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  • 2020-2024
  • 1985-1989  (6)
  • 1975-1979  (5)
  • 1945-1949  (1)
  • 1920-1924  (3)
  • Cell & Developmental Biology  (15)
  • 1
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Morphology 189 (1986), S. 145-156 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The structural organization of the compound eye of the largest known isopod, Bathynomus giganteus, is described from four specimens maintained in the laboratory for as long as two months. Living specimens have not previously been available for study. The two triangular compounds eyes measure about 18 mm on the dorsal edge and are separated by an interocular distance of 25 mm. They face forward and slightly downward and may have significant overlap in visual fields. Each eye contains about 3,500 ommatidia in animals of body lengths from 22.5 cm to 37.5 cm. The packing of ommatidia is not uniform across the retina, but is nearly hexagonal in the dorsal central region and nearly square in the ventral and lateral periphery.The dioptric elements in each ommatidium consist of a laminar cornea, which is flat externally and convex internally, and a bipartite crystalline cone. Sometimes seven and sometimes eight retinular cells closely appose the proximal tip of the cone and bear the microvilli of the rhabdom. Proximal to the rhabdom the retinular cells form thin pillars near the periphery of the ommatidium, and the central portion along the optic axis at this level is occupied by interstitial cells that contain massive arrays of clear vesicles thought to serve as reflective elements. The arhabdomeral segments of the retinular cells and the interstitial cells rest on a basement membrane. Within each ommatidium the basement membrane has two extensions with cylindrical cores and thin sheets of dense material and collagen-like filaments. These sheets occupy spaces between adjacent interstitial cells up to the level of the rhabdomeral segments of the retinular cells. Arrays of pigment cells with relatively weak light-screening properties separate adjacent ommatidia.Animals were fixed both in light within a week of being brought from depth into daylight, and after 2 months of maintenance in constant darkness following such daylight exposure. In both cases, microvilli of the rhabdom were severely disrupted and the retinular cytoplasm contained numerous multivesicular bodies. Exposure to natural daylight appears to cause irreversible structural damage to the photoreceptors of these animals.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The expression of the von Willebrand factor (vWF) gene by cultured endothelial cells from the porcine pulmonary artery, aorta, and lung was compared at the levels of messenger (m)RNA and antigen. Steady-state levels of vWF mRNA were determined by dot-blot analysis using a partial human vWF cDNA as the hybridization probe; vWF mRNA from cultured aortic endothelial cells, and vWF antigen secreted into the culture supernatants were barely detectable. In contrast, vWF mRNA and antigen from the pulmonary artery endothelial cells were approximately eight to nine times that demonstrated by aortic cells. Levels of vWF mRNA and antigen in cultured lung cells were intermediate of those found in the pulmonary artery and aorta and correlated with the estimated number of cells demonstrated to be of endothelial origin in the mixed cell populations grown from the lung. Differences between the levels of vWF mRNA found in cultured cells from the pulmonary artery and those found in the aorta were maintained in cells processed directly from these vessels. Correlation between the levels of vWF mRNA and antigen in endothelial cells from different vessels of the pig suggests that the differential control of vWF synthesis is at the level of transcription. Furthermore, maintenance in cultured cells of the difference in transcription rates that were observed in vivo suggests that vWF gene expression is not exclusively regulated through environmental factors.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 195 (1979), S. 311-316 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Unilateral ovariectomy (ULO) was carried out on rats at Day 8 of gestation: term is Day 23. The effect on peripheral plasma progesterone levels at Day 16 and on growth and cellular changes in the remaining corpora lutea (CL) at Day 17 was determined by comparison with results from control and sham-operated rats. ULO increased the volume of remaining CL by 18% at Day 17. At Day 16 this effect was only apparent in rats with three or fewer CL remaining. CL hypertrophy was due to an increase in the volume of individual luteal cells and not to cell hyperplasia. Luteal cell nuclear volume also increased as did the number of endothelial cells per corpus luteum. The proportion of the corpus luteum occupied by vascular space did not alter.ULO had little effect on mean plasma progesterone levels at Day 16 (92 ± 7 ng/mltreated; 86 ± 11 ng/ml controls). In rats with three or fewer CL remaining, however, progeserone levels were low (51 ± 7 ng/ml).It was concluded that ULO can enhance the growth of corpora lutea and perhaps increase their rate of progesterone production.