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  • 1970-1974  (405)
  • 1950-1954
  • 1920-1924
  • 1971  (405)
  • Cell & Developmental Biology  (405)
  • 101
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 170 (1971), S. 437-455 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The endodermal cells of the visceral yolk sac have been studied from the seventh to eleventh day of gestation. The absorptive capacity of the cells is established by the seventh day as indicated by the presence of microvilli, coated invaginations and vacuoles, the apical canalicular system and abundance of absorptive droplets and vacuoles in these cells. Changes in cellular structure during the next three to four days include the development of the cisternal system of the rough endoplasmic reticulum, an increase in mitochondrial number and their localization near absorptive droplets and the formation of multiple Golgi complexes. Intercellular spaces form between the endodermal cells by eight to eight and one-half days and coincide with the disappearance of the basal lamina separating the endoderm and mesoderm (angioblastic cords); these changes correlate with the formation of the vitelline vessels. As the vitelline circulation becomes functional, the visceral basal lamina is re-established, the intercellular clefts decrease in prominence and the absorptive storage droplets and vacuoles decrease in size and number.The apical junctional complex of the endodermal cells forms a continuous barrier for the direct passage of material from the yolk sac cavity to the developing vitelline vessels as established by the use of ruthenium red. The absorption and intracellular storage of macromolecules in the visceral endodermal cells was traced through the intermicrovillous apical coated invaginations, coated vesicles, apical canaliculi and storage vacuoles using ferritin.Immunofluorescent studies indicate the presence of immunoglobulin (anti-mouse gamma globulin) in the cytoplasm of the visceral endodermal cells as early as 9 to 11 days. Several blast-like cells which also were observed in the vitelline vessels at 11 days exhibited positive fluorescence for immunoglobulin.
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  • 102
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 171 (1971), S. 21-37 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Mouse oocytes obtained at various times after administration of HCG or after culture were studied with the electron microscope. Gradual changes were observed in the perivitelline space, plasma membrane and cortical cytoplasm. Disappearance of the regular microvilli, the formation of lamellae-like processes and vesicular bodies were observed. A progressive increase in the number of cortical granules and multivesicular complexes was observed simultaneously with the disappearance of the rough endoplasmic reticulum. In general, eggs which were matured either in vivo or in vitro showed similar patterns of morphological differentiation. Degenerative changes were seen in most eggs cultured for 17 hours, but not for nine hours or less. In aged tubal eggs recovered at 26 and 36 hours after injection of HCG, the number of cortical granules was decreased relative to previous stages and their extrusion from the egg was apparent. The fertilizability of the eggs matured in vitro and the role of the cortical granules are discussed in terms of the reaction of the zona pellucida.
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  • 103
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 171 (1971) 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
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  • 104
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: A radioautographic study of epithelial cell proliferation in the vaginas of mice during the estrous cycle, pregnancy, lactation, and under certain experimental conditions is reported. Data were expressed as labeled cells per 1000 basal cells counted. The proportion of labeled cells that were basal or nonbasal was determined. The highest rates of proliferation were recorded during the estrous cycle, specifically during late diestrus, proestrus and early estrus. During pregnancy the rates of proliferation increased from metestrous levels beginning on day three and reaching a maximum on day 4 just before implantation, followed by a decrease on days 6 and 8. There was an increase on day 12 followed by a more marked increase on day 19, the last full day of pregnancy. On the first day post partum the rate of proliferation was very low. A small increase followed during early lactation.Data on rates of vaginal epithelial proliferation were used to infer the estrogen secretion pattern during reproduction in the mouse. In addition it was concluded that progesterone augmented the proliferative response of the vaginal epithelium to estrogen, specifically promoting proliferation of nonbasal cells. Experiments using mated, castrated mice and estrogen or progesterone replacement confirmed these conclusions.Data and conclusions are discussed relative to recently reported data on ovarian plasma estrogen and progesterone content in rats during reproduction.
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  • 105
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 171 (1971), S. 39-52 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Explants of the embryonic rat palate have been treated by adding sodium fluoride and sodium pyruvate to the culture medium. Fluoride, at specific concentrations, causes retardation of palatal shelf growth so that fusion does not occur during the culture period. Partial or complete fusion does occur if fluoride levels are reduced.Sodium pyruvate added to the medium advances the time of fusion of explants over that found in controls. When combined with fluoride in the medium, pyruvate can reverse the effects of fluoride on shelf growth and permit complete fusion to take place in a laige percentage of explants.The mode of action of flucride or pyruvate under these experimental conditions has not been determined. However, the known effects of fluoride as an enzyme inhibitor must be considered.
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  • 106
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Tissue cultures of fetal rat adrenals were used to study effects of cycloheximide on the ACTH-induced synthesis of mitochondrial inner membranes in the cortical cells. Cycloheximide alone added to the culture medium in concentrations of 100-0.25 μg/ml killed the cortical cells during six days of treatment. At the dosage level of 0.15 μg/ml/6 days, it induced a decrease in the size of mitochondria and an increase in the pleomorphism of mitochondria. Cycloheximide at a concentration of 0.015 μg/ml/6 days induced no change in the ultrastructure of cortical cells. When cycloheximide in concentrations of 0.15 μg/ml/6 days was added to the culture medium together with 100 mU/ml/6 days of ACTH, the ACTH-induced changes of mitochondrial inner membranes (formation of 600 Å vesicles) was completely inhibited. It also suppressed the ACTH-induced development of smooth surfaced endoplasmic reticulum, hypertrophy of Golgi apparatus, development of microvilli and accumulation of lipids. However, it had no effects on the ACTH-induced increase in the number of polysomes 01 the increase of heterochromatin in the nucleus. Cycloheximide (0.08 μg/ml/6 days) given together with 100 mU/ml/6 days of ACTH had incomplete inhibitory effects on the ACTH-induced differentiation of the cortical cells. Cycloheximide (0.015 μg/ml/6 days) given together with ACTH resulted in only slight inhibition of ACTH-induced ultrastructural differentiation of adrenal cortical cells in vitro.The present observations suggest that (1) the stimulatory effect of ACTH on mitochondrial protein synthesis is dependent upon nuclear control of protein synthesis; (2) a specific cytoplasmic mitochondrial protein synthesis stimulating factor in the cytoplasm of cortical cells is dependent on ribosomal protein synthesis and is a mediator of ACTH action on the mitochondrion; (3) despite their apparent autonomy, the mitochondria in cortical cells are kept under nuclear control; (4) the only direct locus for the trophic effect of ACTH is in the nucleus.
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  • 107
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    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 171 (1971) 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
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  • 108
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    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 171 (1971), S. 237-245 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The mucosa of the turtle bladder was separated from underlying tissue by blunt dissection and its composition characterized. Although large amounts of non-epithelial tissue were removed by the dissection, a considerable amount of connective tissue and a small amount of smooth muscle were always present in the isolated layer. The epithelial cells were described and anatomical features of significance in water and ion transport studies examined. The columnar epithelial cells of the mucosal layer were arranged in clusters bounded by crypts. The cells were larger near the bladder neck than in the distal regions of the bladder. Single smooth muscle cells were found immediately beneath the epithelial cell layer. Long intercellular channels separated the cells. Possible roles of these features in water and ion transport were discussed.
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  • 109
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    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 171 (1971), S. 273-282 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Thirty-day old female rats were injected with 0.2 μg of 17-Beta-Estradiol daily for 30 days, and sacrificed at varying intervals. Decalcified crosssections of mandible, femur and tibia were prepared and measurements were made of: (1) number of osteons in two fields, (2) average number of lamellae per osteon, (3) average Haversian canal diameter, and (4) number of non-Haversian (primary) longitudinal canals in two ×40 microscopic fields. Pro-longed estrogen administration resulted in (1) earlier opening of vaginal plates, (2) lower rate of gain in body weight until treatment was stopped, (3) inhibition of linear bone growth but not of bone diameter, (4) decrease in the ratio bone-weight/body-weight, and (5) accelerated age changes in the aforementioned histologic variables; namely, increase in the first two and decrease in the latter two histologic measurements. Regression analyses indicated that as compared to long bones, consistently more accurate estimates of age at death could be derived from mandibular histology. It was concluded that bone microstructure is a sensitive measure of the metabolic state of the organism and the quantitative histologic techniques utilized here have important applications in diagnostic pathology, anthropology and in studies of development and aging.
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  • 110
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    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 171 (1971), S. 417-441 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Ruthenium violet, closely related to ruthenium red, supplements the ultrastructural knowledge of the plasma membrane complex. Amoebae throughout were handled individually with braking pipettes and were exposed to ruthenium violet alive, during fixation with acrolein and OSO4, or during dehydration. Ruthenium violet was less toxic than ruthenium red but still killed the amoebae. Conventional methods reveal a filamentous layer 2000 Å thick, an amorphous layer 150 Å thick, and a typical trilaminar plasma membrane (48 Å center-to-center). Ruthenium violet binds to the plasma membrane, and to the extraneous coats revealing globules in the filamentous layer. The diameter of the globules decreased according to the stage of processing at which the amoebae first encountered ruthenium violet; they were 1200 Å in diameter when amoebae were alive, 600 Å in acrolein and 300 Å in dehydration. The appearance of the filamentous layer varied when ruthenium violet was replaced by very pure ruthenium red or red containing ruthenium brown (typical of commercial ruthenium red). The globules could be demonstrated without using ruthenium dyes when amoebae were treated after fixation with uranyl acetate or phosphotungstic acid. The relationship of extraneous coats of amoebae is compared with the coats and laminae of animal tissue cells.
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  • 111
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    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 171 (1971), S. 509-515 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Four-week-old female mice were injected with estradiol, and the following day received intraperitoneally one μC/gm body weight of thymidine-methyl 3H. At various intervals following the injection of thymidine-3H, pairs of mice were sacrificed, the pubic symphyses excised and prepared for radioautographs of transverse sections. Examination of the radioautographs revealed that the highest percentage of labeled cells was to be found in the osteoprogenitor cell population at all time intervals examined. The number of osteoclasts and the percentage of labeled osteoclasts rose progressively. The percentage of labeled osteoblasts rose and then fell, but was at all times much less than that of the osteoprogenitor cell population.Since the osteoprogenitor cell population was the only one in which the percentage of labeled cells was high enough to account for the rise in the percentage of labeled osteoclasts, the conclusion was drawn that the labeled osteoclasts arose from the labeled osteoprogenitor cells.In support of the above conclusion, and in keeping with the theory that the osteoprogenitor cell undergoes “differential” mitosis, one daughter cell going on to become an osteoclast or an osteoblast and one daughter cell remaining in the osteoprogenitor cell population, the number of silver grains over the labeled osteoclast nuclei was observed to be roughly one-half that over the labeled osteoprogenitor cell nuclei.
