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  • 2015-2019
  • 1985-1989  (3,087)
  • 1930-1934
  • 1840-1849
  • 1988  (3,087)
  • Life and Medical Sciences  (1,786)
  • Analytical Chemistry and Spectroscopy  (1,301)
Source
Material
Years
  • 2015-2019
  • 1985-1989  (3,087)
  • 1930-1934
  • 1840-1849
Year
Keywords
  • 101
    Electronic Resource
    Electronic Resource
    Dynamics of microtubules visualized by darkfield microscopy: Treadmilling and dynamic instability (1988)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 10 (1988), S. 229-236 
    Details
    ISSN: 0886-1544
    Keywords: microtubule ; treadmilling ; MAPs ; dynamic instability ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Individual microtubules undergoing treadmilling in vitro were visualized by darkfield light microscopy, and the relationship between treadmilling and dynamic instability was studied as a function of microtubule-associated proteins (MAPs). In order to demonstrate treadmilling directly by real-time observation, we constructed three-block microtubules, the center-block of which was decorated with Tetrahymena dynein. The decorated block can easily be distinguished from undecorated blocks in the darkfield microscope because the decorated one appears much thicker. At steady-state conditions, the length of an undecorated block at one end increased and that at another end decreased, while the decorated center-block did not change in its length. The results from these direct observations show that calf brain 3X-microtubules exhibit a treadmilling flux of 0.9 μm/h.Using a similar microscopy technique, we previously demonstrated that phosphocellulose PC-microtubules existed in either the growing or the shortening phase and alternated quite frequently at steady-state conditions (dynamic instability). How does treadmilling relate to dynamic instability? An image recording of individual 3X-microtubules containing MAPs revealed that the microtubules undergo treadmilling and do not exhibit any dynamic instability. This evidence shows that MAPs suppress the dynamic instability of microtubules. That is, treadmilling can take place in the steady state only after microtubules have been stabilized by MAPs.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970100127
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  • 102
    Electronic Resource
    Electronic Resource
    Detection of single fluorescent microtubules and methods for determining their dynamics in living cells (1988)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 10 (1988), S. 237-245 
    Details
    ISSN: 0886-1544
    Keywords: video microscopy ; digital image processing ; fluorescence photobleaching ; microtubule dynamics ; living cell dynamics ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The ability to tag biological molecules fluorescently and to detect their distribution in living cells has promoted the study of cytoplasmic organization in general and microtubule dynamics in particular. The techniques that we have selected and developed allowed the determination of spatial and temporal changes of the microtubule network in living fibroblasts at the level of individual microtubules. We have employed two general approaches for determining pattern changes: direct video microscopy and photobleaching and subsequent observation. Direct observation of fluorescent microtubules by high-definition video microscopy provided good spatial resolution at several time points, but was limited to the less congested and thinner periphery of the cell. This approach was made possible by a relatively bright, photostable reporter, xrhodamine-tubulin, and showed that microtubules underwent rounds of assembly and disassembly from their ends. Bleaching and subsequent observation of lysed cells improved the signal to noise ratio by extracting soluble chromophore and permitted observations in congested areas, but was limited to a single time interval. This approach demonstrated that microtubule domains were replaced one by one and that turnover was most rapid at the cell periphery. Antibodies specific for nonbleached chromophore can be used to enhance the signal to noise ratio further or to extend spatial resolution by the use of immunoelectron microscopy. Direct video microscopy and photo-bleaching are two approaches to the study of dynamics that have complementary strengths and wide application to the biology of living cells.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970100128
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  • 103
    Electronic Resource
    Electronic Resource
    Vesikin, a vesicle associated ATPase from squid axoplasm and optic lobe, has characteristics in common with vertebrate brain MAP 1 and MAP 2 (1988)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 10 (1988), S. 246-254 
    Details
    ISSN: 0886-1544
    Keywords: axoplasmic transport ; motility ; microtubules ; MAPs ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Vesikin, a protein that can associate with squid axoplasmic vesicles or optic lobe microtubuies, has been implicated as a force-generating molecule involved in microtubule-dependent vesicle transport [Gilbert and Sloboda, 1986, 1988]. Because vesikin crossreacts with an antibody to porcine brain microtubule associated protein 2 (MAP 2), studies were conducted to compare squid vesikin and brain MAPs. When taxol stabilized microtubules containing vesikin as a microtubule associated protein were incubated in the presence of ATP, vesikin dissociated from the microtubule subunit lattice. This behavior would be expected for an ATP-dependent, force generating molecule that serves as a crossbridge between vesicles and microtubules. When chick brain microtubules were treated under the same conditions, MAP 2 remained bound to the microtubules while MAP 1 dissociated in a manner similar to vesikin. One dimensional peptide mapping procedures revealed that, although digestion of vesikin and MAP 2 generated several peptides common to both proteins, vesikin and MAP 2 are clearly not identical. Furthermore, the addition of vesikin or MAPS 1 and 2 to purified tubulin stimulated microtubule assembly in a manner dependent on the concentration of added protein. These findings demonstrate that brain MAPs share characteristics common to squid vesikin and support the suggestion that brain MAPs 1 and 2 might act as a force generating complex for vesicle transport in higher organisms.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970100129
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  • 104
    Electronic Resource
    Electronic Resource
    Microtubule-associated organelle and vesicle transport in fibroblasts (1988)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 10 (1988), S. 255-262 
    Details
    ISSN: 0886-1544
    Keywords: regulation of organelle transport ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Allen Video-enhanced constrast/differential interference constrast (AVEC-DIC) microscopy was used in conjunction with video intensification immunofluorescence microscopy to demonstrate that organelles and vesicle (particles) can move in either direction along microtubular linear elements in fibroblasts [Hayden et al., 1983]. Since it is not possible to determine the number of microtubules making up a linear element with light microscopy alone, AVEC-DIC microscopy was used in conjunction with whole-mount electron microscopy to show bidirectional transport along a single microtubule [Hayden and Allen, 1984]. These studies demonstrate that the structural polarity of the microtubule does not determine the direction of particle motion, and since dynein is an asymetric molecule, a simple microtubule-dynein-particle hypothesis cannot explain bidirectional transport along a single microtubule.Very little is known about regulation of particle transport in most cell types. Human embryonic lung fibroblasts grown on glass coverslips were serum-deprived for 24 hours and re-fed with serumless medium; the particle translocations/5 minutes were then determined The cells were then re-fed with either serumless medium, serum-containing medium, or serumless medium containing some bioactive factor, and the particle translocations/5 minutes were again determined for the same cells. Medium containing 10% fetal bovine serum inhibited particle translocation by 51.8%. Of the bioactive factors tested, only vasopressin produced a significant reduction in particle translocations (38%). This suggests that protein kinase C or calcium/calmodulin kinase could be involved in regulating particle transport.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970100130
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  • 105
    Electronic Resource
    Electronic Resource
    Fast axonal transport alterations in amyotrophic lateral sclerosis (ALS) and in parathyroid hormone (PTH)-treated axons (1988)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 10 (1988), S. 321-330 
    Details
    ISSN: 0886-1544
    Keywords: organelle motion ; video microscopy ; computer motion analysis ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Video-enhanced contrast techniques have been used to study fast axonal transport of organelles in diseased and normal human axons. A broad perspective on the importance of axonal transport in the pathogenesis of human neurological disorders is presented and problems in dealing with human nerve summarized. Results from analysis of organelle traffic in axons from motor nerve in patients with amyotrophic lateral sclerosis (ALS) show: (1) higher mean speed of anterograde organelles, (2) lower mean speed of retrograde organelles, and (3) lower retrograde organelle traffic density. Hyperparathyroidism, another human clinical syndrome, can mimic ALS. The effect of parathyroid hormone (PTH) on axons in vitro is to increase the mean speed of both anterograde and retrograde organelle traffic. The dose response curve and time course of the PTH effect are delineated. Dihydropyridine calcium channel antagonists block the PTH effect, implicating extracellular calcium in the alteration of organelle traffic speed. The results are discussed in relation to neuronal function and the regulation of fast axonal transport.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970100136
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  • 106
    Electronic Resource
    Electronic Resource
    Localization of mitotic-apparatus-associated 51-kD protein in unfertilized and fertilized sea urchin eggs (1988)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 10 (1988), S. 496-505 
    Details
    ISSN: 0886-1544
    Keywords: centrosome ; spindle matrix ; postembedding immunofluorescent labeling ; mitotic apparatus ; sea urchin eggs ; 51-kD protein ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The 51-kD protein, a protein component of the mitotic apparatus in sea urchin eggs, is involved in the aster-forming activity previously shown in vitro [Toriyama et al., 1988]. Postembedding immunofluorescent labelings of eggs from fertilization through first cleavage showed that the 51-kD protein is localized in sperm asters, centrosomal regions, spindles, basal regions of astral microtubules, and regions surrounding daughter nuclei at telophase in situ. Immunofluorescence and immunoblot analyses detected the 51-kD protein uniformly in unfertilized eggs, but not in spermatozoa. When unfertilized eggs were treated with taxol, the 51-kD protein was shown to be associated with taxol-induced cytasters. Immunoblot analysis revealed that similar protein species are present in the mitotic apparatus of other species of sea urchin. It was suggested that the 51-kD protein may be involved in microtubule nucleation and microtubule matrix in sea urchin eggs in vivo.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970100406
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  • 107
    Electronic Resource
    Electronic Resource
    The ciliary cycle during hyperpolarization-induced activity: An analysis of axonemal functional parameters (1988)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 11 (1988), S. 275-290 
    Details
    ISSN: 0886-1544
    Keywords: ciliary motility ; inclination ; polarity of beating ; sliding velocity ; sliding translocation rate ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Motor responses of the frontal cirri of the ciliate Stylonychia were recorded at the axial view of the ciliary base with high-speed cinematography. Voltage-clamp applying sustained hyperpolarizing voltage steps was used to explore the properties of the ciliary cycle modulated by the membrane potential. Upon hyperpolarization between - 1 and - 13 mV, a previously inactive frontal cirrus reoriented from a neutral posture and started beating so that the axis of the beating cone of a proximal cirral segment assumed an orientation near 100° (proceeding counterclockwise from posterior = 0°) and inclination near 60° (0° = perpendicular to the cell surface). The major beating amplitude was limited to about 150°. Increasing hyperpolarization increased the spatial polarity of the cycle (ratio of major over minor amplitude, from 2 to 2.4). Rates of the power stroke increased with hyperpolarizations up to - 4 mV but were consistently smaller than those of the return stroke during the ciliary cycle (ratio: 0.4 to 0.6; = temporal polarity). Comparison of different hypothetical beat forms (0-shape, D-shape, and egg-shape) showed that the orientation-time data are the major determinants of the angular velocity and rate of reorientation of the cilium during the cycle. Geometric transformation of these data led to descriptions of the cycle of a proximal ciliary segment in terms of active sliding velocities and rates of unidirectional sliding translocation between identified doublets. Three voltage-sensitive functional parameters of the cilium - the inclination (which is noncyclic) and the rates of active sliding and sliding translocation (both of which are cyclic in nature) - are discussed as generating the spatial and temporal properties of the ciliary beat.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970110406
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  • 108
    Electronic Resource
    Electronic Resource
    Effect of metabolic inhibitors on sucrose-induced metaphase spindle elongation and spindle recovery (1988)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 11 (1988), S. 291-302 
    Details
    ISSN: 0886-1544
