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  • 1985-1989
  • 1975-1979  (553)
  • 1978  (553)
  • Cell & Developmental Biology  (553)
  • 1
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 190 (1978), S. 243-255 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The L-proline analog, L-azetidine-2-carboxylic acid, (LACA) was injected into embryonated eggs of the common fowl, Gallus domesticus at daily doses of 350 μg/egg on one or several days between 8 and 12 days of incubation. Treatment at nine-days of incubation preferentially retarded embryonic growth to the twelfth day but recovery of growth rate occurred by 15 days of incubation. Relationships between growth and LACA-inhibited aspects of collagenogenesis are discussed.The earliest aged embryos from which isolated stem cells from membrane bones will form secondary cartilage is ten days of incubation. Secondary chondro-genesis on the quadratojugal, a membrane bone of the skull, was inhibited by treatment of whole embryos with LACA at nine days of incubation but not by treatment at eight days. We concluded that an event involving collagen began at nine days of incubation, was blocked by LACA, and was part of the process of chondrogenic determination of these stem cells. Addition of LACA to the medium in which already determined stem cells from the quadratojugal were cultured prevented expression of the chondrogenic phenotype. This proline analog is then a useful probe for events relating both to determination and to expression of the differentiated state, and allows conclusions to be drawn regarding the role of col-lagenogenesis in these events.
    Additional Material: 12 Ill.
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  • 2
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 190 (1978), S. 285-298 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Ovarian cysts which developed spontaneously from the rete ovarii in the ovaries of guinea pigs have been examined in 1- and 2-year-old animals by scanning and transmission electron microscopy. Two cell types have been described, a tufted cell with numerous motile cilia and a non-tufted cell with a solitary cilium. While the non-tufted cell exhibited numerous smooth coated vesicles in its lateral and basal regions, no signs of secretion to the lumen of the cyst have been seen and occluding junctions have not been observed.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 190 (1978), S. 299-311 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Satellite cells exhibit a number of distinct morphological changes after denervation which appear to be a direct response to nerve section or altered functional state of the muscle fibers. These changes appear generally related to increased movement and overall activation of the cells. After longer periods of denervation many satellite cells appear to separate from their fibers and become free cells in the interstitial space. It is proposed that this mechanism provides a cellular source for the small-diameter, immature fibers dispersed throughout the muscle after two to three weeks. Although neo-formation of myofibers appears to be a feature of denervated growing muscle, an increase in total fiber population was not observed. It is suggested that in the absence of a viable nerve supply the new fibers degenerate.
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  • 4
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Snell adrenocortical tumor 494 was implanted into male Sprague-Dawley rats and recovered 7, 14, 21, 28 or 35 days following initial detection by palpation (7-10 days following transplantation). Electron microscopic, stereologic and biochemical analyses of the tumor were compared to adrenals of normal animals to serve as a baseline for further studies of the effects of chemotherapeutic agents on tumor cells. Tumor cells possessed oval or elongated mitochondrial profiles with tubular cristae, one or two very large (〉 5μ) lipid droplets, abundant ribosomes and coated vesicles, and sparse rough and smooth endoplasmic reticulum. Stereologic evaluation revealed that tumor lipid volume was 41% and mitochondrial volume 29% that of the normal adrenal controls. Tumor nuclei were 2.5 times larger than adrenocortical nuclei while cellular volumes were similar. On a net weight basis, tumor cholesterol was 55%, cholesterol ester 2.2%, and lipid phosphate 25% of respective mean values for normal adrenal glands. The tumor cholesterol: cholesterol ester ratio progressively decreased with time, but remained 18-fold greater than the normal adrenal. Plasma corticosterone levels in tumor-bearing rats were elevated 3-fold by 14 days after initial detection. The adrenals of the tumor-bearing host exhibited marked involution, the extent of which was directly related to tumor size.
    Additional Material: 3 Ill.
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  • 5
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Large MtTW15 pituitary tumors produced 200- to 800-fold elevations in serum growth hormone (GH) and prolactin (PRL) levels. Female tumor hosts showed doubling in body weight, milk secretion, and a 2-fold hepatosplenomegaly. Pituitaries of host animals were reduced by about 50% in both weight and concentrations of GH and PRL. Large tumors were well-encapsulated, multinodular and showed variable amounts of necrosis and hemorrhage. Cytofluorometric analysis revealed a range of 100-fold in nuclear DNA content of tumor parenchymal cells which were chromophobic, pleomorphic and frequently mitotic. Concentrations of hormones in tumors were less than in normal pituitaries and highly variable with the ratio of GH/PRL ranging up to 30-fold within the same tumor. Immunostaining and linear scanning quantitation showed that about 50% of the tumor cells contained immunodetectable hormones. Comparison of immunostained adjacent sections showed that hormone-containing tumor cells were pleomorphic, unequally distributed within nodules, lacking in distinctive identifying morphological characteristics and that they contained GH or PRL but not both hormones simultaneously. Collectively our results show that large MtTW15 tumors are comprised of a markedly heterogeneous population of tumor cells and they suggest that the hormone-containing cells are monohormonal secreting tumor cells which can produce GH or PRL but not both hormones.
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  • 6
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 190 (1978), S. 795-809 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The gross morphology of the vas deferens of the rat and the changes that occur along its length are reported. It is shown that the organ can be divided into proximal, distal and terminal portions. Each portion is histologically unique and is situated in a different part of the body. The differences are discussed in relation to the function of the organ and their possible role in the consequences of vasectomy.
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  • 7
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 190 (1978), S. 811-826 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Heavy meromyosin (HMM) labeling was used to identify the nature of the filaments which form bundles in the cytoplasm of the pericytes in brain tissue. Rat brain tissue pieces were incubated in glycerol solutions at 4°, and then transferred into buffer (pH 7.0), (1) without HMM, (2) with HMM, (3) with HMM + 5 mM ATP, and (4) with HMM + 2.5 mM Na+ pyrophosphate. In pericytes from untreated tissue, smooth-surfaced microfilaments, averaging 6 nm in diameter, appear to branch and anastomose and to anchor on the plasma membrane. After exposure to HMM, the number and the density of the microfilaments are strikingly increased. These tightly-packed microfilaments are now heavily coated with exogenous HMM thus increasing in width to 18-20 mm. They intertwine in closely-woven networks. After incubation in HMM solutions containing ATP or Na+ prophosphate, they are no longer coated with thick sidearms. It can thus be concluded that these microfilaments are of actin-like nature. In addition, after incubation in ATP, they are intermingled with, and converge onto the surfaces of, thick, tapered filaments, which we have tentatively identified as of myosin-like nature. Thus, it appears that certain of the major elements necessary for contraction are present in brain pericytes.
    Additional Material: 10 Ill.
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  • 8
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 192 (1978), S. 19-39 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: A light and transmission electron microscopic study was performed on 67 ductus arteriosus (DA) specimens from rabbits (31 days normal gestation period) ranging in age from 21 days of gestation to 4 days after birth. Some fetuses were permitted to breath before sampling, while others were not. The aorta and pulmonary trunk served as controls. The objectives of the study were to identify the earliest cellular alterations leading to closure of the DA, to study in detail the sequence of cellular changes in closure of the DA, and to correlate these observations with what is known about the physiological factors involved in closure of the DA. Changes in the architecture of the DA wall were seen as early as on the twenty-sixth day of gestation and involved the appearance of increased numbers of radially or longitudinally reoriented smooth muscle cells in the intima and fragmentation of the internal elastic lamina. The progress of these changes continued and intensified until the end of gestation. At that stage the inner one-half of the medial smooth muscle cells was reoriented, and the lumen was significantly reduced by a greatly expanded intima which often contained many intercellular “ghost bodies.” Very few mitoses were seen during DA closure, especially during 29 to 31 days of gestation. It is concluded that cellular changes involved in closure of the DA of the rabbit fetus begin far in advance of birth and breathing. These cellular changes are highly analogous to those which occur in the early pathogenesis of arterial intimal fibromuscular lesions. Closure of the DA, therefore, seems to afford an excellent, natural model for study of key cellular events involved in the production of arterial fibromuscular lesions.
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  • 9
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 192 (1978), S. 59-71 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The majority of human cardiac glands that lie immediately distal to the termination of esophageal epithelium are compound or branched tubular glands. They empty into overlying gastric pits. The glands of this region are often organized into lobule-like complexes by the surrounding connective tissue of the lamina propria. The secretory tubules contain mucous cells, parie-tal cells and endocrine cells. The mucous cell is the most common cell type observed and appears to comprise two populations. The majority are pyramidal in shape and show numerous spherical, electron-dense secretory granules. Profiles of rough endoplasmic reticulum are observed scattered throughout the cytoplasm and Golgi complexes occupy a supranuclear position in relation to forming secretory granules. Morphologically this cell type appears similar to the mucous neck cell of the fundus. Secretory granules of a second mucous cell type are mottled in appearance and show an area of increased electron density near the limiting membrane. Parietal cells are observed and appear identical to those in the fundus. The large number of endocrine cells present raises questions concerning the traditional concept of the function of these particular glands.
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  • 10
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
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  • 11
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 192 (1978), S. 215-224 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The role of biogenic amines in the activation of thyroid follicu-lar cells by thyrotropin (TSH) was studied. 5-hydroxytryptamine (5-HT) was chosen as the amine to study and apical pseudopod formation, assessed by scanning electron microscopy, was used as the index of follicular cell activation. All experiments were done on dogs. TSH and 5-HT were both potent inducers of pseudopod formation. The action of TSH but not that of 5-HT was antagonized by the amine depleting drug reserpine. Reserpine depleted the thyroid of 5-HT in newborn, adolescent, and adult dogs. It is concluded that one or more biogenic amines, such as 5-HT, are probably involved in follicular cell activation by TSH.
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  • 12
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 192 (1978), S. 235-244 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The ability of the mammary gland to take up and organically bind radioiodide was studied in non-pregnant, pregnant, and lactating rats. Autoradiography was used to determine whether duct cells or alveolar cells are responsible for iodination in the rat mammary gland. Iodination was not detected in mammary glands from non-pregnant rats, but occurred late in the twelfth day of gestation and continued throughout pregnancy and lactation. Protein-containing vacuoles in alveolar cells and casein-like proteins in milk were the major sites where iodination occurred within the gland. Milk proteins in the lumens of ductules adjacent to alveoli were also iodinated. In contrast, ducts, myoepithelial cells, fat cells, blood vessels and other histological components of the gland did not show iodinating capability. Cytochemistry was also used to identify endogenous mammary peroxidase activity in the same glands, and it was found that the presence and location of this enzyme was correlated with the ability to iodinate.
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  • 13
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 191 (1978), S. 371-376 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Satellite cells in rat muscles were studied by freeze-fracturing. They were found not to be fusiform but to have several narrow projections embedded in grooves of the muscle fibre membrane. Short projections of the muscle fibre covering the outer face of the satellite cells were observed as well. In the P-face of the cell membrane of satellite cells, membrane particles and caveolae were less frequently seen than in the P-face of the muscle membrane. Thus the surface of the satellite cells looked more smooth than that of the muscle fibres. Junctions between muscle fibre and satellite cell were not found. The presence of cytoplasmic extensions of satellite cells may suggest that these cells are motile.
    Additional Material: 5 Ill.
