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  • 1
    Electronic Resource
    Electronic Resource
    Effects of antidiuretic hormone on cellular conductive pathways in mouse medullary thick ascending limbs of Henle: I. ADH increases transcellular conductance pathways (1984)
    Springer
    The journal of membrane biology 80 (1984), S. 201-219 
    Details
    ISSN: 1432-1424
    Keywords: renal tubule transport ; medullary thick ascending limb ; ADH ; K+ conductance ; Na+,K+,Cl− cotransport ; cell conductance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Summary This paper reports experiments designed to assess the relations between net salt absorption and transcellular routes for ion conductance in single mouse medullary thick ascending limbs of Henle microperfusedin vitro. The experimental data indicate that ADH significantly increased the transepithelial electrical conductance, and that this conductance increase could be rationalized in terms of transcellular conductance changes. A minimal estimate (G c min ) of the transcellular conductance, estimated from Ba++ blockade of apical membrane K+ channels, indicated thatG c min was approximately 30–40% of the measured transepithelial conductance. In apical membranes, K+ was the major conductive species; and ADH increased the magnitude of a Ba++-sensitive K+ conductance under conditions where net Cl− absorption was nearly abolished. In basolateral membranes, ADH increased the magnitude of a Cl− conductance; this ADH-dependent increase in basal Cl− conductance depended on a simultaneous hormone-dependent increase in the rate of net Cl− absorption. Cl− removal from luminal solutions had no detectable effect onG e , and net Cl− absorption was reduced at luminal K+ concentrations less than 5mm; thus apical Cl− entry may have been a Na+,K+,2Cl− cotransport process having a negligible conductance. The net rate of K+ secretion was approximately 10% of the net rate of Cl− absorption, while the chemical rate of net Cl− absorption was virtually equal to the equivalent short-circuit current. Thus net Cl− absorption was rheogenic; and approximately half of net Na+ absorption could be rationalized in terms of dissipative flux through the paracellular pathway. These findings, coupled with the observation that K+ was the principal conductive species in apical plasma membranes, support the view that the majority of K+ efflux from cell to lumen through the Ba++-sensitive apical K+ conductance pathway was recycled into cells by Na+,K+,2Cl− cotransport.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01868439
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  • 2
    Electronic Resource
    Electronic Resource
    Effects of antidiuretic hormone on cellular conductive pathways in mouse medullary thick ascending limbs of Henle: II. Determinants of the ADH-mediated increases in transepithelial voltage and in net Cl− absorption (1984)
    Springer
    The journal of membrane biology 80 (1984), S. 221-233 
    Details
    ISSN: 1432-1424
    Keywords: rental tubule transport ; medullary thick ascending limb ; intracellular voltage recording ; ADH ; K+ conductance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Summary Cellular impalements were used in combination with standard transepithelial electrical measurements to evaluate some of the determinants of the spontaneous lumen-positive voltage,V e , which attends net Cl− absorption,J Cl net , and to assess how ADH might augment bothJ Cl met andV e in the mouse medullary thick ascending limb of Henle microperfusedin vitro. Substituting luminal 5mm Ba++ for 5mm K+ resulted in a tenfold increase in the apical-to-basal membrane resistance ratio,R c /R bl , and increasing luminal K+ from 5 to 50mm in the presence of luminal 10−4 m furosemide resulted in a 53-mV depolarization of apical membrane voltage,V a . Thus K+ accounted for at least 85% of apical membrane conductance. Either with or without ADH. 10−4 m luminal furosemide reducedV e andJ Cl net to near zero values and hyperpolarized bothV a andV bl , the voltage across basolateral membranes; however, the depolarization ofV bl was greater in the presence than in the absence of hormone while the hormone had no significant effect on the depolarization ofV a , Thus ADH-dependent increases inV b were referable to greater depolarizations ofV bl in the presence of ADH than in the absence of ADH 68% of the furosemide-induced hyperpolarization ofV a was referable to a decrease in the K+ current across apical membranes, but, at a minimum, only 19% of the hyperpolarization ofV bl could be accounted for by a furosemide-induced reduction in basolateral membrane Cl− current. Thus an increase in intracellular Cl− activity may have contributed to the depolarization ofV bl during net Cl− absorption, and the intracellular Cl− activity was likely greater with ADH than without hormone. Since ADH increases apical K+ conductance and since the chemical driving force for electroneutral Na+,K+,2Cl− cotransport from lumen to cell may have been less in the presence of ADH than in the absence of hormone, the cardinal effects of ADH may have been to increase the functional number of both Ba++-sensitive conductance K+ channels and electroneutral Na+,K+,2Cl− cotransport units in apical plasma membranes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01868440