    Keywords: mitosis ; mitotic apparatus ; microtubules ; kinetochores ; metabolic inhibitors ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Hyperosmotic sucrose treatment of metaphase PtK-1 cells has been shown to produce a reversible concentration-dependent effect on spindle elongation linked to a functional alteration in the connection of the chromosome to the spindle (Pover et al.: European Journal of Cell Biology 39:366-372, 1985). Spindle elongation, similar to that which occurs at anaphase B, is thought to be driven by the compression stored in the form of microtubule curvature in the nonkinetochore (nkMT) population of microtubules at metaphase (Snyder et al.: European Journal of Cell Biology 35:62-69, 1984 and 39:373-379, 1985). Addition of metabolic inhibitors to Ham's F-12 salts with deoxyglucose (D/F-12 medium) containing 0.4 M sucrose and 1 mM DNP does not within statistical error affect the rate and extent of sucrose-induced spindle elongation; rates and extents are 60-75% of normal anaphase B motions. Electron microscopic analysis of metaphase cells treated with D/F-12 medium and 0.4 M sucrose with 1 mM DNP demonstrates that spindle microtubules lose curvature and become straight in appearance, typical of microtubule organization in untreated anaphase cells. Sucrose-treated cells released into D/F-12 medium show a rapid reduction in spindle length; however, cells treated with either 0.4 M sucrose or 0.4 M sucrose and 1 mM DNP-containing D/F-12 medium and released into DNP-containing D/F-12 medium do not exhibit a significant reduction in spindle length. Electron microscopic analysis links changes in spindle length with microtubule/kinetochore associations. These data suggest that energy required for the initial phases of spindle elongation during anaphase is preloaded into the mitotic spindle by metaphase and does not require additional energy to be expressed as examined by sucrose-induced spindle elongation in the presence of metabolic inhibitors. Second, energy is required to make or maintain (or both) functional chromosome associations with the spindle as measured by reduction in spindle length following sucrose removal.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970110407
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  • 109
    Electronic Resource
    Electronic Resource
    Unique isoactins in the brush border of rat intestinal epithelial cells (1988)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 11 (1988), S. 318-325 
    Details
    ISSN: 0886-1544
    Keywords: actin ; contractile proteins ; microvilli ; cytoskeleton ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The mammalian genome contains 20-30 genes encoding a family of actins. To date, however, only six proteins (four muscle and two nonmuscle isoforms) encoded by this multigene complex have been identified. We have isolated two actins from the brush border of rat intestinal epithelial cells that have isoelectric points and N-terminal peptides characteristic of the cytoplasmic β- and γ-actins. However, using a panel of actin-specific monoclonal antibodies, we show that these actins contain a set of epitopes that distinguishes them from any of the known cytoplasmic or muscle isoforms. These unique actins share features of both the nonmuscle and muscle isoforms, suggesting that they represent an intermediate in the evolution of the specialized muscle actins.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970110409
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  • 110
    Electronic Resource
    Electronic Resource
    Isolation of an immunoreactive analogue of brain fodrin that is associated with the cell cortex of Dictyostelium amoebae (1988)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 11 (1988), S. 303-317 
    Details
    ISSN: 0886-1544
    Keywords: spectrin ; actin ; membrane skeleton ; cytoskeleton ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: We have used a polyclonal affinity-purified antibody made against chicken brain fodrin (both 240 and 235 Kd subunits) as a probe to determine if a fodrinlike protein exists in amoebae of Dictyostelium discoideum. In Western blots of whole cells and the isolated cell cortex, polypeptides measuring 220 and 70 Kd are recognized by the fodrin antibodies. In situ localization by indirect immunofluorescence with antifodrin indicates that the immunoreactive polypeptides are cortical. The immunoreactive analogues copatch and cocap with concanavalin A. At the level of resolution of the electron microscope, immunocytochemistry with antifodrin and colloidal gold confirms that the immunoreactive analogues are cortical proteins associated with microfilaments on the cytoplasmic side of the plasma membrane. We have isolated and characterized the 220 Kd protein to determine if it is similar to fodrin and to investigate its relationship to the 70 Kd polypeptide. The 220 Kd protein can be extracted from the cortex in the absence of detergent and isolated by gel filtration and sucrose density gradient sedimentation. The 220 Kd is a rod-shaped protein 118 ± 17.8 nm (N = 37) in length. It has a sedimentation coefficient of 9.3 S and Stokes' radius of 13 nm and exists as a dimer of approximately 500,000 daltons (Mr). Isolated 220 Kd binds to actin filaments in vitro when assayed by rotary shadowing. Morphological criteria distinguish 220 Kd from Dictyostelium myosin II heavy chain (215 Kd) and the filaminlike protein at 240 Kd. The 70 Kd polypeptide appears to be a cleavage fragment of the 220 Kd, since it is found after prolonged storage when formerly only the 220 Kd was present. Furthermore, the 220 and 70 Kd polypeptides exhibit similar one-dimensional peptide maps when treated with TPCK trypsin. On the basis of its physical and immunoreactive characteristics, and location in the cell, the 220 Kd may be a fodrinlike protein.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970110408
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  • 111
    Electronic Resource
    Electronic Resource
    Announcement (1988)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 11 (1988), S. 326-326 
    Details
    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970110410
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  • 112
    Electronic Resource
    Electronic Resource
    Maturation of hagfish gland thread cells: Composition and characterization of intermediate filament polypeptides (1988)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 11 (1988), S. 31-45 
    Details
    ISSN: 0886-1544
    Keywords: cytoskeletal maturation ; keratinlike filaments ; holocrine secretion ; cytoskeleton ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Previous studies with the hagfish, a primitive vertebrate, have shown that the gland thread cells (GTCs) each contain a single thread (∼60 cm long in average-sized cells) in the form of a concisely coiled cytoskeletal entity destined for export by holocrine secretion. The thread in relatively immature GTCs consists almost entirely of intermediate filaments (IFs) bundled in parallel alignment with far fewer microtubules (MTs). The three thread polypeptides described earlier (α, basic; β acidic; γ, most acidic; each with a Mr of 63-64 kD) are now further evaluated with respect to in vitro assembly, cross-reactivity with IF polypeptides from higher vertebrates, and peptide sequence homology with known IF polypeptides. The overall results mainly suggest that the hagfish polypeptides are keratinlike substances but lamins or a new type of IF is not ruled out. However, cross-reactivity is weak with mammalian keratins; the 8-11-nm filaments formed from mixtures of α and γ in vitro are generally linear rather than the curvilinear structures usually formed by keratin and nonkeratin IFs; and mixtures of α and β tend to yield 9-12-nm granules or granular strings. Polypeptide analyses on GTCs segregated on the basis of maturational stage show a progressive increase in β/γ values which correlates with cell maturation, but the α/(β+γ) ratios remain near 1. Inasmuch as β and γ have many similar properties, the documented increase in the amount of the β component in aging GTCs might in part be the result of a failure in a posttranslational modification system and may contribute to the ultrastructural changes that accompany thread maturation in preparation for holocrine secretion and subsequent modulation of the viscoelastic properties of mucus.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970110105
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  • 113
    Electronic Resource
    Electronic Resource
    Rapid quantification of 11 prostanoids by combined capillary column gas chromatography and negative ion chemical ionization mass spectrometry: Application to prostanoids released from normal human embryonic lung fibroblasts WI38 in a culture medium (1988)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 15 (1988), S. 25-32 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The rapid and simultaneous quantification of 11 prostanoids has been carried out with a short-capillary gas chromatograph and negative ion chemical ionization (ammonia) mass spectrometer.The methoxime-trimethylsilyl ether-pentafluorobenzyl esters (MO-TMS-PFB) of nine prostanoids, PGA1, PGA2, PGB1, PGB2, PGD2, PGE1, PGE2, 6-oxo-PGF1α and TXB2 and the TMS-PFB of two prostanoids, PGF1α and PGF2α, were separated in less than 5.5 min on a bonded OV-1 capillary column 0.25 mm i.d. × 6 m (0.15 μm thickness) using hydrogen as a carrier gas. PGD2, PGE2, PGF2α, 6-oxo-PGF1α and TXB2 were quantified up to 2.5 fmol injected (0.1 pmol derivatized) and both PGA2 and PGB2 up to 25 fmol injected (1 pmol derivatized).In order to maintain the stability of the prostanoids containing a carbonyl group, such as TXB2 during the purification and derivatization steps of biological materials, methyl acetate was used in place of methyl formate as an eluant for Sep-Pak C18 purification.Normal human embryonic lung fibroblasts W138 (5.63 × 105 cells in a log phase) produced: PGA2 15.28, PGB2 13.48, PGD2 7.95, PGE1 2.62, PGE2 177.76, PGF2α 25.14, 6-oxo-PGF1α 27.33 and TXB2 61.00 pmol in 10 ml of Eagle minimal essential medium.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200150105
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  • 114
    Electronic Resource
    Electronic Resource
    Measurement of urinary lactic, 3-hydroxybutyric, pyruvic and acetoacetic acids in a single analysis using selected ion monitoring and stable isotope labelling techniques (1988)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 15 (1988), S. 57-62 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Sodium borodeuteride treatment of urine expected to have large concentrations of pyruvic and acetoacetic acids produces lactic and 3-hydroxybutyric acids labelled with deuterium. Mass fragmentographic techniques applied to the trimethylsilyated extract of the urine spiked with more extensively labelled analogues as internal standards permit the reliable determination of lactic, pyruvic, 3-hydroxybutyric and acetoacetic acids in a single analysis.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200150108
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  • 115
    Electronic Resource
    Electronic Resource
    Characterization of trichothecenes by ammonia chemical ionization and tandem mass spectrometry (1988)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 15 (1988), S. 79-87 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Ammonia and deuterated ammonia chemical ionization (CI) mass spectra and collisionally activated dissociation (CAD) mass spectra of ammonium adduct ions are presented for ten trichothecenes. The samples were introduced by direct exposure probe. Effects of ion source temperature and pressure on the ammonia CI gas plasma and the formation of the ammonium adduct ion were studied. The CI conditions were optimized to produce a maximal yield for the ammonium adduct ion of trichothecenes, i.e. the parent ion for tandem mass spectral analysis. Besides source temperature and pressure, proton affinity and the stability of the ammonium adduct ion affect the relative abundance ratio of [M + H]+:[M + NH4]+ in ammonia CI and CAD mass spectra. The ratio [M + H]+:[M + NH4]+, and hence the stability of the ammonium adduct ion, are largely determined by the functional groups (hydroxy, carbonyl, acetoxy, and isovaleroyloxy) and their location in the trichothecene nucleus. The most abundant fragment ions in the ammonia CI spectra and the most abundant daughter ions in the CAD spectra of the ammonium adduct ions are formed by the losses of ammonia and functional groups as neutrals in various combinations.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200150205
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  • 116
    Electronic Resource
    Electronic Resource
    The application of gas chromatographic/mass spectrometric techniques to spin trapping. Conversion of α-phenyl N-tert-butyl nitrone (PBN) spin adducts to stable trimethylsilylated derivatives (1988)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 15 (1988), S. 111-116 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reaction of an aminoxyl and the corresponding hydroxylamine with silylating agents is studied in detail. The gas chromatographic/mass spectrometric analysis of the products is consistent with the production of an unsaturated product when an alkyl group with exchangeable hydrogens is attached to the nitrone group. The structure of this compound is confirmed by deuteration. It is concluded that aminoxyls themselves do not derivatize wth silylating agents.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200150209
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  • 117
    Electronic Resource
    Electronic Resource
    Gas chromatography/mass spectrometry and gas chromatography/tandem mass spectrometry of methyl ester/methoxime/trimethylsilyl ether derivatives of prostaglandins (1988)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 15 (1988), S. 129-138 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Electron impact mass spectra of methyl ester/trimethylsilyl ether derivatives of prostaglandin F2α and methyl ester/methoxime/trimethylsilyl ether derivatives of prostaglandin E2, prostaglandin D2, 6-oxo-prostaglandin F1α and 2,3-dinor-6-oxo-prostaglandin F1α are presented. Most of the prostaglandins studied have additionally been 2H-labelled at different sites in order to assign the corresponding fragment ions. Collisionally activated decomposition mass spectra of the most intense parent ions in the high-mass region were taken. High-intensity, prostaglandin-characteristic daughter fragments will allow a reliable quantification of prostaglandins in biological fluids and a reduction of sample clean-up.
