electron microscopy to determine the effects of this catecholamine depleting drug on the dense cored cytoplasmic granules of the parenchymal chief cells.Electron microscopic investigations of sympathetic paraganglia from treated animals revealed a marked decrease in granule opacity as compared to that seen in cells from control animals. The cells with granules reduced in opacity following reserpine treatment could be consistently distinguished from those of non‐treated animals which led us to assume that the drug depleted the amine content from its storage site in the granule without completely destroying the granule structure. These results further substantiate our earlier speculations that the granules in abdominal paraganglion chief cells of the mouse contain catecholamines.
A comparative study of sebaceous gland ultrastructure in subhuman primates. III. Macaques: Ultrastructure of sebaceous glands during fetal development of rhesus monkeys (Macaca mulatta)
Authors: Bell Mary 
Published: February 2005

AbstractSebaceous glands from fetal rhesus monkeys have been studied from the onset of their differentiation to complete maturation. Sebaceous differentiation in fetuses closely parallels that in adults with the exception that agranular endoplasmic reticulum is virtually absent from differentiating cells during early ontogeny, whereas it is abundant in their counterparts in adult animals. As the adult pattern of sebaceous differentiation becomes established, the amount of agranular endoplasmic reticulum increases in these cells. Golgi zones are prominent in differentiating cells during early ontogenetic development.
The structure of Tomes' granular layer in dog premolar teeth
Authors: Shackleford John M. 
Published: February 2005

AbstractMicroradiographic, polarized light, phase‐contrast and scanning electron microscopic aspects of Tomes' granular layer were studied in undemineralized and demineralized premolar teeth from four dogs. The microradiographic studies show Tomes' layer to consist of a narrow zone of hypomineralized‐hyperorganic dentinal matrix subjacent to the cementum. The zone appears as a series of focal points in cross sections or as an interrupted line in apico‐coronal cuts through the tooth. Polarized light and phase‐contrast microscopy demonstrate a morphological pattern similar to that of the microradiographs. Scanning electron microscopy suggests one component of Tomes' layer to be fibrillar. Tomes' granular layer of dog teeth may be important in protecting the tooth from sudden insults or large occlusal forces transferred to dentine via the periodontal ligament.
Ultrastructure of the thyroid gland of the cream hamster
Authors: Nève Pierre , Wollman Seymour H. 
Published: February 2005

AbstractThe typical thyroid epithelium of the cream variant of the Syrian hamster differs from that of other common mammalian species. One obvious difference noted by light microscopy is that the cells contain numerous PAS‐positive granules apical to the nucleus. By electron microscopy these granules are dense granules resembling lysosomes. The cells have exceptionally long microvill and numerous junctions and interdigitations of lateral plasma membranes with those of their neighbors. Many organelles in the cells are stratified rather than arranged at random. In addition to the dense granules and centrioles, the Golgi apparatus is usually located at the level of the apical end of the nucleus. The granular reticulum is primarily in the basal half of the cell, although some is apical. Microtubules are especially abundant and are located ainly close to the lateral surfaces and around the nucleus, although some are near apical or basal plasma membranes. The microtubules frequently appear to be in contact with mitochondria and dense granules, but their role in the positioning or stratification of organelles is uncertain.
Frog pineal photoreceptor renewal: Preliminary observations
Authors: Bunt Ann Heffington , Kelly Douglas E. 
Published: February 2005

AbstractThe intracranial epiphysis of the adult frog, Rana pipiens, has been examined by electron microscopic cytochemistry and radioautography. Acid phosphatase is localized within vacuoles of macrophages free in the lumen, in subspherical vesicles of the ellipsoid portions of photoreceptive cell inner segments, and in occasional heterogeneous cytoplasmic inclusions of the supportive cells.The distribution of radioactivity in the epiphysis at intervals of 1, 3, 5, 9, 14, 25, and 60 days following injection of tritiated leucine, as determined by quantitative radioautography, is consistent with an hypothesized process of continual renewal of photoreceptive cell outer segments. The pattern of radioautographic labeling of the pineal photoreceptors, which resembles more closely that of retinal cones than rods, is correlated with previous morphologic and electrophysiological studies of these cells.The radioautographic and cytochemical data suggest that macrophages within the epiphyseal lumen are involved in phagocytosis and, ultimately, in digestion of degenerate outer segments. They may perform a function similar to that of pigment epithelial cells of the lateral eye retina.
Effects of unilateral ovariectomy of the pregnant hamster on the remaining ovary
Authors: Chatterjee Amar , Greenwald Gilbert S. 
Published: February 2005

