bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nascent muscle fiber appearance in overloaded chicken slow‐tonic muscle
Authors: Kennedy J. M. , Eisenberg B. R. , Reid S. K. , Sweeney L. J. , Zak R. 
Published: February 2005

AbstractThe application of a weight overload to the humerus of chickens induces a hypertrophy of anterior latissimus dorsi (ALD) muscle fibers. This growth is accompanied by a rapid and almost complete replacement of one slow‐tonic myosin isoform, SM‐1, by another slow‐tonic isoform, SM‐2. In addition, a population of small fibers appears mainly in extrafascicular spaces and, concurrently, three additional myosin bands are detected by gel electrophoresis. Five antibodies against myosin heavy chain (MHC) isoforms were selected as immunocytochemical probes to determine the cellular location and nature of these myosins. The antibodies react with ventricular, fast skeletal muscle and either SM‐1 or SM‐2, or both the slow‐tonic MHCs. The antifast and antiventricular antibodies react with myosin present in the 10‐day embryonic ALD muscle but do not react with myosin in posthatch ALD muscle. The small fibers in overloaded muscle contain a myosin isoform characteristically expressed during the embryonic stage of ALD muscle development and therefore are named nascent myofibers. Some of the nascent myofibers do not react with the antibody to both slow‐tonic MHCs, indicating the lack of the normal adult slow‐tonic myosins which are expressed in 10‐day embryos. In order to explore the origin of the nascent fibers, an electron microscopic study was performed. Stereological analysis of the existing fibers shows a stimulation of numbers and sizes of satellite cells. In addition, the volume occupied by nonmuscle and undifferentiated cells increases dramatically. Myotube formation with incipient myofibrils is seen in extrafascicular spaces. These data suggest that new muscle fiber formation accompanies hypertrophy in overloaded chicken ALD muscle, and the process may involve satellite cell migration.
Pulmonary intravascular macrophages in domestic animal species: Review of structural and functional properties
Authors: Winkler Gian C. 
Published: February 2005

AbstractIn dogs, laboratory animals, and man, the clearance of bacteria and participates from blood occurs predominantly in hepatic Kupffer cells and splenic macrophages. In contrast, removal of blood‐borne particulates in calves, sheep, goats, cats, and pigs occurs predominantly in pulmonary intravascular macrophages (PIMs). Review of recent studies indicates that PIMs are a resident cell population, junctionally adherent to the capillary endothelium of lungs and morphologically similar to hepatic Kupffer cells. PIMs are a pulmonary constituent of the mononuclear phagocyte system with respect to secretory, endocytic, and functional properties. Differentiated PIMs are rare in newborn pigs, and the majority of cells closely apposed to capillary endothelium consists of monocytes, which are occasionally in mitosis. In 7‐day‐old and older pigs, most cells apposed to capillary endothelium have characteristics of differentiated PIMs. This suggests a monocytic origin of PIMs in pigs. Perinatal colonization of lung capillaries by monocytes and their subsequent differentation into PIMs represent a component of postnatal lung development. Estimates of relative PIM numbers in ovine and porcine lung parenchyma suggest cell densities similar to that of rat hepatic Kupffer cells. Apart from phagocytic properties, PIMs participate in the removal and disintegration of aged and impaired blood cells. After phagocytic stimulation, isolated PIMs secrete oxygen radicals, which are essential for microbicidal function. Similarly, by secreting bioactive lipids, stimulated PIMs may contribute to regulation of pulmonary hemodynamics. After receiving minute amounts of bacterial endotoxin, pulmonary injury is pronounced in sheep, calves, pigs, and cats, but not in laboratory animals and dogs. This presumably is related to the secretion of bioactive lipids by PIMs.
Microcirculatory pathways in normal human spleen, demonstrated by scanning electron microscopy of corrosion casts
Authors: Schmidt E. E. , MacDonald I. C. , Groom A. C. 
Published: February 2005

