bluuebunny/crossref_metadata_2025_split huggingface dataset:
Glycoprotein synthesis in the Golgi apparatus of spermatids during spermiogenesis of the rat
Authors: Clermont Yves , Tang X. M. 
Published: February 2005

AbstractDuring steps 1–7 of spermiogenesis the Golgi apparatus contributes to the formation of the acrosomic system which develops at the surface of the nucleus. Later, in step 8, the Golgi apparatus detaches from the acrosome and remains suspended in the elongated cytoplasm until it degenerates during step 16. Using 3H‐fucose as a tracer and the radioautographic technique, we observed that the Golgi apparatus incorporates the tracer and delivers the labeled glycoproteins to the developing acrosomic system during steps 1–7 of spermiogenesis, to multivesicular bodies during steps 1–9, and to the remaining cytoplasm and plasma membrane during steps 1–15. Throughout these steps of spermiogenesis the Golgi apparatus does not show major changes in structure; it is composed of a cortex made up of connected stacks of saccules and a medulla showing a loose aggregate of vesicular profiles. Glycoprotein synthesis in this Golgi apparatus, before and after it contributes lysosomal glycoproteins to the growing acrosomic system, was quantitatively assessed in electron microscope EM radioautographs of tissue sections from animals sacrificed at 1, 4, 8, and 24 h of 3H‐fucose injection. The incorporation of the labeled sugar was found to remain quantitatively similar during steps 1–15 of spermiogenesis, and therefore, no shift in glycoprotein synthesis took place following separation of the Golgi apparatus from the acrosomic system. Throughout these steps, fucose molecules are first incorporated in the cortex of the organelle and subsequently transported to the medulla, where they temporarily accumulate before being delivered, depending on the step of spermiogenesis, to the acrosomic system, to the multivesicular bodies, and also, presumably, to the plasma membrane.
Distribution of actin in isolated seminiferous epithelia and denuded tubule walls of the rat
Authors: Vogl A. W. , Soucy L. J. , Lew G. J. 
Published: February 2005

AbstractWe have studied the distribution of actin, using NBD‐phallacidin as a probe, in isolated sheets of seminiferous epithelia and denuded tubule walls of the rat. Sheets of intact seminiferous epithelia were separated from tubule walls using EDTA in PBS. The isolated epithelia and denuded tubule walls were fixed, mounted on slides, made permeable with cold acetone (−20°C), and then treated with NBDphallacidin.Actin was observed in myoid cells, in ectoplasmic specializations of Sertoli cells, and in Sertoli cell regions adjacent to tubulobulbar processes of late spermatids. In myoid cells, filament bundles course in circular and longitudinal directions relative to the tubule wall. In Sertoli cells viewed at an angle perpendicular to the epithelial base, actin filaments in ectoplasmic specializations adjacent to junctional complexes circumscribe the bases of the cells. Filament bundles in ectoplasmic specializations adjacent to germ cells closely follow the contour of and are arranged parallel to the long axis of the developing acrosome. Sertoli cell regions adjacent to tubulobulbar processes of late spermatids stain intensely with NBD‐phallacidin.Isolated seminiferous epithelia, combined with NBD‐phallacidin as a probe for actin, provide an ideal model system in which to study further the contractile properties of Sertoli cell ectoplasmic specializations and the possible involvement of these structures in events that occur during spermatogenesis.
Ultrastructure of the anterior buccal gland of the rat
Authors: Nicholas Suzanne , Redman Robert S. 
Published: February 2005

AbstractThe anterior buccal gland of the rat is a mucous salivary gland which develops as a branch of the main (Stensen's) duct of the serous parotid gland, a few mm from its oral orifice. The purpose of the present study was to further characterize the mature gland by means of electron microscopy and the histochemical demonstration of myoepithelial cells. The tubuloacini were found to have intercellular extensions (canaliculi) of the lumina, prominent Golgi complexes, and mucous secretory granules with a biphasic substructure. Discharge was by exocytosis of individual granules. The tubuloacini joined directly to striated ducts; no intercalated ducts were seen. First‐order excretory ducts had larger lumina and shorter columnar cells, with fewer mitochondria and basal infoldings, than the striated ducts. Myoepithelial cells invested the tubuloacini but not the ducts. The anterior buccal gland has several features that are unusual for a minor salivary gland of mucous type, and which are usually associated with serous glands such as the parotid. It should provide a particularly interesting model for investigating factors which control the differentiation of secretory and myoepithelial cells, and the glycosylation of polypeptides to form mucous secretory products.
Osteoblast and osteoclast precursors in primary cultures of calvarial bone cells
Authors: Burger Elisabeth H. , Boonekamp Piet M. , Nijweide Peter J. 
Published: February 2005