AbstractUnilateral ovariectomy of hamsters on day 1 of pregnancy resulted in an increase in weight of the remaining ovary by day 4, primarily by increasing the number of antral follicles. The ovulability of these follicles was tested by injecting 20 IU human chorionic gonadotropin (HCG) on day 12 of pregnancy. Following this treatment, the unilaterally ovariectomized animals ovulated 29.4 eggs whereas intact animals ovulated 16.6 eggs per ovary. In both instances, the number of antral follicles ovulated by HCG was between 40% and 50% of the number present. Luteal weight was unaltered by semispaying, indicating that the regulation of corpus luteum growth does not fit a negative feedback system.The ability of exogenous steroids to prevent ovarian compensation was assessed by injecting either progesterone (2 mg) or estradiol cyclopentylpropionate (1 μg) daily from days 8 to 11 of pregnancy. Either steroid injected into the semispayed hamsters prevented the expected increase in the remaining ovary in weight, follicular development and the ovulatory response to HCG. The same hormonal treatment of intact, pregnant animals slightly increased mean ovarian weight but did not affect follicular development.These results suggest that unilateral ovariectomy of the pregnant hamster, by decreasing peripheral level of ovarian steroids, partially reduces the inhibition of gonadotropin secretion and therefore leads to ovarian compensation.
Fine structure of ultimobranchial follicles in the thyroid gland of the rat
Authors: Nève Pierre , Wollman Seymour H. 
Published: February 2005

AbstractThe mature ultimobranchial follicle of the rat consists of two or more layers of cells (U cells) surrounding a lumen containing cell debris. The ultrastructure of the outer, or basal, U cell is characterized by the presence of half desmosomes on the basal plasma membrane and pinocytotic vesicles near it, by little granular reticulum but an abundance of free ribosomes, by clusters of fibrils connected to desmosomes and possibly free in the cytoplasm. The cell ages by accumulation of clusters of fibrils and it undergoes differentiation to form more apical U cells which contain fewer ribosomes and have fibrils dispersed in the cytoplasm. The apical U cell is desquamated into the lumen and ultimately becomes a carcass containing a dense matting of fibers and vacuoles containing a reticulated material resembling that in the lumen. U cells are observed associated with typical thyroid epithelium in the thyroid of the newborn rat in relatively large follicles containing colloid and desquamated cells. They also form rods of cells in the very young rat. Mixed follicles containing both U cells and typical thyroid epithelium occur at all ages.
Role of chondrocytes and hydrocortisone in resorption of proximal fragment of Meckel's cartilage: An in vitro and in vivo study
Authors: Melcher A. H. 
Published: February 2005

AbstractThe possibility that chondrocytes of the proximal fragment of Meckel's cartilage may participate in resorption of the extracellular substance of the cartilage and outlive its removal, has been investigated in vitro and in vivo. Mandibles from 18 day in utero mouse foetuses were cultured for 14 days on an an antibiotic‐free chemically defined medium. When tested histochemically for acid phosphatase heavy deposits of reaction product were evident in cells in areas where resorption appeared to be occurring. When maintained on medium containing 1.0 μg/ml hydrocortisone, groups of chondrocytes hypertrophied and were reactive for acid phosphatase, and this was accompanied by loss of intervening extracellular substance. These changes were intensified by increasing the oxygen tension of the environment and by further supplementing the medium with 1.0 μg/ml triiodothyronine. Chondrocytes in the vicinity of sites of resorption could incorporate 3H‐proline and 3H‐thymidine. In vivo, chondrocytes in the vicinity of resorbing areas in two to three day post‐partum animals were highly reactive for acid phosphatase, and could incorporate 3H‐thymidine, 3H‐proline, and 3H‐uridine. These observations have been interpreted to suggest that resorption of the proximal fragment of Meckel's cartilage is not necessarily accompanied by death of the chondrocytes, and that the chondrocytes may participate in removal of the extracellular substance. Furthermore, the response of the chondrocytes of Meckel's cartilage to hydrocortisone in vitro appears to differ from the response that has been reported to occur in a number of other cells in vitro.
Fine structure of sinusoids and portal capillaries in the liver of the adult sheep and the newborn lamb
Authors: Gemmell Robert T. , Heath Trevor 
Published: February 2005