AbstractConfusion regarding microcirculatory pathways in normal human spleen has arisen due to extrapolation from pathological material and from other mammalian spleens, not to mention difficulties in tracing intricate three‐dimensional routes from the study of thin sections or cut surfaces of tissue. We examined microcirculatory pathways in normal human spleens freshly obtained from organ transplant donors. A modified corrosion casting procedure was used to obtain an open view of vessels and their connections. Our results demonstrate: (1) „arteriolar‐capillary bundles”︁ within lymphatic nodules and extensive branching of arterioles; in the marginal zone (MZ); (2) the marginal sinus around lymphatic nodules; (3) the peri‐marginal cavernous sinus (PMCS) outside the MZ or immediately adjacent to the nodule itself; the PMCS receives flow via ellipsoid sheaths and MZ, or directly from arterial capillaries, and drains into venous sinuses; (4) fast pathways for flow into venous sinuses via ellipsoid sheaths; (5) arterial capillary terminations in the reticular meshwork of the red pulp or MZ („open”︁ circulation); direct connections to venous sinuses also occur („closed”︁ circulation), although rarely; and (6) numerous open‐ended venous sinuses in the MZ, allowing a large proportion of the splenic inflow to bypass the red cell filtration sites in the reticular meshwork and at venous sinus walls.
Cytoarchitecture of the fetal murine soleus muscle
Authors: Ontell Marcia , Bourke Dianna , Hughes Donna 
Published: February 2005

AbstractThe organogenesis of the soleus muscle of the 120 ReJ mouse (a mixed muscle, which in the adult contains approximately equal numbers of slow‐twitch oxidative and fast‐twitch oxidative‐glycolytic myofibers) was studied in spaced, serial transverse, and longitudinal sections of muscles of 14‐, 16‐, and 18‐day in utero and 1‐ and 5‐day postnatal mice. A discrete soleus muscle was distinguished by 14 days in utero. It consisted of groups of closely apposed primary myotubes displaying junctional complexes and a pleo‐morphic population of mononucleated cells. Between 14 and 16 days in utero there was little de novo myotube formation. At 16 days in utero, basal lamina surrounded groups of primary myotubes; and primitive motor endplates were found on these myotubes. At 18 days in utero, the basal‐lamina‐enclosed groups of primary myotubes were no longer present. At this stage, basal lamina surrounded clusters (consisting of one primary myotube and one or more secondary myotubes) or independent myotubes (single myotubes surrounded by their own basal lamina). Cluster formation and cluster dispersal occurred concurrently, beginning at 18 days in utero and extending until birth. At birth, there was still a substantial population of immature, secondary myotubes that interdigitated with larger, more mature primary myofibers. At this stage, intermuscular axons had begun to myelinate, and posteynaptic specialization of the motor endplates had begun. Cluster dispersal and myonuclear migration was completed during the first 5 days postnatally with the muscle taking on adult characteristics. Beginning at 16 days in utero and extending into the neonatal period, there was evidence of myotube death in the soleus muscle.
Morphometric analysis of the developing mouse soleus muscle
Authors: Ontell Marcia , Hughes Donna , Bourke Dianna 
Published: February 2005

AbstractThe pattern of organogenesis of the soleus muscle of the 129 ReJ mouse was evaluated quantitatively using spaced, serial, ultrathin sections and computer‐assisted morphometric analysis. Muscles from 14‐, 16‐, and 18‐day in utero mice and muscles of 1‐ and 5‐day‐old mice were analyzed to determine age‐related alterations in the maximal girth and length of the muscle, number of myotubes, cluster frequency, and the lengths and diameters of myotubes. Primary myotubes are found in the muscle at 14 days in utero. There is little de novo myotube formation between 14 and 16 days in utero, this interval being principally one of primary myotube growth and maturation. The interval between 16 and 18 days in utero is marked by extensive secondary myotube formation, with more myotubes being formed during this period than in any period studied. Morphometric data support the hypothesis that secondary generation myotubes use primary myotubes as a scaffold on which they are formed. Morphometric data also confirm the hypothesis that cluster formation and cluster dispersal occur concurrently during the prenatal period. Secondary myotubes continue to form until birth. At birth, the soleus muscle contains the adult number of myofibers. The first 5 days postnatally are marked by myofiber growth and maturation.
Light and electron microscopic observation on the cervical epithelium of the rabbit. I
Authors: Odor D. Louise , Blandau Richard J. 
Published: February 2005