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  • 14
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The intrahepatic distribution of nerves in the rat was studied using neurohistochemical and electron microscopic methods. Innervation was restricted primarily to vessels in the portal space and hilus. Both adrenergic and cholinergic fibers were observed in the adventitia of hepatic arteries, and to a lesser extent adjacent to portal veins. Some of the cholinergic fibers, however, were not contiguous with the vasculature. Near the hilus many of these fibers were associated with ganglia while peripherally some coursed into the immediately adjacent parenchyma where end bulbs abutted on hepatocytes. Ultrastructurally, scattered small nerves, devoid of neurolemma, were found contiguous with the portal lamina of hepatocytes. Nerve fibers deeper within the lobule were not seen but numerous gap junctions were observed between contiguous hepatocytes. Central and sublobular hepatic veins lacked innervation but adrenergic nerves were demonstrated in the walls of larger hepatic veins. Innervation of the biliary system was sparse. While nerves were interposed between vessels and bile ducts, such nerves tended to be associated more closely with the vasculature.
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  • 15
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 191 (1978), S. 391-395 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The growth of the pelvic fin bud has been studied with the SEM along with the characteristics of the pseudoapical epidermal ridge which occupies the free margin of the bud. SEM revealed fluffy protuberances in many of the epidermal cells, distinguishing the fin bud territory from adjacent areas. When the pseudoapical ridge appears, all the cells show this feature but their relative number decreases and these cells, termed the “tassel cells,” are finally restricted to the base of the fin bud. This particular surface structure of the superficial cells may be unique to the fish, since it has not been heretofore reported in SEM studies of tetrapod limb bud.
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  • 16
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: White adipose tissue was obtained from the mesentery, epididymis, omentum and subcutis of rats which were fed, fasted or fasted and then refed. Tissue samples were prepared using the glyoxylic acid method to detect adrenergic nerves by fluorescence histochemistry. Other tissue samples were fixed with an aldehyde solution containing sodium molybdate which is specific forcatecholamine granules in nerve terminals. Thin and serial thick sections (0.25-0.5μm) were viewed with a conventional electron microscope and with the high voltage electron microscope. With fluorescence microscopy it was found that most of the blood vessels except veins and venules were richly innervated. The most extensive branching of nerves down to the capillary level was found in the mesentery and epididymal fat of fasted-refed rats. Relatively few adipocytes appeared to be innervated. With electron microscopy, nerve terminals were found distributed with most blood vessels including capillaries, and with some adipocytes. Only 2-3% of all adipocytes were innervated by adrenergic nerves. It is suggested that in the adipose tissue sites studied the major adrenergic innervation is mainly for the supply of blood vessels.
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  • 17
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 192 (1978), S. 277-287 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The ultrastructural changes in hepatocytes of rats subjected to selective biliary obstruction (SBO), wherein the biliary system draining approximately two-thirds of the liver is obstructed, were evaluated by quantitative electron microscopy or stereology. The remaining unobstructed portion of the organ compensates for this loss of bile secretion by functioning in a hyper-secretory mode. This animal model permits the comparison of hepatocellular fine structure associated with the conditions of nonsecretion and hypersecre-tion of bile with that found in normal secreting sham-operated rats. Since recent evidence suggests the presence of lobular gradients in hepatic structure and function, both centrolobular and periportal hepatocytes were examined. The low incidence of Golgi membrane profiles in high magnification electron micrographs results in a low confidence level of sampling and, thus, necessitates the application of a novel parameter for estimating the amount of Golgi complex, i.e., the Golgi-rich area.For the most part, the lobular variation in hepatic fine structure in the sham-operated animals was similar to that described by Loud ('68). However, the periportal parenchyma contained approximately twice the volume of Golgi-rich area as the centrolobular tissue. The amount of cytoplasmic lipid increased significantly in the SBO unobstructed lobes, although there were few or no changes in the other intracellular organelles or inclusions except those related to the Golgi complex. The volume of Golgi-rich area increased significantly in the centrolobular tissue of the SBO unobstructed (hypersecretory) lobes to the extent that both intralobular zones contained similar amounts of this component. These data suggest that the Golgi complex is a dynamic unit which responds to changes in hepatocellular activity and may be involved in bile secretion.
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  • 18
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 192 (1978), S. 289-295 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The tail bud was completely extirpated down to the yolk from 65 embryos at stages 13-17 to determine whether the posterior part of the noto-chord originates from the tail bud or from a more anterior region (i.e., prospective notochordal region). About 40% of the 44 surviving embryos developed near-normal tails, con̈taining a localized defective region beginning near the base of the tail and extending a short distance posteriorly, about 15% developed truncated, cone-shaped tails, containing a defective region beginning near the base of the tail and extending towards the tip, and about 45% developed short, ventral tail remnants, containing a localized defective region beginning near the base of the tail and extending a short distance posteriorly. The tail was absent in only one embryo. These differences were probably due primarily to variation in the amount of healing and regeneration that occurred, and were independent of the stage at which the operation took place. The tail region has a tremendous capacity for regeneration since a near-normal tail frequently developed. The location of the beginning of the defective region near the base of the tail suggests that the tail bud primarily gives rise to tail structures. All embryos had neural tube defects, about 30% developed large, midline somites within the defective region, and about 25% developed an ourenteric outgrowth. The notochord was always normal within the defective region. These results are consistent with the view that the tail bud contributes cells to the posterior part of the neural tube, but not to the notochord.
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  • 19
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 192 (1978), S. 297-303 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Freeze-fracture of rat gastric mucosa revealed a specific set of intramembranous particles in the plasma membrane of the parietal cells. The particles were small and of square shape and formed orthogonal arrays in the P-face with corresponding orthogonal arrays of pits in the E-face. Arrays, scattered among usual globular particles, were particularly numerous at the basal pole of the cell and less concentrated on the lateral side. They were not present in the apical microvillar membrane nor in the membranes of intracellular tubulovesicles. As in other cell types in which similar arrays were described previously (e.g., astrocytes, “light” cells of the kidney collecting tubule), their presence in parietal cell membranes suggest some specialized function of these membranes not shared by plasma membranes showing only a population of globular particles. This function has yet to be identified.
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  • 20
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 192 (1978), S. 305-317 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: In an attempt to determine the pattern of collagen phagocy-tosis by fibroblasts in the periodontal ligament, a stereologic investigation of the mesial root of the maxillary first molar of the rat was undertaken. The distribution of fibroblasts containing intracellular collagen fibrils was studied at the electron microscope level in the periodontal ligament along resorbing and non-resorbing surfaces of the alveolar wall. It appeared that fibroblasts with collagen-containing vacuoles were more or less randomly distributed across the width of the periodontal ligament. No major differences were observed among the alveolar, cemental and intermediate zones of the ligament. However, local variations in the occurrence of cells containing intracellular collagen fibrils may occur. A relatively high concentration of ingested collagen fibrils was seen in fibroblasts located in the direct vicinity of osteoclasts, but not in the vicinity of osteoblasts. These observations suggest that remodelling of collagen is even-ly distributed throughout the ligament, but may be influenced by local circumstances, such as the occurrence of bone resorption.
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  • 21
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    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 191 (1978), S. 479-486 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Circadian rhythms in DNA synthesis are described for the tongue epithelium, five different regions of the alimentary canal (gut) -esophagus, stomach, duodenum, jejunum and rectum- and bone marrow in a group of BDF1 male mice. A circadian rhythm is also described for the mitotic index in the corneal epithelium in the same mice. The data document for the first time in the same animals the dramatic variation in cell division encountered from one region of the gut to another. This variation is seen in the amplitudes of the rhythms as well as in the over-all 24-hour means. On the contrary, the phasings of the rhythms in the different regions of the gut are remarkably similar. In this study, where the mice were standardized to 12 hours of light (0600-1800) alternating with 12 hours of darkness, the peak of the DNA-synthesis rhythm occurred around the time of transition from dark to light, and the trough around the time of transition from light to dark. The implications of these findings, and those of others, to the study of cell kinetics and to cancer chemotherapy are discussed.
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  • 22
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The otic placode takes its origin from surface ectoderm. Prior to the arrival of neural crest cells, surface epithelial cells adjacent to the neural folds are squamous in shape and synthesize primarily interstitial bodies. However, by 26 hours of development, neural crest cells, using the undersurface of the epithelium as a substratum, migrate away from the neural tube. Cells of surface epithelium above the neural crest cells assume a columnar shape, and the amount of intercellular space between adjacent epithelial cells is consequently reduced. Placode cells show extensive interdigitation apically as they pseudostratify and invaginate, while it appears that many of the basal cells contribute components to the underlying extracellular matrix. This extracellular matrix interface between surface epithelium and neural crest cells is distinctly fibrillar and less granular than that found between ordinary head ectoderm and primary mesenchymal cells. Just prior to complete invagination as an otocyst, otic placode cells in a region near the ventrolateral wall of the hindbrain extend cell processes through discontinuities in the basal lamina and leave the otocyst. These are likely to be the cells which contribute to the formation of the acoustico-facialis ganglion. These observations support the hypothesis that the development of the otic placode is the result of a tissue interaction between surface epithelium and neural crest cells.
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  • 23
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 191 (1978), S. 487-501 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The labial ridge epidermis of the anuran tadpole, which is the formative site of horny teeth, was studied with the electron microscope. The triangular epidermis covering the apex of the labial ridge was composed of horny teeth cells arranged in a columnar shape, keratinocytes, secretory epidermal cells, two kinds of non-epidermal cells and Merkel cells. Individual non-epider-mal cells were identified as neutrophils and macrophages respectively.In addition, the fine structure, distribution and cytochemistry of the Merkel cell were studied. The fine structure of Merkel cells in the labial ridge epidermis was not so different from those of other vertebrates reported previously by other workers, except for the presence of numerous glycogen particles. The presence of Merkel cells in the labial ridge epidermis was very frequent, and they were arranged in a line at a uniform level of the triangular epidermis. They were usually located in the third cell layer from the base of the epidermis.PAS and azure A stains were used on semithin epoxy sections to reveal the Merkel cells, and both stained them intensely. On the other hand, though glutaraldehyde-silver techniques and permanganate fixation were used to detect monoamines in the Merkel cells ultracytochemically, a positive reaction was observed on the pigment granules.
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  • 24
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The effects of 5α-androstane-3α,17β-diol (3α-diol) and 5α-androstane-3β, 17β-diol (3β-diol) were studied in rats hypophysectomized and treated daily for 30 days with the steroids, starting on the day of surgery (hypophysectomized, H) or 30 days following the removal of pituitary (hypophy-sectomized regressed, HR). The ability of 3β-diol to maintain and restimulate the prostate glands and seminal vesicles of castrated (C) and castrated regressed (CR) rats, respectively, was also studied. This androgen (3βdiol) was able to maintain as well as rejuvenate to some degree the sexual accessory glands of all treatment groups. The prostate glands and seminal vesicles in both castrated experimental groups showed increased stimulation with progressively higher dosages of 3β-diol. At all dose levels, stimulation of seminal vesicles of CR rats was comparable to that of non-regressed castrates. The prostate glands, on the other hand, showed better maintenance in the higher dosage group. In H rats, the stimulation of sexual accessory glands by both androgens was not significantly different than normal controls. The seminal vesicles and prostate glands of HR rats treated with 3α-diol were well stimulated and comparable to those of H rats treated with 3α-diol. The seminal vesicles of HR rats treated with 3β-diol were also well stimulated, though not to the extent as those with 3α-diol treatment. The prostate glands of the 3β-diol treated HR rats were significantly smaller than those of the 3α-diol treatment group. However, these miniature glands were morphologically stimulated as evidenced by mitosis of parenchymal cells and accumulation of secretory products in the alveoli. This study clearly indicates that 3β-diol is biologically active and the degree of stimulation varies with the animal preparation in which the andro-gens were tested.
