bluuebunny/crossref_metadata_2025_split huggingface dataset:
Bronchoalveolar casting using formalin‐fixed canine lungs and a low viscosity silicone rubber
Authors: Nettum John A. 
Published: February 2005

AbstractA method for creating tough, flexible, bronchoalveolar casts from formalin‐fixed canine lung is described. A lung was washed using simple methods and fixed in 10% neutral‐buffered formalin. While still wet with formalin, an intact lobe was injected with silicone sealant, Silsastic 734 RTV (Room Temperature Vulcanizing), using a caulk gun. Following digestion with protease and corrosion with potassium hydroxide, a bronchoalveolar cast was recovered giving detail as shown using scanning electron microscopy or conveniently seen by stereo light microscopy. This method should be useful for micro‐anatomy studies of normal and diseased lungs. © 1993 Wiley‐Liss, Inc.
Development of innervation of skeletal muscle fibers in man: Relation to acetylcholine receptors
Authors: Hesselmans L. F. G. M. , Jennekens F. G. I. , Van Den Oord C. J. M. , Veldman H. , Vincent A. 
Published: February 2005

AbstractThe aim of this study was to establish the time scale of developmental changes in innervation of skeletal muscle fibers in man. Specimens of thigh and intercostal muscle from 19 embryos and 18 infants were examined with histological methods which enabled the discrimination between fetal (gamma) and adult (epsilon) types of acetylcholine receptors (AChRs).At 8 weeks of development, AChRs were distributed diffusely in the myotube membranes. Following onset of innervation in approximately the ninth week the length of the AChR positive area diminished and reached its shortest size at the sixteenth developmental week. At the sixteenth and eighteenth week some nerve terminals opposed the muscle membrane outside the AChR positive area. Decrease in the number of nerve terminals, strongly suggesting elimination of polyneuronal innervation, started in the sixteenth week and was completed in the twenty‐fifth week. This fetal (gamma) type of AChR could no longer be demonstrated after the thirty‐first week. The length of the end‐plates as determined by the presence of AChRs increased again in the last week before birth and reached a plateau size by the end of the first year after birth.It is concluded that in man the transition from poly‐ to mononeuronal innervation takes place between the sixteenth and twenty‐fifth weeks of development. The evidence available suggests that the retraction of nerve terminals is preceded by loss of AChRs from the muscle membrane facing the terminals. There is no relationship between retraction of nerve terminals and the switch from fetal to adult type of AChR. The size of the presynaptic apparatus changes little after the first year of life. © 1993 Wiley‐Liss, Inc.
A new model of vasculogenesis and angiogenesis in vitro as compared with vascular growth in the avian area vasculosa
Authors: Flamme Ingo , Baranowski Andreas , Risau Werner 
Published: February 2005

AbstractIn cultures of dissociated quail epiblast the basic constituents of the vascular system, blood cells and endothelial cells can be induced by basic fibroblast growth factor (Flamme and Risau, Development, 116:435–439, 1992). As we show here, in those cultures three types of vascular plexus differentiate spontaneously under different culture conditions: At the 3rd day a vascular plexus appears in situ closely resembling the vascular plexus of the quail area opaca vasculosa (vasculogenesis). Vascular sprouts are formed, extending long filopodia at their tips. Such filopodia are shown to build the first intervascular bridges in the growing vascular plexus of the area vasculosa at embryonic day 3. Connections of filopodia turn out to be precursors of new capillaries interconnecting pre‐existing blood vessels (angiogenesis). Two further types of in vitro capillary plexus differentiate in long term endothelial cell cultures derived from induced angioblasts. Whereas one closely resembles so‐called angiogenesis in vitro, the third type comprises mainly multinucleated giant endothelial cells lining loop like capillaries and represents a differentiation of aging endothelial cell culture. Thus, the present in vitro model is an approach to the sequence of angioblast induction, vasculogenesis, and angiogenesis. © 1993 Wiley‐Liss, Inc.
A scanning and transmission electron microscopic analysis of the cerebral aqueduct in the rabbit
Authors: Meller S. T. , Dennis B. J. 
Published: February 2005