AbstractThe light and electron microscopy of the cervical epithelium of ovulatory, estrous, and long‐term ovariectomized rabbits have been studied to determine what structural changes occur under different hormonal conditions. The percentage of nonciliated secretory cells is 49.6 in ovulatory, 43.6 in estrous, and 23.7 in long‐term ovariectomized rabbits, and of ciliated cells is 50.2 in ovulatory, 56.2 in estrous, and 76.3 in long‐term ovariectomized animals. The values for the ovulatory and estrous rabbits are significantly different at the P <0.05 level from those of the ovariectomized animals.In all 3 groups the general ultrastructure of the normal ciliated cells is similar. Interestingly, the Golgi complex is very prominent in all. Glycogen bodies occur frequently only in ciliated cells of ovariectomized and occasionally of estrous animals. Abnormalities in cil‐iation are quite common in the ovariectomized rabbits.The structure of the nonciliated secretory cells varies appreciably within and between the 3 groups. In these cells from well‐developed epithelia of certain ovulatory and estrous animals, the apical cytoplasm contains secretory granules of at least three types. In addition, very irregularly shaped, dense, perinuclear granules occur, which may be another type of secretory granule or lysosomes. As compared to ciliated cells, the secretory cells have less prominent Golgi complexes, more abundant bundles of intermediate filaments, a more extensive glycocalyx on their apical surface, and more heterochromatic nuclei. In comparison to the cells of well‐developed epithelia, the nonciliated cells of some other ovulatory and estrous rabbits are less well differentiated with fewer or no secretory granules and less well developed organelles. In the nonciliated cells of the long‐term ovariectomized rabbits, there are no secretory or dense perinuclear granules. There is a decrease in the number of organelles that are involved in secretion, in the size of the cells, and in the amount of nuclear euchromatin.
Formation and differentiation of extraembryonic mesoderm in the rhesus monkey
Authors: Enders Allen C. , King Barry F. 
Published: February 2005

AbstractDifferentiation of extraembryonic mesoderm in the rhesus monkey was studied from the epithelial penetration stage of implantation (stage 4) through the first week of postimplantation development (to stage 6). It was found that the first cells that appeared between the primitive endoderm (hypoblast) and trophoblast were separated from the latter by a basal lamina but appeared to be either loosely attached to the endoderm or to have been detached from it. Cells in this intermediate position differentiated cytologically into mesenchymal cells, which, by stage 5, had a distinctive intraendoplasmic reticulum marker. This differentiation occurred prior to the time at which the primitive streak could be recognized. By the time the primitive streak was readily discernible (stage 6), the extraembryonic mesoderm had already produced substantial extracellular matrix. The sequence of differentiation was repeated, with a 1‐ to 2‐day lag, in the secondary implantation site. No evidence of a contribution from cytotrophoblast or primitive streak to the extraembryonic mesoderm was found. It is concluded that the origin of the first extraembryonic mesoderm in the rhesus monkey is probably a two‐step process, with formation of a reticulum from primitive endoderm followed by differentiation in situ into mesenchymal cells. The first blood vessels formed also differentiated in situ from the extraembryonic mesenchymal cells. Primitive capillaries were identifiable as early as the 13th day of pregnancy.
Three‐dimensional network of cords: The main component of basement membranes
Authors: Inoue S. , Leblond C. P. 
Published: February 2005

AbstractBasement membranes were divided into two types: (1) thin basement membranes, such as those of the epidermis, trachea, jejunum, seminiferous tubule, and vas deferens of the rat, the ciliary process of the mouse, and the seminiferous tubule of the monkey, and (2) thick basement membranes, such as the lens capsule of the mouse and Reichert's membrane of the rat. High‐magnification electron microscopy was used to examine both types after fixation either in glutaraldehyde followed by postosmication or in potassium permanganate.The basic structure of thin and thick basement membranes was found to be a three‐dimensional network of irregular, fuzzy strands referred to as “cords”; the diameter of these cords was variable, but averaged 4 nm in all cases examined. The spaces separating the cords differed, however. In the lamina densa of thin basement membranes, the diameter of these spaces averaged about 14 nm in every case, whereas in the lamina lucida it ranged up to more than 40 nm. Intermediate values were recorded in thick basement membranes. Finally, the third, inconstant layer of thin basement membranes, pars fibroreticularis, was composed of discontinuous elements bound to the lamina densa: i.e., anchoring fibrils, microfibrils, or collagen fibrils. In particular, collagen fibrils were often surrounded by processes continuous with the lamina densa and like‐wise composed of a typical cord network. Finally, two features were encountered in every basement membrane: (1) a few cords were in continuity with a 1.4‐ to 3.2‐nm thick filament or showed such a filament within them; the filaments became numerous after treatment of the seminiferous tubule basement membrane with the proteolytic enzyme, plasmin, since cords decreased in thickness and could be reduced to a filament, and (2) at the cord surface, it was occasionally possible to see 4.5‐nm‐wide sets of two parallel lines, referred to as “double tracks”.On the basis of evidence that the filaments are type IV collagen molecules and the double tracks are polymerized heparan sulfate proteoglycan, it is proposed that cords are composed of an axial filament of type IV collagen to which are associated glycoprotein components (laminin, entactin, fibronectin) and the double tracks of the proteoglycan.
Ultrastructural observations on human sublingual gland
Authors: Riva Alessandro , Tandler Bernard , Riva Francesca Testa 
Published: February 2005