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  • 25
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    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 192 (1978), S. 555-583 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The histology and fine structure of the testis, epididymis and sex accessory glands were studied in young adult male rats administered testosterone enanthate, 120 μg/100 g body weight, three times weekly for 4, 8, or 12 weeks. The weights of the testis and epididymis decreased, and animals treated for 11 weeks were infertile. Alterations were found in the seminiferous tubules of all rats treated for 8 or 12 weeks, including the presence of many degenerating germ cells and a-large decrease or absence of late spermatids. Study of different stages of the cycle of the seminiferous epithelium showed that the greatest number of degenerating germ cells, step 7 spermatids and pachytene primary spermatocytes, occurred at stages VII-VIII of the cycle. Some normal appearing spermatogonia, primary spermatocytes and early spermatids remained in most seminiferous tubules. Sertoli cells contained many lipid droplets and lysosome-like bodies, and degenerating cells were surrounded by Ser-toli cell cytoplasm. The Leydig cells of treated animals were greatly reduced in size. Sperm progressively disappeared from the lumen of the middle segment and proximal part of the terminal segment of the epididymis after treatment for 8 or 12 weeks. Changes in the middle segment also included the appearance of intraepithelial cavities containing debris, and the presence within the epithelium of phagocytic cells that resembled leukocytes. The lumen of the proximal part of the terminal segment was often collapsed, while in the distal part of the terminal segment, the lumen was filled with cellular debris and degenerating sperm. Organelles of the principal cells of the epididymal epithelium appeared to be qualitatively unaltered. The weight of the sex accessory glands remained close to normal, and the presence of normal ultrastructural features suggested that production of secretions continued.
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  • 26
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    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 192 (1978) 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
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  • 27
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: In the present study, neuro-epithelial bodies (NEB) were identified by scanning electron microscopy (SEM) within the bronchial epithelium of near-term rabbit fetuses. The surface features and topography of NEB were correlated by light and transmission electron microscopy.In SEM, the surfaces of NEB were easily visualized in smaller peripheral airways because of paucity of ciliated cells in these regions. The NEB formed crater-like pits, which were lined with microvilli and had smooth-surfaced non-ciliated cells around the rim. Stereo-pair photographs revealed that the latter cells protruded above adjacent bronchiolar mucosa. The SEM also revealed that NEB were preferentially located near or at bronchiolar bifurcations.This is the first report of the three-dimensional structure of pulmonary NEB. Their direct contact with the airway lumen, as well as their strategic location in bronchiolar mucosa, support the suggestion that they are intrapulmonary receptors and help to regulate air-flow in peripheral airways.
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  • 28
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    The @Anatomical Record 190 (1978), S. 99-111 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: An electron-opaque substance, lanthanum, was utilized to determine when germ cells of the rat first cross the blood-testis barrier in adult spermatogenesis. Intravascularly perfused lanthanum was shown to surround all spermatogonia, preleptotene spermatocytes and early leptotene spermatocytes of Stage IX in the adult rat testis. Lanthanum was excluded from the spaces around more mature cells by newly-formed tight junctions between adjoining Sertoli processes. These processes had previously intervened between the leptotene cells and the basal lamina. The results are in close agreement with those of a previous study (Russell, '77a) which indicated that leptotene cells are the first cells of adult spermatogenesis to enter the intermediate compartment and to reside beyond a permeability barrier.
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  • 29
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    The @Anatomical Record 190 (1978), S. 155-159 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Dorsal roots and spinal ganglion cells of adult cats were studied for acetylcholinesterase (AChE) content. An inverse correlation exists between cell size and AChE activity; large neurons are AChE-negative whereas small ones are intensely AChE-positive. A few AChE-positive fibers were demonstrated in the dorsal roots. A possible correlation between AChE activity and substance P content of primary sensory neurons is discussed.
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  • 30
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    The @Anatomical Record 190 (1978) 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
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  • 31
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    The @Anatomical Record 190 (1978), S. 755-781 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Electron microscopy of the normal human thymus demonstrates a supporting framework of epithelial-reticular cells with long branching cytoplasmic processes joined by desmosomes. In the interstices of the epithelial-reticular cell processes lie lymphocytes, macrophages, and rare myoid cells. Both small and large lymphocytes are evident. No desmosomes are observed between the lymphocytes and the epithelial-reticular cells. Macrophages are most numerous in the cortex where they often contain phagocytized nuclear debris. The possible functional significance of the above-described fine structural features is discussed.
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  • 32
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    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 190 (1978) 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
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  • 33
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    The @Anatomical Record 190 (1978), S. 783-793 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The Fink-Heimer silver impregnation and the autoradiographic methods were used to study the fiber projections of the cingulate cortex in the squirrel monkey. It was found that this cortex provides inputs to the striatum, thalamus and several areas of isocortex. Evidence was found for a number of fiber projections (1) Fibers from the anterior limbic area were traced to the central part of the head of the caudate nucleus, putamen, septum, dorsomedial nucleus of the thalamus, anterior hypothalamus and lateral basal nucleus of the amygdala. (2) Projections from the cingulate area were traced to the lateral part of the head of the caudate nucleus, putamen, and to the centromedian, anterior, lateral dorsal, and lateral ventral thalamic nuclei and to medial nuclei of the base of the pons. (3) There were projections from the retrosplenial area of the anterior, lateral dorsal, dorsomedial, and posterior thalamic nuclei and lateral nuclei of the pons. These results indicate that most of the cingulate gyrus is an intermediate structure between the thalamus and overlying cortex. The anterior limbic area forms a bridge between the thalamus and other areas of the cingulate gyrus and the frontal cortex. (4) The retrosplenial area and the posterior part of the cingulate area bridge the adjacent visual sensory association cortex and pelvic areas of the sensory motor cortex, respectively. These areas of the cingulate gyrus project directly to the striatum as well as to the thalamus, structurally providing limbic system input to subcortical motor structures.
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  • 34
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Notochordal extracellular matrix consists of a continuous basal lamina, amorphous materials and microfibrils embedded in a ground substance of low electron density. Together they comprise the notochord sheath and are of considerable interest because of their suspected role in early embryonic tissue interactions. The notochord is particularly well-suited to morphological investigation of extracellular matrix because it is one of the few embryonic epithelia which produces ultrastructurally recognizable stroma in vitro without the advantage of a collagenous substratum. Furthermore, these matrix components produced in vitro are morphologically identical to those observed in vivo. The present study uses ruthenium red staining to demonstrate that notochordal microfibrils exhibit collagen-like cross-banding patterns both in vivo and in vitro. Collagenase and testicular hyaluronidase digestion studies designed to localize collagen and glycosaminoglycans show a reduction of microfibrillar diameters by 30-35%. Furthermore, these enzyme treatments frequently result in enhanced striations of microfibrils. When cis-hydroxyproline (a proline analog) or beta-aminoproprionitrile (BAPN, a lathyrogenic compound) is added to the culture medium, a similar reduction in microfibrillar diameters is seen. Moreover, increased ruthenium red-positive surface coats and large collagen fibrils are frequently present in BAPN-treated cultures, implying a stimulatory metabolic effect.We conclude that most, if not all, notochordal extracellular matrix components are composed of both collagen and glycosaminoglycans and suggest that the entire extracellular matrix should be considered a macromolecular composite which acts in concert to induce or stabilize developmental interactions.
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  • 35
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    The @Anatomical Record 191 (1978) 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
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  • 36
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Contracting fibrous tissues from skin wounds in pigs, and scars around silicone implants in humans, contained fibroblasts that had multiple bundles of 60-80 Å microfilaments with electron-dense bodies, features typical of contractile fibroblasts both in vivo (myofibroblasts) and in vitro. These in vivo fibroblasts contained many 220 Å diameter microtubules, which paralleled plasma membranes in the long axis of the cells. The spatial orientation of the microtubules in these myofibroblasts strongly suggests a bracing or scaffolding function.
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  • 37
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    The @Anatomical Record 192 (1978), S. 269-275 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: A freeze-fracture study has revealed rod-shaped intramembra-nous particles on the plasma membrane P-face (cytoplasmic leaflet) of the mi-tochondria-rich cell (or flask cell) of Xenopus laevis and Rana ridibunda epidermis. Such particles have previously been found in all other mitochondria rich cells examined by this technique, namely, the MR-cell of toad bladder epi-thelium, the dark cèll of rat kidney collecting tubule, and the flask cell of Xenopus kidney collecting tubule. These particles are assumed, therefore, to be closely connected with the function of this cell type.
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  • 38
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    The @Anatomical Record 191 (1978), S. 397-413 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The present study utilizes the scanning electron microscope (SEM) to reveal the surface morphology of proximal tubular cells and the parietal cells of Bowman's capsule of the adult rabbit nephron. To facilitate the examination of the basal surface of these cells, proximal tubules were dissected free and treated with collagenase to remove the basememt membrane. Other blocks of tissue were cryofractured to expose the lateral cell surfaces of the proximal tubules. Our investigation has shown that the lateral and basal surfaces of both the convoluted and straight segments of the proximal tubule have numerous processes. However, the arrangement and degree of branching is distinctly different in the two segments. The convoluted segment has large lateral ridges which form at the base of the microvilli and fan out to divide into lateral-basal processes. Many of the lateral-basal processes reach the basement membrane intact, interdigitating with complementary processes from adjacent cells. However, some of the lateral-basal processes branch into short, knobby projections (basal villi) which may also reach the basement membrane. Patches of basal villi are interspersed between broad regions of interdigitating lateralbasal processes. Therefore, in the convoluted segment, the lateral-basal processes form the major part of the basal cell surface. In tubular cells of the pars recta, unlike convoluted tubular cells, the majority of the ridges remain unbranched and pass directly to the basal surface where they divide into elaborate basal villi. Thus the basal surface of the pars recta cells is highly complex, appearing leaf-like, being a composite of numerous basal villi with a few lateral ridges.The basal surface of some parietal cells of Bowman's capsule have parallel ridges, which results in patches of striations.
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  • 39
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    The @Anatomical Record 191 (1978), S. 415-432 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Morphological and functional differentiation of the mucosal surface epithelium of the bursa Fabricii was studied in White Leghorn chicken fetuses and newly hatched chickens. First signs of differentiation towards two types of epithelial cells appeared on the thirteenth day of incubation: The apical cells of the epithelial buds projected towards the lumen, and an increase in the number of Golgi regions was observed in the epithelial cells between the buds. On day 15 the follicle-associated epithelium contained small apically situated vacuoles, and large mucin granules appeared in the interfollicular surface epithelium. Towards the day of hatching both epithelial cell types were arranged to a monolayered or pseudostratified cylindrical epithelium. The follicle-associated epithelium had invaginations and small vacuoles in the apical cytoplasm, whereas the interfollicular surface epithelium had numerous microvilli on its apical surface and large mucin granules in the apical cytoplasm. In functional studies, endocytosis of colloidal carbon was demonstrated in four out of ten 19-day-old fetuses and in all chickens studied immediately after hatching.