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  • 112
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    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 171 (1971), S. 559-565 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Paired membranous lamellae were observed in tumor cells from chloroleukemic rats and human embryonic mesenchyme during mitosis. These structures are morphologically identical. Their role during karyokinesis and their relationship to the nuclear envelope is discussed. In addition, it is suggested that at least two mechanisms for breakdown and restoration of nuclear envelope exist during mitosis: (1) vesiculation and (2) lamellation (the formation of membranous lamellae).
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  • 113
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    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 169 (1971), S. 23-32 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The incidence and patterns of association of tendon organs (TO's) with muscle spindles was studied in serial histological sections of the extensor digitorum brevis (EDB) muscles of an adult cat. Some observations were obtained from the medial gastrocnemius and soleus muscles of a second cat, and the EDB muscle of a two-toed sloth. An intimate relation of a TO to a nearby spindle, wherein the “spindle tendon” passes alongside the TO to attach to the aponeurosis, was found for 50% of cat EDB TO's, and 20 to 25% of the TO's in the other muscles. In cat EDB samples both TO's and spindles found in “tendon organ-spindle dyads” had larger cross-sectional areas at the equator than “solitary” units, and dyad TO's received the attachments of more extrafusal fibers than did solitary TO's. A number of the “solitary” TO's were found to be in line at a greater distance with spindles that lay along the extrafusal fibers inserting onto the TO. The possible developmental and functional significance of these findings is discussed.
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  • 114
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The plantar sweat glands of the rat have been studied by light and electron microscopy. These glands differ from conventional eccrine sweat glands of man, other primates, and cats in that the secretory segment contains only one type of secretory cell. This cell is characterized by a relatively nondescript cytoplasm containing numerous vesicles, extensive interdigitations of adjacent plasma membranes and small microvilli projecting into the lumen. In the resting gland, two types of cells can be distinguished on the basis of mitochondrial morphology. Some cells contain mitochondria in condensed configurations, and others contain mitochondria in the more orthodox configuration. Following stimulation, these differences are not pronounced; and the condensed mitochondria have evidently changed into more orthodox mitochondria in appearance. No distinct cytologic pathway for secretion could be defined, correlated with the most unusual ionic composition of the sweat in this animal (very high levels of potassium). The sweat glands of the rat foot pad then are unique as compared with other cutaneous glands both in their cytologic appearance and in the chemical composition of the sweat they elaborate.
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  • 115
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    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 169 (1971), S. 33-40 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The principal intrinsic ganglion sites in the human infant's heart have been described. They are arranged in six main groups. While most ganglia are associated with the atria, ventricular neurons have also been identified and their significance regarding possible ventricular parasympathetic innervation is discussed. The ganglia vary considerably in size, with most of the larger ones lying on the superior aspect of the heart near the superior vena cava, the aorta and pulmonary artery. They all possess well-defined capsules. Most of the contained neurons appear to be multipolar, but pseudounipolar and occasional bipolar forms have been detected. Two plexuses exist in the parietal pericardium. Large complicated nerve endings described by previous writers have not been identified, but free endings might exist. Networks in the subepicardium, subendocardium and associated with the coronary arteries have been demonstrated and their functional significance is discussed. Nerve endings, either simple or complicated, were not seen in relation to these plexuses in this investigation.
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  • 116
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Eggs of Ambystoma maculatum were separated into three groups and maintained at 5°, 8° and 14°C, respectively, until stage 27. At this stage the otic vesicle was extirpated from the right side, thus eliminating the VIIIth cranial ganglion and root. The number of cases in which Mauthner's cell (MC) failed to differentiate in the absence of VIIIth roots was compared among the three temperature groups.In a total of 713 animals, MC was absent on the side of operation in 200 cases (28.05%). Comparison of the three temperature groups with respect to the absence of MC is as follows: 14°, 39 of 212 cases (18%); 8°, 83 of 266 cases (31%); 5°, 78 of 235 cases (33%). Statistical analysis of these data demonstrates a significant difference between either one of the colder groups and the 14° group with regard to suppression of MC. When the two colder groups are tallied as a single sample, the difference is even more significant. There is no significant difference between the 5° and 8° groups. These results indicate that the differentiation of MC is more dependent upon the ingrowth of VIIIth root fibers when morphological development has been delayed by prolonged hypothermia.
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  • 117
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The study of the fine structural organization of the various components of the neck of mature spermatozoa of rabbit, monkey and man has demonstrated that the striated columns of the connecting piece implant on the proximal centriole, that the distal centriole does not disappear but persists albeit in a modified form and that the central tubules of the axoneme of the flagellum terminate at the lower vault of the proximal centriole. Of the two centrioles, the most plausible candidate for the role of basal body of the flagellum and center of the sperm motility appears to be the proximal centriole. This hypothesis is supported directly by the apparent continuity of this centriole with all the contractile elements of the flagellum, and indirectly by the consideration that the distal centriole cannot be a basal body in that its lumen is traversed throughout by a central pair of tubules. The orientation of the proximal centriole at an angle to the flagellum, a unique situation since basal bodies are normally oriented on the same axes of cilia and flagella, has been tentatively accounted for by the particular type of motility of the spermatozoon.
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  • 118
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    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 169 (1971), S. 259-485 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
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  • 119
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    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 169 (1971), S. 487-499 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: A light and electron microscopic study was conducted on the X cell of the normal dog pancreas. These cells were identified by their acidophilic cytoplasmic granules which do not stain with iron or phosphotungstic acid hematoxylin and also show a distinctive multilobate nucleus. They were found to be neither argyrophilic nor argentaffinic. Ultrastructurally, when fixed in osmium alone, the X cell cytoplasm contained numerous rounded, smooth membrane bound secretory granules with content of low electron density. However, after double fixation in glutaraldehyde and osmium the granules appeared irregularly round, ovoid or kidney shaped with content which may vary from electron lucent to homogeneously electron dense with gradations between. The functional significance of the X cell is unknown. However, its structure showed it to be a distinct, active secretory element, independent of other pancreatic exocrine and endocrine cell types.
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  • 120
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    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 169 (1971), S. 613-625 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: In sections of thymus stained with the tannic acid-phosphomolybdic acid-amido black (TPA) technique, the epithelial reticular cells can readily be identified by the well-stained tonofibrils in their cytoplasm. In the cortex, flattened epithelial reticular cells form a continuous layer on the inner surface of the capsule and along the interlobular septa. Within the cortex proper, stellate epithelial reticular cells are widely dispersed as a loose network. In the medulla, two zones, referred to as “outer” and “inner” medulla, are distinguished. The outer medulla, like the cortex, contains epithelial reticular cells, but these are more voluminous, are more richly provided with tonofibrils and form a denser network than in the cortex. In the inner medulla no epithelial reticular cells can be seen but instead connective tissue cells and fibers make up the supporting framework. A layer of flattened epithelial reticular cells demarcates the outer from the inner medulla. This layer of cells also extends along the outer surface of blood capillaries seen in the outer medulla and cortex. Around the larger blood vessels, this layer of epithelial reticular cells is separated from the vessel wall by a connective tissue perivascular space. Hence, the inner medulla is continuous with the perivascular spaces and, like them, is supported by connective tissue. Thus, the epithelial reticular cells constitute the supporting framework of the cortex and outer medulla and separate these regions from the connective tissue of the capsule, interlobular septa, blood vessels and inner medulla.
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  • 121
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: An electromyographic investigation of the mylohyoid muscle was undertaken to determine its activity relative to isolated movements of the tongue and mandible and during various functions involving multiple parts of the oral apparatus. Data was obtained from 20 subjects. Using bipolar fine-wire electrodes, the anterior fibers were found to be more active than the posterolateral fibers in a majority of activities performed. Tongue movements produced slightly more activity in the postero-lateral fibers; the anterior fibers were more active during mandible movements. During mastication, deglutition, sucking and blowing, both the anterior and postero-lateral fibers were markedly active.
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  • 122
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    The @Anatomical Record 169 (1971), S. 705-715 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The cartilage plates covering the lumbar vertebral bodies were examined macro- and microscopically in infants and children. Particular attention was given to the distribution of vascular canals within these plates. Some of the canals are responsible for the formation of spoke-like ridges of cartilages. The latter develop as the vertebral body expands in height and girth. The canals show a characteristic distribution and end blindly in the neighborhood of the anulus fibrosus.The cartilage plates are known to provide a growth zone for the center of the vertebrae. In addition, they appear to contribute also to the growing intervertebral disc. The present investigation suggests that an association exists between the blind endings of the vascular canals and the interstitial lamellar growth of the anulus fibrosus at the time of active, postnatal disc expansion.Comparison of differences in shape of infantile lumbar vertebrae were made in various cases with a known history. These studies suggest that weight bearing and movement influence the development of a particular shape. It can be demonstrated that in the absence of normal stresses some lumbar vertebrae grow taller and have a decreased anterior-posterior diameter.
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  • 123
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    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 170 (1971) 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
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  • 124
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    The @Anatomical Record 170 (1971), S. 31-39 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The microvascular architecture of the adult human testis was studied from autopsy material using microangiography. The intratesticular arterial vessels show peculiar coiling independent of the age of the subject. These arteries run in either a centripetal or a centrifugal direction and give rise to inter-tubular and peritubular capillary networks which are basically similar to those of the rodent testis. Venous drainage is directed either towards the surface of the testis or towards the rete testis. Some capillaries in the vicinity of the seminiferous tubules penetrate some of the layers of the tunica propria. The rete testis has a completely different and rather sparse microvascular architecture, and both the rete and the tunica albuginea receive blood from extratesticular sources as well as from the testis.
