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  • 1
    Electronic Resource
    Electronic Resource
    The Fine Structure of the Gregarine Pyxinoides balani Parasitic in the Barnacle Balanus tintinnabulum (1967)
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 14 (1967), S. 0 
    Details
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: SYNOPSIS. The fine structure of the eugregarine Pyxinoides balani was studied and compared with that of other gregarines previously examined with the electron microscope. P. balani contains cell organelles comparable to those in the archigregarine Selenidium hollandei. These include mitochondria, Golgi complexes, granular and agranular endoplasmic reticulum, membrane-limited granules, vacuoles and myonemes. A comparison of the distribution and fine structure of these organelles with those of the above archigregarine was made. The possible function of the Golgi complex in assisting in producing the transverse septum is suggested.The surface of P. balani is composed of a surface-membrane complex different from that of S. hollandei, and similar to those of the eugregarines previously studied. The complex is composed of an outer plasmalemma, subjacent pentalaminar layer, and underlying, homogeneous, electron-dense layer. The pentalaminar layer is 140–170 Å thick and has a structure reminiscent of fused cell membranes seen in tight junctions, myelin figures and nerve myelin. The pentalaminar layer is derived from subsurface cisternae found in sporozoites. The underlying, homogeneous, electron-dense layer is 450–500 Å thick. Pores and caveolae are found as specializations of the pentalaminar and homogeneous electron-dense layers. Endoplasmic reticulum is closely associated with the caveolae. The location of the pentalaminar layer at the surface and the presence of pores and caveolae in its structure suggests some transport and/or segregation function.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1550-7408.1967.tb02034.x
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  • 2
    Electronic Resource
    Electronic Resource
    Controlled Release of Contraceptive Steroids from Biodegradable and Injectable Gel Formulations: In Vivo Evaluation (1995)
    Springer
    Pharmaceutical research 12 (1995), S. 864-868 
    Details
    ISSN: 1573-904X
    Keywords: levonorgestrel ; ethinyl estradiol ; precirol ; labrafil ; controlled release ; injectable gels ; biodegradability ; biocompatibility
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Purpose. The purpose of this study was to investigate in vivo biocompatibility, biodegradability and biological effects of contraceptive steroids, such as levonorgestrel and ethinyl estradiol, released from gels prepared with a combination of derivatized vegetable oil (Labrafil 1944 CS) and glyceryl ester of fatty acids (Precirol ATO 5). Methods. Biocompatibility, biodegradability, and in vivo effects of levonorgestrel and ethinyl estradiol were studied by histologic evaluation of rat tissue, visual estimate of changes in gel size, and assessment of drug effects on reproductive cyclicity of female rats, respectively, following subcutaneous injection of gel formulations. Results. Histological evaluation of the tissue samples following an injection of the gel revealed an inflammatory reaction for about 7 days, after which the tissues did not show any inflammatory response. Complete degradation of the gels containing 10% wax was observed between 5 and 6 weeks. Normal rat estrous cycles were completely blocked by the contraceptive steroids released from the gels. Gel formulations containing 0.25% w/w levonorgestrel were more effective in blocking the estrous cycle of female rats compared to the oil formulations containing an identical drug loading. The duration of the biological effect induced by levonorgestrel appears to be dose-related. The gel formulation containing 2.00% ethinyl estradiol was superior to oil formulation containing an identical drug loading in terms of controlling drug release and toxicity. Conclusions. These observations suggest that Labrafil-Precirol gels are biocompatible and biodegradable. Moreover, controlled release of steroids is possible in vivo for a prolonged period of time.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1016261004230
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  • 3
    Electronic Resource
    Electronic Resource
    A study on the fine structure of developing spermatozoa from the oligochaete,Enchytraeus albidus (1967)
    Springer
    Cell & tissue research 82 (1967), S. 257-269 
    Details
    ISSN: 1432-0878
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Studies on the fine structure of spermatids and spermatozoa of the oligochaete,Enchytraeus albidus, demonstrate the differentiation of acrosome, flagella, nucleus and associated structures. Developing spermatids are found syncytially arranged and interconnected to a central nutrient mass. Acrosomal and flagellar development is typical of other spermatozoa. Electron densities associated with developing acrosomal vesicles form sub-acrosomal structures whose origin and possible function is compared to similar sub-acrosomal structures in other spermatozoa. The disposition of microtubules subjacent to the elongating acrosome and flagellar basal body and circumferentially arranged around the nucleus is described. Comparisons are made of their arrangement during differentiation with microtubular arrangements in other cells undergoing similar form differentiation. It is suggested that the microtubules play a role in the elongation of these spermatids. Blebs of the inner nuclear membrane are present in developing spermatids and are compared to intranuclear membranes found elsewhere.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01901705