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  • 40
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    The @Anatomical Record 191 (1978), S. 433-445 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The anatomy of parts of the pelvic outlet and perineum is described in an adult male gorilla. Two previously undescribed muscles are presented: (1) The puborectalis muscle, completely separated from the levator ani, arises from the region of the symphysis and forms a sling for the rectum while it also substitutes for the perineal membrane. (2) The puboampullaris muscle, a paired smooth muscle, arises from the pubis and inserts into the rectum to elevate the rectum while additionally providing support for the urogenital viscera. The levator ani muscle is recounted to point out its lack of attachment to the pelvic viscera while allowing a hiatus in which the rectum is exposed within the perineum. The sphincter urethrae muscle is presented emphasizing its true sphincteric characteristics, its absence of lateral attachments and its similarity to man. Other muscles of the pelvis and perineum as well as urogenital viscera are described or modified where necessary. The manner in which these structures enter into the support of the pelvic viscera is considered.
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  • 41
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: At the 7-8 somite stage of embryonic chick development (29-31 hours of incubation), a slightly elliptical island of thickened ectoderm appears laterally on either side of the most distal constricture of the rhombencephalon at the level of the anterior intestinal portal. The appearance and extent of this auditory placode is precisely correlated with the subjacent accumulation of neural crest cells. By 33 hours of incubation, there is a distinct depression in the developing otic placode, and by 40 to 45 hours, the placode is visibly invaginated, forming an epithelial vesicle or otocyst. Carefully staged embryos were serially sectioned, and the area underlying the developing otic placode was traced with a planimeter. It was found that placode size (area 60,000 μm2) is nearly unchanged from 30 to 42 hours of development. During this time interval, the placode cells first become columnar, show nuclear orientation, and then pseudostratify. The increase in placode cell number during this time interval is not likely to be the result of localized, accelerated cell division: the population doubling time of placode cells is eight and one-half hours and the mitotic index of 2.5% is similar to that of cells in an equivalent area of adjacent, non-placode forming head ectoderm. A model of otic placode formation is proposed which suggests that by 30 hours of development, a discrete population of placode forming cells is segregated from head ectoderm. Subsequent epithelial pseudostratification results from accumulation of this dividing population within the limits of the placode.
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  • 42
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    The @Anatomical Record 192 (1978), S. 319-323 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: In the gingiva of the mouse incisor, connective tissue cells were observed which were undergoing mitosis and contained collagen fibrils enclosed in vacuoles in their cytoplasm. The presence of intracellular collagen was noted in the majority of the dividing cells. On the basis of this observation it is suggested that renewal of the fibroblast population in the gingiva occurs preferentially by division of differentiated fibroblasts rather than by division of cells with a lower degree of differentiation.
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  • 43
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    The @Anatomical Record 192 (1978) 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
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  • 44
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    The @Anatomical Record 192 (1978), S. 325-335 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Subepicardial and subendocardial arteries and arterioles in both the left and right normal canine ventricle were examined histochemically to determine their metabolic profiles. Aerobic metabolic capacity was assessed by determining the reactivities of the enzymes cytochrome oxidase, succinate dehydrogenase and NAD-isocitrate dehydrogenase. Glucose-6-phosphate dehy-drogenase was examin̈ed to assess activity of the hexose-monophosphate-shunt. The substrate glycogen was determined as an evaluation of anaerobic metabolic capacity, while the amounts of deoxyribonucleic and ribonucleic acid were assessed as an indication of protein synthesis. Results of the present investigation indicate that despite known hemodynamic differences, the metabolic profile of the coronary vasculature is similar in all regions of ventricular myocar-dium. Reactivities of the enzymes succinate and NAD-isocitrate dehydrogenase and cytochrome oxidase are greater in smooth muscle of arterioles than in arteries. This suggests that arteriolar smooth muscle has a higher capacity for aerobic metabolism than does arterial smooth muscle. The greater reactivity of glycogen in arterial, than in arteriolar smooth muscle, suggests that arterial muscle is more adapted for anaerobic metabolism. Deoxyribonucleic and ribonu-cleic acids demonstrate a low reactivity in both arteries and arterioles from all regions of ventricular myocardium which conforms to the opinion that under normal conditions, coronary vasculature is quite stable with little cell proliferation. Glucose-6-phosphate dehydrogenase shows little reactivity in all myocar-dial vessels which implies a low capacity for nucleic acid and protein synthesis.
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  • 45
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    The @Anatomical Record 192 (1978), S. 337-350 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: This light microscopic study of the cardiac junctional tissues was based on 27 human embryos, fetuses and postnatal hearts. Evidence was presented that superficial and deep portions of the postnatal AV node were derived from two cellular primordia in the posterior wall of the common atrium at the 6-mm stage. The small right primordia was associated with the right venous valve and gave rise to the loosely organized superficial AV node that extended posteriorly to the coronary sinus ostium. A larger left primordia formed the more compact deep subdivision of the AV node located against the anulus fibrosus. In most postnatal hearts the two subdivisions are partially or completely fused to form the adult AV node. Failure of the nodal primordia to fuse during cardiogenesis may result in two separate nodal cell aggregates above the anulus. The present observations provide a rational explanation for the two AV nodal masses described in the literature and an additional specimen that is illustrated in this communication.An AV bundle was first identified in a 13-mm embryo and appeared to be derived from large clear cells of the posterior AV canal. At 25 mm the bundle formed a broad band across the top of the IV septum and continued into both ventricles. At this stage multiple cell strands penetrated the endocardial cushion to connect the AV bundle to the two nodal primordia. Failure of normal fusion between the AV node primordia and AV bundle can result in a variety of junctional anomalies including congenital heart block.
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  • 46
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Previous experiments indicate that bone cells respond to external stimuli with fluctuations of cyclic nucleotide levels. The objective of this experiment was to study the response of alveolar bone to the application of tensile forces through an examination of the osteoblastic staining pattern for cAMP and cGMP. Cat canines were tipped by 80-g force for 0 to 48 hours. Fresh frozen, unfixed, undecalcified jaws were sectioned sagittally and stained immuno-histochemically for cAMP and cGMP. In tension sites, osteoblastic staining intensity for cAMP decreased gradually from one to three hours, and then increased by 24 hours. Intense staining for cGMP, visible in osteoblasts of all treated cats, peaked after three hours of treatment and then again at 24 hours. Generally, groups of cGMP-stained osteoblasts were found adjacent to unstained osteoblasts. The observed fluctuations in the osteoblasts staining pattern for cAMP and cGMP indicates involvement of these substances in the early response of osteoblasts to mechanical stimuli in vivo.
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  • 47
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    The @Anatomical Record 192 (1978), S. 351-361 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Cyclic AMP and cyclic GMP, considered to be cell proliferation regulators, have been reported to fluctuate in proliferating fibroblasts in vitro. The objectives of this experiment were to study the localization, distribution and staining patterns of these cyclic nucleotides in mechanically-stressed, proliferating periodontal fibroblasts in vivo. Cat canines were tipped by force applications for 0 to 48 hours and serial sagittal sections of fresh frozen, unfixed, undecalcified jaws were processed immuno-histochemically for the localization of cAMP and cGMP. Periodontal tension sites were studied microscopically. Fibroblastic staining for cAMP, which was localized mainly in the cell periphery, did not change appreciably as a result of tension. However, staining intensity increased one hour after the application of force, decreased after 6 hours and increased again at 24 hours. Staining for cGMP, initially covering the entire cell area, was concentrated over nuclei three hours after onset of tension, and diffused over cell periphery and cytoplasm thereafter. Intensity of staining for cGMP was maximal at 3 hours and low at 12 and 48 hours. These results demonstrate that stress-induced fibroblastic responses in vivo involve alterations in staining intensity for both cyclic nucleotides which may correspond with fluctuations of these regulators, reported to occur in vitro in various stages of the mitotic cycle. Moreover, this technique enables the identification of the involved cells in a stimulated, non-synchronized cell population.
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  • 48
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Submandibular glands of male mice were stained for nerve growth factor by light microscopic immunocytochemistry. Nerve growth factor (NGF) was present in the granules of granular tubule cells, with the immunoreactive material often concentrated at the periphery of granules. Administration of the α-adrenergic agent, phenylephrine, to animals resulted in a marked depletion of NGF-containing granules from granular tubules. Some release also occurred following administration of the β-adrenergic agent, isoproterenol. Cholinergic stimulation (pilocarpine) did not result in appreciable loss of immunoreactive granules from these cells. In vitro results were not as clear cut, immunocytochemically, as those obtained with intact animals. It is concluded that discharge of NGF from male mouse submandibular glands is mediated predominantly by α-adrenergic activation, and that this phenomenon is readily demonstrated in the intact animal.
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  • 49
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    The @Anatomical Record 192 (1978), S. 389-405 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The parotid gland of the nine-banded armadillo (Dasypus novemcinctus) was examined by electron microscopy. In general, the ultrastructural morphology of this gland appears similar to that described in other species. The most unusual feature of the gland is that the secretory granules of the acinar cells contain a wide variety of substructures. These substructures range from a single dense core within a homogeneous matrix to a more complex cordlike network extending throughout the granule. It is suggested that this diversity of substructures is indicative of a maturation process of the secretory granules. The intercalated ducts are secretory. The myoepithelial cells are numerous, extend throughout the gland, and are associated with the striated ducts.
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  • 50
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    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 192 (1978), S. 407-421 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The globule leucocyte is a cell with a wide distribution in the digestive, respiratory, biliary, urinary and genital tract epithelia of homeotherms. It occurs in the crypts of the rat small intestine and within the epithelium on the villous bases but not on the remainder of the villi. A characteristic feature of this cell is the presence of acidophilic cytoplasmic granules, 0.5 to a few m̈m in diameter. The nucleus resembles that of intraepithelial intestinal lymphocytes. In this investigation, a quantitative study was made of the effect of thyroidectomy and/or castration on the number of globule leucocytes in the duodenal crypts of immature and adult rats. In sham-operated rats, globule leucocytes were rare, occurring with a frequency of 1 or 2 per 1,000 epithelial cells. After thyroidectomy, they increased to 14-20 per 1,000 epithelial cells. Castration did not influence the number of globule leucocytes but resulted in an increase in the number, size and acidophilia of their cytoplasmic granules. In immature rats, but not in adults, castration combined with thyroidectomy enhanced the effect of thyroidectomy, increasing globule leucocyte number to 32 per 1,000 epithelial cells.Treatment of thyroidectomized-castrates with thyroxine, initiated 38 days after operation, reduced the crypt globule leucocyte population to normal, whereas treatment with testosterone did not. Growth hormone failed to influence the elevated number of globule leucocytes in thyroidectomized rats, suggesting that this action of thyroxine was not mediated via an influence on growth hormone release.Because of their similar nuclear morphology, intraepithelial crypt lymphocytes were also counted and there was no obvious relationship in the fluctuations of these two cell populations.It is suggested that the greater number of crypt globule leucocytes in thyroid deficiency may reflect changes in the intestinal secretory immunoglobulin system and this is being investigated, beginning with a study of the distribution of IgE.