AbstractBone cells obtained by digestion of fetal mouse or chicken calvaria were tested for their ability to form or resorb bone in vitro. The isolated cells were precultured for 6 days and subsequently cocultured for 11 days with periosteum‐free noninvaded fetal mouse long bone rudiments. Bone formation and resorption during coculture were evaluated by histology and 45Ca release from prelabeled bones. The calvarial origin of cells in cocultures was traced by labeling the cells with 3H‐thymidine before coculture, followed by autoradiography.Many osteoblasts and osteoclasts as well as fibroblasts developed from mouse periosteal cells released late in the sequential digestion procedure and previously denoted as “osteoblastlike” (BL). No or few osteoblasts and osteoclasts but many fibroblasts developed from early released cell fractions that have previously been denoted as “osteoclastlike” (CL).Only osteoblasts and fibroblasts but not osteoclasts developed from chicken calvarial cell fractions. The osteoblasts developed primarily from cell fractions from the inner layer of the periosteum, previously denoted as “osteoblastlike” (OB). Cells obtained from the outer layer of the periosteum (PF) gave rise mainly to fibroblasts.These studies show that osteoblast and osteoclast precursor cells are maintained in monolayer cultures of periosteal cell fractions. However, sequential digestion of mouse calvaria does not lead to separation of the two types of bone cells. Rather, osteoclast and osteoblast precursors are released jointly, from the periosteal cell layers closest to the bone surface. In the chicken cell fractions osteoclast precursors are absent after preculture, resulting in a more homogeneous population of osteoblast and fibroblast but not osteoclast precursors.
Three‐dimensional observation of the intrahepatic lymphatics by scanning electron microscopy of corrosion casts
Authors: Yamamoto Kazuhide , Phillips M. James 
Published: February 2005

AbstractThe three‐dimensional arrangement of intrahepatic lymphatics was demonstrated in the rabbit liver by scanning electron microscopy of corrosion casts. These casts were prepared by injecting resin into the common bile duct at a pressure that caused resin to leak from the bile ducts in the small portal tracts and drain into the lymphatics. The lymphatic channels were composed of straight vessels and anastomosing short side branches. The anastomoses were especially rich at the bifurcation of the portal tracts and formed a network. The terminal branches were blind‐ended. Constrictions suggesting valves were occasionally observed.
Gap junctions in rat sublingual gland
Authors: Nagato Toshikazu , Tandler Bernard 
Published: February 2005

AbstractGap junctions were observed in rat sublingual gland to link serous cells to serous cells, mucous cells to mucous cells, and myoepithelial cells to myoepithelial cells. In addition to connecting homologous cells, gap junctions were present between conterminous serous and mucous cells. Since the rat sublingual gland is innervated solely by parasympathetic nerves, the presence of gap junctions between disparate secretory cell types raises the possibility that serous and mucous cells in this organ secrete simultaneously in response to parasympathetic stimulation.
Report of a rare human variation: Absence of the radial artery
Authors: Poteat William L. 
Published: February 2005

AbstractA case of unilateral absence of the radial artery is reported. The arterial system of the specimen was developmentally primitive with the anterior interosseous artery the chief blood supply to the forearm and hand. A “superficial ulnar artery” of small caliber supplemented the supply of the hand. Three large branches of the anterior interosseous artery supplied the hand with the lateral terminal branch replacing the radial artery distal to the wrist. The superficial palmar arch was formed by an anastomosis of the media and lateral terminal branches of the anterior interosseous artery. No deep palmar arch was present, but three palmar metacarpal arteries arose from a perforating artery which branched from a large dorsal branch of the anterior interosseous artery. The median artery was of small caliber and could not be traced beyond the midforearm. Based on this specimen and a review of other forearm and hand arterial variations, it is postulated that the ulnar artery may developmentally precede the median artery.
On nerves and teeth in the lower jaw of the cichlid Tilapia mariae
Authors: Holje L. , Hildebrand C. , Fried K. 
Published: February 2005