AbstractIn adult sheep, the hepatic sinusoids have an endothelial lining with numerous gaps and fenestrae and are surrounded by a complete basal lamina. In newborn lambs, the sinusoids have a relatively thick endothelium with fewer gaps, and the space of Disse contains a partially formed endothelial basal lamina. In both adult sheep and lambs, perisinusoidal cells appear to form a network around the sinusoid. In portal areas, the endothelium of the smaller capillaries is fenestrated, but the larger capillaries have unfenestrated walls and are enmeshed in processes of pericytes. Projections of endothelial cells partially or completely occlude the lumen of some portal capillaries, and of a large majority of sinusoids scattered throughout the lobule.
A radiographic and histologic study of bone in the active and hibernating bat (Myotis lucifugus)
Authors: Whalen Joseph P. , Krook Lennart , Nunez Eladio A. 
Published: February 2005

AbstractA radiographic and histologic study of bat bones showed that there is a progressive loss of bone tissue during hibernation and abrupt reversal at arousal. Enhanced osteolysis accounted for the bone loss; osteoclasia was not observed.
Histological and radiographic study of the spheno‐occipital synchondrosis in cynomolgus monkeys, Macaque Irus
Authors: Adams D. , Harkness M. 
Published: February 2005

AbstractThe spheno‐occipital synchondroses of 20 cynomolgus monkeys have been examined histologically and radiographically. The findings by these two methods have been compared and correlated with the dental age of the monkeys. The radiographic examination was carried out on the isolated clivus region while serial sections were used for histological examination. Comparison of the synchondrosis by the two methods resulted in six disagreements when the synchondroses were classified as open, partly closed or closed. It is suggested that this difficulty is due to superimposition of shadows on the radiographs and small degrees of histological union not being recognised radiographically. It is further suggested that care should be taken in determining the age at closure when radiographs alone are used as the criterion. The dental age at initial closure appeared to vary widely in some cases occurring at an early mixed dentition stage and in others as late as the adolescent dentition. The closure of the synchondrosis was not related to the eruption time of any particular tooth. The pattern of closure did not conform to the classical type, i.e., from above downwards nor indeed was any consistent pattern revealed in either the radiographs or histological sections.
An analysis of Tomes' granular layer
Authors: Ten Cate A. R. 
Published: February 2005

AbstractSeventy‐five‐ to one‐hundred‐micron slices of undemineralized human teeth were examined by transmitted light, incident light and polarized light microscopy, to determine the nature of Tomes' granular layer in root dentine. Transmitted light examination showed that the granules occupied differing levels within the section. Incident light microscopy showed that the granules were true spaces and polarized light microscopy showed that fibre orientation was not the cause of the granular layer. When thin sections (1 μ‐0.75μ) of a tooth slice containing Tomes' granular layer were examined by light and electron microscopy no evidence of any spaces were found in the region where they had been demonstrated in the thick 75‐100 μ section. Looping of the terminal portions of the dentinal tubules was found. A model system has been used to show that sectioning of this loop region could produce a space visible in thick sections and corresponding to a granule of Tomes' layer. It is suggested that this looping of dentinal tubules in root dentine, and not in the dentine beneath enamel, is the result of different rates of dentine deposition in these two areas.
Prolonged survival of fragments of liver transplanted to an ectopic site in the mouse
Authors: Seller Mary J. 
Published: February 2005

AbstractFragments of liver were successfully transplanted to an ectopic site in the kidney cortex of the mouse. Survival was followed for varying periods of time. In some cases both syngeneic grafts and allogeneic grafts placed in mice previously made immunologically tolerant to the genotype of the donor were still alive one year later. However, extensive amounts of liver tissue would not survive, at the best, strips of about 30 cells thick grew, and various measures tried to promote an increase in this amount were not successful.
The specialized lingual papillae of Tachyglossus aculeatus I. Gross and light microscopic features
Authors: Doran G. A. , Baggett H. 
Published: February 2005

AbstractThe tongue of the echidna, Tachyglossus aculeatus is divided structurally and functionally into two distinct parts; a free rostral portion covered by stratified squamous epithelium bearing filiform papillae and a fixed caudal portion formed by a trapezoidal pad which bears highly specialized keratinized spines. These spines are similar in their morphology to the horny teeth of the living cyclostome Myxine and the hard keratin of rat filiform papillae.The gross and light microscopic structure of the lingual spines is described and their use as a masticatory organ (by occlusion with a similar set of spines on the palate) is discussed in relation to the animal's diet and method of feeding.