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  • 51
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    The @Anatomical Record 192 (1978), S. 423-433 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Cell separation techniques and scanning electron microscopy (SEM) were used to characterize the surface morphology of small lymphocytes in mouse bone marrow. Lymphocyte-rich fractions and unfractionated suspensions of bone marrow and spleen cells from 9-10-week-old C3H male mice were glutaraldehyde-fixed, syringed onto gelatin-coated silver membranes, dehydrated in ethanol, infiltrated with amyl acetate, critical point dried, coated with gold-palladium and examined by SEM. High proportions of cells were retained on the membranes. Purified spleen small lymphocytes showed unimodal distribution curves for cell diameter (mode, 3.4 μm) and for number of surface microvilli (mode, 55-60). Bone marrow small lymphocytes were identified initially in lymphocyte-rich marrow fractions and in erythroblast-depleted marrow from polycythemic mice as well as in normal whole marrow. The cells resembled spleen small lymphocytes in size distribution and they showed microvilli. However, the number of visible microvilli was lower on small lymphocytes in the bone marrow (mode, 35-40) than in the spleen. While in each small lymphocyte population the total number of microvilli was greater on larger cells than on smaller ones, the density of microvilli per unit area of cell surface tended to decrease with increasing cell size. The results establish that the small lymphocytes in mouse bone marrow, mainly locally-produced immature cells, have villous surfaces, but the number of microvilli per unit cell surface area is less than that on peripheral small lymphocytes, as seen in the spleen. Neither in the bone marrow nor in the spleen are subpopulations of small lymphocytes distinguishable solely by numbers of microvilli. The findings suggest that microvilli on bone marrow small lymphocytes may undergo further development during post-mitotic maturation, surface receptor expression and migration of the cells to peripheral lymphoid tissues.
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  • 52
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The half-life of rat adrenocortical mitochondria was determined by high resolution autoradiography and liquid scintillation spectroscopy as previously described (Mazzocchi et al., '76). The results obtained by the two approaches were in good agreement. In the normal rats the half-life of adrenocortical mitochondria averaged 11 days. ACTH significantly increased mitochondrial half-life to about 16 days, and chloramphenicol significantly decreased this parameter in both untreated and ACTH-administered rats to about seven days. It is suggested that the ACTH-induced maintenance and slowing down of the degradation rate of adrenocortical mitochondria requires continuous mitochondrial DNA-dependent protein synthesis.
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  • 53
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The frequency of occurrence, distribution and morphology of supraependymal neurons associated with the third ventricular wall of the guinea pig were investigated by correlative scanning and transmission electron microscopy. Each of the specimens was located on the ciliated ventricular wall between the inferior border of the thalamus and the non-ciliated ependyma associated with the median eminence. Prominent clusters of neuronal perikaria in association with massive process bundles were observed in 7 of the 31 specimens examined. In those specimens lacking prominent neuronal networks a more diffuse array of independent nerve fibers was sometimes seen on the ependymal surface. Neuronal perikaria exhibited numerous surface protrusions and were covered by a rich meshwork of crisscrossing, varicosed fibers. Many of these cells were associated with multiple processes of varying diameters and lengths which either coursed independently over the ventricular surface or formed fasciculated bundles. As process bundles traversed the ependymal surface, individual processes branched off and either terminated within the ventricular lumen or penetrated the subjacent ependymal lining. Fibers also made contact with adjacent supraependymal neuronal elements. Correlative transmission electron microscopic observations indicate that both the perikaria and processes of such supraependymal networks possess ultrastructural features characteristic of neurons. The morphological characteristics of the intraventricular neuronal networks suggest that they may be engaged in functional interactions with the cerebrospinal fluid, with adjacent supraependymal neuronal elements and with the subjacent neuropil.
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  • 54
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The freeze-fracture appearance of fenestrations of sinusoidal endothelial cells has been reassessed in perfusion-fixed rat liver. Fenestrations, limited to the attenuated portions of the endothelial cell cytoplasm are usually round or oval in shape, with diameters ranging from 40-600 nm. Within a given fenestrated region, they are disposed in clusters forming sieve plates. In addition, the presence of wide, irregularly shaped openings suggest that adjacent fenestrations may coalesce and result in the larger openings. Our data thus confirm the existence of both small and large fenestrae in the endothelial wall, in contradistinction to previous studies showing only regular, medium-sized (100 nm) openings.
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  • 55
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The purpose of this study was to examine some cytological features of guinea pig amniotic epithelium which may be related to epithelial permeability. In addition to fine structural studies, the amnion was stained with ruthenium red to demonstrate the glycocyalyx and exposed to an exogenous protein (peroxidase) to ascertain some of the permeability characteristics of the intercellular junctions. The apical microvillous border had a distinct glycocalyx of filaments 3-5 nm in diameter and up to 0.3 μm in length. These filaments stained with ruthenium red as did a narrower zone of glycocalyx adjacent to the outer leaflet of the plasma membrane. Epithelial cells were joined laterally by numerous desmosomes and by tight junctions; no evidence of a classical junctional complex was observed. When cells were exposed to ruthenium red or peroxidase, the tracer was impeded in its penetration between cells, probably by tight junctions. The presence of tight junctions indicates that the intercellular space is not continuous from the amniotic cavity to the underlying connective tissue, and undoubtedly the junctions play a role in controlling transepithelial permeability. The experiments with peroxidase also demonstrated the capacity of the cells to endocytose protein, especially at their lateral and basal surfaces. Late in gestation, increasing numbers of cells underwent cytological changes similar to cells undergoing keratinization. These changes included the disappearance of most of the cell organelles and the thickening of the plasma membrane by the addition of an electron-dense layer to the inner (cytoplasmic) leaflet. The apparent keratinization of cells may result from increased abrasive trauma caused by the fetus or may be related to accumulation of various waste products in the amniotic fluid. In any event, the cytological modifications, especially of the plasma membrane, may indicate a change in cell permeability properties late in gestation.
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  • 56
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    The @Anatomical Record 190 (1978), S. 143-153 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Development of porcine conceptuses included transitions of five stages: blastocysts of spherical, ovoid, and tubular forms containing an embryonic disc and trophoblast, extremely elongated filamentous blastocysts, and stages of embryogenesis between days 9 and 18 after mating. Embryonic survival was reduced by 17% during this period. In this litter-bearing species, intense alteration in distribution patterns occurred at days 11 and 12, when blastocysts rapidly elongated to filamentous forms. Increased embryo mortality did not result from rapid changes in distribution patterns of conceptuses within the same uterine horn at this time. Filamentous blastocysts quickly reached lengths often exceeding 60 cm, and these conceptuses became regularly spaced with no overlap of tubular membranes from other embryos in that horn. The number of concep-tuses within a uterine horn ranged from 1 to 13. Protein in individual concep-tuses was used as an indicator of growth and denoted exponential increase, but at a lower rate for blastocysts of spherical, ovoid, and tubular forms as compared with that found in filamentous blastocysts and embryogenesis stage conceptuses. Growth of a conceptus, based upon its protein content, was independent of the developmental stage or potential loss of those neighbors nearest that conceptus.
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  • 57
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    The @Anatomical Record 190 (1978), S. 177-199 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The development of the middle ear and tympanum of Gallus gallus has been studied in embryos Hamilton-Hamburger stages 20-46. Particular attention was paid to the pattern of expansion of the pharyngeal pouch forming the tympanic cavity, and the histogenesis of the tissues of the region of the vestibular window. It is concluded that pouch expansion is brought about by simple epithelial growth into regions devoid of mesenchyme. The mesenchyme does not show significant cell death, but differentiates as connective tissue, macro-phages, and sinus vascular spaces. The epithelium of the mature cavity is of endo-dermal origin, and there is no indication of celomic contributions. We provide a detailed morphological analysis of the development of the footplate from cells of both the second visceral arch and the otic capsule. These detailed observations on the patterns of chondrification of columella and capsular tissues permit the presentation of a model for cellular interactions leading to the differentiation of the annular ligament.
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  • 58
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    The @Anatomical Record 190 (1978), S. 201-215 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The histogenesis of the popliteal lymph node in the rat and the popliteal and inguinal lymph nodes in the rabbit was examined by light microscopy. Special emphasis has been laid on the initial lymphocyte population in the lymph node anlage. In the rat on the seventeenth day of gestation lymphoid cells populate a limited mesenchymal area along the vein wall. The next day the mes-enchyme shows a bulb-shaped outgrowth causing an indentation in the wall of a lymph vessel, running parallel to the vein and having a saccular widening at this place. The bulb-shaped lymphoid outgrowth fills up the widened lymph vessel; the subcapsular sinus originates from the remaining parts of the lymph vessel. At birth the lymph node can be divided into a primitive cortex consisting of an area with evenly scattered lymphocytes among the basic network of reticular cells and a medulla. About three days after birth an ovoid area containing a dense concentration of lymphocytes is observed in the inner cortex. In the next days it expands in both lateral and medullary direction but not into the outer cortex. Primary follicles appear in the outer cortex 18 days after birth.The development of the inguinal and popliteal lymph nodes in the rabbit shows the same characteristics as the histogenesis of the popliteal lymph node in the rat.The morphogenesis of the lymph node is summarized in a schematic diagram.
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  • 59
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    The @Anatomical Record 190 (1978), S. 223-231 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The prefusion epithelium of human palatal processes was examined for evidence of specialization which might facilitate epithelial adherence with the opposing palatal process. A surface coat stained with ruthenium red (RR) was found on all apical aspects of the palatal epithelium. In the prefusion regions, RR staining was also observed in the spaces between the superficial cells of the epithelium and in necrotic cells. Adjacent oral and nasal epithelium excluded the RR below the level of the apical junctional complex. In the absence of RR, a dense material was observed in the most superficial intercellular spaces of the prefusion region. Many superficial cells in the area were in various stages of necrosis. The combination of degenerating surface cells and an accumulation of a poly-anionic substance such as glycoprotein may facilitate epithelial adherence between opposing human palatal processes.
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  • 60
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    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 190 (1978) 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
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  • 61
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    The @Anatomical Record 190 (1978), S. 659-677 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: In the guinea pig, the narrow part of the epididymis that traverses the upper pole of the testis and passes downward over the entire length of the gonad is composed exclusively of efferent ductules and the initial segment (zone I) of the epididymal duct. At the beginning of zone II, the narrow contour of zone I expands into a large globular region which lies adjacent to the caudal pole of the testis. The globular region of the guinea pig epididymis is commonly referred to as the cauda epididymidis but in the present study, examination with the light microscope reveals that it is composed of five histologically distinct zones (zones III through VII). A detailed histological analysis of the characteristics of the epithelium in the seven zones of the guinea pig epididymis and in the efferent ductules and ductus deferens was undertaken to obtain a better understanding of structure-function relationships in the epididymis of the guinea pig. It was found that each of the zones could be readily distinguished on the basis of its histological features and primarily on the basis of the appearance of the principal cells.