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  • 3
    Electronic Resource
    Electronic Resource
    Morphology of the pineal organ in the salamander Ensatina eschscholtzi (1981)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 169 (1981), S. 191-206 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The pineal organ of Ensatina eschscholtzi, a terrestrial and secretive species of salamander of the family Plethodontidae, is a photoreceptive structure lying on the dorsal surface of the diencephalon. The pineal is flattened with a broad lumen and consists of three cell types: photoreceptors, supportive cells, and neurons. Pineal photoreceptors are typical vertebrate photoreceptors and possess outer segment formations which, however, are frequently contorted and disorganized. Sloughing of apical portions of outer segments and vesiculation along the lateral edges of outer segment membrane disks are consistently observed and presumed to represent mechanisms of outer segment membrane recycling. Photoreceptors have basal processes which synapse with neural dendrites. Synapses between photoreceptor basal processes are occasionally observed. All synapses are characterized by synaptic ribbon structures of variable number, size, and configuration. Dense-core vesicles are occasionally observed mingled with clear synaptic vesicles within photoreceptor basal processes. Supportive cells within the pineal function in phagocytosis and recycling of shed outer segment membrane material, and neurons are localized at the lateral margins of the organ. The latter send axons into the ipsilateral side of the dorsal diencephalon. The pineal organ of Ensatina shows marked variation in overall size (cell total), cell type proportions, absolute neuron number, and ratio of photoreceptor number to neuron number for individual pineals. None of these morphological parameters is correlated with body size, sex, or season, and it is assumed that such variability represents significant variation in photosensory capabilities. It is suggested that the pineal organ of Ensatina is a partially degenerate photoreceptive structure.
    Additional Material: 16 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1051690206
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  • 4
    Electronic Resource
    Electronic Resource
    An ultrastructural study of the leukocytes of the channel catfish, Ictalurus punctatus (1980)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 164 (1980), S. 1-23 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Ultrastructural studies on blood leukocytes of the channel catfish, Ictalurus punctatus, show the presence of heterophils (neutrophils), small lymphocytes, monocytes, and thrombocytes. Monocytes cannot always be distinguished from large lymphocytes. Cells resembling macrophages or transitional forms between monocytes and macrophages are occasionally seen. Blood eosinophils and basophils are not found. Thrombocytes and small lymphocytes are the most abundant leukocytes, while monocytes are the least frequently encountered leukocyte. Glycogen, present in all leukocytes, is most abundant in heterophils and least abundant in monocytes. Although monocytes are similar to heterophils in size and shape, a greater amount of rough endoplasmic reticulum, free ribosomes, and fewer granules are observed in monocytes. Heterophils possess oval or elongate granules, which often contain a crystalline or striated structure; small tubules which resemble smooth endoplasmic reticulum, and cristae which traverse the long axes of the mitochondria are frequently seen. Small lymphocytes are characterized by the presence of pseudopodia, many free ribosomes, numerous large mitochondria, dictyosomes (Golgi), and long profiles of rough endoplasmic reticulum. The dictyosomes are often associated with a large zone of exclusion. Bundles of microtubules are observed near the elongated ends of thrombocytes. Deep indentations of the plasmalemma, which give the appearance of vacuoles, are also seen in thrombocytes.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1051640102
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  • 5
    Electronic Resource
    Electronic Resource
    Characteristics of plasma membrane isolated from a mouse T lymphoma line: comparison after nitrogen cavitation, shearing, detergent treatment, and microvesiculation (1982)
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 20 (1982), S. 127-138 
    Details