AbstractAn examination of the surface of the cerebral aqueduct with the scanning electron microscope revealed that the walls of the cerebral aqueduct were so heavily ciliated that most of the ependymal surface was obscrued, yet certain specialized supreapendymal structures could be discerned lying on (or embedded within) this matt of cilia. These structures were determined by transmission electron microscopy and Golgi analysis to be either macrophages, supraependymal neurons, dendrites from medial periaqueductal gray neurons, or axons of unknown origin. Some axons, which were found to contain vesicles, appeared to make synaptic contacts with ependymal cells. Using the transmission electron microscope, the ependymal lining was found to consist of two different cell types: normal ependymal cells and tanycytes which have a long tapering basal process that was observed to contact blood vessels or, more rarely, seemed to terminate in relation to neuronal elements. While there have been previous reports on the structure of the third and lateral ventricles in other species, there are limited reports in the rabbit. The present report is not only the first description for the rabbit, but it is the first complete scanning and transmission electron microscopic analysis of the cerebral aqueduct in any species. © 1993 Wiley‐Liss, Inc.
Structure, innervation, and age‐associated changes of mouse forearm muscles
Authors: Carry Michael R. , Horan Steven E. , Reed Shelley M. , Farrell Robert V. 
Published: February 2005

AbstractIn spite of a decline in muscle strength with age, the cause of the overall decrease in motor performance in aged mammals, including rodents, is incompletely understood. To add clarity, the gross organization, innervation, histochemical fiber types, and age‐associated changes are described for mouse forearm muscles used in a variety of motor functions. The anterior (flexor) and posterior (extensor) forearm compartments have the same arrangement of muscles and gross pattern of innervation as the rat. Two primary histochemical fiber types, fast/oxidative/glycolytic (FOG) and fast/glycolytic (FG), with characteristic hitsochemical staining patterns were observed in all forearm muscles. Additionally, there was a small population of slow/oxidative (SO) fibers confined to the deep region of a single muscle, the flexor carpi ulnaris (FCU).Between 18 and 26 months the FCU muscle displayed fibers with morphological features distinct from earlier ages. Fibers displayed a greater variation in size, a loss of their uniform polygonal shape, and a dramatic increase in clumps of subsarcolemmal mitochondria, lysosomes, and lipofuscin granules. Many of the fibers had a distinctly atrophic, angular shape consistent with recent denervation. Morphometric analyses of the FCU's source of innervation, the ulnar nerve and one of its ventral roots (C8), were consistent with the denervation‐like changes in the muscle fibers. Although, there was no net loss of myelinated axons between 4 and 26 months of age, there was a significant increase in the density of degenerating cells in both the ulnar nerve and ventral root C8. © 1993 Wiley‐Liss, Inc.
Transport pathways for macromolecules in the aortic endothelium. II. The distribution analysis of plasmalemmal vesicles reconstructed by serial sections
Authors: Ogawa Kazushige , Taniguchi Kazuyuki 
Published: February 2005

AbstractThree‐dimensional organization of vesicles was examined to elucidate the transendothelial transport properties for macromolecules in rat aortic endothelium using ultrathin serial sections and horseradish peroxidase (HRP) as a tracer molecule. A total number of reconstructing vesicles was 1,298 in nine series electron micrographs, if each vesicular entity was counted as one regardless of composite number of vesicles. The vesicles could be classified into the following six types: HRP‐positive luminal, abluminal and intercellular invaginations; HRP‐positive channels; HRP‐positive and ‐negative vesicles. The vesicular invaginations and the channels occupied 97.8% and 0.9% of the total vesicles, whereas HRP‐positive and ‐negative free vesicles were found in 0.8% and 0.5%, respectively. The average numerical density of the luminal invagination was 41.1/μm2 and approximately equal to that of the abluminal invagination (42.0/μm2), whereas the frequency of the latter was 1.4 times higher than that of the former since the abluminal surface of the endothelium was more irregular to increase a surface area. Each endothelial region varied in the vesicular density and the peripheral region generally showed the higher density, although the transendothelial channels composed of vesicles were not always found in every peripheral region. These results suggest that the shuttle hypothesis is unsuitable to explain “vesicular transport” in the arterial endothelium as well as in the capillary endothelium and that the channels in the peripheral region mainly control transendothelial transport for macromolecules via vesicles. © 1993 Wiley‐Liss, Inc.
Modulation of the Golgi apparatus in Saccharomyces cerevisiae sec7 mutants as seen by three‐dimensional electron microscopy
Authors: Rambourg A. , Clermont Y. , Képès F. 
Published: February 2005