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  • 125
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    The @Anatomical Record 170 (1971), S. 57-74 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The origin and development of the sphincter pupillae muscle was studied in Taricha torosa by electron microscopy. The larval optic cup with its inner and outer epithelial layers is completely enshrouded by a primary basal lamina. The epithelium can be divided into E and R regions, according to the types of distributed pigment granules, ellipsoidal (E) and round (R). The E region includes the outer layer except the pupillary zone; the R region the inner layer and pupillary zone. The boundary dividing these regions is distinct enough to be called the E-R boundary. Clusters of fine filaments develop in the pigment-containing R cells adjacent to the E-R boundary during metamorphosis. Such R cells subsequently increase their population to form abundle swelling into the anterior ocular chamber. This bundle formation is accompanied by acquisition of a nerve supply from the iridial stroma, and the emergence of collagen fibers as well as secondary basal (or external) laminae surrounding each cell of the bundle. The adult muscle cells retain numerous round pigment granules, desmosomes, and intermediate junction.These facts support the neuroectodermal origin of this sphincter pupillae muscle.
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  • 126
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Sections of uterine cervix from ovariectomized mice treated with relaxin (R) or estradiol benzoate (EB) alone or EB and R in combination were exposed to dialyzed iron solutions prior to epoxy embedding. Control mice were untreated or received the hormone vehicles. Prior to iron staining, some sections were exposed to: (1) 0.05% testicular hyaluronidase for four hours at 37°C; or (2) acidified methanol for four hours at 60°C. Ultrastructurally, the uterine cervical walls from control mice and those treated with R contained densely packed bundles of collagenous fibrils and cells that resembled fibrocytes with few organelles. Except for spurious intracellular iron deposits, there was no iron staining of extracellular components.Fibroblasts of cervices from mice treated with EB or EB and R were larger with highly developed endoplasmic reticulum and Golgi components. Small cytoplasmic vesicles were present close to the cell surface and each contained a thin inner rim of material. The stroma was characterized by widely dispersed bundles of collagenous fibrils in a greatly expanded cervical wall where there was extracellular iron staining that was prominent near cell surfaces and between individual fibrils within an amorphous material. Brief digestion with testicular hyaluronidase resulted in a reduction of extracellular iron staining, although deposits remained adjacent to cell surfaces, between fibrils and within cytoplasmic vesicles. Acidic methylation caused severe tissue damage so that an assessment of iron deposition in thin sections was impossible.
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  • 127
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    The @Anatomical Record 170 (1971), S. 147-181 
    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 normal mouse adrenal cortex and the zona glomerulosa as stimulated by sodium restriction and repressed by high salt intake is reported. The mitochondria are zone specific, the endoplasmic reticulum tubular and the endothelium fenestrated. An intimate relationship between elements of reticulum, mitochondria and lipid droplets is seen in all animals. The rough reticulum is poorly developed in all but the glomerulosa of salt-restricted animals. The Golgi apparatus, associated vesicles and surface microvilli are relatively more developed in the inner cortical zones and in the glomerulosa cells of stimulated animals, whereas surface coated pits and vesicles do not vary. Lysosome-like granules are more prominant in the control reticularis and in the glomerulosa of animals on high salt intake.In stimulated glomerulosa cells, there is an early depletion of lipid droplets and a transient increase in rough reticulum followed by a progressive increase in smooth reticulum and Golgi apparatus. At three weeks, the lipid droplets are restored. In repressed glomerulosal cells, there is atrophy of the cytoplasmic organelles while lipid droplets are increased in number and osmiophilia. An accompanying feature is the appearance of cytoplasmic β-glycogen. These observations are discussed as to their relation to adrenocortical steroidogenesis and secretion.
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  • 128
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    The @Anatomical Record 170 (1971), S. 225-234 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The dorsal epidermis of fetal and newborn rats was examined to determine the difference in ability of the basal cells to bind tritiated thymidine during different stages of epidermal morphogenesis. Five rats were examined for each time period from the eleventh day of gestation to the fifth day after birth. The number of labeled cells in 5000 basal cells was counted and expressed as a percentage. The labeling index is ∼ 10% from the eleventh to the fifteenth fetal day. It increases to ∼ 30% by the eighteenth day, decreases to ∼ 10% from the twenty-first day until the first postpartum day and drops to 5% or less from the second to fifth day. These changes in labeling index are accompanied by and apparently correlated with the normal differentiation of rat epidermis. The growth of the epidermis is continuous during the course of the study. Keratohyalin granules begin to form on the eighteenth day and by the twentieth day the first cornified cells appear. The s. corneum becomes progressively thicker each day thereafter. The s. Malpighii, on the other hand, decreases somewhat in thickness after birth. The labeling index curve represents a relationship between basal cell activity and control or influencing mechanisms inherent in the maturational system of skin. The increase and decrease are not related to growth alone, but appear to be related to differentiation.
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  • 129
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Male and female A/Jax mice 10-18 days of age were given one, two, or three daily subcutaneous injections of Serpasil (Reserpine USP; 2.5 mg/kg) and sacrificed 24 hours after the last injection. Abdominal extra-adrenal tissue was processed for electron microscopy to determine the effects of this catecholamine depleting drug on the dense cored cytoplasmic granules of the parenchymal chief cells.Electron microscopic investigations of sympathetic paraganglia from treated animals revealed a marked decrease in granule opacity as compared to that seen in cells from control animals. The cells with granules reduced in opacity following reserpine treatment could be consistently distinguished from those of non-treated animals which led us to assume that the drug depleted the amine content from its storage site in the granule without completely destroying the granule structure. These results further substantiate our earlier speculations that the granules in abdominal paraganglion chief cells of the mouse contain catecholamines.
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  • 130
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    The @Anatomical Record 170 (1971) 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
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  • 131
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: An electromyographic study of elbow flexors and extensors was conducted using 20 adult human subjects to determine if cocontraction occurred during voluntary movement. The interplay of proprioceptive reflex influences arising in the primary and secondary endings of the muscle spindle and in the Golgi tendon organ provide the neurophysiological basis for cocontraction. Whether or not cocontraction occurs during a movement is dependent on the degree to which one proprioceptive influence predominates over the others. This in turn appears to be dependent on factors such as those described below.Incidence and degree of cocontraction was greater during extension than during flexion movements. This may be attributed to the influence of muscle spindle secondary endings.Cocontraction increased with increasing load. Proprioceptive reflexes arising in tendon organs may be involved in this phenomenon.No evidence was found to indicate that the incidence of cocontraction increased with increasing precision of movement. In general, cocontraction was less in skilled and strong subjects than in average subjects during all types of movements.Under the special circumstances of voluntarily attempted cocontraction, evidence of reciprocal inhibition of the antagonist appeared. Proprioceptive reflex activity from tendon organs and from muscle spindle secondary endings are implicated as primarily responsible for this inhibition.
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  • 132
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    The @Anatomical Record 170 (1971), S. 303-308 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Quantitative counts of the greater petrosal nerve fibers of the mouse with the electron microscope have shown that, on an average, 70.8% and 28.7% of the total nerve fibers (1,111) were unmyelinated and myelinated fibers respectively. Unexpected high incidence of unmyelinated fibers in the greater petrosal nerve may indicate that it contains a fair amount of sympathetic post-ganglionic fibers. The unmyelinated fibers in the nerve may well represent parasympathetic preganglionic fibers.
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  • 133
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    The @Anatomical Record 170 (1971), S. 357-363 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Microradiographic, polarized light, phase-contrast and scanning electron microscopic aspects of Tomes' granular layer were studied in undemineralized and demineralized premolar teeth from four dogs. The microradiographic studies show Tomes' layer to consist of a narrow zone of hypomineralized-hyperorganic dentinal matrix subjacent to the cementum. The zone appears as a series of focal points in cross sections or as an interrupted line in apico-coronal cuts through the tooth. Polarized light and phase-contrast microscopy demonstrate a morphological pattern similar to that of the microradiographs. Scanning electron microscopy suggests one component of Tomes' layer to be fibrillar. Tomes' granular layer of dog teeth may be important in protecting the tooth from sudden insults or large occlusal forces transferred to dentine via the periodontal ligament.
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  • 134
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    The @Anatomical Record 170 (1971) 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
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  • 135
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    The @Anatomical Record 170 (1971), S. 413-419 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The relationship between the Sertoli cell counts, some measurable parameters of the seminiferous tubules and the dimensions of the Sertoli cell nuclei were examined in both normal and degenerate testes. Highly significant differences were found between rams in the numbers and in the dimensions and volumes of the Sertoli cell nuclei and in the diameters of the seminiferous tubules. The Sertoli cell counts were corrected for the differences in nuclear volume by dividing the count by the calculated nuclear volume. The Sertoli cell counts were corrected for changes in the area of the seminiferous tubule wall by multiplying the count by the square of the tubule radius. Correction for either nuclear volume or tubule area alone increased the differences between the Sertoli cell counts, but a simultaneous correction for both factors equalized the counts so that there were no significant differences between rams in the number of Sertoli cells per tubule cross-section. It was concluded that, in normal and degenerate ram testes, counts of the Sertoli cell nuclei in the seminiferous tubule cross-sections, when corrected for differences in nuclear volume, would provide a valid basis for comparing volume-corrected counts of spermatogenic cells in different animals and in different treatments.
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  • 136
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    The @Anatomical Record 169 (1971), S. 65-69 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: In the head process to early head fold stage chick embryo, the cells which will form the pulmonary veins are located in the mesoderm near the posteromedial edges of the heart-forming regions. At the 26 somite to early limb bud stage, the presumptive pulmonary vein cells have been folded to the midline of the embryo as part of the splanchnic mesoderm and form the endothelial plexus which courses through the dorsal mesentery of the sinoatrial region of the heart.
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  • 137
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Rat lungs were fixed by perfusion of fixatives through pulmonary vessels which resulted in good fixation of bronchioles. This technique allows the preservation of a hitherto not described extracellular lining of the bronchiolar surface, which by conventional fixation (immersion or instillation of the fixatives into the airways) is washed out. The cilia appear to be embedded in an extra-cellular, amorphous material. This material is often lined at its surface by a strongly osmiophilic layer. Tubular myelin figures can also be identified. Comparison with recent physiological and biochemical work, which establishes the presence of surface-active material in the airways, strengthens the conclusion that this layer is related to bronchiolar “surfactant” fixed in situ. A mixed origin of this material from the Clara cells and from the alveolar surface lining layer is suggested.