    ISSN: 0730-2312
    Keywords: electron microscopy ; plasma membrane ; lymphoma cells ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Plasma membrane was isolated from the mouse T lymphoma cell line WEHI-22 using four different methods of cell disruption followed by centrifugal fractionation. Disruption by nitrogen cavitation or by shearing with a cell pump produced plasma membrane vesicles of similar buoyant density (1.10 g/ml) and morphological appearance. Few C-type virus particles were present. Cell disruption with 2% Tween-40 produced membrane vesicles of similar morphology but lower density (1.09 g/ml). All of the above preparations resulted in vesicles with aggregated intramembranous particles after freeze fracture. Microvesiculation with a sublytic concentration of a lysophosphatidylcholine analog (ET-12-H) (0.0032% w/v) produced small membrane vesicles which could be isolated without differential centrifugation. However, these had a slightly higher density than vesicles prepared by cavitation or shearing and were co ntaminated by virus particles. Unlike the other preparations, vesicles prepared with ET-I2-H had dispersed intramembranous particles. The enzyme γ-glutamyl transferase was enriched from 20- to 45-fold in the membrane preparations and proved a suitable plasma membrane marker for these cells whose 5′-nucleotidase content is very low.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcb.240200205
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  • 6
    Electronic Resource
    Electronic Resource
    Novel surface specialization on a sea anemone egg: “Spires” of actin-filled microvilli (1982)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 174 (1982), S. 207-216 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The ultrastructure of the “spiny” surface of Tealia crassicornis eggs is examined in detail by scanning and transmission electron microscopy in order to understand its function. Long microvilli are clustered together in spiral aggregates of 50-75 microvilli called “spires.” There are about 15,000 spires per egg. Dense bundles of microfilaments making up the cores of these microvilli are shown to be composed of actin by staining with the fluorescent dye nitrobenzoxadiazole (NBD)-phallacidin. It is postulated that the bundles of actin and the spires of microvilli are stiff and provide reinforcement to the egg surface. Such postulated properties would provide physical protection for these large eggs which, unlike the eggs of most invertebrates, appear to lack all extracellular investing coats.
    Additional Material: 18 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1051740209
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  • 7
    Electronic Resource
    Electronic Resource
    Electromyography of the opercularis muscle of Rana catesbeiana: An amphibian tonic muscle (1983)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 175 (1983), S. 17-26 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The opercularis muscle of Rana catesbeiana originates on the suprascapular cartilage of the shoulder girdle and inserts on the otic opercular element. It is part of the levator scapulae musculature and lies dorsomedial to the levator scapulae superior and inferior muscles. Bipolar electrode recordings from all three muscles show electrical activity linked to cyclical firing of the posterior intermandibularis muscle, an important ventilatory muscle. The opercularis muscle shows low amplitude, erratic signals when animals are sumerged. Upon emergence of the snout region, the opercularis muscle shows rhythmic low amplitude activity at twice the rate of buccal pumping. Lung ventilation is synchronized with this rhythm and at ventilation the opercularis muscle shows higher amplitude activity. Upon submergence, opercularis activity again shows low level activity with no rhythmic pattern. Opercularis muscle activity has a major low frequency component (about 30 Hz) that probably corresponds to activity of tonic muscle fibers. Higher frequency signals (about 200-250 Hz) comparable to those of the levator scapulae muscles are also present and probably represent activity of phasic muscle fibers. Activity of the opercularis muscle is correlated with conditions in which aerial respiration is possible, and this pattern of activity supports an opercularis role in aerial hearing and/or detection of substrate vibrations. As far as we know, this is the first report of electromyographic analysis of a vertebrate tonic muscle.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1051750103
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  • 8
    Electronic Resource
    Electronic Resource
    Effect of physiological concentrations of insulin and antidiabetic drugs on RNA release from isolated liver nuclei (1983)
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 23 (1983), S. 223-229 
    Details
    ISSN: 0730-2312