AbstractThe three‐dimensional configuration of the Golgi apparatus has been examined with the electron microscope in thick Golgi sections of Saccharomyces cerevisiae prepared from a wild‐type strain and from sec7 mutants maintained for various periods of time at the nonpermissive temperature of 37°C and then returned to the permissive temperature of 24°C. Reduced osmium postfixation of glutaraldehyde fixed specimens stained intensely the content of Golgi elements and thus facilitated their three‐dimensional characterization. In wild‐type S. cerevisiae, the Golgi elements usually appeared as isolated networks of membranous tubules dispersed throughout the cytoplasm. Along such networks, distensions filled with stained material were similar in size to nearby secretory granules, suggesting that the latter formed by fragmentation of the Golgi elements. In sec7 mutants maintained at 37°C in low (0.1%) glucose medium, secretion granules progressively decreased in number and soon disappeared. Concomitantly the networks of Golgi tubules increased in size and complexity, lost their distensions, and then transformed into flattened sacules forming stacks of up to seven or eight saccules that were similar to the Golgi stacks seen in mammalian cells. However in contrast to the latter, connections between the saccules were evident and Golgi‐associated small vesicles were generally absent. Following return to the permissive temperature (24°C), secretion granules reappeared, the Golgi stacks progressively decreased in size, and resumed their initial state of separated small tubular networks. Thus in sec7 mutant, grown at 37°C in low glucose medium, segregation of secretory granules is blocked. As a result, Golgi membranes accumulate to form a continuous system of stacked and interconnected saccules. © 1993 Wiley‐Liss, Inc.
Ultrastructure of lipid‐containing cells of the anterior pituitary gland of the domestic chicken, Gallus domesticus
Authors: Liu Raymond C. M. , Lea Robert W. , Sharp Peter J. , Maxwell Martin H. 
Published: February 2005

AbstractA combination of light and electron microscopy techniques was applied to characterize a luteinizing hormone (LH)‐gonadotroph‐like cell in the anterior pituitary gland of the adult domestic chicken. This cell type (mean ± sem, 91 ± 8 μm2) was larger than typical LH‐gonadotrophs (71 ± 5 μm2, P < 0.01) and seen in pituitary glands from adult males but not those from adult females of the same age. The ultrastructural features of these cells were similar to typical LH‐gnoadotrophs in the same section, except for the presence of large (1,126 ± 77 nm diameter), round, or polymorphic electron‐dense inclusions (14 ± 3 per cell) in the cisternae of the endoplasmic reticulum. When resin sections of anterior pituitary gland were stained with the vapours from the fixative osmium tetroxide and a solution of potassium ferricyanide, inclusions were found that appeared to be lipid in nature and were circumscribed by the cisternal membranes of the endoplasmic reticulum. These lipid inclusions were associated occasionally with acid phosphatase and lysosome‐like bodies. The cellular pigment, lipofuscin, considered to be a marker of aging, was absent from the anterior pituitary glands from these adult chickens. These observations suggest that the appearance of lipid in LH‐gonadotrophs is unlikely to be age‐related and an alternative explanation is discussed in relation to a sex difference in the LH response of adult chickens to gonadotrophin‐releasing hormone (GnRH). © 1993 Wiley‐Liss, Inc.
Spontaneous cortical granule release and alteration of zona pellucida properties during and after meiotic maturation of mouse oocytes
Authors: Okada Akiko , Inomata Kenichirou , Nagae Takeshi 
Published: February 2005

