bluuebunny/crossref_metadata_2025_split huggingface dataset:
Microcorrosion casts of hamster luteal and follicular vasculature throughout the estrous cycle
Authors: Forsman Allan D. , McCormack John T. 
Published: February 2005

AbstractGolden hamster (Mesocricetus auratus) ovarian microcorrosion casts were studied as a model system to analyze angiogenesis that occurs in the corpus luteum (CL) during the estrous cycle. Growth of the vasculature in the hamster CL occurs rapidly with complete formation and subsequent degeneration occurring during the 4‐day estrous cycle. This study followed the growth of these vessels by casting the ovarian vasculature at 4‐hour intervals during the formation of the CL, viewing the casts on a Scanning Electron Microscope (SEM), and comparing the consecutive casts. This study revealed that the microvasculature of the CL forms rapidly from the vessels of the theca folliculi of newly ruptured follicles and that this growth is in an internal direction. This method of casting, when used in conjunction with the high magnification provided by the Hitachi field emission high resolution SEM, enabled us to analyze the growing tips of the vascular sprouts. The vasculature of the CL grows throughout day 1 and well into day 2 of the cycle. Flat veins, characteristic of the external suface of a mature CL, formed by the afternoon of day 2. Obvious degeneration of the vasculature of the CL took place throughout day 3. This study provided a detailed description of the angiogenesis that occurred throughout the rapid formation of the hamster CL and showed that this method produced casts of suitable quality for exprimental observations. © 1992 Wiley‐Liss, Inc.
Scanning and transmission electron microscopy of venous sphincters in the rat lung
Authors: Aharinejad S. , Böck P. , Lametschwandtner A. , Firbas W. 
Published: February 2005

AbstractThe rat pulmonary microvasculature was studied using scanning and transmission electron microscopy of vascular corrosion casts and tissue sections. Special emphasis was placed on small pulmonary venous vessels. The shape of vascular casts was analyzed and interpreted concerning the wall composition of corresponding vessels studied in tissue sections. On the casts of pulmonary venules and small pulmonary veins, narrow or wider annular constrictions were regularly observed. Within these constrictions, marks of circularly running grooves were seen as an additional structural detail, which obviously mimic impressions of single or grouped smooth muscle cells. The depth of the constrictions varies; it may be more or less pronounced, occasionally narrowing down the luminal diameter to approximately 50%. These constrictions are caused by muscular sphincters. In tissue sections of small pulmonary veins, sphincter regions were identified as abruptly appearing single or grouped true smooth muscle cells. Smooth muscle cells may be arranged side by side in a group or bundle or even staked in two or three layers. Between the sphincter regions, the venous wall consists merely of endothelium and an accompanying connective tissue layer. The smooth muscle cells of a sphincter are regularly positioned between endothelial layer and elastic lamina. The smooth muscle cells next to the endothelium form myoendothelial junctions. Autonomic nerves near the sphincters were never seen. The venous sphincters described are suggested to be effective devices involved in blood flow regulation. Blood‐borne substances or local tissue hormones might govern sphincter function. © 1992 Wiley‐Liss, Inc.
Immunocytochemical localization of rat intestinal 15 kDa protein, a member of cytoplasmic fatty acid‐binding proteins
Authors: Amano Osamu , Kanda Tatsuo , Ono Teruo , Iseki Shoichi 
Published: February 2005

AbstractRat intestinal 15 kDa protein (I‐15P) is a member of the family of cytoplasmic fatty acid‐binding proteins. Using a specific antiserum against I‐15P, we studied the tissue distribution and subcellular localization of this protein in the entire rat body. By immunoblot analysis of cytosolic proteins, I‐15P was detected not only in the distal portion of small intestine but also in the ovary and adrenal gland. Immunohistochemically, I‐15P was localized to the absorptive epithelial cells as well as a subpopulation of enterochromaffin cells in the intestine, the lutein cells in the ovary, and subpopulations of cortical cells in the adrenal gland. Furthermore, I‐15P‐like immunoreactivity was also demonstrated in the surface mucous cells of stomach and the granular convoluted tubule cells of submandibular gland. Immuno‐electron microscopy showed that the immunoreactivity was confined to the cytoplasmic matrix region, except in the enterochromaffin cells and granular convoluted tubule cells, where it was localized in the secretory granules. The present findings suggest that I‐15P plays a role in the cellular metabolism of steroids.© Willey‐Liss, Inc.
Adaptation of cancellous bone to aging and immobilization in growing rats
Authors: Chen Meng Meng , Jee Webster S. S. , Ke Hua Zhu , Lin Bai Yun , Li Qing Nan , Li Xiao Jian 
Published: February 2005