    Additional Material: 8 Ill.
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    URL: http://dx.doi.org/10.1002/bms.1200150303
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    A gas chromatographic/mass spectrometric assay for catechol estrogens in microsomal incubations: Comparison with a radiometric assay (1988)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 15 (1988), S. 157-161 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A gas chromatographic/mass spectrometric assay for quantifying two catechol estrogens, 2-hydroxyestradiol and 4-hydroxyestradiol, in microsomal preparations is described. The assay employs deuterium-labeled analogs of the catechol estrogens as internal standards and permits quantification of catechol estrogens, in microsomal incubations, at low (1-2) μM concentrations. The compounds are analyzed as their trimethylsilyl derivatives following separation by capillary gas chromatography.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/bms.1200150307
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  • 119
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    Electron capture negative ion chemical ionization analysis of arachidonic acid (1988)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 15 (1988), S. 175-178 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A highly sensitive (subpicomole level) and structural specific method for the analysis of arachidonic acid esterified to complex glycerophospholipids has been developed using combined capillary gas chromatography and mass spectrometry. The methodology is based upon the formation of the pentafluorobenzyl ester of arachidonic acid, which is efficiently ionized using electron capture negative ion chemical ionization conditions to yield an abundant carboxylate anion at m/z 301. Quantification is carried out following hydrolysis of the complex glycerophospholipid in the presence of a known amount of (2H8) araachidonic acid. The use of this method is illustrated by the quantification of arachidonic acid within the glycerophospholipid classes isolated from resident peritoneal macrophage cells isolated from HS mice.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/bms.1200150309
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    Mass spectral investigations on trichothecene mycotoxins. V. Direct analysis of satratoxins by tandem mass spectrometric techniques (1988)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 15 (1988), S. 185-191 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Under chemical ionization conditions, satratoxins preferentially produce negatively charged molecular ions (M-·) over the positively charged protonated molecules. Collisionally activated dissociation of the M-· ions resulted in daughter ions and neutral losses which were characteristic of the macrocyclic ester bridges. Direct tandem mass spectrometric methods of analyses wee developed and applied for the detection and quantification of satratoxins in Stachybotrys atra fermentation broths. Minimum detectable levels for satratoxin standards were 5 pg. A synthetically modified macrocyclic trichothecene, 8-ketoverrucarin A, was used as an internal standard for the quantification of satratoxins in fermentation samples.
    Additional Material: 10 Ill.
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    URL: http://dx.doi.org/10.1002/bms.1200150402
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    Thermospray liquid chromatography tandem mass spectrometry: Application to the elucidation of zolpidem metabolismThis work was presented in part at the 4th Symposium on Liquid Chromatography/Mass Spectrometry and Mass Spectrometry/Mass Spectrometry, Montreux (Switzerland), October 22-24, 1986. (1988)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 15 (1988), S. 223-228 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: This paper discusses the possible advantages of thermospray liquid chromatography/tandem mass spectrometry LC/MS/MS for metabolic mapping. The technique was applied to the study of the metabolism of zolpidem, a new hypnotic with an imidazo-pyridine moiety. When compared to other chromatographic/mass spectrometric-based techniques, reversed phase high-performance liquid chromatography coupled with thermospray LC/MS/MS appears to be the fastest method available today for elucidation of unknown metabolic structures, since it allows identification by direct injection of concentrated urine. However, it was noted during the thermospray process that loss of formaldehyde from a hydroxymethyl amide metabolite occurred. This degradation was not observed when this metabolite was analysed by gas chromatography/mass spectrometry following trimethylsilylation.
    Additional Material: 9 Ill.
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    URL: http://dx.doi.org/10.1002/bms.1200150406
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  • 122
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    Fast atom bombardment mass spectrometry of high-molecular-weight fraction of porphyrin-based photodynamic therapy drugs (1988)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 15 (1988), S. 257-263 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Photodynamic therapy (PDT) involves the treatment of tumor tissue with a photosensitizer and light to effect the delineation and/or eradication of the tumor. PDT is a two step process: (1) incorporation of photosensitizer into the cell where it must be retained by tumors in vivo; and (2) illumination of the tumor cell with light to effect cell death. Hematoporphyrin derivative (HPD) is a complex mixture of porphyrins currently used for PDT in the clinical setting. Hematoporphyrin-based oligomers of up to five subunits were determined using fast atom bombardment mass spectrometry of the high-molecular-weight fraction of the drug. Reduction of this fraction with LiAlH4 permitted determination of the covalent bond linking the monomers in these oligoporphyrins. Application of these analytical procedures to the determination of the composition of different preparations of HPD will be described.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/bms.1200150505
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  • 123
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    (18O)quinolinic acid: Its esterification without back exchange for use as internal standard in the quantification of brain and CSF quinolinic acid (1988)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 15 (1988), S. 291-293 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In the process of developing a high-sensitivity negative chemical ionization gas chromatographic/mass spectrometric assay for brain and cerebrospinal fluid (CSF) levels of quinolinic acid (QUIN, 2,3-pyridine dicarboxylic acid), (18O4)QUIN was prepared. Its properties as an internal standard were compared with those of the structural isomer 2,4-pyridine decarboxylic acid (2,4-PDC) previously used by others. All oxygen atoms in QUIN were labeled by heating in 3N HCl/(18O)water for 48 h at 80°C. Back-exchange of (18O4)QUIN was prevented during derivatization to an electron-capturing dihexafluoropropanol ester by using trifluoroacetylimidazole as catalyst instead of perfluroacyl anhydrides. When mixtures of QUIN and (18O4)QUIN and/or 2,4-PDC were followed through a procedure to isolate and quantify brain and CSF QUIN, the variability in the ratio of QUIN:2,4-PDC was greater than for QUIN:(18O)QUIN. We conclude that (18O)QUIN is the preferred internal standard in gas chromatographic/mass spectrometric quantification of brain and CSF QUIN, and that (18O)-labeled carboxylic acids may be esterified effectively without back-exchange using acylimidazole reagents.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/bms.1200150509
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  • 124
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    252CF plasma desorption mass spectrometry of a polycyclic peptide antibiotic, Nisin (1988)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 15 (1988), S. 305-310 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The polycyclic peptide antibiotic, Nisin, has been analysed by plasma desorption mass spectrometry using two different sample preparation techniques and two versions of the commercial plasma desorption mass spectrometer, and a prototype with high resolving power. The spectra obtained allow identification of a major component and two minor analogues. Extensive fragmentation is observed in samples prepared by the electrospray technique, whereas only ions indicating the molecular weight are produced when the sample is adsorbed on nitrocellulose.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/bms.1200150602
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    Gas chromatography/mass spectrometry and gas chromatography/mass spectrometry/mass spectrometry of methyl ester/methoxime/trimethylsilyl ether derivatives of thromboxanes (1988)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 15 (1988), S. 139-142 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Electron impact mass spectra of methyl ester/methoxime/trimethylsilyl ether derivatives of thromboxane B2 (TxB2) and 2,3-dinor-TxB2 and methyl ester/trimethylsilyl ether derivative of 11-dehydro-TxB2 are presented. Additionally, the derivatives of (2H4)-thromboxanes and methyl ester (2H3)-methoxime/trimethylsilyl ether derivatives of TxB2 and 2,3-dinor-TxB2 and (2H3)-methyl ester/trimethylsilyl ether derivative of 11-dehydro-TxB2 were investigated. Collision-induced dissociation mass spectra of the most intense parent ion in the high-mass region were taken. Collisionally activated decomposition mass spectra of the [C(12)-C(20)]+ ion of TxB2 and 2,3-dinor-TxB2 show an intense but not specific daughter ion, whereas the collison-induced dissociation mass spectrum of the [M - (C(16)-C(20)]+ ion of 11-dehydro-TxB2 results in the formation of numerous daughter ions.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/bms.1200150304
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    Collisional spectroscopy as a screening procedure for the determination of 2-(2-furoyl)-4(5)-(2-furanyl)-1H-imidazole from acid hydrolysis of B-poly(L-Lysine) and B-albumin (1988)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 15 (1988), S. 7-11 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The direct determination of 2-(2-furoyl)-4(5)-(2-furanyl)-1H-imidazole (FFI), present in the acid hydrolysis products of B-poly(L-lysine) and B-albumin and which appears to be a key intermediate in the physicochemical changes occurring during the incubation of protein with glucose, has been carried out by collisional spectroscopy, using a commercial double-focusing, reverse-geometry mass spectrometer and without any sample derivatization and chromatographic separation procedures.
    Additional Material: 6 Ill.
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    URL: http://dx.doi.org/10.1002/bms.1200150103
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    A gas chromatographic/mass spectrometric screening, confirmation, and quantification method for estrogenic compounds (1988)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 15 (1988), S. 45-56 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A method is described for the screening, quantification and confirmation of a variety of estronenic substances in animal tissues. A solid-phase extraction technique combined with a liquid/liquid extraction allows for rapid sample preparation and high throughput for the following compounds in bovine liver, muscle and kidney: diethylstilbestrol, dienestrol, hexestrol, zeranol, taleranol, zearalanone, zearalenone, zearalenol, estradiol and estriol. Gas chromatography/mass spectrometry and selected ion monitoring is used for the determination with detection limits ranging from 50 to 150 ppt.
    Additional Material: 9 Ill.
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    URL: http://dx.doi.org/10.1002/bms.1200150107
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    Packed column supercritical fluid chromatography/mass spectrometry using a thermospray source in the filament-on mode (1988)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 15 (1988), S. 105-109 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Combined packed column supercritical fluid chromatography/mass spectrometry has been effected using a thermospray ion source in the filament-on mode. If organic modifiers are used with carbon dioxide as the supercritical mobile phase, chemical ionization mass spectra are obtained. With carbon dioxide electron impact type mass spectra are obtained. The potential of the system is illustrated with studies of mixtures of carbamate and organochlorine pesticides and a crude ergot fermentation extract.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200150208
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    The identification of biologically important thiols (1988)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 15 (1988), S. 123-128 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A new mass spectral method has been developed and used to identify biologically important thiols. This method is based upon the use of C-14 labeled N-para-bromophenylmaleimide (BPM) to selectively derivatize thiols. The isotopic label facilitates the isolation and purification of trace quantities of the maleimide thiol adducts by high performance liquid chromatography (HPLC) with radioactivity detection. The use of the bromine atom in the thiol derivative greatly enhances the detectability of the parent and fragment ions containing the BPM moiety because of the generation of the characteristic N + 2 doublet ions. Several examples of the use of this method to identify non-volatile thiol peptides such as glutathione (GSH) and homoglutathione (hGSH) by fast atom bombardment mass spectrometry (FAB-MS) are described in this report.