AbstractExocytosis of cortical granules (CGs) and the concomitant electron density changes of the zona pellucida (ZP) in the absence of sperm penetration were investigated in mouse oocytes processed with tannic acid containing fixation at various stages during and after maturation. After fusion of the CG membrane with the plasma membrane, the CG contents became very electron‐dense, due to tannic acid. CG material is seen to be made up of coarse granular structures which gradually change to fine amorphous structures, which accumulate within the developing perivitelline space (PVS).When the coarse CG material attaches to the ZP, small domains exhibiting higher electron density appeared, and the number of these domains gradually increased. Release of CG was observed from metaphase I through metaphase II. In metaphase I to immediately after ovulation, the higher electron density of ZP and CG release was restricted to the cortical area overlying the meiotic spindle. Finally, the CG‐free domain formed itself overlying the meiotic spindle as a result of CG release. However, in oviductal ova, CG release additionally occurred in the hemisphere opposite the spindle. At this stage the entire PVS was well developed and contained numerous fine electron‐dense materials. Moreover, the inner half of the ZP increased in electron density as well. This change in electron density of the ZP might be associated with released CG material.These results suggest that the “partial cortical reaction” may play an important role in conditioning the ZP prior to ZP reaction. © 1993 Wiley‐Liss, Inc.
Intense vascular sprouting from rat femoral vein induced by prostaglandins E1 and E2
Authors: Diaz‐Flores Lucio , Gutierrez Ricardo , Valladares Francisco , Varela Hilda , Perez Miguel 
Published: February 2005

AbstractThe formation of new capillaries from the rat femoral vein was specifically explored to assess whether venous vessels of this caliber may participate in the process of angiogenesis. Prostaglandins of the E series (PGE1 and PGE2) were administered into the soft connective tissue surrounding the rat femoral vessels as angiogenic inducers. In these conditions, between 2 and 7 days, a great number of new capillaries were observed in the media of the femoral vein, arising from the endothelial cells (EC) in the intima. The events of the capillary growth from the femoral vein included EC activation, local degradation of the basal membrane followed by migration and proliferation of EC, solid sprout formation with posterior canalization, development of a new basal membrane, and appearance of pericytes around the new capillary. Although numerous vascular buds were also observed arising from the small venules and capillaries in the periadventitial tissues, they were separated at first from those in the media of the femoral vein by the venous adventitia. Later, connections were observed between both newly formed microcirculations. The present study shows the capacity of PGE1 and PGE2 in the extravascular position of inducing capillary sprouting from veins. Furthermore, the observations provide greater evidence that vessels with characteristics similar to those of the rat femoral vein may contribute to angiogenesis, on occasion with an intense neovascularization. This fact may be of interest for the establishment of a functional circulation after angiogenesis by anastomoses of the new capillaries with those arising from pre‐existing vessels of greater caliber than the venules. © 1994 Wiley‐Liss, Inc.
Microcirculation of gills and accessory respiratory organs from the air‐breathing snakehead fish, Channa punctata, C. gachua, and C. marulius
Authors: Olson K. R. , Roy P. K. , Ghosh T. K. , Munshi J. S. D. 
Published: February 2005

AbstractSnakehead fish of the genus Channa have well‐developed air‐breathing organs (ABO) yet retain their gill arches for respiratory and non‐respiratory functions. Alterations in the macrocirculation accompany inclusion of the ABO and appear to enhance gas exchange efficiency (Munshi et al., 1994. Anat. Rec. 238:77–91). In the present study, the microcirculatory anatomy of gill and ABO from two facultative air‐breathing Channa, C. punctata and C. gachua, and one obligate air‐breather, C. marulius, were examined in detail using scanning electron microscopy (SEM) of vascular corrosion replicas and fixed whole‐sectioned tissue. The results show that the circulation in the filaments from the first, second, and third gill arches is similar to that found in water‐breathing teleosts. Fourth gill arch microcirculation of C. punctata is not different from the other three, whereas in C. marulius, it has been greatly modified into a network of low‐resistance vascular shunts, although remnants of an intralamellar filamental microcirculation remain. The vascular shunts are formed from extensions of afferent and efferent lamellar arterioles and the complete, or nearly complete, loss of a lamellar sinus. The vasculature of the ABO has been highly modified in all species into a coiled‐spiral capillary network with a constricted aperture guarding a dilated capillary dome at the epithelial surface. Microvilli are found congregated on the aperture endothelium of C. punctata but they are virtually absent from C. marulius endothelium. Less than 15% of the ABO capillary surface appears to face the epithelium and thereby contributes directly to gas exchange. These findings suggest that the microvascular modifications observed in Channa entail more than a simple increase in the contact surface between ABO vessels and air and they may serve other unknown physiological functions. © 1994 Wiley‐Liss, Inc.
Anatomical variations of the intrinsic muscles of the thumb
Authors: Jan Serge Van Sint , Rooze Marcel 
Published: February 2005