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  • 138
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: In Tadarida, the endodermal cells that form the yolk sac originally delaminate from the inner cell mass and proliferate to form a complete lining of the trophoblastic vesicle, creating a bilaminar omphalopleure. These cells remain squamous until the splanchnic mesoderm migrates in between the two layers of the omphalopleure, at which time they begin to hypertrophy. The current study is an analysis of the cytological changes that accompany this hypertrophy as well as additional changes that occur throughout the remainder of the gestation period. Among the early changes are: (1) the formation of numerous microvilli along the apical surface of the cells, (2) the appearance of coated vesicles, also along the apical plasma membrane, (3) the establishment of a system of absorption tubules in the apical cytoplasm, (4) an increase in mitochondria, and (5) the appearance of glycogen within the channels of the membranous organelle.A wave of hematopoietic activity follows the migration of splanchnic mesoderm around the trophoblastic vesicle, and at this time the erythroblasts and embryonic erythrocytes can be seen in a close relationship with the endodermal cells.Subsequent changes include the enlargement of the membranous organelle and the appearance of a paracrystalline membranous structure. In addition, the endodermal cells store large quantities of lipid and glycogen that are substantially depleted just before birth.
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  • 139
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: In the molossid bat, Tadarida brasiliensis cynocephala, there is a prominent diffuse endotheliodichorial placenta over the parietal area of the uterus prior to mid-gestation. During the neural groove stage the syncytium rapidly increases in quantity, and cells from the cytotrophoblast have been observed being contributed to the syncytium. The transitional cells become swollen and the plasma membranes between the syncytium and the transitional cell fuse, become porous, and rupture. The contents of the transitional cell then “flow” into the syncytial area.
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  • 140
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    The @Anatomical Record 169 (1971), S. 515-531 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Type A spermatogonia in the mouse can be separated into five successive classes on the basis of nuclear morphology and stage of the cycle in which they occur. Enumeration of all types throughout the cycle of the seminiferous epithelium reveals that the As spermatogonia are the stem cells. They divide throughout the cycle and, especially at stages IX to I, form chains of cells which then give rise to spermatogonia A1 at stages II-VIII. The A1 cells divide in IX to form the A2, which divide in XI to form A3, and the A3 cells divide in I to form the class A4 spermatogonia. Spermatogonia A4 give rise only to the In type; there is no evidence for the formation of either As or A1 from A4 spermatogonia. Repeated injections of 3H-thymidine and tracing the history of labeled cells to 15 days after labeling supported the conclusion obtained from morphological and numerical data that As spermatogonia are the stem cells of the testis.
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  • 141
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    The @Anatomical Record 169 (1971) 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
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  • 142
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    The @Anatomical Record 169 (1971), S. 637-649 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Pituitary glands of 30 ♀ rats from one to seven and one-half months old were fixed in glutaraldehyde followed by osmium tetroxide. One five-month gland was fixed in Karnovsky's paraformaldehyde mixture.Cilia in the residual cleft at all ages and in the electron lucid vesicles found in the pars distalis during the first two months occur in great numbers per cell and show the 9 + 2 pattern (9 peripheral doublets around 2 central tubules slightly separated from each other) characteristic of kinocilia. The spaces into which these cilia project may contain disintegrating cells as well as colloid-like material of variable density.Cilia found in or between parenchymal cells of the pars distalis usually occur one per cell and lack central tubules. One of the doublets is often displaced toward the center. Cilia have been seen in three types of granular as well as in non-granular cells. A pair of cilia enclosed in the same membrane was found once within and twice between parenchymal cells.Central tubules appear to develop only in locations (cleft and vesicles) where motility is possible. The single cilia found in parenchymal cells may be considered immature and are presumably non-functional.
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  • 143
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Recent data indicate active transport of Na+ and K+ by the main excretory duct (MED) of the rat submandibular gland. In view of these data submandibular MED's of four adult rats were investigated by transmission electron microscopy. Luminal surfaces of two MED's were examined with the scanning electron microscope. The duct is surrounded by connective tissue, blood vessels and neuron perikarya. Blood supply to the ductal epithelium consists of a plexus of sinusoidal capillaries. Three principal cell types compose the epithelium: light cells, dark cells, and basal cells. The basal cells resemble those of striated ducts except for the presence of numerous hemidesmosomes along basal plasma membranes of MED basal cells. Light cells show basal infoldings, and bulbous enlargements may occur at their distal aspects. Dark cells are narrow, electron dense cells with prominent microvilli at the luminal surface. Intercellular clefts penetrate MED epithelium from the lumen to a depth of one-third the epithelial thickness. Surfaces of the clefts are lined by dark and light cells. Intercellular tissue spaces are present at lateral boundaries of all cells and extend from the epithelial base to distal cytoplasmic levels.
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  • 144
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    The @Anatomical Record 169 (1971), S. 727-730 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: This paper describes the morphology of the popliteus muscle based on the dissection of 15 human cadaver's knees. The muscle is found to have three origins: the strongest from the lateral femoral condyle is already wellknown, but there is also an important band from the fibula and a firm attachment to the posterior horn of the lateral meniscus. The femoral and fibular origins form the arms of an oblique Y-shaped ligament, the base of which is formed by the capsule and the meniscal origins. This previously was described as a separate entity, the “arcuate ligament,” attached to the belly of the muscle, but it is not a separate ligament. Rather it is a condensation of the fibers of origin of the popliteus including those from the fibula.
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  • 145
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The fine structure of the synchronized cultures of B16 melanoma cells at different days of incubation was studied.Our observations demonstrate that the endoplasmic reticulum first develops in the dividing cells as simple flattened smooth cisternae, which become paired or multilamellated during nuclear reconstruction and form annulate lamellae as well as typical endoplasmic reticulum with ribosome-studded membranes in the postmitotic and interphase cells.The presence of both premelanosomes and melanosomes in dividing cells is unequivocal evidence that functionally mature melanocytes are capable of proliferation.
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  • 146
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: It is possible to divide the ultrastructural events which take place in the mouse Leydig cell during postnatal differentiation into two periods. The first period includes the changes taking place during the first three weeks after birth, whereas the second period comprises the events occurring from the fourth week on. During the first period the cytoplasm contains a poorly developed smooth endoplasmic reticulum. After the tenth day a slight increase in the number of vesicles and tubules of the smooth endoplasmic reticulum is observed. Clusters of glycogen particles (beta type) and lipid droplets are very numerous in this period.At the beginning of the second period the smooth endoplasmic reticulum hypertrophies considerably occupying a large area of the cytoplasm. This period is also characterized by the appearance of double-walled tubules, of numerous interdigitations between neighboring Leydig cells and primary lysosomes in close relation to lipid droplets. A marked decrease in the number of glycogen particles and lipid droplets are also found. In the adult mouse (after day 50) numerous cisternae of the smooth endoplasmic reticulum are concentrically arranged (whorls).The formation of new membranes in the Leydig cell undergoing differentiation and the control of such differentiation are discussed.
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  • 147
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    The @Anatomical Record 170 (1971), S. 401-411 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The opisthonephric kidneys of both larval and adult Petromyzon marinus lack a renal portal system. The tubules are supplied with arterial blood from the glomus through a system of efferent arterioles, capillaries, and sinusoids with the latter draining into the venous system. The adult kidney possesses a more complex and larger system of sinusoids than ammocoetes and these sinusoids reach the venous system through large subcapsular sinuses. Paralleling of tubules with sinusoids and arterioles in the ventral portion of the adult kidney resembles the association of the vasa recta with the tubules of the renal medulla in the mammalian kidney. This may suggest a mechanism important to tubular transport in adult lampreys. The intertubular tissue of ammocoetes is infiltrated with haemopoietic tissue while large numbers of phagocytes within the adult sinusoids may be involved in the destruction of blood cells.
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  • 148
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    The @Anatomical Record 170 (1971), S. 421-435 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The source of the new nuclei appearing during the growth of muscle fibers was examined in the tibialis anterior muscle of young Sherman rats (14-17 days of age) using radioautography at various intervals after a single injection of a small, non-toxic dose of 3H-thymidine (2 μCi/g body weight). Two techniques were employed: (1) labeled nuclei were detected in 1 μ thick radioautographs examined in the light microscope, and identified by simultaneous electron microscope examination of an adjacent section. The nuclei were then classified either as “true” muscle nuclei (within the plasmalemma of the fibers) or as belonging to “satellite cells” (which are mononucleated cells with scanty cytoplasm wedged between plasmalemma and basement membrane). (2) Muscle fibers freed by collagenase digestion were radioautographed one hour after 3H-thymidine injection in order to determine the total number of labeled nuclei (true muscle nuclei plus those of satellite cells) per unit length of fiber.Certain nuclei within the basement membrane of muscle fibers are labeled one hour after 3H-thymidine and, therefore, synthesize DNA. The electron microscope demonstrates that these nuclei invariably belong to satellite cells, never to true muscle nuclei. Furthermore, the total number of labeled nuclei per unit length of fiber doubles between 1 and 24 hours; and, therefore, the labeled satellite cell nuclei undergo mitosis.Following mitosis, half of the daughters of satellite cells are incorporated into the fibers to become true muscle nuclei. The remaining half divides again later; and half of their daughter cells are incorporated. Thus, satellite cells in young rats divide repeatedly and function as a source of true muscle nuclei.
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  • 149
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    The @Anatomical Record 171 (1971), S. 117-216 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
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  • 150
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    The @Anatomical Record 171 (1971), S. 99-115 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The intracranial epiphysis of the adult frog, Rana pipiens, has been examined by electron microscopic cytochemistry and radioautography. Acid phosphatase is localized within vacuoles of macrophages free in the lumen, in subspherical vesicles of the ellipsoid portions of photoreceptive cell inner segments, and in occasional heterogeneous cytoplasmic inclusions of the supportive cells.The distribution of radioactivity in the epiphysis at intervals of 1, 3, 5, 9, 14, 25, and 60 days following injection of tritiated leucine, as determined by quantitative radioautography, is consistent with an hypothesized process of continual renewal of photoreceptive cell outer segments. The pattern of radioautographic labeling of the pineal photoreceptors, which resembles more closely that of retinal cones than rods, is correlated with previous morphologic and electrophysiological studies of these cells.The radioautographic and cytochemical data suggest that macrophages within the epiphyseal lumen are involved in phagocytosis and, ultimately, in digestion of degenerate outer segments. They may perform a function similar to that of pigment epithelial cells of the lateral eye retina.
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  • 151
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    The @Anatomical Record 171 (1971), S. 227-236 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: One hundred and thirty-six unfixed fetuses below 500 gm of body weight were examined and the brain, liver, lung, kidney, heart, adrenal, thymus, spleen, and thyroid were weighed. The ratios of organ weight to body weight could be divided into four general patterns: (1) constant; liver, heart, brain, and thyroid (2) increasing; thymus, adrenal, and spleen (3) initially increasing and then reaching a plateau; kidney, and (4) increasing and then decreasing; lung. Graphs of the mean and 95% confidence levels along with the formulas used for derivation are given for each organ on the basis of body weight.