    Additional Material: 8 Ill.
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    URL: http://dx.doi.org/10.1002/bms.1200150302
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    In vivo metabolism of (+)-trans-Delta-9-tetrahydrocannabinol in the mouse (1988)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 15 (1988), S. 117-122 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: (+)-trans-Delta-9-tetrahydrocannabinol [(+)-delta-9-THC], a biologically inactive isomer of (-)-trans-delta-9-THC, the major psychoactive constituent of cannabis, was administered intraperitoneally to male Charles River CD-1 mice; hepatic metabolites were extracted with ethyl acetate and isolated by chromatography on Sephadex LH-20 in chloroform. The metabolites were converted into trimethylsilyl (TMS), 2H9-TMS and methyl ester/TMS derivatives for examination by gas chromatography/mass spectrometry and additional samples were prepared by reduction of metabolic fractions with lithium aluminium deuteride. Sixteen metabolites were characterized: these were alcohols and carboxylic acids, together with several of their hydroxylated analogues. The major biotransformation pathway was hydroxylation at C(11) to give the major metabolite, followed by oxidation of this compound to a carboxylic acid. Hydroxylated analogues of these two compounds were substituted mainly in the side-chain. Although metabolism was very similar to that of the naturally occurring (-)-isomer as far as positions of substitution were concerned, some differences were observed. These related mainly to the positions of hydroxylation on the side-chain, where 1′-hydroxylation was preferred to hydroxylation at the 2′-position. The major difference in metabolism between the two isomers was that much less oxidation of the 11-hydroxy group to a carboxylic acid occurred and there was less hydroxylation at the 8-position. Thus, 11-hydroxy-(+)-trans-delta-9-THC was the major metabolite and most other metabolites were hydroxylated derivatives of this compound.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/bms.1200150210
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    Negative ion chemical ionization gas chromatography/mass spectrometry and gas chromatography/tandem mass spectrometry of prostanoid pentafluorobenzyl ester/methoxime/trimethylsilyl ether derivatives (1988)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 15 (1988), S. 143-151 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Negative ion chemical ionization mass spectra of prostaglandin F2α, prostaglandin E2, prostaglandin D2, 6-oxo-prostaglandin F1α, 2,3-dinor-6-oxo-prostaglandin F1α, thromboxane B2, 2,3-dinor-thromboxane B2, and 11-dehydro-thromboxane B2 pentafluorobenzyl ester (PFB)/methoxime/trimethylsilyl ether derivatives are presented. Collisionally activated decomposition mass spectra of the [M - PFB]- ions at collision energies of 8-24 eV and argon collision gas pressures of 1-2 mTorr almost show only fragmentation of trimethylsilanol, (CH3)2Si=CHOH, (CH3)2Si=CH2 and methanol whereas, except for carbon dioxide loss, only few low-intensity fragments from the carbon skeleton of the prostanoids are observed.
    Additional Material: 10 Ill.
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    URL: http://dx.doi.org/10.1002/bms.1200150305
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    Continuous flow fast atom bombardment liquid chromatography/mass spectrometry: Studies involving conventional bore liquid chromatography with simultaneous ultraviolet detection (1988)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 15 (1988), S. 179-182 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A conventional bore liquid chromatograph has been interfaced to quadrupole and magnetic sector mass spectrometers configured for fast atom bombardment ionization via a continuous flow FAB probe. It is shown that post-column addition of FAB matrix and in-line ultraviolet detection facilities do not significantly compromise chromatographic integrity and that high quality mass spectra are obtainable from such FAB LC/MS studies.
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    Rapid identification of drug metabolites with tandem mass spectrometry (1988)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 15 (1988), S. 193-204 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A method which involves the use of tandem mass spectrometry (MS/MS) for the identification of drug metabolites has been demonstrated with a triple quadrupole mass spectrometer. The method is based on the fact that metabolites usually retain various substructures of the original drug molecule. MS/MS is capable of rapidly identifying molecules with characteristic substructures without prior separation. It is shown that this method makes it possible to postulate possible drug metabolite structures rapidly and systematically without the use of standards. The MS/MS method, as it was applied to the identification of the metabolites of a new antiepileptic drug, zonisamide, is discussed. In this case it was possible to identify isomeric metabolites due to their differences in vaporization times off the probe and their different daughter spectra. The complementary uses of the neutral loss and parent scans for the determination of the site of metabolism is demonstrated. A new figure of merit, the limit of identification, is introduced. The amount of the epoxide metabolite of carbamazepine necessary for its reliable identification in urine was shown to be 0.4 ng/μl. The application of various techniques to confirm preliminary findings with this MS/MS method are described.
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    URL: http://dx.doi.org/10.1002/bms.1200150403
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    Masthead (1988)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 15 (1988) 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200150101
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    Mass spectral investigations on trichothecene mycotoxins IV - collisionally activated dissociation mass spectra (negative ion) of some macrocyclic trichothecenes (1988)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 15 (1988), S. 13-24 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Macrocyclic trichothecenes are di- and triesters of simple trichothecenes such as verrucarol and oxygenated verrucarols. They form the negatively charged molecular (M-·) ions more effectively than the positively charged protonated molecules under chemical ionization (methane) conditions. This is proposed to be due to extended conjugation at the macrocyclic ester bridges of the molecules. The M-· ions of several macrocyclic trichothecenes undergo collisionally activated dissociation (argon) yielding the daughter ions characteristic of the ester bridges. Structures for various specific and abundant ions observed in the tandem mass spectra are proposed. The daughter ions and experimental conditions for the specific detection of these trichothecenes are selected. A semi-synthetic macrocyclic trichothecene is found to be an adequate internal standard for the analysis of macrocyclic trichothecenes under collisionally activated dissociation (CAD) conditions. Low nanogram (1-2) quantities of roridin H and satratoxins are detected under these conditions. Preliminary results indicate the applicability of this negative ion chemical ionization/tandem mass spectrometric method for the analysis of macrocyclic trichothecenes in real samples.
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    URL: http://dx.doi.org/10.1002/bms.1200150104
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    Masthead (1988)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 15 (1988) 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200150201
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    Evaluation of the quantitative analysis of a steroid sulphate using fast atom bombardment and tandem mass spectrometry (1988)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 15 (1988), S. 99-104 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Dehydroepiandrosterone sulphate (DHAS) has been quantified in human blood serum by fast atom bombardment (FAB)/tandem mass spectrometry of immunoadsorption extracts. FAB of DHAS yielded abundant ions corresponding to the intact steroid sulphate; these were selected by a double-focusing mass spectrometer prior to collisionally activated decomposition in a quadrupole collision cell and mass analysis by a quadrupole mass filter. [HSO4]- (m/z 97) was the sole prominent daughter ion. For quantitative analyses the quadrupole mass filter was set to transmit m/z 97 and a narrow-range magnet scan yielded a spectrum of parents, including m/z 367 and 369, corresponding to DHAS and the (2H2)-analogue (used as internal standard), respectively. Serum concentrations by this procedure were in good agreement with data obtained by gas chromatographic/mass spectrometric analyses of DHA heptafluorobutyrate, formed by direct derivatization of the steroid sulphate.
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    URL: http://dx.doi.org/10.1002/bms.1200150207
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    Determination of sodium salts of monensins A and B in the premix and the fermentation broth by electron impact mass spectrometry (1988)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 15 (1988), S. 153-156 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Electron impact mass spectrometry has been used to determine the ratio of monensin A and B, and monensin A with monensin B as an internal standard in extracts of the premix and the fermentation broth. From the data obtained the total amount of monensin A and B was calculated and compared with the results of photometric determination. The relative width of the confidence intervals for the determination of monensin A and B ratio was 2% (2%) in the premix (fermentation broth), 5% (7%) for monensin A, 13% (14%) for monensin B and 5% (6%) for the total amount of monensins A and B. The limit of determination of monensins was about 100 ng. The difference in the results of photometric and mass spectrometric determination was significant for fermentation broth. No significant difference was found in the premix.
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    URL: http://dx.doi.org/10.1002/bms.1200150306
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    A mass spectral study of cyclophosphamide concerning a thermally induced rearrangement reaction (1988)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 15 (1988), S. 163-173 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The electron impact mass spectra of cyclophosphamide (1) are very sensitive towards experimental conditions in view of the kind of sample handling, the type of mass spectrometer used and the temperature of evaporation. The reason for this phenomenon is the elimination of HCl from the molecular ion by a specific 1,5-hydrogen transfer yielding an ion at m/z 224 which is structurally related to the bicyclic compound 4 with its typical fragment ions at m/z 175 and 147. Thermal excitation of the sample increases the intensity of this fragmentation pathway. The fragmentation pattern of 1 and the thermally induced rearrangement reaction has been elucidated by means of isotopic labelling, high-resolution data, metastable ion analysis and some tandem mass spectrometric experiments. Various samples of 1 monohydrate and its commercially available preparations, which are triturates with sodium chloride, differing in the crystal size distribution, showed nearly identical mass spectra on two different magnetic mass spectrometers, provided that the materials were introduced as solids under careful control of the evaporation temperature. The fragmentation via m/z 224 prevails in case of non-crystalline, pre-dissolved samples on one of the instruments used which might be explained by a differing construction of the ion source and the sample cup holder. The conclusions of Mruzek et al. concerning different proportions of stereoisomers in pharmaceutical preparations of 1 lack any analytical evidence.
    Additional Material: 9 Ill.