AbstractTwo‐and‐half month‐old female rats were subjected to right hindlimb immobilization or served as controls for 0, 1, 2, 8, 14, and 20 weeks. The right hindlimb was immobilized by bandaging it against the abdomen, thus unloading it. Cancellous bone histomorphometry was performed on microradiographs and double‐fluorescent labeled 20 μm sections of the distal femoral metaphyses. Primary spongiosa bone loss occurred rapidly by 2 weeks, and secondary spongiosa bone loss occurred rapidly by 8 weeks of immobilization, and then equilibrated at 60% less bone mass than age‐related controls. The negative bone balance induced by immobilization was caused by transient increase in bone resorption, decrease in bone formation, and longitudinal bone growth. The dynamic data of secondary spongiosa cancellous bone showed that percent eroded perimeter was transiently elevated by 55 to 82% between 1 and 8 weeks, percent labeled perimeter was transiently depressed by 32% to 50% between 1 and 14 weeks, mineral apposition rate was depressed by 23% and 19% at 1 and 2 weeks, and bone formation rate‐bone area referent was transiently depressed by 35% and 59% at 1 and 2 weeks. All the above parameters were at age‐related control levels by 20 weeks of immobilization. However, bone formation rate‐tissue area refent was depressed (‐65%) throughout the study. Immobilization depressed completely longitudinal bone growth by 2 weeks and remained so. Only 0.65 mm of new metaphysis was generated in the immobilized versus 2.1 mm in controls during the study period. The immobilization induced an early cancellous bone loss which equilibrated at a new steady state with less bone and a normal (age‐related control) bone turnover rate. When these findings were compared to an earlier study of 9‐month‐old virgin females subjected to right hindlimb immobilization up to 26 weeks, we found the adaptive responses of the cancellous bone were identical except that they occurred earlier and equilibrated sooner in younger rats.© Willey‐Liss, Inc.
Cystogenesis of the ovarian antral follicle of the rat: Ultrastructural changes and hormonal profile following the administration of dehydroepiandrosterone
Authors: Anderson Everett , Lee Mong‐Ting , Lee Gloria Y. 
Published: February 2005