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  • 152
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    The @Anatomical Record 171 (1971), S. 247-258 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Mature ultimobranchial follicles in the Fischer rat thyroid are characterized by being lined by two or more layers of cells (U cells) and by having an abundance of desquamated cells in the lumen. Such follicles, of variable size and shape, were found in almost every lobe in rats at least 30 days old. They were usually in the interior of the lobe in contact with perivascular connective tissue. Ultimobranchial follicles with multiple layers of cells were not observed in the two-day-old rat indicating that these follicles are an example of postnatal development. The most common precursor in the rat was a follicle, relatively large compared with the usual thyroid follicle, containing some cells or debris. Other precursor structures included narrow tubes, sheets or spheroids of cells characteristically having little cytoplasm. Intermedlate forms between these precursors and mature ultimobranchial follicles were recognized. Cells were desquamated while nucleated, and, later, the nuclei disappeared. Thus, in some follicles non-nucleated debris accumulated. Many follicles were composed of mixed populations of cells, both typical thyroid epithelium and U cells. The relative abundance of the two cell types varied markedly as did the proportions of colloid and cell debris.
    Additional Material: 29 Ill.
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  • 153
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The temporal pattern of increase in number of neuroglia in spinal cord white matter and the amount of multiplication in situ of these cells were studied in rats ranging from less than 12 hours following birth to 30 days of age. Autoradiographs of sections from animals killed four hours after injection of tritiated thymidine were studied; counts of the total neuroglial population and of the number of labeled neuroglia were made in the white matter of each half of the cord (hemisection). During the first two weeks following birth, the number of neuroglia per hemisection increased six times; thereafter, the population appeared to be stable. The increases in number of labeled neuroglia appeared to parallel the rise in total population, particularly during the period of greatest population increase, i.e., days 7 through 12. After 12 days, when the total population stabilized, there was a marked and rapid decrease in the number of labeled cells. The walls of the central canal were examined in view of the role this area plays in the initial development of the nervous system. In rats killed during the first 14 days postnatally, the dorsal and ventral walls were incomplete; however, numerous, unidentified cells adjacent to these walls were oriented as if entering the dorsal median septum and the ventral median sulcus. By 22 days the central canal area had more of its adult appearance.
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  • 154
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    The @Anatomical Record 171 (1971), S. 329-345 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The three types of bone cells in the nasal turbinates had characteristic ultrastructural features. Osteoblasts were located in areas of new bone formation and had abundant endoplasmic reticulum, prominent Golgi apparatuses, numerous vesicles, and cytoplasmic processes that penetrated the adjacent osteoid. Osteocytes had variable ultrastructural characteristics. The predominant cell filled the lacuna, had few organelles, smooth plasma membranes, and was interpreted to be a mature resting osteocyte. Some osteocytes appeared to be transitional between osteoblasts and mature osteocytes. Evidence of matrix formation was seen near osteocytes with well developed organelles, whereas osteocytes with swollen mitochondria, dense bodies and irregular plasma membranes appeared to be involved with resorption of bone. Multinucleated osteo-clasts contained numerous mitochondria and had crystals or unmineralized collagen fibrils between folds and within vacuoles of the cytoplasmic projections forming the brush border.
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  • 155
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    The @Anatomical Record 171 (1971), S. 347-368 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The properties of the inorganic dye ruthenium red are presented with emphasis upon its use for electron microscopy of cells and tissues. Although commercial ruthenium red often can be used directly, it always contains various impurities and by-products. One of these, termed ruthenium violet, can be isolated and is useful by itself. Absorption spectra of the ruthenium dyes and common impurities are given so that an assay is possible for any sample. Convenient fixative recipes containing ruthenium red or violet are provided together with constraints necessary for a reliable reaction to label extracellular acidic mucosubstances. Perfusion was not successful. The specificity of the ruthenium red reaction was evaluated by spot testing with 57 substances, and by titration with chemically defined pectins. The results indicate that ruthenium red, as a hexavalent cation, precipitates a large variety of polyanions by ionic interaction, and that its classical reaction with pectin is typical rather than specific. New data are presented regarding its reaction with phospholipids. For electron microscopy, a further reaction with OsO4 amplifies the feeble electron density, which is the counterpart of its intense optical labeling, to a practical level resulting in strong contrast. An hypothesis is presented for the mechanism underlying this intensification.
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  • 156
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    The @Anatomical Record 171 (1971), S. 471-475 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: No spaces were seen within the tight junctions of descending thin limb cells of Henle's loop in rat kidney, although spaces 70 Å in diameter and larger had previously been reported in studies utilizing rabbit kidney. Colloidal lanthanum added to the fixative solutions was not able to penetrate these rat tight junctions.
    Additional Material: 4 Ill.
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  • 157
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The structure of the developing sinuses of the bone marrow was studied in extramedullary autotransplants of the marrow in rats just before the onset of hemopoiesis. Sinuses are highly branching channels with walls consisting of a single layer of endothelium. The wall thickness varies considerably but larger sinuses generally have a thinner wall. Endothelial cells may overlap and interdigitate displaying junctional densities. Abrupt thinning of endothelium was observed in some areas but no apertures were noted. The endothelium is sometimes surrounded by collagen, but no basement membrane is present. Twenty-four percent of the endothelial surface is covered by pericytes and often rarified cytoplasmic spurs extend into perisinus areas. Microfilaments were seen under the cell membrane of pericytes. Medium-sized lymphocytes are frequently seen in the sinal lumen and intersinal tissue and they may constitute hemopoietic stem cells.
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  • 158
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    The @Anatomical Record 171 (1971), S. 517-527 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: This investigation examined the development of intramedullary Schwann cells. The presence of these cells in spinal cords of rats irradiated when three days old and examined 15 or more days later had been noted previously in this laboratory. The present study is an autoradiographic evaluation of spinal cords from groups of rats receiving a single injection of tritiated thymidine at an interval from 7 to 15 days after irradiation (3 days of age) and killed four hours to seven days following injection. The earliest post-irradiation interval at which the intramedullary Schwann cells were present was at nine days in only one animal. These cells were seen in approximately half of the rats injected and killed 11 days after irradiation and in all in the 15-day-group. In all of these cases the animals were killed four hours after injection of tritiated thymidine and a portion of this cell population was labeled. When the time between injection and autopsy was delayed for three or seven days, a decrease in intensity of the labeling was apparent and many cells were lightly labeled, indicating that cell proliferation had occurred. Although the evidence was not conclusive, the results suggested that the intramedullary Schwann cells were probably progeny of cells derived from the dorsal roots, the latter cells having been stimulated to migrate into and to divide within the spinal cord.
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  • 159
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: This study was carried out to determine the effects of denervation of the pulp organs of teeth, particularly on the odontoblasts and their processes. Therefore, resection of the inferior alveolar, cervical sympathetic, or a combination of both types of nerves supplying the mandibular incisor teeth of New Zealand white rabbits was performed and the results compared to adjacent, unaltered teeth. Neural stains were used to evaluate the presence or absence of nerve elements, while histochemical and titrametric methods were employed to determine the presence, location and concentration of cholinesterase enzymes in these teeth. Dilation of blood vessels was noted after cervical sympathetic resection and larger nerve trunks as well as peripherally located fine fibers were absent in the pulps following inferior alveolar nerve resection. Further, irregular dentin formation and associated small openings in the tips of the teeth were observed after nerve resection. Titrametric analysis indicated a significant decrease in the concentration of cholinesterase in the pulp organ of incisors 15-19 days after resection of either the inferior alveolar nerve or both inferior alveolar and cervical sympathetic nerves. Only a slight decrease in the concentration of cholinesterase was noted after removal of the cervical sympathetic nerve alone. Histochemical results confirmed a decrease in cholinesterase after resection of the inferior alveolar, cervical sympathetic or both nerves. The concentration of the oxidative enzyme, succinic dehydrogenase, however, increased after all three types of nerve resection. This increase was apparent particularly in the odontoblastic cells underlying the predentin.
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  • 160
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    The @Anatomical Record 169 (1971) 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
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  • 161
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The possibility of the formation of new lobules in rat liver during the course of compensatory growth has been investigated. Two methods inducing regeneration were used: the method of subtotal hepatectomy and the method of porcelain bead implantation. Observations were made at 28, 42, 56, 68, 84 and 112 days after subtotal hepatectomy, and at 28 and 42 days after implantation of the bead.The results obtained from subtotal hepatectomy were expressed as the lobular radius (or portal-central vein distance) measured in micra. The values were 404 μ at the twenty-eighth day after hepatectomy and 324 μ at the one-hundred-twelfth day. The results obtained from bead implantation were 352 μ at the twenty-eighth day after implantation and 305 μ at the forty-second day.It is concluded that regenerating rat liver undergoes structural changes involving new lobule formation between the fifty-sixth and the one-hundred-twelfth day after subtotal hepatectomy, and sometime after the fourth week after bead implantation. The difference in times after which structural changes occur is explained by the difference in intensity of stimulus in the two methods.
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  • 162
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    The @Anatomical Record 169 (1971), S. 585-591 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: A three-dimensional reconstruction of the rod profiles seen in inner and outer rat incisor enamel was made from serial 1 μ cross sections of a decalcified upper incisor. The enamel rod was found to be an elongated structure which travelled incisally relative to its origin and ran continuously from the dentino-enamel junction to the enamel surface. The rod was divisible into an inner and outer enamel portion. The inner enamel portion began at the dentinoenamel junction and travelled incisally for about 20 μ with either a mesial or lateral tilt towards the outer enamel. The outer enamel portion of the rod was straight and ran incisally for about 60 μ as it gradually approached the enamel surface.Inner enamel portions of rods were arranged in rows parallel to the cross sectional plane of the incisor. All the rods in each row were tilted either mesially or laterally such that individual rods of adjacent rows crossed each other at 90°. Outer enamel portions of rods were not arranged in rows but all passed incisally parallel to one another.