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    URL: http://dx.doi.org/10.1002/bms.1200150308
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    B. A. Garetz and J. R. Lombardi. Advances in laser spectroscopy, volume 3. J. Wiley & Sons, Ltd. 1986 ISBN 0-471-90990-A £33.50 (1988)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 15 (1988), S. 183-183 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200150312
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  • 141
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    Identification of metabolites of tiropramide in human urine (1988)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 15 (1988), S. 205-209 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The metabolites of tiropramide were extracted from the urine of healthy volunteers given tiropramide hydrochloride orally. Eight metabolites of tiropramide were found by gas chromatography/mass spectrometry. Three were identified on the basis of their mass spectra, retention times and comparison with synthetic standards. For the others a probable structure is proposed on the basis of their mass spectra.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200150404
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  • 142
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    Mass spectrometric characterization of some human metabolites of flumecinol (1988)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 15 (1988), S. 229-232 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The mass spectrometric behaviour of six human metabolites formed by hydroxylation in various positions of the α-ethyl group or/and on the phenyl ring of 3-trifluoromethyl-α-ethyl-benzyhydrol (flumecinol) and seven related compounds has been studied. The electron impact mass (EI) spectra of these compounds show significant and characteristic effects of substituents, but many of them suffer from weakness or even from absence of the M+· peak owing to the very facile primary loss of the α-aliphatic chain, i.e. no direct information can be obtained about the size of the molecule and that of this chain. It is demonstrated for derivatives possessing a hydroxylated α-ethyl group that the difficulties in structural characterization due to the lack or weakness of M+· and [M + H]+ peaks in their EI and chemical ionization mass spectra, respectively, can be overcome by studying their silylated or boronated derivatives. Furthermore, silylation enables us to obtain a clear base for distinction of the primary and secondary alcohols of this type.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200150407
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  • 143
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    Synthesis of deuterium-labelled elliptinium and its use in metabolic studies (1988)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 15 (1988), S. 243-247 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The 9-hydroxy-2-(U-2H3) methylellipticinium acetate (elliptinium) was synthesized with an isotopic purity of at least 96%. The structure was confirmed by proton nuclear magnetic resonance and direct probe fast atom bombardment mass spectrometry. A mixture of elliptinium and its deuterated analogue was administered intravenously to rats. In urine, after analysis by liquid chromatography/mass spectrometry (LC/MS), unchanged drug and N-acetylcysteinylelliptinium were found. In bile, after ion-pair extraction and LC/MS, the glutathionyl-elliptinium was found in addition to the parent drug and the N-acetylcysteine adduct.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200150502
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  • 144
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    Determination of boldenone sulfoconjugate and related steroid sulfates in equine urine by high-performance liquid chromatography/tandem mass spectrometry (1988)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 15 (1988), S. 283-289 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Sulfoconjugated anabolic steroids were separated by micro-bore high-performance liquid chromatography. The eluent was introduced into the atmospheric pressure ion source of the triple-quadrupole mass spectrometer via an ion spray liquid chromatograph/mass spectrometer interface operated in the negative ion mode. The limit of detection was 10 pg on-column by selected ion monitoring of the molecular ion and the response increased linearly over a concentration range of 2.4 orders of magnitude. Following work-up by a liquid-solid extraction procedure of equine urine samples, full-scan daughter ion spectra of boldenone sulfate could be obtained up to 17 days after a therapeutic dose of boldenone undecylenate to a horse.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200150508
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  • 145
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    Laser desorption/fourier transform ion cyclotron resonance mass spectrometry: Digoxin, digitoxin, and their reduced and sugar-hydrolyzed metabolites (1988)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 15 (1988), S. 295-302 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Mass spectra of digoxin and digitoxin (the most widely prescribed drugs for treatment of congestive heart failure) and a complete set of their 14 dihydro- and sugar-hydrolyzed metabolites have been obtained via laser desorption/ionization with a Fourier transform ion cyclotron resonance (LD/FT/ICR) mass spectrometer. The most intense peak is typically the pseudomolecular [M + K]+ ion, but fragment ions corresponding to loss of 1--3 sugars and hydroxyls are also observed. LD/FT/ICR mass spectra for all 16 compounds were produced with a single set of sample and spectrometer parameters. No matrix peaks are present. Finally, LD/FT/ICR provides dynamic mass accuracy within ≈5 ppm throughout a mass range of 404 〈 m/z 〈 819.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200150510
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  • 146
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    Conjugation reactions of polyaromatic quinones to mono- and bisglutathionyl adducts: Direct analysis by fast atom bombardment mass spectrometry (1988)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 15 (1988), S. 329-332 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The conjugation products of several reactive quinones with glutathione have been identified by fast atom bombardment mass spectrometry. Appropriate conditions have been developed which enabled the direct, dynamic mass spectral analysis of spontaneous, as well as glutathione transferase catalysed conjugation reactions. Applications to a series of quinones provided the direct detection and differentiation of the formation of mono- and bisglutathionyl adducts between regioisomeric quinone substrates in that only 1,4-quinones yielded bisglutathionyl adducts, which were not observed for the 1,2-isomers.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200150605
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  • 147
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    Collisional spectroscopy in structural characterization of melanins 2 - laser desorption experiments on bio- and synthetic tryptophan melaninsFor part 1 see Ref. 13. (1988)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 15 (1988), S. 353-355 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Melanins1 are naturally occurring macromolecules whose structural complexity appeared evident from the first researches of Quilico.2 Their structural characterization remains a difficult problem, mainly due to the physico-chemical properties of such compounds. Melanins are insoluble in organic solvents as well as aqueous solutions and are infusible. Consequently the traditional chemical degradation and physicochemical methods such as ultraviolet, infrared, 1H and 13C nuclear magnetic resonance, ESR (electron spin resonance), XPS (X-rays photoelectron spectroscopy) and X-ray diffraction have led, until now, to limited information on melanin chemical structure1,3.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200150608
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  • 148
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    Automated measurement of the concentration and 13C enrichment of carbon dioxide in breath and blood samples using the finnigan MAT breath gas analysis system (1988)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 15 (1988), S. 365-367 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The operation and performance of the Finnigan MAT automated Breath Gas Analysis System for the routine analysis of 13C breath tests taken in 20-ml Vacutainers is described. Up to four samples per hour can be analysed with a standard deviation of δ13C of 〈0.05%o being achieved over the range 10-50 μmol CO2. The equipment can also be used for the automatic measurement of the concentration and 13C enrichment of CO2 derived from carbonate or bicarbonate solutions, including blood and other physiological fluids.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200150703
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  • 149
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    FAB and tandem mass spectrometry for endorphin- and ACTH peptides of molecular weight to 2000 (1988)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 15 (1988), S. 649-657 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Four β-endorphins (β-endorphin 6-17, 2-17, 1-16, and 1-17) and two adrenocorticotropic hormone (ACTH) peptides (ACTH 1-10 and (1-16)-NH2) were studied by using fast atom bombardment coupled with tandem mass spectrometry. The capability to reproduce metastable ion and collisionally activated decomposition spectra on two different commercial sector mass spectrometers in two different laboratories was found to be acceptable (deviations in relative abundance are less than ± 50%). The endorphin peptides fragment metastably or upon collisional activation to give abundant B-series ions as well as Y-series ions, whereas Y-series ions are the principal ionic species produced upon the desorption by fast atom bombardment. The ACTH peptides also fragment to give Y-series ions, but of relatively low abundance compared to those from the endorphins. For both sets of peptides, high-energy collisionally activated decomposition and metastable ion decomposition daughter ion spectra are precise, structurally informative - even for peptides up to m/z 2000 - and complementary to spectra of daughter ions produced by desorption ionization alone.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200151203
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  • 150
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    Analysis of sub-microgram quantities of nucleotides by fast atom bombardment mass spectrometry (1988)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 15 (1988), S. 547-551 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Nucleotides of the structure P1,Pn-di(adenosine-5′)-n-phosphate (n = di- through penta-) in the form of salts, and P1,P4-di(guanosine-5′)tetraphosphate sodium salt have been analyzed by fast atom bombardment (FAB) mass spectrometry. A 0.2 molar solution of p-toluenesulfonic acid in glycerol has been evaluated as a matrix. In this matrix, the metal ions of the nucleotide salts are readily exchanged for protons, resulting in a simple spectrum with only one peak in the molecular ion region corresponding to the free phosphoric acid of the nucleotide plus or minus a proton (positive or negative mode), instead of the multiplicity of peaks arising from a series of metal and matrix adduct ions found with glycerol as matrix. The detection limit for analytes using this matrix is improved by a factor of ten compared to glycerol alone. It appears that the high acidity and the surfactant properties of p-toluenesulfonic acid both contribute to this result. Useful spectra are obtained from 250 ng of each of the above mentioned nucleotides, with the detection limit being somewhat lower in the positive mode. However, both positive and negative FAB spectra are useful and the results are complementary.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200151007
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  • 151
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    Nucleophilic reactions between biological conjugates and tetraalkylammonium ion pair reagents during desorption chemical ionization (1988)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 15 (1988), S. 571-576 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Tetraalkylammonium salts, commonly used as ion pair reagents in chromatography, were found to react with biological conjugates under desorption chemical ionization conditions in a mass spectrometer. The reactions occur for aromatic glucuronide and glucoside conjugates using solid samples loaded on the direct exposure probe. Evidence is presented that several mechanisms contribute to the degradative alkylation of benzo(a)pyrene glucuronide. This undesirable process can be prevented by using ammonium or trialkylammonium instead of tetra-alkylammonium salts in the chromatographic separation. Nucleophilic attack on the tetraalkylammonium cations in the energized condensed phase was found to occur also for some simpler aromatic compounds.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200151010
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  • 152
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    A rapid method for the structural characterization of sulphated phlorotannins by negative ion fast atom bombardment mass spectrometry and acetylation on the target (1988)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 15 (1988), S. 595-602 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A method for a rapid and direct structural determination of sulphated phlorotannins has been developed by using a combination of negative ion fast atom bombardment mass spectrometry and acetylation on the target. The structural variations of sulphated phlorotannins include: (i) the number of monomeric phloroglucinol units involved; (ii) the mode of their connectivity; (iii) the orientation of hydroxy groups on aromatic carbon atoms; (iv) the presence of the substituents other than hydroxy groups on aromatic carbon atoms; and (v) the number of sulphate esters on the hydroxy groups. Additionally, the acidic protons on the sulphate groups can be easily substituted by sodium or potassium cations, depending on the mode of isolation. In the negative ion mode, several ions were observed and a determination of molecular size and molecular parameters (i)-(v) appeared to be rather speculative. After adding diluted hydrochloric acid to the sample in order to substitute alkali ions for protons, the hydrolysis of sulphate groups has been observed. The acetylation on the target, however, represents a rapid method to observe the molecular ions, and from the mass differences the molecular parameters can be easily calculated. This procedure also demonstrates the general possibility of studying rapid chemical reactions by fast atom bombardment mass spectrometry.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200151104
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  • 153
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    Masthead (1988)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 15 (1988) 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200151201
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  • 154
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    The use of alkoxycarbonyl derivatives for the mass spectral analysis of drug-thioether metabolites. Studies with the cysteine, mercapturic acid and glutathione conjugates of acetaminophen (1988)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 15 (1988), S. 637-647 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Alkoxycarbonyl derivatives of the cysteine-, N-acetylcysteine- and glutathione conjugates of acetaminophen have been prepared in aqueous buffer solutions and their chromatographic and mass spectrometric properties examined. Structurally informative fragmentation patterns of the cysteine- and N-acetylcysteine derivatives were obtained when their methyl esters were subjected to analysis by direct insertion chemical ionization (CH4) mass spectrometry, although field desorption and liquid secondary ion mass spectrometric techniques were required in order to obtain satisfactory spectral data for derivatives of the glutathione adduct. Treatment of ethoxycarbonyl derivatives of the three acetaminophen metabolites with N-methyltrifluoroacetamide-based silylating reagents led to the formation of a common volatile product which was ideally suited to analysis by gas chromatography/electron impact mass spectrometry. A mechanism is proposed for the formation of this novel derivative, which appears to possess a benzo-1,3-thioxalane structure, and its mass spectral characteristics are reported. Finally, the utility of alkoxycarbonyl derivatives for the analysis of drug - thioether conjugates in biological fluids is discussed in terms of their advantages for aqueous phase derivatization, purification by high-performance liquid chromatography and characterization by mass spectrometry.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200151202
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  • 155
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    Bromo- and bromochloro-polynuclear aromatic hydrocarbons, dioxins and dibenzofurans in municipal incinerator fly ash (1988)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 15 (1988), S. 669-676 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A fly ash sample found to contain polychlorinated dioxins and dibenzofurans was analyzed for brominated analytes. Bromochloro-polynuclear aromatic hydrocarbons, dioxins and dibenzofurans, as well as bromo PAH were found in ppt to ppb concentrations. Analytical results were confirmed by high-resolution mass spectrometric accurate mass determinations and by tandem mass spectrometry.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200151205
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  • 156
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    Fast atom bombardment mass spectrometry of protected peptide segments (1988)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 15 (1988), S. 681-684 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200151207
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  • 157
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    A monoclonal antibody to the Ca2+ -ATPase of cardiac sarcoplasmic reticulum cross-reacts with slow type I but not with fast type II canine skeletal muscle fibers: An immunocytochemical and immunochemical study (1988)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 9 (1988), S. 164-174 
    Details
    ISSN: 0886-1544
    Keywords: Ca2+-ATPase of sarcoplasmic reticulum ; immunofluorescence ; myofibers types I (slow) and II (fast) ; II D8 monoclonal antibody ; II H11 monoclonal antibody ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Ca2+ -ATPase of the sarcoplasmic reticulum was localized in cryostat sections from three different adult canine skeletal muscles (gracilis, extensor carpi radialis, and superficial digitalis flexor) by immunofluorescence labeling with monoclonal antibodies to the Ca2+ -ATPase Type I (slow) myofibers were strongly labeled for the Ca2+ -ATPase with a monoclonal antibody (II D8) to the CA2+ -ATPase of canine cardiac sarcoplasmic reticulum; the type II (fast) myofibers were labeled at the level of the background with monoclonal antibody II D8. By contrast, type II (fast) myofibers were strongly labeled for Ca2+ -ATPase of rabbit skeletal sarcoplasmic reticulum. The subcellular distribution of the immunolabeling in type I (slow) myofibers with monoclonal antibody II D8 corresponded to that of the sarcoplasmic reticulum as previously determined by electron microscopy. The structural similarity between the canine cardiac Ca2+ -ATPase present in the sarcoplasmic reticulum of the canine slow skeletal muscle fibers was demonstrated by immunoblotting. Monoclonal antibody (II D8) to the cardiac Ca2+ -ATPase binds to only one protein band present in the extract from either cardiac or type I (slow) skeletal muscle tissue. By contrast, monoclonal antibody (II H11) to the skeletal type II (fast) Ca2+ -ATPase binds only one protein band in the extract from type II (fast) skeletal muscle tissue. These immunopositive proteins coelectrophoresed with the Ca2+ -ATPase of the canine cardiac sarcoplasmic reticulum and showed an apparent Mr of 115,000. It is concluded that the Ca2+ -ATPase of cardiac and type I (slow) skeletal sarcoplasmic reticulum have at least one epitope in common, which is not present on the Ca2+ -ATPase of sarcoplasmic reticulum in type II (fast) skeletal myofibers. It is possible that this site is related to the assumed necessity of the Ca2+ -ATPase of the sarcoplasmic reticulum in cardiac and type I (slow) skeletal myofibers to interact with phosphorylated phospholamban and thereby enhance the accumulation of Ca2+ in the lumen of the sarcoplasmic reticulum following β-adrenergic stimulation.