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  • 62
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The time of onset of brain regulation of the pituitary-Leydig cell system in fetal rats was assessed by fetal encephalectomy, which allowed the pituitary to persist in situ. The effects of encephalectomy were compared with those of fetal hypophysectomy (surgical decapitation). The parameter for in terpretation of these effects was the collective volume of Leydig cells, measured by the method of Chalkley ('43). The normal increase in the collective volume of Leydig cells in fetuses encephalectomized on day 17 of gestation and autopsied on day 18 was not retarded, whereas that in decapitated fetuses of the same age was retarded. In all other one-day experimental periods (day 18-19, 19-20, 20-21, and 21-22), the increase in volume was retarded to approximately the same extent in encephalectomized as in decapitated fetuses. The collective volume of Leydig cells continued to increase to some extent without the brain until day 20, after which it ceased to increase. The results suggest that in fetal rats, the brain control of the pituitary-Leydig cell system begins to operate from day 18 of gestation, when the day following overnight mating was designated as day 1 of gestation.
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  • 63
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    The @Anatomical Record 190 (1978), S. 851-859 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The innervation of the rat cornea was investigated electron microscopically after KMnO4 fixation. Myelinated nerve fibres were observed only in the limbal margin of the cornea, whereas the axons located in the stroma of the avascular cornea were surrounded by the Schwann cell cytoplasm. Axon profiles with small (300-500 A) granular vesicles and another type with agranular vesicles were seen among the non-vesiculated fibres in all parts of the cornea. After superior cervical ganglionectomy it was not possible to find any axons with small granular vesicles. On the other hand, some degenerating axon profiles were observed in the stromal nerve trunks after ganglionectomy. In the epithelium-naked axons with an occasional mitochondrion and a few agranular vesicles penetrated between the epithelial cells. Moreover, axons filled with several mito-chondria were rarely observed in the epithelium, but these were difficult to differentiate from the surrounding epithelial cells.The role of the different nerve types observed in the cornea is discussed. The results suggest that the rat cornea has a dual vegetative innervation.
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  • 64
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    The @Anatomical Record 190 (1978), S. 871-889 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Cilia in neonatal canine articular chondrocytes were studied using morphometric techniques and transmission electron microscopy. The cilia in chondrocytes were morphologically similar to cilia in a variety of other cell types. A chondrocytic cilium consisted of a basal body and a ciliary shaft. The cylindrical basal body was 0.21 μm (S.D. = 0.01 μm) in diameter, 0.50 μm (S.D. = 0.03 μm) in length and contained nine microtubular triplets. The ciliary shaft was 0.196 μm (S.D. = 0.02 μm) in diameter and 1.76 μm (S.D. = 0.80 μm) in length. The number of microtubular doublets in the ciliary shaft varied depending on where along the length of the shaft the section was taken.This study demonstrates that on the average the frequency of cilia in neonatal articular chondrocytes, as estimated stereologically, was about one cilium per cell.
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  • 65
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    The @Anatomical Record 190 (1978), S. 891-903 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: In mature rat soleus muscle it is shown that satellite cells are not evenly distributed over the surface of myofibers but are more numerous in the vicinity of the motor endplate. In this location they commonly lie close to the post synaptic membrane where they are termed perisynaptic satellite cells. In developing muscle several satellite cells may be seen close to the endplate and give the impression of limiting the spread of the axon over the myofiber. In addition these satellite cells make close plasmalemmal contact with Schwann cells and appear as a continuation of the Schwann sheath onto the surface of the myofiber.
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  • 66
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    The @Anatomical Record 191 (1978), S. 1-17 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The small intestines of adult rats were examined by light and scanning-electron microscopy after sublethal doses of methotrexate were injected at 5, 3 and 1 mg, respectively, per rat per day, for three days. Methotrexate inhibited mitosis and thereby disrupted the steady state system of the epithelium. Villi and crypts progressively diminished up to about four and one-half days after the initial injection. Thereafter, recovery began and, by day 7, relatively normal morphology was restored. In the degenerative phase, the loss of crypt-villus continuum was frequently observed, the former crypts forming cyst-like structures. The columnar cells became flat and pleomorphic but epithelial continuity was maintained. Goblet cells apparently decreased in number. Paneth cells, especially in the ileum, appreciably increased in size and number. During the recovery phase, the cystic crypts apparently re-established continuity with the villus epithelium. Size and proportion of all epithelial cell types returned to normal. Scanning electron microscopy showed villus fusion and the cellular pleo-morphism and loss of microvilli during the degenerative phase. During recovery of the villi some alteration in orientation and shape remained as shown by scanning electron microscopy.
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  • 67
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    The @Anatomical Record 191 (1978), S. 31-45 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Prolactin is known to enhance the uptake and metabolism of testosterone in male accessory sex organs and to increase the weight of accessory sex organs from castrated rats over those from controls treated with testosterone alone. The present study was directed toward defining fine structural changes detectable with scanning and transmission electron microscopy which might accompany such responses. Accordingly, rat ventral prostrate gland was examined from castrated animals which had received testosterone propionate and ovine prolactin singly or together, or which had received vehicle only. Unoperated ani-mals served as additional controls. Post-castration glandular atrophy was not influenced by prolactin treatment alone. Testosterone restored epithelial height, secretory product, Golgi complexes and rough endoplasmic reticulum, such that cellular and tissue morphology was generally indistinguishable from that of unoperated controls. Prostatic tissue from animals given testosterone and prolactin simultaneously exhibited pleomorphic, cytoplasmic apical projections which extended into the acinar lumen. Transmission electron microscopy demonstrated that these blebs were devoid of organelles and microvilli; scanning electron microscopy revealed that the blebs were highly wrinkled and more numerous than were the projections observed in tissue from animals treated with testosterone alone, or in tissue from unoperated controls. It is suggested that such blebbing may reflect enhanced apocrine secretion in prolactin/testosterone stimulated restoration of the prostate gland in castrated rats.
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  • 68
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    The @Anatomical Record 191 (1978), S. 47-53 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Bone marrow from adult rats fed a vitamin B6 deficient diet for two weeks was found to have reduced numbers of neutrophils, erythroid cells and small lymphocytes. The numbers of transitional cells were not reduced. Since the small lymphocyte population in the bone marrow consists of B cells and null cells in approximately the same proportion, it was concluded that both cell types were reduced as a result of the deficiency. A complete recovery in the cellularity of the bone marrow was brought about by returning the vitamin B6 deficient animals to a normal diet for four weeks. Other effects of the two-week vitamin B6 deficient diet included a failure to gain weight, a decrease in thymus weight and a reduction in the numbers of white blood cells in the peripheral blood. All of these defects were corrected after the animals had been fed a normal diet for four weeks.
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  • 69
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    The @Anatomical Record 191 (1978), S. 327-343 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Reserpine has been demonstrated in previous studies to induce the accumulation of lipid droplets in ventricular cardiac muscle cells of bats and this effect has been attributed to mediation by the sympathetic nervous system. The present study was done to evaluate the species specificity of this action of the drug. Reserpine caused lipid droplet accumulation in cardiocytes of guinea pigs and mice. However, in contrast to the action of the drug in bats, this action of reserpine in guinea pigs and mice could not be antagonized by chemical sympathectomy with 6-hydroxydopamine or by treatment of animals with phenoxybenzamine, atropine or hexamethonium. Like reserpine, fasting for as little as 24 hours induced lipid droplet accumulation in cardiocytes of guinea pigs and mice. This effect also could not be prevented by treatment with 6-hydroxydopamine indicating that the sympathetic nervous system was not involved in its mediation. Force-feeding guinea pigs given reserpine prevented the accumulation of lipid droplets normally induced by this drug. It is concluded that the lipid droplets accumulation in the hearts of guinea pigs that follows administration of reserpine is not due to a direct cardiotoxicity of the drug but is secondary to the failure of drug-treated animals to eat. Since the autonomic nervous system appears to mediate reserpine's cardiotoxicity in bats, the species difference revealed by these experiments probably results from an underlying physiological difference in the nervous systems of these animals.
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  • 70
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    The @Anatomical Record 191 (1978) 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
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  • 71
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Dense crystalline deposits appeared within vacuoles in rat maturative ameloblasts as a result of repeated injections of sodium fluoride. The crystals assumed varied arrangements but were always observed within intracellular vacuoles. The crystals resemble those of normal enamel and resist microincineration. They are readily dissolved by decalcification and leave behind an organic framework which matches the outline of the crystals. An experimental model is presented which may be useful in further studies of calcium transport, enamel matrix absorption or digestion of cellular debris.
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    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Scanning and transmission electron microscopy have been used to investigate the structure of the papilla neglecta in the lizard, Anolis carolinensis.Situated in the posterior part of the utricle, the receptor is innervated by a branch of the posterior ampullary nerve and is covered by an extracellular membrane that exhibits a tapering extension into the orifice of the utriculo-saccular duct. The neuroepithelium contains two populations of sensory cells within a matrix of sustentacular cells; one population (non-calyceal hair cells) is supplied primarily by boutons and clublike terminals, while the other (calyceal hair cells) is served by calycine terminals that invest from one to five sensory cells. The apices of calyceal hair cells bulge into the utricular lumen and have larger diameters and ciliary counts than non-calyceal cells, but other differences are not marked. Although the bases of calyceal hair cells are deeply indented by calyceal processes, both types show similar afferent synaptic structures confined to the nuclear and infranuclear regions. Efferent terminals synapse on afferent endings and hair cells in both cases; synapses directly on calyceal hair cells lie above the calyx, just beneath the apicolateral junctional complexes. Those complexes are basically similar throughout the receptor, except that a hemispheroidal gap junction between a supporting cell and adjacent hair cell was noted in several instances. Arrays of endoplasmic reticulum and specialized mitochondria occur adjacent to aggregations of afferent synaptic vesicles in both types of sensory cell; it is suggreted that such arrays may participate in the production of the vesicles in a process involving membrane recycling similar to that at the neuromuscular junction. Differences between calycine units and the type I hair cell of mammals are discussed, and evidence that suggests an equilibratory function for the lacertilian papilla neglecta is presented.
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  • 73
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    The @Anatomical Record 191 (1978), S. 503-519 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Intercellular junctions of the excurrent duct system of the adult rat testis were studied by freeze-fracture. In the terminal segment of the seminiferous tubule, where there are no spermatogenic cells, the tight junctions of Sertoli cells consist of many parallel strands of particles. The particles of the junctions predominantly appear on the E face instead of the P face, similar to those of the seminiferous tubules reported previously. From the rete testis to the ductus deferens, the tight junctional particles or smooth strands are mainly found on the P face, and the tight junctions show anastomosing networks. In the ductuli efferentes, whose epithelial lining consists of ciliated and nonciliated cells, the tight junctions between two adjacent nonciliated cells and between nonciliated and ciliated cells are poorly developed. In the former, belt-like gap junctions are often associated with segmented tight junctions. In such area, there are tiny regions, where no junctional elements are observed. Between two ciliated cells, several strands of the tight junctions can be seen. The result of the tracer experiment suggests that the barrier of the ductuli efferentes is weak. In the epididymis, the tight junctions are well developed throughout the duct. Corresponding with the regional variation of the epi-didymal epithelium, the geometrical organization of the tight junction networks varies along the duct. In the ductus deferens, many strands of the tight junctions are scattered throughout the lateral cell surface in addition to the belt-like network of the tight junction in the adluminal area.The number of the tight junctional strands is presented graphically in the various segments of the excurrent duct of the testis.