AbstractThe observation of thirty dissections of intrinsic muscles of the thumb provides some information differing from earlier anatomical studies. The abductor pollicis brevis and the opponens pollicis have been divided into muscles having six or two fascicles (or bellies), respectively. The adductor pollicis muscle has been separated into nine fascicles. Many variations were observed: absence of fascicles, presence of atrophied or supplementary fascicles, or fascicles with varying insertions sites. Neither head of the flexor pollicis brevis muscle seemed to have any fascicles. The distal insertion of its superficial head observed in this work is not in accordance with the usual description found in the literature. A new classification of the thenar muscles is presented based on the present observations. Many variations were observed: some fascicles were absent, others were supplementary or atrophied, and some had variable insertions. The importance and the individual variations of the fascicles are discussed. © 1994 Wiley‐Liss, Inc.
Domains of differential cell proliferation and formation of amnion folds in chick embryo ectoderm
Authors: Miller Sue Ann , Bresee Kimberley L. , Michaelson Cheryl L. , Tyrell Dean A. 
Published: February 2005

AbstractPatterns of cell proliferation in ectoderm epithelium that will form avian amnion correlate with morphogenesis, but not in an obvious pattern with respect to large‐scale folding. At sites where the pre‐axial amnion folds will first appear in 4‐ to 8‐somite embryos, patterns of proliferation do not separate into domains that presage location of the single pre‐axial fold that is commonly described in embryology texts. Instead, increased cell proliferation occurs in a significant, bilateral pattern. In stages with 13 to 27 somites, when lateral amnionic folds are prominent, five paraxial domains of cell proliferation correlate with morphology and show decreasing levels of cell proliferation with distance from the neural axis. Slowly growing areas surround rapidly growing areas and could assist buckling of epithelium by providing constraint on expansion of faster growing areas. Proliferation domains in ectoderm correlate with morphology and morphological events when localized changes in cell shape are lacking and suggest a role for differential cell proliferation in formation of large‐scale epithelial folds in early chick embryos. © 1994 Wiley‐Liss, Inc.
Initial vascularisation in the pig placenta: II. Demonstration of gland and areola‐gland subunits by histology and corrosion casts
Authors: Leiser Rudolf , Dantzer Vibeke 
Published: February 2005

AbstractTissues from 10 pregnant pigs between 9 1/2 and 43 days post coitum (p.c.) were prepared for histology and vascular corrosion casts to examine the vascularisation of the gland and areola‐gland subunits of the early pig placenta. The endometrial vascular networks shown by casts were equal in both glandular and interglandular fields from days 9 1/2 to 14–15 p.c. This represents a cyclic stage uninfluenced by the early implanting embryo on day 13 p.c. By day 15 p.c., the first areola formation was observed both histologically and on casts. The maternal areolar and glandular capillary network developed into a widely meshed loose type, in contrast to the interareolar type which had a dense and parallel architecture. In some cases extremely large, crooked, and highly anastomosed maternal capillaries developed between these two networks. This specialized transition is thought to form the base for the ring‐like seal formation (RSF) of the areolar periphery. A firm materno‐fetal anchor therefore “seals” the areola and its glandular secretory contents from its interareolar surroundings. Therefore, the glandular and maternal areolar vasculatures are clearly discernable from that of the fetal areolar vasculature. The former are associated with the known materno‐fetal substance transfer of the porcine areola‐gland subunit. This association, however, seems to remain unspecialized in early placentation, as only the regular roundish areola—not the irregular areola—can be distinctly detected. © 1994 Wiley‐Liss, Inc.