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    URL: http://dx.doi.org/10.1002/cm.970090208
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  • 158
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    Microtubules in ascidian eggs during meiosis, fertilization, and mitosis (1988)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 9 (1988), S. 219-230 
    Details
    ISSN: 0886-1544
    Keywords: fertilization ; ooplasmic segregation ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The sequential changes in the distribution of microtubules during germinal vesicle breakdown (GVBD), fertilization, and mitosis were investigated with antitubulin indirect immunofluorescence microscopy in several species of ascidian eggs (Molgula occidentalis, Ciona savignyi, and Halocynthia roretzi). These alterations in microtubule patterns were also correlated with observed cytoplasmic movements. A cytoplasmic latticework of microtubules was observed throughout meiosis. The unfertilized egg of M. occidentalis had a small meiotic spindle with wide poles; the poles became focused after egg activation. The other two species had more typical meiotic spindles before fertilization. At fertilization, a sperm aster first appeared near the cortex close to the vegetal pole. It enlarged into an unusual asymmetric aster associated with the egg cortex. The sperm aster rapidly grew after the formation of the second polar body, and it was displaced as far as the equatorial region, corresponding to the site of the myoplasmic rescent, the posterior half of the egg. The female pronucleus migrated to the male pronucleus at the center of the sperm aster. The microtubule latticework and the sperm aster disappeared towards the end of first interphase with only a small bipolar structure remaining until first mitosis. At mitosis the asters enlarged tremendously, while the mitotic spindle remained remarkably small. The two daughter nuclei remained near the site of cleavage even after division was complete. These results document the changes in microtubule patterns during maturation in Ascidian oocytes, demonstrate that the sperm contributes the active centrosome at fertilization, and reveal the presence of a mitotic apparatus at first division which has an unusually small spindle and huge asters.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970090304
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  • 159
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    Dynamics of a fluorescent calmodulin analog in the mammalian mitotic spindle at metaphase (1988)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 9 (1988), S. 231-242 
    Details
    ISSN: 0886-1544
    Keywords: tubulin ; microtubules ; photobleaching ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: We have compared the exchange kinetics of fluorescein-labeled calmodulin and tubulin in the spindles of living mitotic cells at metaphase. Cultured mammalian cells in early stages of mitosis were microinjected with labeled calmodulin or tubulin and returned to an incubator to allow equilibration of the fluorescent protein with the endogenous protein pools. Calmodulin becomes concentrated in the mitotic spindle, and treatments with inhibitors of tubulin assembly show that this concentration is dependent on the presence of microtubules. The steady-state exchange rates of both tubulin and calmodulin were measured by an analysis of fluorescence redistribution after photobleaching (FRAP), using cells preequilibrated to either 26 ± 2°C or 36 ± 2°C. A pulse of laser light focused to a 5-μm diameter column was used to destroy the fluorescence at one pole of a metaphase mitotic spindle. Ratios of fluorescence intensity from the two half-spindles and from the two polar regions were calculated for each image in a post-bleach time series to determine the rates and extents of FRAP. For tubulin, we confirm earlier observations concerning the temperature dependence of the extent of FRAP, but our data do not show a significant temperature dependence for the rate of FRAP. We hypothesize that the reduced extent of tubulin FRAP at the lower temperatures is a result of microtubules that are stable to depolymerization at 26°C and are thus less likely to exchange subunits. Calmodulin's FRAP, however, does not exhibit any of the temperature dependence observed with fluorescent tubulin. At 26 ± 2°C calmodulin exchanges rapidly with the relatively stable population of microtubules, suggesting that calmodulin is bound, either directly or indirectly, to microtubule walls.
    Additional Material: 6 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970090305
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    Distribution of acetylated α-tubulin in retina and in in vitro - assembled microtubules (1988)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 9 (1988), S. 243-253 
    Details
    ISSN: 0886-1544
    Keywords: neurons ; posttranslational modification ; tubulin isoforms ; rod and cone photoreceptors ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: We have used the mouse monoclonal antibody 6-11B-1, specific for acetylated α-tubulin, to determine the distribution of acetylated α-tubulin in in vitro-assembled microtubules and retinal tissue. Analysis by immunoblots revealed that microtubules assembled from bovine brain extracts contain both acetylated and nonacetylated α-tubulin. Immunofluorescence, using 6-11B-1 and antitubulin B-5-1-2, a monoclonal antibody specific for α-tubulin, demonstrated the colocalization of both α-tubulin species in neurons of the retina and that acetylated microtubules are relatively abundant in neurons. However, analysis at higher resolution revealed that rod photoreceptors contain spatially distinct microtubule arrays which differ in content of acetylated α-tubulin and differ in stability. Acetylated microtubules which composed those of the rod outer segment and connecting cilium were resistant to depolymerization in nocodazole or colchicine. In contrast, the nonacetylated microtubules which composed those of the rod-inner segment were depolymerized in nocodazole or colchicine. Therefore, these acetylated microtubules are more resistant to depolymerization than non-acetylated microtubules.
    Additional Material: 6 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970090306
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    Microtubule rearrangements during mitosis in multinucleate cells (1988)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 9 (1988), S. 254-263 
    Details
    ISSN: 0886-1544
    Keywords: microtubule interphase-mitosis transition ; mitotic asynchrony ; maturing centrosomes ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The peroxidase-antiperoxidase (PAP) method for the detection of polymerized tubulin has been used to study the microtubule rearrangements during mitosis in PtK1 and HeLa multinucleate cells obtained by polyethyleneglycol (PEG)-mediated fusion. We demonstrate here that the transition of the microtubular cytoskeleton from interphase to mitosis is an inducible event and independent of the factor(s) responsible for chromatin condensation and nuclear envelope breakdown. However, for the induction of the microtubule rearrangements nuclear envelope breakdown is required. At midprophase, cytoskeletal microtubule rearrangements start for multinucleate PtK1 cells, whereas in HeLa cells such changes are delayed, and a more abrupt transition is observed here. After complete nuclear envelope breakdown (prometaphase) mitotic asters and spindles but no cytoplasmic (interphase) microtubuli can be observed in both systems. Metaphase is characterized by an interaction between the different mitotic poles which show the form of bipolar spindles, but individual separated mitotic poles far removed from the chromatin can also be seen.
    Additional Material: 7 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970090307
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    Comparative study of the beat patterns of american and asian horseshoe crab sperm: Evidence for a role of the central pair complex in forming planar waveforms in flagella (1988)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 9 (1988), S. 264-270 
    Details
    ISSN: 0886-1544
    Keywords: axoneme ; flagellar movement ; helical wave ; planar wave ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: American horseshoe crab sperm flagella have the typical 9+2 structure whereas Asian horseshoe crab sperm flagella have a 9+0 axoneme lacking central pair and central sheaths. Beat patterns of the American and the Asian horseshoe crab sperm were recorded by means of a high-speed video system (200 fields/second) and were compared in order to study the role of the central pair of the axoneme in ciliary and flagellar movement.The American horseshoe crab sperm beat with relatively planar waves, whereas the Asian horseshoe crab sperm beat with right-handed helical waves. These results suggest that the central complex plays an important role in forming planar waves, whereas it is not essential for the conversion of microtubule sliding into axonemal bends.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970090308
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  • 163
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    Cytochalasin-Induced reorganization of actin in allium root cells (1988)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 9 (1988), S. 283-298 
    Details
    ISSN: 0886-1544
    Keywords: colchicine ; microtubule ; mitosis ; rhodamine-phalloidin ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The effect of cytochalasins on F-actin was investigated in Allium root cells stained with rhodamine-phalloidin. With cytochalasin D (CD), the normal interphase network of actin fibers is replaced by dispersed rods and specks similar to those seen in animal cells. However, during division, the specks accumulate at the poles in the form of one to a few large aggregates. The effects intensify with increasing concentration (0.5-5 m̈g/ml) and exposure time (0.5-3 hr). Further, similar behavior is observed with cytochalasin B, but dihydroCB has little effect. Double localizations show that during preprophase, aggregates cluster in association with microtubule foci at the new poles located near the nuclear envelope. From metaphase through anaphase, the aggregates are often found near the tips of kinetochore fibers, while in telophase they are often appressed to the pole side of the daughter nuclei. No association is seen between actin and the other microtubule arrays. The reorganization of F-actin into small specks is unaffected by sodium azide, but aggregation at the poles is very sensitive to this agent. Polar clustering is also blocked by oryzalin, colchicine, and isopropyl n-(3-chlorophenyl) carbamate, but taxol has no effect. Experiments with scleroderma serum 5051 show that CD-induced aggregates are embedded in centrosomal material at the poles. The results reveal that the reorganization of actin in response to cytochalasins differs during the cell cycle. Furthermore, the aggregation of actin during division is probably governed by an energy-dependent interaction with microtubules.