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  • 74
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    The @Anatomical Record 192 (1978) 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
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  • 75
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    The @Anatomical Record 192 (1978), S. 1-17 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The ultrastructure of the tubuli recti was studied in the testes of sexually mature bulls, boars, rams, goats, rabbits and rats fixed by vascular perfusion. The tubuli recti are lined with a simple epithelium that varies in height, from squamous to tall columnar according to the species and the region. The cells are characterized by extensive lateral and tortuous basal plasma membranes and a luminal border with microvilli. Tight junctions and desmosomes are found in the upper half of the lateral borders. The Golgi apparatus is sizable and associated with it are coated vesicles and may smooth vesicles concentrated towards the luminal border. A distal segment of the tubuli recti is found in bulls only and is characterized by a high epithelium which is thrown into folds giving the lumen a festooned appearance. It is suggested that the epithelial cells of the tubuli recti are involved in fluid exchange and in the removal of unwanted spermatozoa.
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  • 76
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    The @Anatomical Record 192 (1978), S. 41-53 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Studies were undertaken to assess the fine structural effects of vasectomy upon the rhesus monkey testis, using 27 monkeys subjected to one of three surgical techniques: control sham operation (COS), unilateral silk vasoligation (USV), or unilateral clasp vaso-occlusion (UCV). The monkeys were sacrificed from 1 to 66 weeks after surgery; tissues were fixed in glutaral-dehyde in collidine buffer and processed for electron microscopy (EM) using routine techniques. No alterations were noted in the seminiferous epithelium of any COS animal; only focal lesions were found in vasectomized animals. These changes correlated with length of time post-vasectomy, a finding consistent with earlier light microscopic studies (Heidger et al., '78). Even at the longest post-operative periods studied, spermatogenesis appeared in most animals to be normal. One animal exhibited areas in which the seminiferous epithelium consisted of Sertoli cells and spermatogonia, only. The seminiferous epithelium of approximately one-third of other animals, both on the vasectomized and contra-lateral sides, exhibited such alterations as development of extensive infoldings and duplication within the basal lamina, and presence within the basal Sertoli cell cytoplasm of late spermatids and sperm tails. These alterations were observed in both UCV and USV animals. The presence of such late germ cells in the basal Sertoli cell cytoplasm was noted by light microscopy; however, lu-minal spermiophages encountered in one animal at the light microscopic level were not detected in our EM study, which underscores the limitations of EM as a survey technique. All UCV animals developed spermatic granulomas of the vas, whereas only 3 of 13 USV animals developed such granulomas. It does not appear that the alterations exhibited by the animals in this study would necessarily dispose toward impaired spermatogenesis following vasovasostomy.
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  • 77
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    The @Anatomical Record 192 (1978), S. 55-58 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Tenotomy of the proximal and distal tendons of the soleus muscle of female Wistar rats was performed and sarcomeric length and muscle fascicle length measured. On the first postoperative day muscle bellies were found shortened and their sarcomeric length considerably reduced. Four weeks following tenotomy, although the muscle bellies remained shortened, sar-comeric length was comparable with that of control muscles. Measurement of muscle fascicle lengths at this time showed that those of experimental muscles were nearly 50% less than those of control muscles. It was concluded from these experiments that a reduction of the number of sarcomeres in series had occurred, thus compensating for the reduced length of the muscle belly.
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  • 78
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    The @Anatomical Record 192 (1978) 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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    Topics: Medicine
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  • 79
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    The @Anatomical Record 190 (1978), S. 1-3 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
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  • 80
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    The @Anatomical Record 190 (1978), S. 5-21 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: In the rabbit a number of large mononuclear cells with ruffled surface membranes travel from the skin and superficial tissues of the leg, via the lymphatics, to the popliteal lymph node: they constitute 40-50% of the total cell population in the afferent lymph. About 10% of these cells are actively phagocytic when tested in vitro and about 3% are found to contain Langerhans granules.After isotopic labelling the majority of lymph-borne mononuclear cells can be detected within the regional node for at least 24 hours; most being located in the paracortex and a few in the interfollicular cortex. It is proposed that these cells, including those containing Langerhans granules, belong to the “mononuclear phagocyte system.”Possible functions of these lymph-borne cells are discussed with particular reference to antigen transport.
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  • 81
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    The @Anatomical Record 190 (1978), S. 41-45 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The lacunar cell layer in rat snake epidermis contains many characteristic intracellular vacuoles. The lipid nature of these large round vacuoles was demonstrated by histochemical and ultrastructural investigations. Rhomboid-shaped clefts, similar to cholesterol ester clefts, were observed in proximity to the vacuoles.
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  • 82
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Normal, rachitic, and vitamin D3-replete chicken growth plates were studied utilizing the potassium pyroantimonate-osmium tetroxide procedure. A marked membrane and mitochondrial calcium was revealed in all specimens in the maturing and early hypertrophic zones which disappeared as heavy matrix mineralization began.The most significant difference shown in the specimens was in the marked intracellular lipid content of chondrocytes in all zones of the rachitic and D3-replete growth plates. There was negligible lipid present in normal specimens.It is suggested that as most of the mechanisms postulated as necessary for calcification are present in rachitic chicks, perhaps the increased intracellular lipid pool results from the formation of abnormal lipids for insertion into the plasma membrane and thus prevents normal calcium transport.Chains of intracellular vesicles were also visualized in maturing and hypertrophic chondrocytes. These were more often seen in rachitic growth plates and in increased numbers in the early D3-replete specimens. The etiology is unknown at the present time.
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  • 83
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The initial differentiation of endoderm at the time of onset of implantation, and the subsequent rapid differentiation of visceral and parietal endoderm were studied in the rat and mouse. Transmission electron microscopy illustrates the reorientation and loosening of embryonic cell mass cells during implantation, as well as cytological evidence that endoderm cells have differentiated. Using scanning electron microscopy, parietal endoderm consists of individual stellate cells with numerous peripheral branching filopodia. As these cells migrate abembryonically, the rest of the embryonic cell mass becomes recom-pacted. The visceral endoderm proliferates and forms a columnar epithelium which has the cytological characteristic of an absorptive epithelium and is able to ingest exogenous proteins. Thus, by 24 hours after implantation, the two endo-dermal derivatives have assumed widely diverse shapes and different types of associations and rates of replication, and are probably performing different functions.
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  • 84
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    The @Anatomical Record 190 (1978), S. 217-222 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The actions of the deep and superficial portions of the ptery-goideus muscle and the depressor mandibulae were studied in the agamid lizard, Uromastix aegyptius, using fine wire electrodes. The EMG signals were recorded, while simultaneously recording the jaw positions during feeding on movie film at 32 fps. Muscle activity varies with different types of food. The deep and superficial portions of the pterygoideus performed different functions. The deep ptery-goideus functioned during opening of the jaws, presumably to protract the jaw. The superficial pterygoideus was strictly a jaw elevator. The depressor mandibu-lae is not the initiator of jaw opening. When biting on tough food items, the deep pterygoideus and depressor mandibular were active.
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  • 85
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    The @Anatomical Record 190 (1978), S. 233-241 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Adrenergic and acetylcholinesterase (AChE)-positive nerves were studied in the rat ovary four days after various experimental denervation procedures. Ablation of pelvic parasympathetic nerves (pelvic neurectomy [PN]) or abdominal vagotomy (AV) had no obvious affect on the adrenergic or AChE-positive nerves in the ovary. Section of the mesovarium resulted in the loss of all histochemically demonstrable adrenergic and AChE-positive nerves. Chemical sympathectomy with 6-hydroxydopamine (6-HD) resulted in the loss of all histo-chemically demonstrable adrenergic nerves. A few AChE-positive nerves remained in the hilar and medullary regions following chemical sympathectomy. When the presumptive parasympathectomy procedures (AV and PN) were combined with chemical sympathectomy, again no adrenergic nerves remained, however a few hilar and medullary AChE-positive fibers persisted after sympathec-tomy plus PN, but no AChE-positive fibers were demonstrable in the AV plus 6-HD group.These findings show that most of the AChE in ovarian nerves is localized in adrenergic nerves. It is suggested that the few AChE-positive fibers remaining in the ovarian hilar area after 6-HD treatment or 6-HD plus PN are derived from the vagus. These few AChE-positive nerves may be postganglionic vagal parasympathetic or they may be sensory fibers.
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  • 86
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    The @Anatomical Record 190 (1978), S. 257-269 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Supraependymal cells in the third ventricle of neonatal male and female rats were examined with scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Supraependymal cells in the third ventrical of adult male rats were also studied with SEM. Many neonate supraependymal cells were round to oval in shape and exhibited varying degrees of surface irregularity. Small finger-like processes or narrow pseudopodia projected from the cell bodies over the underlying ependymal cells. Some neonatal supraependymal cells exhibited flattened cell bodies with broad pseudopodia and few surface irregularities. TEM revealed a variety of cell profiles. Prominent within the cytoplasm of many supraependymal cells were lysosomes, smooth and coated vesicles suggesting pinocytosis, subplasmalemma vacuoles, and occasional lipid droplets. The morphological characteristics of neonatal supraependymal cells suggested they were mononuclear phagocytes. Adult supraependymal cells exhibited more pleomorphic cell shapes with numerous cell processes, varying widely in size and shape, and often extending over the ventricular surface for considerable distances. These observations, in combination with previous studies by other investigators, suggest that some adult supraependymal cells may also be phagocytic in nature. The differences in morphology between adult and neonatal supraependymal phagocytes may relate to the differing third ventricle environment between adult and neonates and/or differences in the origin of the phagocytes with age.
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  • 87
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    The @Anatomical Record 190 (1978), S. 313-625 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
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  • 88
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Mouse uterine glandular epithelium during the lactationally delayed implantation period and after estradiol induction of implantation was investigated using light and electron microscopy. During the delayed implantation period the lumen of this simple tubular gland is narrowed. The glandular epithelial cells have a well developed Golgi complex lateral to the nucleus, and numerous cisternae of smooth and rough endoplasmic reticula (RER) and many electron lucent apical vesicles of sizes up to 0.2 μm in diameter near the luminal border. The basal region contains lipid droplets and dispersed, irregular cisternae of RER. Twenty-four hours after the administration of 17β-estradiol the glandular lumina become dilated but the luminal content does not stain with azure B. Ultrastructurally the glandular cells are not remarkably different from those seen during the delay period. However, by 48 hours after estradiol administration the glandular lumina are not only dilated but filled with material which stains intensely with azure B and is ultrastructurally dense and homogeneous. The apical region of the glandular cells contains granules up to 0.4 μm in diameter composed of electron dense material similar in density to that seen in the glandular lumen. In addition, the Golgi complex has assumed a position apical to the nucleus, and the basal RER has an increased number and more orderly arrangement of cisternae.The changes seen in the uterine glands after the induction of implantation during the delay period are apparently indicative of increased secretory activity of the glandular epithelia. However, the contribution of the glands to the changes in uterine fluid composition has yet to be established.