AbstractThat part of the human sublingual gland that corresponds in morphology to the conventional description of this organ presented in most histology texts (probably the major sublingual gland, in contradistinction to the aggregated small glands that compose the minor sublingual glands) was studied by electron microscopy. The gland is mixed, with slightly more mucous elements than seromucous ones. The mucous cells are arranged in tubules that usually are capped by seromucous demilunes. Seromucous cells also form occasional acini or may be scattered in the walls of the mucous tubules. The appearance of the mucous cells varies with the stage of the secretory cycle that they may be in. Their secretory droplets increase in number and progressively compress cytoplasmic organelles. Filamentous bodies also may be present. Based on secretory‐granule substructure, four different kinds of seromucous cells can be recognized; these may be a morphological expression of asynchronous synthesis of different secretory proteins. The duct system is an abbreviated one compared to the other major salivary glands. The first duct segments, into which the mucous tubules drain, are similar to intercalated ducts. Larger ducts contain mitochondria‐rich cells but lack the basal striations that characterize striated ducts. The paucity of typical striated ducts may be correlated with the elaboration of sodium‐rich saliva by the human sublingual gland.
Endocytosis in the epithelium of the mouse oviduct
Authors: Parr Earl L. , Tung Hai‐Nan , Parr Margaret B. 
Published: February 2005

AbstractWe studied the pathway of serum protein transport into the lumen of the mouse oviduct by localizing several tracer proteins in the oviduct after intravenous injection on days 1, 5, and 11 of pregnancy. Fluorescent proteins were observed in the lamina propria and in vesicles in the lumenal epithelial cells mainly in the preampulla segment on days 5 and 11 of pregnancy. In the isthmus, there was much less fluorescence in the lamina propria and no fluorescent vesicles in lumenal epithelial cells. This is similar to previous observations on day 1 and indicates that the uptake of serum proteins into lumenal epithelial cells in the preampulla is not limited to the time when embryos are present in the oviductal lumen. Horseradish peroxidase (HRP) was present in the lamina propria of the preampulla on days 1 and 5, but direct tracer movement into the oviductal lumen was blocked by the epithelial junctional complexes. Within the epithelial cells, HRP was localized in endocytic vesicles along the basolateral membrane, multivesicular bodies (mvb), elongated dense bodies below the nucleus (bdb), and many small vesicles near the apical surface of the cells. Ferritin was also used as a tracer and was observed in the same locations as HRP. Acid phosphatase in the epithelial cells of the preampulla on day 1 was localized in mvb and bdb, indicating that these structures are lysosomes. It appeared that HRP and ferritin followed two pathways after basolateral endocytosis by the epithelial cells in the preampulla: (1) they were transported to apical vesicles that may release their contents into the oviductal lumen, or (2) they were transported to lysosomes. These observations suggest the occurrence of an intracellular vesicular transport system in the preampulla for the transfer of serum proteins to the oviductal lumen in mice.
Splenic hemopoiesis of the platypus (Ornithorhynchus anatinus): Evidence of primary hemopoiesis in the spleen of a primitive mammal
Authors: Tanaka Yasukazu , Elshi Yoshinobu , Morris Bede 
Published: February 2005