AbstractThe anatomy of the teeth and tooth‐related nerves in the lower jaw was examined in the cichlid Tilapia mariae. This was done in order to establish a basis for studies on dental neuroplasticity in a polyphyodont vertebrate. The region of interest was explored in specimens fixed by glutaraldehyde perfusion, and by using X‐ray photography, maceration, scanning electron microscopy, gross dissection, and light microscopic examination of serial sections. The results show that the lower jaw carries some 60–65 functional teeth. In addition, numerous replacement teeth and tooth germs in various stages of development are located in a cavity in the dentary bone. Numerous nerve bundles are present in immediate relation to the dental follicles of tooth germs. Unerupted teeth do not contain light‐microscopically discernible pulpal axons, but the pulps of functional teeth contain myelinated axons. Both perifollicular and pulpal nerve bundles derive from a nerve plexus, which is formed by branches from r. mandibularis trigemini. This nerve is easily accessible to experimental manipulation, where it courses through the adductor mandibulae muscular complex. Thus, the lower jaw of T. mariae seems to represent a suitable system for the study of tooth‐nerve interactions in a polyphyodont species.
Localized vascular regression during limb morphogenesis in the chicken embryo. I. Spatial and temporal changes in the vascular pattern
Authors: Feinberg Richard N. , Latker Carole H. , Beebe David C. 
Published: February 2005

AbstractMorphogenesis of the vertebrate limb bud depends upon reciprocal interactions between epithelial and mesenchymal tissues. A characteristic limb vascular pattern is essential for normal limb outgrowth. The vascular pattern in the distal portion of the wing bud was examined by ink injection and compared to the sites of cartilage differentiation, as indicated by [35S]‐incorporation.During development, avascular areas arose in three distinct locations within the vascularized mesoderm. These areas corresponded to the distal skeletal elements, referred to as digits 2, 3, and 4. Incorporation of radioactive sulfate was high in the avascular areas and low in the adjacent vascular tissue. Examination of autoradiographs of ink‐injected limbs suggested that the appearance of avascular regions preceded the accumulation of sulfated cartilage matrix. These results indicate that remodeling of the limb vasculature is related to the formation of the skeletal pattern.
Fiber composition of the rat sciatic nerve
Authors: Schmalbruch H. 
Published: February 2005

AbstractThe rat sciatic nerve originates from the spinal segments L4–L6. It is unifascicular at the trochanter; 5–7 mm distally, the nerve splits into two and then into four fascicles. The tibial portion gives rise to the tibial and the sural nerves, and the peroneal portion gives rise to the peroneal nerve and a cutaneous branch that perforates the lateral hamstring muscles to innervate the proximolateral face of the calf.The number and type of the axons in these branches were determined in light and electron micrographs of normal nerves, and after de‐efferentiation or sympathectomy. Deafferentiation was technically not feasible because spinal ganglia and ventral roots were supplied by the same vascular plexus.The tibial nerve contained 1,000 motor and 3,500 myelinated afferent axons, 3,700 sympathetic axons, and 5,400 unmyelinated afferent axons. The peronal nerve contained 600 motor and 1,300 myelinated afferent axons, 1,100 sympathetic axons and 3,000 unmyelinated afferent axons. The sural nerve contained 1,100 myelinated and 2,800 unmyelinated afferent axons; in addition, there were 1,500 unmyelinated sympathetic axons. The cutaneous branch consisted of 400 myelinated and 1,800 unmyelinated afferent axons. Thus, the entire sciatic nerve at midthigh is composed of about 27,000 axons; 6% are myelinated motor axons, 23% and 48% are myelinated and unmyelinated sensory axons, respectively, and 23% are unmyelinated sympathetic axons. The techniques used did not demonstrate sympathetic axons in the cutaneous branch and did not reveal the few motor axons contained in the sural nerve.
Root‐analogue versus crown‐analogue dentin: A radioautographic and ultrastructural investigation of the mouse incisor
Authors: Beertsen W. , Niehof A. 
Published: February 2005