    Keywords: insulin ; anti-diabetic drugs ; tolazamide ; tolbutamide ; RNA transport ; α2u-globulin mRNA ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: The addition of 10-11M insulin to a cell-free system from rat liver promotes the release of messengerlike RNA from isolated prelabeled nuclei. The stimulation was similar whether the nuclei were preincubatcd with insulin, or if insulin was added directly to the cell-free system with or without a protease inhibitor. Dot blot hybridization using cloned cDNA for α2u-globulin mRNA showed that this was one of the messages whose release was enhanced by insulin. Nuclei isolated from rats treated with either of the antidiabetics tolbutamide or tolazamide showed no increase in RNA release in the presence of insulin over the concentration range 10-5-10-14 M. Furthermore, these nuclei did not release detectable levels of α2u-globulin mRNA.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcb.240230119
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  • 9
    Electronic Resource
    Electronic Resource
    Control and virus-transformed baby hamster kidney cells resistant to ethidium bromide. II. Membrane properties (1981)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 106 (1981), S. 137-148 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Aspects of membrane stucture and functions were studied in ethidium bromide resistant cells. Submitochondrial particles were solubilized and electrophoresed. The gel patterns, representing mitochondiral membrane proteins, demonstrated qualitative and quantitative alterations in mitochondrial preparations derived from virus-transformed cells and ethidium bromide resistant cells as compared to the control cells. The plasma membrane glycoproteins were labelled by the sodium borohydride method. The glycoporteins were released with Triton X-100 and electrophoresed. Fluorograms of the gels demonstratred some marked differences between the ethidium bromide resistant cells and their parental strain. The observed alterations in the membrane glycoproteins did not result in altered glucose transport properties or in the elution patterns of plasma membrane glycopeptides as analyzed by Sephadex G-50 chromatography. Dye uptake and binding studies with intact parental and drug resistant cells and their isolated mitochondria demonstrated no alteration of the membrane permeability or the number of binding sites for ethidium bromide. Similar results were also obtained with a cyanine dye. This latter finding was significant in that it permitted one to exclude dye exclusion as a mechanism for ethidium bromide resistance.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcp.1041060115
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  • 10
    Electronic Resource
    Electronic Resource
    Kinetics of clonogenic melanoma cell proliferation and the limits on growth within a bilayer agar system (1984)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 121 (1984), S. 114-124 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Accurate descriptions of the kinetics of cell growth in semi-solid agar clonogenic systems have been difficult because the number of cells in colonies of different sizes is largely unknown. We stained and removed tumor cell colonies from agar, directly counted their cells, and established equations to quantitate the number of cells within colonies of different sizes. We used these equations to quantitate, in terms of cell number and volume, the total amount and kinetics of clonogenic cell proliferation from biopsies of human melanoma and cell lines of several different tumor types. Daily observations of cells in agar and serial photography indicated a 0- to 4-day delay in the onset of proliferation in agar followed by rapid growth and then abrupt cessation of proliferation. We quantified the extent of proliferation of cells from melanoma biopsies of seven patients and 11 cell lines after they were allowed to proliferate in agar until they stopped. Approximately 10% of cells divided one to five times while only 0.01% divided six to nine times. The total number of cells within the colonies at the end of growth was different while the total volume of cells within the colonies per plate was similar; approximately 109 μm3 cellular volume per plate represents an upper limit for proliferation within the closed, nonrefed bilayer agar system. Previous replating studies using the same biopsy cells have shown that clonogenic melanoma cells can self-renew and have more proliferative capacity than that expressed during primary colony formation. Thus, the clonogenic assay only measured initial proliferative capacities. Furthermore, variable delays in the onset of proliferation may contribute to the heterogenity of colony size within clonogenic assays.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcp.1041210114
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