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 195 (1979), S. 357-374 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The morphogenetic events associated with rabbit eggs aged in vitro for 12 to 50 hours prior to mixing with sperm have been examined by light and electron microscopy. After 12 hours in culture, morphological alterations of the meiotic spindle and the cortex of unfertilized eggs were evident. By 24 to 50 hours in culture, unfertilized eggs contained subnuclei, structures which formed when individual and/or groups of meiotic chromosomes dispersed and became invested by a double-laminated structure reminiscent of a nuclear envelope.Although most eggs obtained 11.5 to 12 hours after induced ovulation and in vitro fertilized displayed morphogenetic patterns similar to those described for in vivo fertilized ova, some (10%) contained three pronuclei. Many eggs obtained 13 to 15 hours after induced ovulation and subsequently mixed with sperm in vitro appeared to undergo processes of fertilization typical of in vivo fertilized eggs, however, approximately 30% contained subnuclei in association with the male pronucleus. Few eggs (15%) aged 12 hours prior to in vitro fertilization displayed patterns of pronuclear development and association typical of fertilized unaged ova. Subnuclei developed in many of the fertilized ova. Supernumerary sperm nuclei, which did not develop into male pronuclei, were observed in some zygotes. Cleavage of eggs aged 12 hours prior to fertilization was abnormal or retarded. After 24 hours in culture approximately 16% of the eggs fertilized. Seventy percent of the fertilized eggs failed to Support the development of a male or female pronucleus.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 222 (1988), S. 18-25 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Within the adult mammalian ovary, angiogenesis is associated with development of the corpus luteum (CL). In this study, developing luteal tissue was examined to determine whether its vascularization involves endothelial cell replication and to what extent this proliferation contributes to forming new capillaries. Five rats each at 12, 24, 36, 48, 60, 72, 84, and 96 hr of gestation were given a subcutaneous injection of tritiated thymidine (specific activity 5 Ci/M; 1 uCi/g body weight). One hour later they were anesthetised with sodium pentobarbitone, and the left ovary was processed for light microscopy. Sections were cut through each ovary until three newly formed CL were recognized; a 1-μ section was taken from the maximum diameter of each CL and processed for autoradiographic demonstration of thymidine labeling in endothelial cell nuclei. The same sections were also examined with stereological techniques to quantitate growth of the vascular compartment. The results show that 36.1 ± 5.7% of endothelial cells of invading capillary sprouts divide within 12 hr of ovulation; at 24 hr, 29.0 ± 2.8% are dividing. Within 12 hr after ovulation, blood vessels occupied 5.9 ± 1.4% of the peripheral space of the ruptured follicle but only 1.6 ± 0.5% in the center. However, by 36 hr these respective values were 9.3 ± 1.6% and 8.4 ± 1.9% A further peak in endothelial-cell replication (31.2 ± 5.4%), early on the 3rd day of gestation, corresponded to the very extensive anastomoses within the capillary bed established between this time (13.6% vascularity) and late on the 4th day (about 23%). We conclude that replication of endothelial cells from capillary sprouts accounts for substantial angiogenesis in the developing CL. Labeling in endothelium of the developing CL and the capsule surrounding the CL were greater than in CL of previous cycles and vessels within the ovarian stroma. This finding supports the view that there may be some local control of endothelial-cell replication.