AbstractThe present paper reports on differences between the root‐ and crown‐analogue dentin portions of the continuously growing mouse incisor. Conventional light microscopy and radioautography were used to study dentin formation and the uptake of [3H]‐proline and [3H]‐serine. It was found that, although the dentin apposition rate along the crown‐analogue part (covered by enamel) equalled or slightly exceeded that along the root‐analogue part (covered by cementum), the processing of predentin into dentin was considerably faster in the root aspect.Comparison of the two dentin portions at the ultrastructural level revealed that differences occurred in the morphology of the secretory granules of the odontoblast layer. Two types of granules were observed: those that were and those that were not loaded with electron‐dense particles of 30 nm diameter. While the former type was most frequent along the crown‐analogue aspect of the incisor, the latter type was particularly found along its root‐analogue aspect. This difference may reflect differences between the two dentin portions in the composition of the noncollagenous matrix.
A quantitative cytochemical analysis of large antral follicles in two types of rat polycystic ovaries
Authors: Zoller Lawrence C. , Axelson John F. 
Published: February 2005

AbstractOvaries from normal mature rats, rats injected with testosterone propionate (TP), and from aged rats were removed, and large antral follicles examined by quantitative cytochemical techniques in order to analyze possible enzymatic defects that relate to follicular steroidogenesis. The ovaries from the TP‐injected and the aged rats were polycystic. Lipid deposition was analyzed in frozen sections stained with Sudan black. A microdensitometer was used to measure Δ5‐3β ‐hydroxysteroid dehydrogenase (3βOHD) activity and G‐6‐PD type IH generation in the theca, and in peripheral region, antral region, and corona radiata of large antral follicles. 3βOHD is the enzyme that converts pregnenolone to progesterone. Type IH generation is related to the conversion of androstenedione to estradiol. Lipid droplet deposition was comparable in the three types of follicles. Compared to that in normal preovulatory follicles, 3βOHD activity was similar in identical regions of large antral follicles in TP‐injected rats, but less in the theca and peripheral region of the membrana granulosa of the aged rat. G‐6‐PD type IH generation was less in the peripheral region of large antral follicles of both TP‐injected and aged rats than in preovulatory follicles. Type IH generation was also less in the theca of TP‐injected rats than in the theca of normal rats. This study provides evidence that in spite of their normal appearance, large antral follicles in polycystic ovaries are not physiologically sound. Furthermore, the enzymatic disturbance appears to be different in different types of polycystic ovaries.
Isolation of murine thymic epithelium and an improved method for its propagation in vitro
Authors: Farr Andrew G. , Eisenhardt David J. , Anderson Susan K. 
Published: February 2005

AbstractA reliable and reproducible method for the isolation and propagation of thymic epithelial cells is described. Thymic epithelial cells from enzymatically dissociated thymus stroma are first enriched by separation on a discontinous Percoll density gradient. The cell fractions enriched for epithelial cells are then cultured with irradiated fibroblasts in Ham's F‐12 nutrient medium. Colonies of cells in these cultures contain keratin and exhibit morphologic characteristics of epithelial cells. When subcultured, the epithelial cells no longer require irradiated fibroblasts as filler cells. Some of the epithelial cells in vitro retain expression of class II (Ia) major histocompatibility antigens. The generation of defined cultures of thymic epithelial cells promises to be useful in defining their role in T cell differentiation.
Age associated increase of C cell follicles in guinea pig thyroid glands
Authors: Kameda Yoko 
Published: February 2005