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  • 4
    Electronic Resource
    Electronic Resource
    A comparative study on the fine structure of developing spermatozoa in the isopod, Oniscus asellus, and the amphipod, Orchestoidea sp. (1966)
    Springer
    Cell & tissue research 75 (1966), S. 579-590 
    Details
    ISSN: 1432-0878
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Developing spermatids and mature spermatozoa from the isopod, Oniscus asellus and the amphipod, Orchestoidea sp. have been examined with the light microscope and the electron microscope and have been found to have similar morphologies. As spermiogenesis proceeds the nucleus migrates to one pole of the spermatid at which point an acrosome, contiguous rod, and cross-striated tail develop. The acrosomal vesicle elongates to a cone-shaped, mature acrosome lying at the apex of a cross-striated tail and nucleus which are situated at approximate forty-five degrees to each other. The cross-striated tail originates as an evagination of the spermatid plasma membrane near the acrosomal vesicle. The tail eventually grows to lengths of four to five hundred microns. The mature, tail-like appendage is cross-striated at major 750 to 800 Å, and minor 125 to 150 Å, periodicities. When observed in vitro, mature sperm of both species appear non-motile. Possible homologies of this unusual spermatozoon with other types of spermatozoa are made and it is concluded that: 1) isopod and amphipod spermatozoa should be classified as non-flagellate; 2) the cross-striated tail, previously thought to be a flagellum, is a non-motile structure associated in development and possible function with the acrosome; and 3) the rodlike structure contiguous with the acrosome is similar to perforatoria described in some vertebrate sperm.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00341515
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  • 5
    Electronic Resource
    Electronic Resource
    A comparative study on sub-filament organization in primary myofilaments of basalar direct flight and tibial extensor muscles of the lepidopteran, Achalarus lyciades (1967)
    Springer
    Cell & tissue research 81 (1967), S. 361-365 
    Details
    ISSN: 1432-0878
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Primary myofilaments of direct flight muscle fibers are hexagonally arranged, are surrounded by six secondary myofilaments, and are composed of two sub-unit-fibrils, 90–120 Å in diameter, at mid-sarcomere levels. Primary myofilaments are resolvable into electron-densities 15–25 Å in diameter, which number 3–4 in each sub-fibril at mid-sarcomere levels, and number 6–8 elsewhere. Primary myofilaments of tibial extensor muscle are not found in hexagonal arrays, are surrounded by 10–12 secondary myofilaments, and are resolvable into electron densities which are 15–25 Å in diameter similar to primary myofilaments of basalar flight muscle. However, a binary sub-fibril structure at mid-sarcomere levels is lacking in tibial extensor muscle fibers. The functional significance of the two-sub-fibril organization of myofilaments at midsarcomere levels in basalar direct flight muscle is not known, but may be related to the high rate of excitation-contraction cycles in these muscles.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00342760
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  • 6
    Electronic Resource
    Electronic Resource
    Spermiogenesis in the spider, Pisaurina Sp.: A fine structure studyThis work was supported by U.S.P.H.S. grant NB-06285.The author wishes to express his grateful appreciation for the excellent technical assistance given by Mrs. Ann Florendo and Miss Lou Gipson during the course of this investigation. (1970)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 130 (1970), S. 421-433 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: A fine structure study of spermatids and spermatozoa of the spider, Pisaurina sp. demonstrates that early spermiogenesis is similar to other flagellate spermatozoa. An acrosome forms from a Golgi-derived, acrosomal vesicle, a perforatorium indents acromosome and nucleus, a flagellum with a three-plus-nine tubule substructure is formed and nuclear chromatin condenses during spermiogenesis. Divergence from typical spermatozoa includes the presence of a three-tubule substructure of the central flagellar shaft, progressive rounding-up of late spermatids with concomitant incorporation of previously formed flagellum. This evidence is presented in terms of its possible functional significance in fertilization and gamete fusion in spiders.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1051300403
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  • 7
    Electronic Resource
    Electronic Resource