AbstractImmature 27‐day‐old female Sprague‐Dawley rats were administered daily subcutaneous injections of dehydroepiandrosterone (DHEA, 5 mg/100 g BW) to induce the formation of ovarian follicular cysts. Groups of rats were killed on days 0, 10, 15, 20, 25, and 30. Ovaries from each group of rats were processed for light and electron microscopy and for follicular or cystic fluid hormone analysis. Normal antral follicle fluid, PMSG‐treated preovulatory follicular fluid, and cystic fluids were analyzed for progesterone (P), estrone (E1), estradiol (E2), testosterone (T), Δ4‐androstenedione (Δ4‐A), 5α‐dihydrotestosterone (DHT), luteinizing hormone (LH), follicle stimulating hormone (FSH), and prolactin (PRL).DHEA induced anovulation, acyclicity, and the formation of follicular cysts. In certain antral follicles, there was a dramatic increase in the quantities of smooth endoplasmic reticulum (SER) in the granulosa cells and many mitochondria had tubular cristae. Further depletion of granulosa cell number was associated with intense blebbing of the cytoplasm into the follicle antrum. Formation of the ovarian follicular cyst was completed when the entire cyst was lined by a single layer of transformed granulosa cells in contact via adhering, gap, and tight junctions. These cells had little cytoplasm, mitochondria with lamellar cristae, vast basal and apical bands of microfilaments, and an extensive array of smooth‐surfaced endocytotic invaginations on the basal plasma membrane. These endocytotic pits may subsequently form smooth‐surfaced vesicles and thereby serve as one mechanism for moving fluid from the ovarian interstitium into the cyst. Theca interna cells were rarely observed in the peripheral regions of the cyst. Abundant smooth muscle cells were located beneath the basement membrane of the epithelial cells comprising the cyst wall. These acquired morphological and physiological features may ensure persistence of the ovarian cyst and thus potentiate a chronic pathological condition.In this study it was also shown that progesterone, estrone, and estradiol as well as androgen concentration increased in the follicle after PMSG treatment. With DHEA treatment, the follicular cystic fluid concentrations of these steroids progressively increased to extremely high levels concurrent with the development of the follicular cysts. With respect to pituitary protein hormones, there was no appreciable difference in FSH after PMSG treatment, while there was a decrease in LH and an increase in PRL.The information reported in this and a previous study (Lee et al., Anat. Rec., 231:185–192, 1991) suggests that the ovarian cystic condition that developed after DHEA treatment in rats is associated with elevated levels of circulating serum prolactin and androgens, and extremely high concentrations of steroids as well as FSH and LH in the follicular/cystic fluid.© Willey‐Liss, Inc.
High‐resolution immunolocalization of osteopontin and osteocalcin in bone and cartilage during endochondral ossification in the chicken tibia
Authors: McKee M. D. , Glimcher M. J. , Nanci A. 
Published: February 2005

AbstractThe ultrastructural distribution of two noncollagenous proteins, osteopontin (OPN) and osteocalcin (OC), originally extracted from bone matrix and proposed to play an important role in bone formation, was examined in the matrices of bone and cartilage from embryonic and postnatal chicken tibial growth plates by high‐resolution immunocytochemistry using the colloidal gold technique. In bone, immunolabeling patterns using polyclonal antibodies against chicken OPN and OC were generally similar in that both showed an intense, but regionally variable, labeling of mineralized bone matrix and small mineralization loci dispersed throughout the osteoid and containing prominent condensed organic material. Unmineralized osteoid showed weak‐to‐moderate labeling. In the mineralized bone matrix proper, labeling was predominantly associated with amorphous, electron‐dense patches of organic material among the collagen fibrils. In growth plate cartilage, both proteins first appeared related to calcified cartilage in the hypertrophic zone, although the labeling patterns were somewhat different. For OPN, gold particles were mostly associated with an organic lamina limitans‐like density containing condensed, filamentous organic matrix at the periphery of small nodules and large masses of calcified cartilage, with additional moderate labeling throughout the interior of the calcified cartilage. For OC, labeling was observed over filamentous structures throughout the calcified cartilage matrix, with some, but less, labeling at the periphery. In the lowermost zones of the growth plate, the major reaction using both antibodies was found over a layer of dense, amorphous organic material at the periphery of the calcified cartilage at the future bone/calcified cartilage interface, a labeling pattern that persisted following bone deposition at these sites. OPN and to a lesser extent OC were also concentrated in cement (resting, reversal) lines. Throughout the bone and cartilage of the tibia, cells of both the osteoblastic and the osteoclastic lineages were found directly apposed to labeled surfaces and lamina limitans of organic matrix containing OPN and OC. In summary, it is concluded form the immunocytochemical data presented here that the association of OPN and OC with mineralized regions of the extracellular matrices of bone and cartilage and the accumulation of these proteins at tissue surfaces and interfaces are consistent with the hypotheses that they play a role in the extracellular mineralization process per se and/or that they may mediate cell adhesion and dynamics.© Willey‐Liss, Inc.
Architectural design, fiber‐type composition, and innervation of the rat rectus abdominis muscle
Authors: Hijikata Takao , Wakisaka Hitoshi , Yohro Takeshi 
Published: February 2005