AbstractThe generation of blood cells has been observed in the spleen and in the bone marrow of the platypus. Hemopoiesis was found to be far more active in the spleen than in the bone marrow judging by the number of proliferating hemopoietic elements within a unit area of tissue from each organ. Granulocytes, erythroblasts, and megakaryocytes, with the related immature forms for each cell line, were noted in the spleen. In contrast, there were very few examples of immature forms of these cell lines and a complete absence of mature megakaryocytes in the bone marrow. These findings suggest that the spleen is the primary hemopoietic organ in the platypus. Since the platypus is one of two species representing the most primitive existing mammals, it seems likely that the spleen may be the primary hemopoietic organ in mammalian evolution.
Electron microscopic study of the prenatal development of the thoracic aorta in the rat
Authors: Nakamura Hiroaki 
Published: February 2005

AbstractPrenatal development of the thoracic aorta of the rat during the period ranging from gestational days 12 to 21 was examined by transmission electron microscopic and morphometric studies. The process of wall formation occurred in four major phases. At phase I (gestational day 12), the dorsal aorta consists of an endothelium and loosely surrounding mesenchymal cells. Collagen fibrils and fine filamentous materials are sparsely present in the intercellular space. At phase II (days 13 to 16), the mesenchymal cells begin to differentiate to myoblasts, which have small clusters of myofilaments with dense bodies, rough endoplasmic reticulum, and a discontinuous basal lamina. The differentiating cells form a few compact cell layers around the endothelium. Elastic fibers first occur sparsely in juxtacellular spaces at days 13–14. The thickness of the aorta increases rapidly from 1–3 layers of cells at day 13 to 5–8 layers at day 17, leading to a maximum of 5–9 cell layers at day 20. The differentiation of myoblasts and elastogenesis are initiated in the inner layers, and later progress toward the outer layer of the aortic wall. At phase III (days 17 to 19), the myoblasts continue to develop into typical smooth muscle cells, and elastic fibers rapidly increase in both size and number. At phase IV (day 20 and later), smooth muscle cells have well‐developed myofilaments in the cell periphery, and rough endoplasmic reticulum and other organelles tend to accumulate in the apical portion of the cytoplasm. Elastic laminae appear in a few inner layers of the aortic wall.
Detection and quantification of CUPED, an estrogen‐dependent uterine protein, in uterine fluid and endometrial tissue of estrous and pregnant cats
Authors: Verhage Harold G. , Fazleabas Asgerally T. , Mavrogianis Patricia A. , Jaffe Randal C. 
Published: February 2005

AbstractUterine flushings, media from cultured endometrial explants, and endometrial tissue obtained from estrous and pregnant cats were analyzed for the presence of a previously characterized, high‐molecular‐weight, estrogen‐dependent glycoprotein (CUPED) by polyacrylamide‐gel electrophoresis, Western blots, radioimmunoassay, and immunocytochemistry. Elevated levels of CUPED were present within the flushings, media, and tissue of estrous and 3‐day postcoital animals. High levels of CUPED were also present in the flushings of 5‐day postcoital animals; but the ability of endometrial explants to synthesize CUPED during short‐term culture was greatly reduced, and only some of the endometrial glands contained CUPED secretory granules. CUPED was essentially nondetectable in the flushings, media, and tissues of animals pregnant for 7 or more days. Thus CUPED is present within the uterine lumen of the cycling cat at the time of sperm migration through the uterus and also for the first day or two that the developing blastocyst is present within the uterine lumen. The disappearance of CUPED from the tissue and flushings was correlated with the luteal production of progesterone.
Venous valve anatomy and morphometry: Studies on the duckling using vascular corrosion casting
Authors: Hossler Fred E. , West Russell F. 
Published: February 2005

AbstractThe anatomy and morphometry of venous values associated with the vasculature of the head of the duckling were studied using vascular corrosion casting and scanning electron microscopy. All valves encountered were bicuspid, and casts typically exhibited slight expansions at valve sinuses and deep slits at the sites of valve leaflets. The locations, numbers, and orientations of endothelial nuclei on all surfaces of the valves were clearly revealed by imprints in the casting resin. Endothelial cell densities were significantly higher on the surfaces of valve leaflets (about 10 cells/ 1,000 /μm2) than on other venous surfaces (about 7 cells/ 1,000 μm2). Endothelial nuclei on the medial surface of the valve leaflet were oriented parallel to the long axis of the vessel, whereas those on the lateral surface were oriented perpendicular to that axis. The close proximities of valves in some vessels and the presence of anomalies such as the sharing of leaflets by adjacent valves were readily demonstrated with the corrosion‐casting techniques. These methods provide a useful means for studying the fine, three‐dimensional details of venous valve anatomy.