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 193 (1979), S. 823-830 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The cellular pattern of corpus luteal (CL) growth was studied in rats at Days 6, 10, 12, 14, 16, 17 and 22 of pregnancy: term is Day 23. Measurements were taken of the percentage of the CL occupied by luteal cells, connective tissue and vascular space, luteal cell and nuclear volumes, and the number of luteal and endothelial cells in each of three CL in both ovaries of five rats at each stage of pregnancy. Total CL volume increased from 1.08-3.23 μl over Days 10-17. This was mainly due to an increase in luteal cell volume from 3.72 pl to 9.30 pl. Neither the number of luteal cells per CL (range 212,000-287,000) nor the percentage of the CL occupied by luteal cells (range 85-90%) had much influence on growth. Nuclear volume increased roughly in proportion to cytoplasmic volume but near term it decreased despite little change in cytoplasmic volume. The number of endothelial cells per CL increased steadily from 398,000 at Day 6 to 1,545,000 at Day 22. There was a strong negative correlation (r = -0.78) between the number of luteal cells per CL and mean luteal cell volume that was evident at all stages of pregnancy. There was a positive, but weaker correlation (r = 0.35) between number of luteal cells and CL volume. Thus, CL volume seems to be partly determined by the number of luteal cells at Day 6 but this effect is moderated by local control of luteal cell volume.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 27 (1924), S. 375-404 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    American Journal of Anatomy 172 (1985), S. 87-99 
    ISSN: 0002-9106
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The synthesis and secretion of progesterone by the corpus luteum (CL) may be limited or controlled by transport mechanisms operating between circulating blood and luteal cell cytoplasm. To examine this possibility, the structural features involved in transport, including membrane surface areas and diffusion distances, were quantitated in the CL of 16-day pregnant rats. One ovary from each of eight rats was fixed by perfusion via a cannula inserted into the parametrial artery, and two CL from each ovary were processed for electron microscopy and examined with standard morphometric techniques. For comparison, one CL from each of a further eight ovaries was diced into small cubes, fixed by immersion, and analyzed similarly. In perfusion-fixed CL, there was a substantial volume of vascular space (20% of the total) and interstitial space (5%) and an extensive surface area of capillaries (441 mm2 per CL). The luteal-cell membrane had numerous projections which increased its surface area by a factor of 3.08. Almost 60% of the luteal-cell surface directly faced a capillary, and a further 37% faced interstitial space which probably extended to a capillary surface. Only 3% was in direct contact with a neighboring luteal cell. Despite the extensive interstitial space the harmonic mean thickness, an estimate of likely effective diffusion distance between luteal cell cytoplasm and blood, was only 0.42 μm. This was less than half of the calculated arithmetic mean thickness owing to the presence of surface projections and an uneven capillary endothelium. Results from immersion-fixed CL were qualitatively similar; but the proportion of interstitial space was only 59% of that in perfusion-fixed CL, and the contribution of surface projections to the total area of luteal-cell membranes was significantly reduced. Collectively, these results suggest that membranes and spaces between blood and luteal-cell cytoplasm are structured so as to minimize transport distances.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    American Journal of Anatomy 176 (1986), S. 207-219 
    ISSN: 0002-9106
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Epidermal development of fetal porcine skin was studied in fetuses from 41 days of gestation until birth with scanning and electron microscopy techniques as well as histochemical methods, including immunohistochemistry. The porcine fetus develops a relatively thick and solid multilayered cover of epidermal cells, which is not lost before birth. It consists of tightly packed cells of the periderm and the stratum intermedium. The periderm cells are totally filled with filamentous proteins; in the intermediate cells, the filamentous proteins are concentrated in the cell periphery, forming a thick marginal zone. Immunohistochemically, the cytofilaments could be identified as cytokeratins of lower and higher molecular weights. The first thin stratum corneum lamellae are formed below the stratum intermedium at about 80-85 days of gestation.
    Additional Material: 35 Ill.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 18 (1920), S. 351-354 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
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