AbstractThe rectus abdominis muscle is architecturally compartmentalized by tendinous intersections and is supplied by multiple thoracic nerves. In this study, the rectus abdominis of the rat has been qualitatively and quantitatively examined with regard to muscle dimensions, fiber organization, fiber‐type composition, and innervation. The muscle exhibits architectural heterogeneity and different patterns of innervation among its thoracic, epigastric, and hypogastric parts. The epigastric part, adherent to the rectus sheath via tendinous intersections, represents relatively simple design. It is formed by serially arranged compartments with shorter fibers, compared with the other parts. These compartments are segmentally supplied by thoracic nerves. The hypogastric part is more complex, forms an interdigitation of muscular slips, and has segmental distribution of thoracic nerves in mediolateral direction. The thoracic part much differs from the other parts. It has smaller cross‐sectional areas, compartments composed of abundant nonspanning fibers with intrafascicular termination, and non‐segmental distribution of thoracic nerves. In addition to these craniocaudal specializations among the three parts, the muscle exhibits mediolateral differences in fiber‐type composition. Slow‐twitch oxidative fibers are more densely distributed in the medial half region than the lateral, whereas fast‐twitch glycolytic fibers follow an inverse pattern. The mediolateral differences in fiber‐type composition as well as the craniocaudal specializations in architectural design and innervation imply regionally differentiated recruitments of the muscle in various behaviors.© Willey‐Liss, Inc.
Development of the liver in the chicken embryo. I. Hepatic cords and sinusoids
Authors: Wong Gene K. , Cavey Michael J. 
Published: February 2005

AbstractHemopoiesis in the liver of the chicken embryo begins on day 7 of incubation (Hamburger and Hamilton Stage 30) and peaks on day 14 (Stage 40). During this time frame, the differentiation of hepatic cells was examined by light microscopy, transmission and scanning electron microscopy, and morphometry. The avian liver is a closely packed mass of dendriform cords and discontinuous sinusoids. Hepatocytes are pyramidal in shape, and they ring the bile canaliculi which run through the centers of the cords. Semithin sections, made possible by infiltration and embedding in glycol methacrylate, were stained with hematoxylin and eosin to assess the general architecture of the organ and the lipid content of the hepatocytes and by the periodic acid‐Schiff reaction and hematoxylin to visualize the cytoplasmic stores of glycogen. The number of hepatocytes with demonstrable glycogen fluctuates erratically in early hemopoiesis, and the proportion of glycogen‐containing cells progressively increases as hemopoiesis climbs to a peak. Most differentiating hepatocytes are devoid of lipid droplets until Stages 39 and 40. From Stage 30 to 35, hepatocyte volume falls to its lowest value. Subsequently (Stages 36 to 40), cell volume increases and hepatocytes achieve a relatively uniform size. Ultrastructural changes in the differentiating hepatocytes, including alterations to the mitochondria, endoplasmic reticulum, and Golgi apparatus, are documented. These morphological and morphometric findings on the prehepatocyte population and hepatic vasculature cover 2 of the 3 elements deemed critical to hepatic hemopoiesis in many vertebrates.© Willey‐Liss, Inc.
Quantitative morphological analysis of the pituitary gland in protein‐calorie malnourished rats
Authors: Herbert Damon C. , Yashiro Takashi , Muraki Takeshi , Okano Toshiaki , Hattori Atsuhiko , Suzuki Takuro 
Published: February 2005

AbstractA quantitative analysis of the pituitary gland was conducted to ascertain the effects of protein‐calorie malnutrition on the morphology of the somatotrophs, gonadotrophs, thyrotrophs, and corticotrophs. Male rats were fed a low, 8% protein diet from 20 to 50 days of age, while their age‐matched controls were given a diet containing 27% protein. The hypophyses were then processed for light microscopic immunocytochemical staining using antibodies to growth hormone, the β subunits of luteinizing hormone and thyroid stimulating hormone, and adrenal corticotrophic hormone. The number of each cell type along with an evaluation of the cell, cytoplasmic, and nuclear areas was conducted using a computerized image analyzer. All of these parameters were reduced significantly in the somatotrophs as a result of the low protein diet, while in the gonadotrophs, the cell, cytoplasmic, and nuclear areas were similarly affected. Smaller cell number, cell area, and nuclear area were noted in the corticotrophs of the malnourished animals, while in the thyrotrophs, only the cell and nuclear areas were reduced. The data demonstrate that each pituitary cell type responds in a unique manner to undernutrition. © 1993 Wiley‐Liss, Inc.
Star volume in bone research. A histomorphometric analysis of trabecular bone structure using vertical sections
Authors: Vesterby Annie 
Published: February 2005