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  • 163
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    The @Anatomical Record 169 (1971), S. 559-583 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The structure of the organic matrix close to the mature enamel in 100 gm rat incisors was studied by light and electron microscopy using EDTA decalcified teeth.Under the light microscope, in 0.5 μ Epon sections, the enamel layer of cross sectioned upper incisors was about 60 μ thick. The inner enamel was about 40 μ thick and consisted of an initial enamel layer (4 μ) adjacent to the dentin in which no rod profiles were seen, and an inner layer proper which contained six to eight rows of oval-shaped rod profiles set in a homogeneous background. The profiles in any given row were inclined mesially or laterally and alternated in adjacent rows. The outer enamel was about 20 μ thick and consisted of an outer enamel proper and a 2-4 μ thick final enamel layer which smoothed out the enamel surface. The outer enamel proper contained smaller elliptical rod profiles in a more abundant background. These profiles were not arranged in rows and were oriented at right angles to the enamel surface. The final enamel layer contained no rod profiles and was lined on its outer surface by a PA-Schiff positive layer resembling a basement membrane.Under the electron microscope the matrix of rod profiles and interrod material could be distinguished. This consisted of aggregated tubular (and filamentous) subunits, 250 Å in diameter, with empty space between them. Within the rod profiles the subunits ran parallel to the rod's long axis, whereas in the interrod material the subunits were again parallel but but running at right angles to the subunits of the rods. In addition to forming the material between the rods, the interrod material also formed the initial and final enamel layers.
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  • 164
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    The @Anatomical Record 170 (1971), S. 75-79 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The fine structure of the sheep hepatic sinusoid has been examined. Unlike that of most previously studied mammals, the sheep sinusoid has a continuous endothelial lining and a distinct basal lamina. Another unusual feature of the sheep sinusoidal endothelium is the presence of fenestrae closed by thin, single-layered diaphragms. Between the basal lamina and the hepatic parenchyma, processes of perivascular connective tissue cells are seen in unusual abundance. Particles consistent in size with very low density lipoproteins are found on both sides of the basal lamina, but the mechanism of transport of these particles across the endothelial barrier is unknown.
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  • 165
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Fresh tibias and occipital bones from newborn mice and rats, as well as from 18-day-old mouse and chick embryos, were stained with 10% GBHA and 5% AgNO3 solutions to localize calcium and phosphate or carbonates in sphenules within the cytoplasm of chondrocytes and in the matrix of the calcifying cartilages. The mineralized spherules in the matrix adjacent to the hypertrophied chondrocytes were approximately 0.5 to 1 μ in diameter. This was comparable in size to the spherules found within the cytoplasm of the chondrocytes. The spherules within the core of the spicules distal to the hypertrophied chondrocytes were about 2-3 μ in diameter. The larger spherules were shown to contain an organic core which stained metachromatically with toluidine blue and was also stained with aldehyde fuchsin. The spherules were not visible after PAS reactions due to the intense staining. The labile GBHA and silver acetate positive spherules localized in the chondrocytes may be the source of the extracellular mineralized spherules.
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  • 166
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The pineal organ of the West Coast newt Taricha torosa has been examined electron microscopically one, two and five years after metamorphosis. Although the organ has flattened with concomitant reduction of the lumen, the basic larval organization of the pineal photoreceptors and supportive cells is retained. Photoreceptors demonstrate both basal synaptic regions and outer segments, although the latter are disorganized as compared to the larva. Supportive cells, which increase in volume with age, contain membranous debris suggesting a sequence of phagocytosis of outer segments. Tubular vesticular membrane complexes enclosing 450 Å tubules are found in supportive cell processes adjacent to the basal lamina near blood vessels. Despite these changes the adult pineal organ retains the morphological entities thought to be necessary for photoreceptive function.
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  • 167
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    The @Anatomical Record 170 (1971), S. 235-241 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Alkaline phosphatase (AlPase) has been examined histochemically and biochemically in Swiss White (SW) mouse and Sprague-Dawley (SD) rat embryos during comparable stages of secondary palatal development. In the rats, AlPase was not detectable histochemically until after shelf transposition. Enzyme activity by biochemical assay was low in stages before shelf elevation. The mice, in contrast, showed AlPase in posterior areas of the developing shelves soon after shelf formation by histochemical techniques. With biochemical assays AlPase was higher in mouse than in rat shelves in early stages. After shelf transposition AlPase activity in the rat approached AlPase activity in the mouse by biochemical assays, but was demonstrable only in the posterior areas of the secondary palate by histochemical techniques.
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  • 168
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Questions concerning the nature of the intermediary vascular pattern make up a considerable portion of the literature concerning splenic morphology. Evidence indicates there is a special association between the reticuloendothelial system (RES) and the intermediary capillary terminations. This study was undertaken to characterize the distribution of the RES in the rabbit spleen and to correlate this with the vascular pattern described by Snook ('58). Like cells of the RES throughout the animal body, splenic RE cells can be demonstrated by several histochemical and functional methods. They are metalophilic (argyrophilic), possess several hydrolytic enzymes, and phagocytose injected particulate matter. Cells demonstrated by these methods are found in the marginal zone, and in the lumen of the red pulp sinuses but most are localized in the red pulp cords. This distribution corresponds closely to the termination of arterial capillaries in the marginal zone and pulp cords in the rabbit spleen and supports the general hypothesis that there is a unique and intimate relationship between the vascular system and the RES at these points.The sinus lining cells react characteristically to the techniques employed. They are sporadically metalophilic, strongly positive for nonspecific esterase (endoplasmic reticulum), negative for acid phosphatase (lysosomal), and occasionally contain small particles of injected matter. They probably represent a functionally distinct cell population.
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  • 169
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    The @Anatomical Record 170 (1971), S. 285-301 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Certain cells in the follicular epithelium of lizard (Anolis caro-linensis) ovaries are connected to the oocyte by true intercellular bridges. Unlike other known intercellular bridges, these may form by secondary cell contact and membrane fusion rather than by incomplete cytokinesis. These intercellular bridges are abundant in previtellogenic tertiary follicles, and they contain glyco-gen, ribonucleoprotein particles, and a dense, fibro-granular material which may be exchanged between the two cells. Prior to the onset of yolk accumulation in the oocyte, the intercellular bridges and the pyriform cells from which they originated disappear from the follicular epithelium. The abundance of intercellular bridges in previtellogenic follicles suggests that they may be involved in the maintenance of dormant oocytes during periods of suspended reproductive activity and in the preparation of these oocytes for ensuing periods of intense metabolic activity associated with yolk accumulation.
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  • 170
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    The @Anatomical Record 170 (1971), S. 311-329 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Arterial supply of the cervical spinal cord has been discussed with special reference to the radicular arteries. Thirty-one human spinal cords have been studied with postmortem positive pressure injection techniques using coloured, and radio-opaque media. Observations concluded that radicular arteries were main sources of supply to spinal cord except at the highest segments (C1C2C3), where intracranial vertebral branches contribute. Average number of significant radicular arteries is two or three, in two-thirds of the specimens only one was present. These feeding radicular arteries usually enter into the spinal canal through the intervertebral foramina accompanying C4C5C6 nerve roots to join the anterior and posterior spinal arteries. Anterior, and posterior spinal arteries are probably of segmental origin, and there is only a sparse anastomosis between them. The common radicular artery divides into an anterior, and a posterior branch of which one predominates in size. Cervical radicular arteries may originate from subclavian branches other than vertebral, of these ascending cervical branch of thyrocervical trunk is most important. A terminal zone probably exists at highest thoracic segments where craniocervical, and thoracic radicular flows meet. The filling of the anterior spinal trunk in the cervical region depends on the availability of at least one major anterior radicular artery. Interruption of radicular supply may be precipitated by trauma, spondylosis and other lesions resulting into ischaemia, and myelopathy; the risk is greater if there is only one radicular artery which is involved.
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  • 171
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    The @Anatomical Record 170 (1971), S. 365-379 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: First molar tooth germs were dissected from one-day-old mice; placed for one hour in McCoy's medium containing 10 μc tritiated thymidine and transplanted subcutaneously into young adult animals of the same strain. Seven, 14, 21 and 28 days after implantation the host animals were sacrificed and the transplants harvested. The transplants were then serially sectioned and autoradiographs prepared. Control sections were prepared of first molar tooth germs in situ, after dissection from the jaws and after labelling with tritiated thymidine. Forty-nine of the 115 transplanted tooth germs continued development with the formation of enamel, dentine, cement, periodontal ligament and bone. In some instances the transplanted tooth germs “erupted” through the skin with the establishment of an epithelial attachment. Examination of control sections showed that the transplants consisted of dental organ, dental papilla and a layer of ectomesenchymal cells continuous with the dental papilla and investing the dental organ. Examination of autoradiographs of the transplants showed labelling of cementoblasts and periodontal ligament fibroblasts, thereby establishing their origin from the ectomesenchymal cells investing the tooth germ.
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  • 172
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The chorioallantoic placenta of the bat (Myotis lucifugus) is hemodichorial and has an ectoplasmic layer and an intrasyncytial lamina interposed between the maternal blood space and the underlying endoplasmic portion of the syncytial trophoblast. The barrier and/or transport function of the trophoblast of this species was investigated. When Thorotrast was injected into the maternal vascular system, only small amounts appeared in the trophoblast, and it could not be demonstrated deep to the syncytial trophoblast.Injected peroxidase and ferritin were both rapidly taken up by the trophoblast, these tracers being found in coated vesicles and tubules, in multivesicular bodies, and in dense bodies. Peroxidase was transported across the trophoblast and could be found in macrophages in the fetal connective tissue and in vesicles in the fetal endothelium. Since ferritin is present in the cytotrophoblast, macrophages and fetal endothelium in uninjected as well as injected animals, the exogenous material could not be followed beyond the syncytium. In addition to demonstrating the cytological pathway by which absorbed proteins cross the trophoblast of the chorioallantoic placenta of the bat, the results of this study suggest that the labyrinth in this species should be considered a possible route for passage of endogenous proteins to the fetus.
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  • 173
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The freeze-etch technique was used to study the fine structure of the terminal respiratory membranes of rat lung. Special emphasis was given to the ultrastructure of the type II alveolar cell and its role in formation of the surface active material. Our morphological evidence supports the theory that membrane-bound multivesicular bodies in the cytoplasm of type II cells accumulate phospholipid material to form lamellar structures which are extruded onto the alveolar surface as one of the components of the surface active material. Subsequent loss of the lamellar configuration in the surface active layer is discussed. Electron micrographs demonstrate numerous microindentations that extend into the base of alveolar cells and help establish a close relation with the basal lamella.