    Additional Material: 9 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970090402
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  • 164
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    Micromanipulation studies of the mitotic apparatus in sand dollar eggs (1988)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 10 (1988), S. 172-184 
    Details
    ISSN: 0886-1544
    Keywords: chromosome movement ; spindle elongation ; micromanipulation ; mechanical properties ; mitosis ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Mechanical properties of the mitotic spindle and the effects of various operations of the mitotic apparatus on the chromosome movement and spindle elongation were investigated in fertilized eggs and blastomeres of the sand dollar, Clypeaster japonicus. On the basis of results with mechanical stretching and compression of the spindle with a pair of microneedles and the behavior of an oil drop microinjected into the spindle, it was concluded that the equatorial region of the spindle is mechanically weaker than the half-spindle region. Anaphase chromosome movement occurred in the spindle from which an aster had been removed or separated with its polar end and in the spindle in which the interzonal region had been removed. This fact indicates that chromosomes move poleward in anaphase by forces generated near the kinetochores in the half-spindle. Because of the effects of separation or removal of an aster from the spindle on the spindle elongation in anaphase and the behavior of the aster, it was concluded that the spindle elongation in anaphase is caused by pulling forces generated by asters attached to the ends of the spindle.
    Additional Material: 11 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970100122
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    Dynamics of the endoplasmic reticulum in living onion epidermal cells in relation to microtubules, microfilaments, and intracellular particle movement (1988)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 10 (1988), S. 153-163 
    Details
    ISSN: 0886-1544
    Keywords: intracellular particle motions ; cytoplasmic streaming ; onion (Allium) epidermal cells ; video microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The endoplasmic reticulum (ER) and associated organelle and particle movements in onion (Allium cepa) bulb scale epidermal cells were observed, recorded, and analyzed using computer-assisted video (AVEC-DIC, AVEC-POL and fluorescence) microscopy. The ER is composed of two interconnected sets of filamentous membrane tubules with diameters ranging from 0.1 to 0.5 μm. The first form a more stable, stationary network of intersecting polygonal membrane tubules lying closely appressed to the plasma membrane and continuous with a second very dynamic set of longer membrane tubules that often are located parallel to each other, shifting rapidly around the cytoplasm and forming dynamic knots or organization centers. The ER, mitochondria, and spherosomes fluoresced upon chlortetracycline treatment and are therefore presumed to sequester calcium. ER and mitochrondria also stain with the fluorescent dye, rhodamine 123. Mitochrondria and spherosomes are seen to move in the cytoplasm only along paths parallel to the axis of the ER tubules. Smaller particles (0.5 μm) tend to follow these same paths but may occasionally move independently. Particles and organelles move in close, but not in direct, association with the ER tubules. In optically favored cells, actin filaments were occasionally recorded located in parallel with the ER tubules and directly associated with moving particles. Streaming ceased promptly and reversibly upon treatment with cytochalasin B, which did not visibly disrupt the ER. Short-term treatment with colchicine did not inhibit streaming or disrupt the ER network, whereas long-term (hours) colchicine treatments caused the disappearance of the stationary, cortical polygonal networks and an aggregation of still slowly moving organelles and particles onto now visible actin filaments. This suggests that microtubule breakdown disrupts the three-dimensional distribution of the ER and rearranges actin filaments in the cell's cytoplasm. Actin filaments must be directly involved in generation of movement of the particles and organelles. A three-dimensional model, based on optical sectioning of the epidermal cells, is proposed to illustrate the distribution of the endoplasmic reticulum in onion epidermal cell cytoplasm.
    Additional Material: 8 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970100120
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    Microtubule dynamics in the chromosomal spindle fiber: Analysis by fluorescence and high-resolution polarization microscopy (1988)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 10 (1988), S. 185-196 
    Details
    ISSN: 0886-1544
    Keywords: mitosis ; kinetochore ; video microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: We describe preliminary results from two studies exploring the dynamics of microtubule assembly and organization within chromosomal spindle fibers. In the first study, we microinjected fluorescently labeled tubulin into mitotic PtK1 cells and measured fluorescence redistribution after photobleaching (FRAP) to determine the assembly dynamics of the microtubules within the chromosomal fibers in metaphase cells depleted of nonkinetochore microtubules by cooling to 23-24°C. FRAP measurements showed that the tubulin throughout at least 72% of the microtubules within the chromosomal fibers exchanges with the cellular tubulin pool with a half-time of 77 sec. There was no observable poleward flux of subunits. If the assembly of the kinetochore microtubules is governed by dynamic instability, our results indicate that the half-life of microtubule attachment to the kinetochore is less than several min at 23-24°C.In the second study, we used high-resolution polarization microscopy to observe microtubule dynamics during mitosis in newt lung epithelial cells. We obtained evidence from 150-nm-thick optical sections that microtubules throughout the spindle laterally associate for several sec into “rods” composed of a few microtubules. These transient lateral associations between microtubules appeared to produce the clustering of nonkinetochore and kinetochore microtubules into the chromosomal fibers. Our results indicate that the chromosomal fiber is a dynamic structure, because microtubule assembly is transient, lateral interactions between microtubules are transient, and the attachment of the kinetochores to microtubules may also be transient.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970100123
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  • 167
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    Direct observation of mitotic spindle elongation in vitro (1988)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 10 (1988), S. 210-216 
    Details
    ISSN: 0886-1544
    Keywords: anaphase-B ; diatom spindle ; microtubule sliding ; mitosis in vitro ; video microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Successful reactivation in vitro of anaphase B has recently been achieved with mitotic spindles isolated from the diatom Stephanopyxis turris. When a population of isolated spindles was studied indirectly by using immunofluorescence, nearly all of them were found to have elongated; however, when studied directly by using video microscopy, only a small proportion of spindles elongated. We report here conditions that allow nearly all of the spindles to elongate when observed directly with video microscopy. These direct observations validate previous ones made using indirect immunofluorescence. In addition, we find that the isolated spindles elongate with a linear rate, that the elongation is unchanged after the chromatin surrounding the spindles is digested with DNase I, and that during elongation a phase-dense matrix may accumulate in the spindle midzone.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970100125
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    Masthead (1988)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 9 (1988) 
    Details
    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970090101
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  • 169
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    Adaptation in the motility response to camp in dictyostelium discoideum (1988)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 9 (1988), S. 9-16 
    Details
    ISSN: 0886-1544
    Keywords: adaptation ; cAMP ; cell motility ; chemotaxis ; Dictyostelium discoideum ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: When developing amebae of Dictyostelium discoideum are treated with constant concentrations of cAMP above 10-8 M, the average rate of motility is depressed, with maximum inhibition at roughly 10-6 M. It is demonstrated that shifting the concentration of cAMP from 0 M to concentrations ranging from 10-8 to 10-6 M in a perfusion chamber results in the immediate inhibition of motility. After shifting from 0 M to 10-8 or 10-7 M, the rate of cell motility remains low, then rebounds to a higher level, exhibiting a standard adaptation response. No adaptation is exhibited after a shift from 0 M to 10-6 M, a concentration resulting in maximum inhibition. It is demonstrated that the level of inhibition and the extent of the adaptation period are dependent upon the concentration of cAMP after the shift, and that submaximal inhibition is additive. The characteristics of adaptation in this motility response are very similar to the characteristics of adaptation for the relay system and phosphorylation of the putative cAMP receptor.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970090103
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  • 170
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    Actin filament patterns in mouse lens epithelium: A study of the effects of aging, injury, and genetics (1988)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 9 (1988), S. 17-29 
    Details
    ISSN: 0886-1544
    Keywords: sequestered actin bundles ; polygonal arrays ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Using mainly fluorescence microscopy after rhodamine-phalloidin staining, the F-actin distribution in the mouse lens epithelium was studied with regard to the effects of age, genetic strain, and mechanical injury.These studies have revealed that aside from its association with the plasma membrane the structural organization of F-actin in the mouse lens epithelium in situ is characterized by two major configurations: (1) a filamentous arrangement in such patterns as stress fibers, polygonal arrays (PAs), and meshworks, and (2) a highly concentrated structure called a sequestered actin bundle (SAB).The aging study indicated that the SAB is a consistent character in C57BL/6 mice from the age of 5 wk on, but not in CF1 mice. The size and shape of the SAB change gradually with age as inferred from two-dimensional measurements. The genetic study on the SAB character using hybrids and congenic strains showed that it is inherited as a Mendelian dominant, probably multigenic mode. Finally, the injury study revealed a structural modification in cells around the wound, including flattening of cells at the edge and extension of processes into the wound space. In the rest of the epithelium, injury amplified membrane infolding and fluorescence of polygonal arrays but diminished the size and fluorescence intensity of SABs. These changes are thought to be correlated with wound repair involving cell division and migration.These studies illustrate the variability in F-actin expression in situ in lens epithelial cells that can be induced by intrinsic and extrinsic factors.
    Additional Material: 21 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970090104
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    Dynamic behavior of the transferrin receptor followed in living epidermoid carcinoma (A431) cells with nanovid microscopy (1988)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 9 (1988), S. 30-47 
    Details
    ISSN: 0886-1544
    Keywords: video microscopy ; colloidal gold ; microtubules ; saltatory movement ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Transferrin receptors labeled with the B3/25 monoclonal antibody-gold complexes were followed in living A431 cells by using video-enhanced contrast microscopy. Initially, the antibody-gold complexes bind to receptors which are freely mobile on the upper cell surface; they then become trapped at the inner margins of the peripheral lamellae and internalize. During endocytosis discrete gold-loaded vesicular elements first appear, and then, as they fuse, a heterogenous peripheral endosomal compartment forms. The endosomes from this compartment then begin to migrate centripetally through the cytoplasm in a saltatory way so that within 15 min gold label accumulates in a juxtanuclear endosome compartment. This compartment, which consists mainly of multivesicular bodies, is thus formed by the influx and retention of peripheral endosomal elements and their continued fusion in the juxtanuclear area. Although their overall migration is inward, saltating endosomes frequently reverse their direction of movement. As label builds up in the juxtanuclear area, small vesicles containing gold label continuously pinch off from the larger elements and migrate toward the cell periphery.Experiments with nocodazole and sodium azide show that the saltatory movements, the accumulation and retention of endosomes in the juxtanuclear area, and the separation of vesicles from endosomes are driven by a microtubule-associated, ATP-dependent, motility-generating mechanism.Analysis of the movements shows that although each individual vesicle saltation can occur unpredictably toward the centre or the periphery of the cell, a net centripetal flux is observed. Moreover, it is evident that the probability of migration toward and maintenance in the juxtanuclear area is related to the diameter of the vesicles. We propose a mechanism by which bidirectional saltation along microtubules forming a radial network may be instrumental in the selective concentration of large endosomes in the juxtanuclear area while small vesicles are left free to return to the periphery. This process may be responsible for the sorting of receptors and ligands destined either for intracellular degradation in juxtanuclear lysosomes or, alternatively, for recycling to the plasma membrane.