AbstractConventional bone histomorphometry performed on iliac crest biopsies does not generally provide unbiased stereological estimates of parameters related to bone structure due to the anisotropy of trabecular bone; this, however, can be obtained with vertical sections, which are anisotropic sections, in combination with an anisotropic test system. A practical procedure for obtaining vertical sections from bone is described. The new stereological parameter, the star volume, can provide an unbiased estimation of the absolute mean size of the marrow space and thus give an indirect estimate of the connectivity of trabecular bone structure. The marrow space star volume of vertebral bodies and iliac crest increases with age in both sexes demonstrating that the structural bone changes which occur with age is a topological one with changes in trabecular connectivity. The practical procedure including sampling efficiency for marrow space star volume is described. © 1993 Wiley‐Liss, Inc.
Observations by scanning electron microscopy of oviductal epithelial cells from cows at follicular and luteal phases
Authors: Abe Hiroyuki , Oikawa Taneaki 
Published: February 2005

AbstractThe luminal surfaces of epithelial cells in various regions of the bovine oviduct from cows, at the follicular and luteal phases of the estrous cycle, were examined by scanning electron microscopy. Marked cyclic changes were observed on the surface of the epithelium in the fimbriae and ampulla, but few changes were found in the isthmus and uterotubal junction. The epithelium of the fimbriae and ampulla of oviducts in the follicular phase were densely ciliated, and the cilia concealed the apical processes of the nonciliated cells. In the luteal phase, the nonciliated cells predominated in the epithelium and most of the ciliated cells were hidden by the bulbous processes of the nonciliated cells. The epithelium of the ampullar‐isthmic junction showed similar changes, but to a lesser extent. In the isthmus and at the utero‐tubal junction, the apical surfaces of the nonciliated cells were flat or gently rounded during the estrous cycle. Quantitative examinations by light microscopy showed that the mean percentage of ciliated cells significantly decreased in the fimbriae and ampulla at the luteal phase, but not in the other regions. The height of ciliated cells decreased dramatically in the fimbriae, ampulla, and ampullar‐isthmic junction at the luteal phase. By contrast, the height of nonciliated cells decreased significantly in the ampullar‐isthmic junction, isthmus, and utero‐tubal junction at the luteal phase, but not in the fimbriae and ampullae. The results demonstrate that there are regional variations and cellular differences in the cyclic changes associated with the oviductal epithelial cells in the cow. © 1993 Wiley‐Liss, Inc.
Immunolocalization of basal lamina components during development of chick otic and optic primordia
Authors: Hilfer S. Robert , Randolph Gwendalyn J. 
Published: February 2005

AbstractImmunolocalization of laminin, fibronectin, and type IV collagen was examined during early morphogenetic shape changes of the avian inner ear and eye. The ear was studied from formation of the otic placode to invagination of the otic pit and the eye from the optic vesicle stage to formation of an optic cup. Distribution and intensity of immunoreactivity were compared in the two organ primordia and in adjacent epithelial layers. Laminin formed a continuous layer at the basal surface of the otic ectoderm and adjacent neural tube at all stages. The basal surfaces of the optic and lens epithelia also were continuously covered with laminin throughout development. The otic placode became attached to the neural ectoderm through a single layer of fibronectin and collagen IV between the layers of laminin. The ring‐like attachment between the edges of the optic cup and lens primordium had the same structure. In addition, the central regions of the optic and lens primordia were attached by fibrils containing type IV collagen, whereas finer strands containing fibronectin and laminin also connected the otic epithelium and neural tube. The results are discussed in terms of models of invagination for the two primordia. © 1993 Wiley‐Liss, Inc.