AbstractThe effect of aging on the formation of C cell follicles was examined in the thyroid gland of guinea pigs at various ages ranging from 1 to 29 months. The C cell follicles were demonstrated with the immunoperoxidase methods by using anticalcitonin and antisomatostatin antisera and with PAS reaction. They were already detected in 1‐month‐old guinea pigs but in low number. Thyroid glands from 1‐ to 14‐month‐old animals contained only a small number of C cell follicles and did not reveal the age‐related increase. In aged guinea pigs (20‐ to 29‐month‐old), a dramatic increase of C cell follicles was found, about 13 times as high as the number of other age groups. The C cell follicles through all age groups were present in large clusters of C cells. In the aged guinea pigs, nodular large aggregates of C cells regarded as C cell hyperplasia occurred and numerous C cell follicles were formed in the large cell aggregates. Thus, the conspicuous increase of C cell follicles in aged animals was associated with a proliferative abnormality of C cells. The C cells forming follicles showed moderate to weak immunoreactivity for calcitonin, whereas they showed very intense immunoreactivity for somatostatin. In addition, the colloidlike and flocculent materials stored in the follioular lumina, which were consistently PAS‐positive, were weakly immunoreactive to somatostatin but nonreactive to calcitonin.
Localization of immunoreactive keratins in cyst epithelium of chick ultimobranchial glands
Authors: Kameda Yoko , Ito Miyoshi , Tagawa Takasuke 
Published: February 2005

AbstractThe cyst structures of chick ultimobranchial glands were studied by electron microscopy and immunocytochemistry to characterize the type of intermediate‐sized filaments present in the cells lining cyst lumina. Electron microscopy showed that the majority of the lumen‐bordering cells contained extensive mesh‐works of intermediate‐sized (7–11 nm) filaments, many of which were arranged in bundles. Apical regions of C cells directly bordering on cyst lumina were also filled with thinner (5–6 nm) filaments. Immunoperoxidase staining showed that the majority of cyst epithelial cells were stained intensely with anti‐keratin antiserum, but not with anti‐neurofilament antiserum, which is a specific marker for neuronal differentiation. The cyst epithelium also showed moderate‐to‐weak immunoreactivity for actin. Subsequently, the differentiation and maturation of cyst structures related to intermediate filament expression wore studied. In 18‐day‐old chick embryos, keratin immunoreactivity began to appear in the cell clusters destined to form cysts and in the primordial cysts with small cavities. At this time, fine networks of intermediate filaments were already detected in the cells lining the cystic cavities. At 1 day after hatching, the cysts became a consistent feature of ultimobranchial glands. Intermediate filaments associated in bundles were observed, and the intensity of immunostaining for keratins increased. Thereafter, with progressive enlargement of cysts, numbers of intermediate filaments and intensity of keratin immunoreactivity gradually increased with age. Thus, the data indicate that in cyst epithelium keratin filaments are highly organized and may confer the structural strength necessary for cells lining cyst lumina.
Cell size and shape changes in the myoepithelium of the mammary gland during differentiation
Authors: Emerman Joanne T. , Vogl A. Wayne 
Published: February 2005

AbstractWe have studied changes in myoepithelial cell size and shape during different stages of mouse mammary gland differentiation by using the fluorescent probe for actin NBD‐phallacidin. Pieces of mammary tissue were fixed, mounted on slides, permeabilized with cold acetone (−20°C), and then treated with nitrobenzoxadiazole‐phallacidin. Myoepithelial cells lining ducts of glands at all stages of development are spindle‐shaped structures oriented parallel to the long axis of the duct at the base of the luminal epithelium. In virgin animals, myoepithelial cells also occur as linear tracts oriented parallel to the long axis of small projections along the sides of ducts and terminal end buds. In early pregnancy, small stellate‐shaped cells begin to appear around presumptive secretory units. By late pregnancy, larger star‐shaped units of intense fluorescence appear at the base of alveoli. During lactation, both cell bodies and cell processes further enlarge as these interlacing stellate‐shaped cells encompass the expanded alveoli. In regressing glands, cell size decreases and the processes appear to retract. Although alveoli are virtually absent in the multipartate resting gland, myoepithelial cells remain around lateral buds of ducts. These myoepithelial cells have two distinct shapes: (1) small star‐shaped cells capping the buds and (2) spindle‐shaped cells oriented parallel to the long axis of the buds. A comparison of myoepithelial cell shape in virgin mice and nulliparous women indicates a more developed cell in the human gland at this stage of development. Intact segments of mammary gland combined with NBD‐phallacidin as a probe for actin provide an ideal system for future studies of the control of myoepithelial cell size and shape and their influence on cell functions.