    The fine structure of neuromuscular junctions and contact zones between body wall muscle cells of Ascaris lumbricoides (var. suum) (1965)
    Springer
    Cell & tissue research 67 (1965), S. 196-210 
    Details
    ISSN: 1432-0878
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Neuromuscular junctions and close membrane apposition between body wall muscle cells of Ascaris lumbricoides (var. suum) have been examined with the light and electron microscopes. It was found that the body wall muscle cells send out elongate processes from their basal, myofibril containing portion to terminate on dorsal and ventral nerves. When observed with the aid of the electron microscope the neuromuscular junctions were seen to consist of several muscle cell processes in apposition to a single axon. The intersynaptic cleft was approximately 350–500 Å wide. Both the axolemma and sarcolemma were triple layered membranes which were 75–80 Å thick. Electron dense patches were observed at intervals on the apposed membranes which were due to increased thickness of the inner membrane leaflets of axolemma and sarcolemma. Muscle cell membranes, at the level of the neuromuscular junction, were in “close” apposition resulting in an apparently five-layered membrane complex which was 170–210 Å thick. The sarcolemmata in these regions were separated by 10–50 Å. Presynaptic axons contained mitochondria, microtubules which were 180–270 Å in diameter, and two, morphologically distinct types and sizes of synaptic vesicles. One was 200–600 Å in diameter, with a single, triple-layered membrane bounding a center of low electron density. The other was 600–1200 Å in diameter, with a single, triple-layered membrane bounding a central, electron dense granule of 500–800 Å size. The functional significances of the “close” membrane appositions between body wall muscle cells and of the two types of synaptic vesicles found at the neuromuscular junctions of Ascaris lumbricoides were discussed with respect to their possible role in neuromuscular physiology.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00344469
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  • 8
    Electronic Resource
    Electronic Resource
    Electron microscopy of the motor endplate in rat intercostal muscleSupported in part by Public Health Service Grant No. B-301.Grants to the Radiation Research Laboratory from the Iowa Division of the American Cancer Society have made possible the purchase and maintenance of the electron microscope. (1955)
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 122 (1955), S. 1-15 
    Details
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ar.1091220102
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  • 9
    Electronic Resource
    Electronic Resource
    The fine structure of iridial constrictor pupillae muscle of Alligator mississippiensisSupported by U.S.P.H.S. grant NB-01528 and Research Career Development Award 9-K3-NB-15,255.The author wishes to express his grateful appreciation for the technical assistance given by Miss Gabrielle Rouiller and Miss Ann Barnett during the course of this investigation. (1966)
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 155 (1966), S. 197-215 
    Details
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The iridial constrictor pupillae muscle of Alligator mississippiensis is found to consist of admixed smooth, myoblast-like, and striated muscle cells. Melanophores, bundles of collagen fibrils, nerve cell processes, and smooth muscle cells, which contain melanin granules, are found scattered in the constrictor pupillae muscle. Protoplasmic bridges are present between myoblast-like cells and between myoblast-like and striated muscle cells. Myoblast-like cells contain agranular reticulum, free ribosomes and randomly scattered, or longitudinally oriented filaments of two sizes (50-100 A and 200-250 A). Free ribosomes are found individually and in clusters of 5 to 10. The agranular reticulum is found as anastomosing tubule-shaped and cisternal elements. The striated muscle fibers consist of myofibrillae and a poorly organized sarcoplasmic reticulum and T system, such that triads and diads are not precisely ordered, but randomly scattered throughout the muscle fiber.This data is discussed in terms of the differentiation and function of striated muscle. On the basis of the disposition of triads and dyads it is concluded that the striated muscle of the constrictor pupillae muscle of Alligator mississippiensis is a slow-acting rather than fast-acting muscle.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ar.1091550207
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  • 10
    Electronic Resource
    Electronic Resource
    The fine structure of neuromuscular synapses of gastrocnemii from mouse and frogSupported by grants from the Muscular Dystrophy Associations of America, Incorporated, and the U. S. Public Health Service (Grant No. B-605).The author wishes to express his appreciation to Dr. V. L. van Breemen for use of the electron microscope and to Dr. T. S. Eliot for critical reading of the manuscript. (1958)
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 130 (1958), S. 7-23 
    Details
    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
    URL: http://dx.doi.org/10.1002/ar.1091300103
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