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  • 174
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Structural abnormalities begin in the integument of hairless (hrhr), hairless-rhino (hrhrrh), and rhino (hrrhhrrh) male and female mutant mice prior to the end of the first hair growth cycle. The pilary canals begin to widen and accumulate keratin and sebaceous material. During the first catagen phase the lower internal root sheath coalesces around the terminal part of the hair shaft and abnormal club hairs form. The lower part of the external root sheath fails to follow the ascending club hair and becomes stranded in the dermis. The abnormal club hairs move above their normal anchoring position and fall out of the follicle at the end of the first growth cycle. The formation of abnormal club hairs and the loss of hair probably are related to the mispositioning of the internal root sheath. Subsequent to the loss of hair there are changes in the sebaceous glands and adipose tissue, disorganization of the peripheral neurovascular system, and the formation of cysts that are associated with either the pilary canals or with epithelial units of disorganized hair follicles stranded in the dermis. Cysts arise from proliferation of epithelial tissue; sebaceous cells are not necessary for cyst formation.Comparisons among similar and dissimilar anomalies indicate that the degree of gene action on the integument is in the following order of increased severity: hrhr, hrhrrh, and hrrhhrrh.
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  • 175
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: This study reports an electron microscopic investigation to the spinal meninges of the rat as they exist between the dorsal and ventral nerve roots in upper thoracic and cervical levels of the vertebral column. Between these roots, at a point where they penetrate the spinal dura, the leptomeninges are characterized by a histological pattern comparable to that elsewhere comprising the subarachnoid angle. However, this region is modified and possesses a number of heretofore unknown histological features. The most noteworthy is a lateral recess of the subarachnoid space.The meninges located between the nerve roots do not form a definite lateral boundary for the subarachnoid space. Here the subarachnoid space opens into a lateral recess which extends peripherally between the dorsal and ventral nerve roots. Conspicuous amounts of cellular debris are collected within the lateral recess. Numerous free macrophages congregate here. The lateral recess may be a communicating pathway between the central and peripheral nervous systems by way of the endoneurium of the nerve trunk.
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  • 176
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    The @Anatomical Record 171 (1971), S. 81-97 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The typical thyroid epithelium of the cream variant of the Syrian hamster differs from that of other common mammalian species. One obvious difference noted by light microscopy is that the cells contain numerous PAS-positive granules apical to the nucleus. By electron microscopy these granules are dense granules resembling lysosomes. The cells have exceptionally long microvill and numerous junctions and interdigitations of lateral plasma membranes with those of their neighbors. Many organelles in the cells are stratified rather than arranged at random. In addition to the dense granules and centrioles, the Golgi apparatus is usually located at the level of the apical end of the nucleus. The granular reticulum is primarily in the basal half of the cell, although some is apical. Microtubules are especially abundant and are located ainly close to the lateral surfaces and around the nucleus, although some are near apical or basal plasma membranes. The microtubules frequently appear to be in contact with mitochondria and dense granules, but their role in the positioning or stratification of organelles is uncertain.
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  • 177
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    The @Anatomical Record 171 (1971), S. 217-220 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
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  • 178
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    The @Anatomical Record 171 (1971), S. 221-225 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Unilateral ovariectomy of hamsters on day 1 of pregnancy resulted in an increase in weight of the remaining ovary by day 4, primarily by increasing the number of antral follicles. The ovulability of these follicles was tested by injecting 20 IU human chorionic gonadotropin (HCG) on day 12 of pregnancy. Following this treatment, the unilaterally ovariectomized animals ovulated 29.4 eggs whereas intact animals ovulated 16.6 eggs per ovary. In both instances, the number of antral follicles ovulated by HCG was between 40% and 50% of the number present. Luteal weight was unaltered by semispaying, indicating that the regulation of corpus luteum growth does not fit a negative feedback system.The ability of exogenous steroids to prevent ovarian compensation was assessed by injecting either progesterone (2 mg) or estradiol cyclopentylpropionate (1 μg) daily from days 8 to 11 of pregnancy. Either steroid injected into the semispayed hamsters prevented the expected increase in the remaining ovary in weight, follicular development and the ovulatory response to HCG. The same hormonal treatment of intact, pregnant animals slightly increased mean ovarian weight but did not affect follicular development.These results suggest that unilateral ovariectomy of the pregnant hamster, by decreasing peripheral level of ovarian steroids, partially reduces the inhibition of gonadotropin secretion and therefore leads to ovarian compensation.
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  • 179
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    The @Anatomical Record 171 (1971), S. 259-272 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The mature ultimobranchial follicle of the rat consists of two or more layers of cells (U cells) surrounding a lumen containing cell debris. The ultrastructure of the outer, or basal, U cell is characterized by the presence of half desmosomes on the basal plasma membrane and pinocytotic vesicles near it, by little granular reticulum but an abundance of free ribosomes, by clusters of fibrils connected to desmosomes and possibly free in the cytoplasm. The cell ages by accumulation of clusters of fibrils and it undergoes differentiation to form more apical U cells which contain fewer ribosomes and have fibrils dispersed in the cytoplasm. The apical U cell is desquamated into the lumen and ultimately becomes a carcass containing a dense matting of fibers and vacuoles containing a reticulated material resembling that in the lumen. U cells are observed associated with typical thyroid epithelium in the thyroid of the newborn rat in relatively large follicles containing colloid and desquamated cells. They also form rods of cells in the very young rat. Mixed follicles containing both U cells and typical thyroid epithelium occur at all ages.
    Additional Material: 20 Ill.
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  • 180
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: An ultrastructural analysis of the mesothelial cells of the yolk sac of the bat throughout gestation is presented. At first these cells are closely associated with the cytotrophoblast but become displaced by action of the allan-tois and collapse of the yolk sac. The mesothelial cells are exposed to the exo-coelom and develop cytological features characteristic of absorptive cells. Among these features are: (1) long microvilli extending from the apical and lateral plasma membranes and (2) absorptive canaliculi and tubules as well as absorptive vacuoles in the superficial cytoplasm. There is a paucity of mitochondria and rough endoplasmic reticulum throughout the existence of this cell type. After midgestation, granules containing numerous crystalloids appear in the cytoplasm of most of the cells. These are apparently the result of the absorption of protein-aceous material from the exocoelom. The crystalloids disappear before birth, and the mesothelium becomes degenerative in appearance. This sequence of development of the cytological features suggests a dynamic role for the mesothelium throughout its existence that involves absorption and storage of proteinaceous material from the exocoelom for use by the embryo.
    Additional Material: 3 Ill.
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  • 181
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Longitudinally-oriented bundles of closely-aligned motoneuron dendrites in Lamina IX of cat spinal cord were examined. These dendrites were interrelated in one of several ways: (1) They were separated by a space of several microns containing small myelinated and unmyelinated fibers, synaptic boutons, and glial processes; (2) Some dendrites were separated by a gap of 0.2-0.5 μ which contained only an attenuated astrocyte process; (3) The plasma membranes of the adjacent dendrites were occasionally found in direct apposition and in most of these instances there was no detectable specialization of the opposing membranes; (4) There were definite modifications along the appositional membranes. These zones were characterized by a gap of ∼ 180 Å, and symmetrical, non-polarized aggregations of electron-opaque material were found along the cytoplasmic surfaces of the membranes.It is suggested that the spatial arrangement and appositional relations of these dendrites represent a morphological substrate for the weak electrical facilitation known to occur between motoneurons in the cat spinal cord.
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  • 182
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    The @Anatomical Record 171 (1971), S. 369-415 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The inorganic dye, ruthenium red, stains extracellular materials in animal tissues which probably are acidic mucopolysaccharides. It complements other techniques, its advantages being fine grain, high resolution and good contrast. Localization is shown in mouse and rat muscle, heart, lung and intestine, frog cartilage and cells scraped from oral epithelium of human beings. Attention is paid to collagen bundles, the cell/collagen interface and particularly the myotendinal junction, cartilage matrix and agar gel, desmosomes, intestinal microvilli, erythrocytes and vascular endothelium, nerve fibers and the T-system of striated muscle. Although ruthenium red generally is excluded by plasma membranes, it penetrates giving intracellular density, if the membrane is broken. Even when the cell membrane is intact, exceptions occur with selective staining of the T-tubules or the sarcoplasmic sacs depending upon the state of contraction of the muscle cell, and with intracellular staining of certain nuclei and epithelial cells. Ruthenium red stains intracellular lipid droplets revealing lamellae, and stains myelin forms grown from crude egg lecithin but cannot penetrate deeply. It is localized in extracellular materials which have an important mechanical function. Its exclusion by cell membranes permits tracing tortuous cellular invaginations and those exceptions to its exclusion invite a comparison of the localization of the dye with the function of the cell.
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  • 183
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: In all mammalian species examined thus far, the media of the adult mammalian portal vein consists of two mutually perpendicular smooth muscle zones separated by a fibrous layer. The cells of the muscle zone nearest the intima are arranged circumferentially and resemble smooth muscle of other vessels; the muscle cells of the thicker, vascularized outer zone are longitudinal and contain mitochondria and pinocytotic vesicles in great abundance, suggesting relatively high metabolic activity. The adult configuration is not present at birth and only develops during the first three postnatal weeks in the rat. Partitioning of the media commences at about three days and contrasting orientation and composition of the cells of the two muscle zones is not established until seven to ten days after birth. Vasa vasorum appear in the outer muscle layer at about two weeks and nerve fibers appear even later. Post-natal establishment of a special, double layered neuromuscular structure may be related to the adaptation of the portal circulation to the effective closure of the ductus venosus.
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  • 184
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    The @Anatomical Record 171 (1971), S. 529-544 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The morphological characteristics of the tail artery and of the superficial epigastric neurovascular bundle, fast-frozen in vivo with a cryosurgical probe in less than one second, were examined in norepinephrine and in deoxycorticosterone acetate (DOCA)-induced systemic hypertension. Acute vasoconstriction produced by norepinephrine begins in the innermost muscle layers and extends by degrees to the outer layers. The pull of the inner cells is distributed through the wall by a network of radially disposed collagen fibers. No qualitative signs of vasoconstriction were observed either in arteries or arterioles in advanced DOCA hypertension. Here, the pattern was dominated by hypertrophy, apparent in the size of the smooth muscle cells and of their nuclei and in a considerable accentuation of cell boundaries indicating an increase in the paracellular matrix.