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  • 89
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    The @Anatomical Record 190 (1978), S. 627-637 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Freeze-fracture replication technique was utilized to study the morphology of type II alveolar epithelial cells and alveolar contents in the late gestation of rabbit fetuses. It was shown that the lamellar inclusion bodies of type II cells were enveloped by the usual type of unit membrane with membraneassociated particles of 15 nm diameter. The interior of the inclusion bodies was composed of multiple stacks and/or whorls of membranes which were devoid of membrane-associated particles. Small vesicles within the inclusion were found more frequently with this technique than in chemically fixed thin-sectioned preparations.The intra-alveolar contents were comprised of two components; spherical bodies, which were identical to the internal contents of the lamellar bodies of type II cells, and tubular elements. These tubules most often appeared rectangular on cross-fractured faces. Triangular and hexagonal fracture faces were also noted. The tubules were seen to rest on the surfaces of the spherical components. Our observations suggest that the tubular element of the alveolar contents is formed through the interaction between the discharged lamellar body content and the alveolar fluid, and further suggest that at least the major constituent of type II cell lamellar bodies is lipid not bound to protein.Three new observations were made in this study; the absence of membraneassociated particles on the interior of the lamellae of the inclusions, the crossfractured profiles of tubular elements of the alveolar contents, and the occasional multicompartmental nature of type II cell inclusions.
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  • 90
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The ultrastructure of myogenesis in the mouse hind limb has been studied from day 12 to birth. Mononucleated cells with myofilaments are small and infrequent during myogenesis and never line myotubes. Only mononucleated cells without myofilaments cover the myotubes and are involved in mass fusion. These mononucleated cells are pleomorphic and undifferentiated during early myogenesis. They have a heterochromatic nucleus and many accumulate mitochondria and lengthen during days 16-18. After day 18 they are normally elongate with a heterochromatic nucleus and packed with free ribosomes. The multinucleated cell development may be divided into four stages. 1. Immature myotube (days 14-15). Their fibrils are small, out of register and some poorly defined. Many myofilaments are not in rigid hexagonal alignment. The sarcoplasmic reticlum is simple and randomly oriented and triads are absent. Large clumps of glycogen occur between euchromatic nuclei which are in chain formation. 2. Mature myotube (days 16-18). Small groups of fibrils show alignment. Glycogen granules and sarcoplasmic reticulum become numerous between fibrils. Triads are sparse and mitochondria cluster in subsarcolemmal regions and between nuclei. 3. Young myofibers are present by day 19. More fibrils are aligned and compact. The filaments are in a rigid hexagonal array, the glycogen is dispersed and nuclei are peripherally located and moderately heterochromatic. Triads are frequent but often obliquely oriented and mitochondria are elongate and numerous between fibrils. 4. Mature myofibers occur postnatally (2 weeks).
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  • 91
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    The @Anatomical Record 191 (1978), S. 19-29 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Brachymorphic (bm/bm) mice are disproportionately short in stature. Past biochemical studies on neonatal mice (Orkin et al., '76) demonstrated that epiphyseal cartilage from these mutants synthesizes glycosamino-glycans (GAG) that are undersulfated. In this study, synthesis of GAG, as determined autoradiographically with Na2 35SO4 and 3H-glucosamine was reduced in all areas of bm/bm epiphyses both in vivo and in vitro as compared to normal C57BL/6J mice. Incorporation of both isotopic precursors into GAG of the brachymorphic proliferative zone was reduced to a greater extent than in the reserve zone. In addition, incorporation of these precursors into GAG of epiphyseal cartilages in vitro, as determined biochemically, was reduced by 40%. In contrast, the incorporation of 3H-leucine and 3H-proline into protein did not show differences between mutant and normal epiphyses. These results suggest that alterations in GAG synthesis in bm/bm epiphyseal growth plates are not exclusive to any one zone, but do appear to be most pronounced in the proliferative zone.
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  • 92
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    The @Anatomical Record 190 (1978), S. 47-63 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The ultrastructural characteristics of the nerve plexus that accompanies the ovarian vessels of the rat were studied. The nerve fibers were primarily unmyelinated with less than 5% myelinated. Two types of neuronal cell bodies were found along these nerves. They were located at variable distances along the nerve bundle. The first and more numerous was a larger cell type similar to the autonomic postganglionic neuron. The second and smaller cell type had granulated vesicles throughout the cytoplasm. Synapses of the axodendritic type and synapses between the neuronal cell bodies were found. Most of the synapses possessed agranular vesicles. The presence of neuronal cell bodies is an important characteristic to consider in evaluating denervation of the ovary by interruption of this nerve plexus.
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  • 93
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    The @Anatomical Record 190 (1978), S. 79-97 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: At least six different types of nuage, as judged by morphological appearance, were found in spermatocytes of the adult rat testis. These were characterized by form, distribution, and association with other organelles. The appearance (with time) and the dissociation of some nuage types were recorded in conjunction with other events of the spermatogenic cycle. The data indicate that all types of nuage behave in a dynamic way. Especially interesting were the findings concerning the chromatoid body. This structure was first observed in mid-pachytene spermatocytes. By late diplotene and during the first meiotic division, it had lost its prominence such that its eventual fate could not be determined. Large dense (0.5 μm) bodies appeared de novo in the cytoplasm of newly formed secondary spermatocytes. They were seen scattered throughout the cell and in association with mitochondria. With time these bodies appeared to coalesce to form the large definitive chromatoid of a type similar to that known to be present throughout most of the remainder of spermiogenesis.
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  • 94
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    The @Anatomical Record 190 (1978), S. 127-141 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The simultaneous demonstration of lysozyme using the unlabelled antibody enzyme method and mucosubstances by staining with the periodic acid-Schiff (PAS) and Alcian Blue pH 2.5 techniques has led to the identification of a new subpopulation of mucus-producing cells containing lysozyme in small intestinal specimens from normal rats and from patients with inflammatory bowel diseases. These cells, containing both mucosubstances and lysozyme, are located in the lateral walls of the crypts of Lieberkuhn, but can occasionally be found also in or near the tips of the villi. The specific staining for lysozyme was observed in the apical and/or basal cytoplasm of these mucus-producing cells and was readily detected in sections counterstained for mucosub-stances with Alcian Blue. The localization of these mucus-producing cells was similar both in the normal rat and in the pathological human specimens. Absorption controls and controls where a non-immune serum was substituted for the specific antilysozyme serum confirmed the specificity of the lysozyme localization.
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  • 95
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: An in situ heart lung preparation was developed to label lymphatics of the actively beating dog heart with subsequent fixation by vascular perfusion. Immediately after interstitial injections of trypan blue and colloidal carbon, a rich plexus of lymphatic vessels was visualized in the epicardium of the actively beating heart. With this method of fixation, tissue preservation is generally excellent and uniform throughout the heart. In thin sections examined with the electron microscope, lymphatic vessels are easily recognized by the content of plasma proteins which is preserved as an electron dense precipitate that is evenly dispersed throughout the lumen. An extensive plexus of thin walled lymphatic vessels is observed throughout the epicardial, myocardial and subendocardial regions. Numerous anchoring filaments are observed closely apposed to the abluminal endothelial surface which extend into the surrounding connective tissue. The distribution and ultrastructure of the cardiac lymphatic vessels are discussed in relation to their role in the removal of interstitial fluid from the heart.
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  • 96
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    The @Anatomical Record 191 (1978), S. 203-219 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The present paper deals with a scanning electron microscopic investigation which was undertaken in order to make a direct study of geometrical conformations of thymocytes, to determine the effect of external mechanical forces and finally to analyse the relation of the cell surface morphology to the differentiation and release of thymocytes into circulation. Thymocytes in situ revealed a striking polyhedral configuration with distinct edges and angles that permit a close orientation of cells in a minimum space. This conformation is probably acquired under the influence of forces in the microenvironment of the cells. The immature thymocytes in the cortex were smooth surfaced and constituted a homogeneous population with regards to surface morphology except for slight variations in the size and angles of various facets of the polyhedra. A minority of the cell population occupying the medulla, however, exhibited a departure in possessing surface undulations and stubby protuberances. Thymocytes isolated in suspension and those in postcapillary venules of thymus did not show the polyhedral shape characteristic of the cells in thymic tissue. They were always rounded, with their surfaces often exhibiting undulations or microvilli The variations observed in situ are discussed in light of external mechanical forces, cell surface characteristics and the inherent properties of differentiating thymocytes.
    Type of Medium: Electronic Resource
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  • 97
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Thirty additional parasellar gross dissections and light microscopic examinations have been carried out, confirming a previous observation that the sympathetic nerve or nerves running with the carotid artery gives off a multitude of fine branches at irregular intervals on the way up, but the largest residual component joins the sixth cranial nerve and leaves to join the first division of the fifth cranial nerve. No similar fibers can be found by us to join the third or fourth cranial nerve. Based on the observations that section of the sympathetic in the neck results in a Horner's syndrome and that section of the ophthalmic artery at its point of departure from the carotid does not result in any part of Horner's syndrome nor does section of the external, internal or common carotid in the neck, it is assumed that these fibers process the functions the absence of which result in Horner's syndrome.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 98
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 191 (1978), S. 227-238 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Twelve-day-old hypertransfused neonatal rats nursed for four days by a twice-bled mother exhibited higher 48-hour RBC-59Fe incorporation than control neonates nursed by a normal mother. Erythropoietin (Ep) in plasma of 12-day-old hypertransfused neonates suckled for four days by twice-bled mothers was initially equivalent to approximately 0.5 IU/day. This calculation was based on the observation that reticulocytosis induced in these animals was similar to that produced in neonates of the same age injected intra-peritoneally with 0.5 IU Ep for four days while nursing from normal mothers. The reticulocyte maturation curve was shifted to the left in 12-day-old hy-pertransfused neonates suckled by anemic mothers, and in 12-day-old normal neonates rendered anemic by bleeding, while nursing from normal mothers. This left-shift of the reticulocyte maturation curve was also evident in 12-day-old hypertrans fused neonates injected with Ep.Decreases in relative percentages of nucleated RBC was evident in spleens of 12-day-old neonates nursed by anemic mothers and spleens of 12-day-olds injected with Ep. Significant reduction in nucleated RBC were noted in both spleen and marrow of 12-day-old anemic neonates.These results suggest: (1) Ep, present in increased amounts in the anemic mother, is transmitted through milk to nursing neonates thereby stimulating erythropoiesis in these animals; (2) Ep may not stimulate stem cell differentiation towards the erythroid compartment but rather acts on already differentiated erythroid cells by influencing their rate of maturation.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 99
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 191 (1978), S. 239-251 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The structure, distribution, density and innervation of arteri-ovenous anastomoses (AVAs) have been compared in the skin of Weddell and elephant seals, as part of a study of the structure and function of arteriovenous anastomoses in mammals.In both genera AVAs were coiled vessels with the segmental structure typical of “epithelioid” anastomoses and possessed a dense peripheral adrenergic innervation.In both Weddell and elephant seals there was no statistically significant difference between the mean density of AVAs in body skin and flipper skin. The majority, approximately 71% of AVAs occurred superficially in the dermis, fewer (23%) occurred in the deeper dermis, and 6% were present in the thick hypodermis (blubber). The density of AVAs in Weddell and elephant seals is approximately eight times greater than that reported in other animals and the superficial position of anastomoses over the whole of the body surface is characteristic of phocid seals.When open, AVAs in Weddell and elephant seals allow maximal heat loss from the skin surface by passing large volumes of blood into the superficial veins. AVAs in seals are important in dissipation of body heat, particularly when the animals are out of the water, and the entire surface area is thermo-regulatory rather than specific regions such as the flippers.
    Additional Material: 2 Tab.
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  • 100
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 191 (1978) 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
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