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  • 185
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    The @Anatomical Record 171 (1971), S. 545-557 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Further work with mitochondria containing prismatic cristae has revealed that this type occurs as a constant feature and in some abundance in the dorsolateral region of the spinal cord of the cat at cervical, thoracic and lumbar levels. All such mitochondria occur in astrocytes. The most common forms are long rods with an abundance of matrix and very few cristae. The matrix in the majority of such mitochondria is of moderate density and without discernible organization. In others the matrix consists of closely packed rodlets with or without occasional prismatic cristae. A frequent pattern is a core of longitudinal rodlets surrounded by a rim of circumferential ones. In the circumferential zone a single row of triangular cristae is present. The unusual mitochondria vary greatly in size, from 0.2-5.0μ Mitochondria containing ordered arrays of cristae that are triangular in cross section are for the most part much smaller than those with very few cristae and smaller than similar mitochondria described in the Syrian hamster. It is concluded that close packing in the matrix (obviously hexagonal in many instances) is the cause of the prismatic shape of the cristae.
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  • 186
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    The @Anatomical Record 171 (1971) 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
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  • 187
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    The @Anatomical Record 171 (1971) 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
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  • 188
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The relative weight of the Mongolian gerbil adrenal is one of the largest of any animal species. The adrenal cortex of the gerbil can be divided into three major zones and one zone located between th zona fasciculata and zona reticularis. Mitochondrial cristae of zona glomerulosa cells are plate-like, those of the zona fasciculata are tubular whereas cristae are extensively developed and plate-like in the zona reticularis. Lipid droplets are numerous in fasciculata cells and sparse in glomerulosa and reticularis cells. Fasciculata and glomerulosa cells contain tubules of smooth endoplasmic reticulum whereas rough reticulum predominates in reticularis and border cells. Abundant lysosomes are found in glomerulosa cells; lysosomes are aggregated beneath the cell membrane of reticularis cells. Whorls of concentric lamellae of rough endoplasmic reticulum are localized exclusively to cells in the border zone. Cells in the border zone resemble those of the reticularis because of a virtual absence of smooth endoplasmic reticulum although mitochondrial cristae are tubular and therefore similar to those of the zona fasciculata. It is suggested that cells in the border zone represent a reserve of cells which may transform into fasciculata cells upon stimulation.
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  • 189
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Chick embryo spinal cord has been explanted at two-day stages, when few or no cells have formed axons, and cultured for five to seven days. The effects of various culture methods and the presence or absence of other tissues on differentiation have been studied. Many cells with axons and numerous nerve fibers were seen in silver-stained sections of completely isolated neural tube cultured in a fold of vitelline membrane, as well as in neural tube explanted with adjacent tissues and in isolated neural tube recombined with somites. Electron micrographs of corresponding cultures showed cell bodies similar to those of fairly early nerve cells in vivo and processes with the structure of axons. Some characteristic differences in cell fine structure and in histological organization among these types of cultures were observed. Isolated neural tube cultured directly on a millipore filter did not survive or differentiate as well. These observations indicate that initial phases of nerve cell differentiation can proceed in organ culture and that there is no specific requirement for interaction with adjacent mesodermal tissues. This system can be used profitably for further investigation of factors controlling various aspects of differentiation in the central nervous system.
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  • 190
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    The @Anatomical Record 169 (1971), S. 71-95 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The intracellular distribution of mucosubstances in the acinar cells of the rat sublingual gland has been studied at the electron microscopic level by means of two histochemical techniques: PA-silver methenamine for the detection of vicinal glycols and colloidal thorium for the detection of polyanions. By both methods the secretory granules in the mucous acinar cells were selectively stained. The reaction products were visualized as dense closely packed precipitates covering the entire matrix of the individual mucous granules. Similar reaction products were also often observed within the Golgi apparatus of the mucous cells. In striking contrast, the secretory granules and Golgi apparatus of the demilunar cells exhibited no demonstrable selective staining by either method. It is concluded that the secretory granules of the mucous acinar cells are largely composed of mucosubstances containing vicinal glycols and polyanions and that the secretory granules in demilunar cells contain no demonstrable content of such mucosubstances.
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  • 191
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    The @Anatomical Record 169 (1971), S. 97-104 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: A simple method for in vitro studies of human subcutaneous adipose tissue is described. Explants of adipose tissue have been maintained in vitro for 30 weeks in Parker medium 199. The morphology of cultured explants compared well with that of freshly excised specimens. In the absence of serum there was no outgrowth of fibroblast-like cells. When human serum was added to the medium at concentrations exceeding 5% there was a proliferation of fibroblast-like cells. This cell proliferation could still be obtained when serum was added after two weeks of culture in a serum free medium. The adipose cells were isolated with collagenase and the cell size determined. Explants with an initial mean cell size larger than about 95 μ showed a significant decrease in cell size during the incubation. This could not be attributed to a traumatic effect. Metabolic differences between large and small adipose cells was suggested as a possible reason.
    Additional Material: 7 Ill.
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  • 192
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    The @Anatomical Record 169 (1971), S. 105-113 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Investigations were made on the morphological and histochemical nature of the ellipsoid sheaths of two different types of spleens, sinusal and non-sinusal, as found in the dog and cat respectively.Ellipsoid cells of dog and cat spleens respond similarly with Marshall's silver impregnation method as well as demonstrate activity for the hydrolytic enzyme, acid phosphatase. Both technics substantiate ellipsoid involvement in the reticuloendothelial system. Nonspecific esterase, another hydrolytic enzyme commonly found in phagocytic cells, was demonstrated in the cat ellipsoid cells but not in similar cells of the dog spleen indicating a basic difference in the physiological activity of the dog and cat ellipsoid cells.
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  • 193
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    The @Anatomical Record 169 (1971) 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
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  • 194
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    The @Anatomical Record 169 (1971), S. 115-127 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The fine structure of the interstitial cells of Leydig has been examined in the squirrel monkey, Saimiri sciureus, during the non breeding portion of the year when the testes are essentially azoospermic. Interstitial cells are present in abundance as a layer, several cells thick, on the inner aspect of the tunica albuginea. Cytologically, the cells possess the characteristics usually associated with cells which synthesize and secrete steroid hormones: an abundant agranular endoplasmic reticulum in the form of anastomotic tubules; mitochon-chondria with both lamellar and tubular cristae; only a few strands of granular endoplasmic reticulum; a Golgi apparatus and associated vesicles, some of which are of the coated variety; a varying population of lipid droplets and dense bodies. Some of the dense bodies appeared to be lipofuscin pigment. A previously undescribed inclusion was frequently encountered which consisted of arrays of a honeycomb like structure. Most frequently these structures were present near the cell periphery or in blunt protrusions of the cytoplasm.
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  • 195
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The fine structure of spermatozoa of two species of monkey, Macaca mulatta and Macaca nemestrina, and man was studied following fixation of seminal fluids in buffered picric acid-formaldehyde (PAF). The various components of the sperm have been studied mostly in light of the behavior of this cell at the time of conjugation with the ovum.The possible equivalence between acrosome and lysosomes has been discrussed considering the origin, enzymatic activity, and mechanism of action of these two classes of organelles. The fine morphology of the post-acrosomal cap has been found to be comparable to that of a septate desmosome. We have introduced the hypothesis that the cap plays a role in establishing and maintaining adhesion between the spermatozoon and the ovum at the time of gamete conjugation. The formation of the scrolls of the nuclear membrance in the posterior region of the nucleus has been put into relation with the modifications of volume and shape of the spermatid nucleus. The function of the scrolls could be to increase the surface through which nucleocytoplasmic exchanges take place. The possibility that the presence of a voluminous cytoplasmic droplet in human spermatozoa is a sign of cellular immaturity has also been discussed.
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  • 196
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The origin of supernumerary gonapophyses in a polymorphic variant of Aedes stimulans has been determined histologically. Genotypic males (Mm) will develop gonapophyses on abdominal segment 8 when primordia on the larvae are subjected to a high-to-low thermal regimen. The gonapophyses develop from the normally evanescent podal buds of the eighth imaginal disc. Their course of development is similar to that of the normal gonapophyses that arise from the podal buds of the ninth imaginal disc.
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  • 197
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: There are approximately 650 scolopidial units in Johnston's organ of the tobacco hornworm moth, Manduca sexta. These sensory units exhibit greater complexity than noted previously (Gray, '60; Howse, '65; Uga and Kuwabara, '65; Moeck, '68; Ong, '69; Schmidt, '69).Each scolopale is innervated by a bipolar neuron whose dendrite terminals are modified into three ciliary structures. The largest of these differentiates near the tip into a multitubular structure. The remaining two cilia are structurally similar along the entire length of the scolopale shaft. From each of their bases, a collagen-like structure differentiates into numerous microtubules which extend proximally into individual channels of dendritic cytoplasm. A third channel, with a less developed root apparatus, was apparent for the largest cilium.Preliminary evidence suggests a proprioceptive function for this structure rather than an auditory one.
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  • 198
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The frontal wall of Schizoporella unicornis (Johnston) develops as a partition of the coelom just before ascus formation. The ascus develops proximally from the proximal border of the aperture. S. unicornis, therefore, belongs to the monothetic Order Cryptocystidea. The outer part of the opercular cuticle is lost during development.
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  • 199
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The general morphology of the mucous gland cell and the nature of the secretory granule in esophageal glands of the newly hatched chick have been described. Lightly basophilic supporting cells, attached to secretory cells by desmosomes and containing tonofilaments, are located on the basal lamina. Electron microscopic studies showed a morphological polarity of the Golgi complex which suggests that mucous precursors are transported from other sites within the cell to the Golgi complex for further packaging into secretory granules. Finally, acid mucopolysaccharides (AMPS) were specifically stained using the Thorotrast technique and not detected in the rough endoplasmic reticulum, the transitional elements, or in the lamellae at the forming face of the Golgi complex. Conversely, AMPS are found in the vicinity of the mature face of the Golgi complex, and in the secretory granules. The acquisition of cytochemical reactivity for AMPS within the Golgi complex is discussed.
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  • 200
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The presence of developmental stages of lymphocytes and their precurors, as revealed by serial and thin sections of hemopoietic organs of normal adult newts (Notopthalmus viridescens) suggests that lymphopoiesis is limited to the thymus, medulla of the spleen and, to a lesser degree, the intestine. Stromal cells, small lymphocytes, granulocytes, mature erythrocytes and melanocytes were observed either within or near the parenchyma of the thymus. The urodele thymus differs from the thymus of anurans and higher vertebrates in that it lacks a cortex and a medulla, myoid cells and Hassall's corpuscles.
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