    Additional Material: 13 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970090105
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    Ultrastructure and motion analysis of permeabilized paramecium capable of motility and regulation of motility (1988)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 9 (1988), S. 73-84 
    Details
    ISSN: 0886-1544
    Keywords: cilia ; metachronal waves ; electron microscopy ; calcium ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Structural and behavioral features of intact and permeabilized Paramecium tetraurelia have been defined as a basis for study of Ca2+ control of ciliary reversal. Motion analysis of living paramecia shows that all the cells in a population swim forward with gently curving spirals at speeds averaging 369 ± 19 μm/second. Ciliary reversal occurs in 10% of the cell population per second. Living paramecia, quick-fixed for scanning electron microscopy (SEM), show metachronal waves and an effective stroke obliquely toward the posterior end of the cell. Upon treatment with Triton X-100, swimming ceases and both scanning and transmission electron microscopy reveal cilia that uniformly project perpendicularly from the cell surface. Thin sections of these cells indicate that the ciliary, cell, and outer alveolar membranes are greatly disrupted or entirely missing and that the cytoplasm is also disrupted. These permeabilized paramecia can be reactivated and are capable of motility and regulation of motility. Motion analysis of cells reactivated with Mg2+ and ATP in low Ca2+ buffer (pCa7) shows that 71% swim forward in straight or curved paths at speeds averaging 221 ± 20 μm/second. When these cells are quick-fixed for SEM the metachronal wave patterns of living, forward swimming cells reappear. Motion analysis of permeabilized cells reactivated in high Ca2+ buffers (pCa 5.5) shows that 94% swim backward in tight spirals at a velocity averaging 156 ± 7 μm/second. SEM reveals a metachronal wave pattern with an effective stroke toward the anterior region. Although the permeabilized cells do not reverse spontaneously, the pCa response is preserved and the Ca2+ switch remains intact. The ciliary axonemes are largely exposed to the external environment. Therefore, the behavioral responses of these permeabilized cells depend on interaction of Ca2+ with molecules that remain bound to the axonemes throughout the extraction and reactivation procedures.
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    URL: http://dx.doi.org/10.1002/cm.970090108
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    Motility of the spirochete leptospira (1988)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 9 (1988), S. 101-110 
    Details
    ISSN: 0886-1544
    Keywords: prokaryotic motility ; periplasmic flagella ; hydrodynamics ; model ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Spirochetes are a group of bacteria with a unique ultrastructure and a fascinating swimming behavior. This article reviews the hydrodynamics of spirochete motility, and examines the motility of the spirochete Leptospira in detail. Models of Leptospira motility are discussed, and future experiments are proposed.The outermost structure of Leptospira is a membrane sheath, and within this sheath are a helically shaped cell cylinder and two periplasmic flagella. One periplasmic flagellum is attached subterminally at either end of the cell cylinder and extends partway down the length of the cell. In swimming cells, each end of the cell may assume either a spiral or a hook shape. Translational cells have the anterior end spiral shaped, and the posterior end hook shaped. In the model of Berg et al., the periplasmic flagella are believed to rotate between the sheath and the cell cylinder. Rotation of the anterior periplasmic flagellum causes the generation of a gyrating spiral-shaped wave. This wave is believed sufficient to propel the cells forward in a low-viscosity medium. The cell cylinder concomitantly rolls around the periplasmic flagella in the opposite direction - which allows the cell to literally screw through a gel-like viscous medium without slippage. This model is presented, and it is contrasted to previous models of Leptospira motility.
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    URL: http://dx.doi.org/10.1002/cm.970090202
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    51-kd protein, a component of microtubule-organizing granules in the mitotic apparatus involved in aster formation in vitro (1988)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 9 (1988), S. 117-128 
    Details
    ISSN: 0886-1544
    Keywords: centrosome ; aster-forming activity ; tubulin polymerization ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Mitotic apparatuses (MAs) isolated from sea urchin metaphase eggs were chilled on ice to depolymerize microtubules, homogenized, and incubated with tubulin. This caused formation of many small asters with microtubules focusing on granules which were probably fragments of the centrosome. The aster-forming protein components of the granules in the homogenized MAs were solubilized in 0.5 M KCl containing 50% glycerol. After dialysis against low-ionic-strength buffer solution, proteins congregated to form granular assembly capable of initiating aster formation. Phosphocellulose column chromatography enabled the separation of the aster-forming protein fraction which contained a 51,000 molecular weight protein (51-kd protein) as a major component. The protein fraction possessing the aster-forming activity was also prepared from methaphase whole egg homogenate, and the elution profile of the 51-kd protein on phosphocellulose column also coincided with that of the aster-forming activity. The granular assembly reconstituted from the phosphocellulose fraction formed asters whose microtubules show the same growth rate and length distribution as those of asters reconstructed from the granules in the homogenized MAs. Anti-51-kd protein antibody that was raised in rabbit and affinity-purified stained the center of asters which were reconstructed either from the granules in the homogenized MAs or from the granular assembly reconstituted from the phosphocellulose fraction. These results suggest that the 51-kd protein is a component in the aster-forming activity of the centrosomal component in vitro.
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    URL: http://dx.doi.org/10.1002/cm.970090204
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    Subcellular sequestration of an antigenically unique β-tubulin (1988)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 9 (1988), S. 175-183 
    Details
    ISSN: 0886-1544
    Keywords: cytoskeleton ; microtubules ; monoclonal antibodies ; cell morphogenesis ; tubulin ; Trypanosoma brucei ; subflagellar microtubule quartet ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Tubulin from Trypanosoma brucei was characterized by Western blotting using well defined monoclonal antibodies reacting with α- or β-tubulin and a new monoclonal antibody, 1B41, raised against a microtubule-enriched fraction of T. brucei, which specifically reacts with the β-subunit of tubulin from either T. brucei or rat brain. This antibody has been used to examine the subcellular distribution of the corresponding antigen in T. brucei by indirect immunofluorescence. The epitope recognized by 1B41 is restricted to a thin line extending from the basal body region to the anterior end of the cell body. To determine the relationship between the immunoreactive zone and the flagellum, double-label immunofluorescence was performed in both interphase and mitotic cells with 1B41 and a flagellar marker, the monoclonal antibody 5E9, specific for the paraflagellar rod polypeptides of trypanosomes. These experiments revealed that the immunoreactive tubulin was contained in a part of the subpellicular cytoskeleton that remained in a constant spatial correspondence with the flagellum throughout the cell division cycle. The β-tubulin recognized by 1B41 may be segregated into the microtubular structures associated with a cisterna of the endoplasmic reticulum forming the subflagellar microtubule quartet (SFMQ). These results suggest that the presence of an antigenically unique β-tubulin defines a subpopulation of microtubules possessing specfic dynamic properties that may be involved in the morphogenesis of daughter cells during the division of T. brucei.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970090209
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    Polymorphonuclear leukocyte locomotion is insensitive to lowered cytoplasmic calcium levels (1988)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 9 (1988), S. 184-189 
    Details
    ISSN: 0886-1544
    Keywords: cell locomotion ; cell motility ; calcium ; polymorphonuclear leukocyte ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Chemotactic factors stimulate the rate of locomotion of polymorphonuclear leukocytes (PMNs). To investigate the importance of cytoplasmic calcium we have examined the ability of the chemotactic peptide N-formylnorleucyl eucylphenalanine (FNLLP) to stimulate the locomotion of PMNs whose cytoplasmic calcium levels were reduced by incubation in EGTA or in EGTA plus the calcium ionophores, ionomycin or A23187. Locomotion was assayed by migration through micropore filters and by time-lapse videomicroscopy. Cells in EGTA exhibited similar or slightly reduced rates of locomotion compared to cells in Hanks' balanced salt solution (HBSS). The peptide dose dependence for the stimulation of locomotion was similar in medium containing calcium or EGTA. The presence of 1 μM ionophore plus EGTA had no effect on the stimulation of locomotion by peptide. The presence of ionophores (1 μM) plus external calcium inhibited locomotion.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970090210
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  • 177
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    Acrylamide treatment of PtKl cells causes dephosphorylation of keratin polypeptides (1988)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 11 (1988), S. 24-30 
    Details
    ISSN: 0886-1544
    Keywords: intermediate filaments ; phosphorylation ; cytoskeleton ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Treatment of PtKl cells with 5 mM acrylamide for 4 hr results in alterations in the distribution of keratin filaments within the cells. This effect is reversible within 18 hr. Labeling of PtKl cells with 32P demonstrates that there are four phosphorylated keratins, having Mr of 56 k, 53 k, 45 k, and 40 k. Phosphate associated with these polypeptides appears to turn over with a t1/2 of 12 hr. Incubation of labeled cells in 5 mM acrylamide results in approximately 50% dephosphorylation of keratins within 2 hr, which is 3 times faster than normal turnover. Recovery of cells from acrylamide is accompanied by rephosphorylation of keratins within 18 hr. Analysis by 31P NMR spectroscopy shows that acrylamide treatments are accompanied by a transient decrease in soluble inorganic phosphate. This is followed by a rapid increase in Pi which gradually returns to normal levels. These studies show a strong correlation between phosphorylation of PtKl cell keratins and morphological response of keratin filaments to acrylamide. These observations suggest that normal distribution of keratin filaments may be, in part, mediated by protein phosphorylation.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970110104
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  • 178
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    Masthead (1988)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 11 (1988) 
    Details
    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970110201
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  • 179
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    Spindle microtubule dynamics: Modulation by metabolic inhibitors (1988)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 11 (1988), S. 97-105 
    Details
    ISSN: 0886-1544
    Keywords: spindle microtubules ; mitosis ; FRAP ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Recent experiments have shown that spindle microtubules are exceedingly dynamic. Measurements of fluorescence recovery after photobleaching (FRAP), in cells previously microinjected with fluorescent tubulin, provide quantitative information concerning the rate of turnover, or exchange, of tubulin subunits with the population of microtubules in living cells at steady state. In an effort to elucidate the pathways and factors that regulate tubulin exchange with microtubules in living cells, we have investigated the energy requirements for tubulin turnover as measured by FRAP. Spindle morphology was not detectably altered in cells incubated with 5 mM sodium azide and 1 mM 2-deoxyglucose (Az/DOG) for 5 minutes, as assayed by polarized light microscopy and antitubulin immunofluorescence. In FRAP experiments on these ATP-depleted cells, the average rate of recovery and the average percent of bleached fluorescence recovered were reduced to 37% and 30% of controls, respectively. When the inhibitors were removed, cells continued through mitosis, and rapid FRAP was restored. In the presence of azide and glucose, the rate of recovery and percent of fluorescence recovered were only slightly reduced, demonstrating that energy production via glycolysis can support microtubule turnover. Longer incubations with Az/DOG altered the microtubule organization in mitotic cells: astral microtubules lengthened and spindle fibers shortened. Furthermore, both astral and spindle microtubules became resistant to nocodazole-induced disassembly under these conditions. Together these observations indicate that microtubule dynamics require ATP and suggest a relationship between microtubule organization and turnover.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970110203
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  • 180
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    Iontophoretic localization of Ca-sensitive sites controlling activation of ciliary beating in macrocilia of Beroë: The ciliary rete (1988)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 11 (1988), S. 126-138 
    Details
    ISSN: 0886-1544
    Keywords: Ca sensitivity ; macrocilia activation ; membrane rete ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Macrocilia are thick compound ciliary organelles found on the lips of the ctenophore Beroë. Each macrocilium contains several hundred axonemes enclosed by a single common membrane around the shaft of the organelle. Macrocilia are activated to beat rapidly and continuously in the normal direction by stimulus-triggered Ca influx through voltage-dependent Ca channels (Tamm, 1988). Heat-dissociated macrociliary cells are spontaneously active without depolarizing stimuli, providing Ca is present (Tamm, 1988). Here we investigate the spatial distribution of macrociliary Ca channels by iontophoretic application of extracellular Ca to different sites along quiescent, “potentially activated” macrocilia of dissociated cells in Ca-free medium. We find that Ca sensitivity for eliciting motility is highest or resides exclusively on the basal portion of the macrociliary surface. This is the first demonstration of local differences in Ca morphologically with a reticulum of unfused ciliary membranes at the base of the macrocilium. This ciliary rete is in direct communication with the surrounding sea water. It is likely that the ciliary rete provides the necessary Ca influx to trigger beating by virtue of its greater Ca conductance (i.e., density of Ca channels) and/or greater total membrane area.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970110206
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  • 181
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    Cytokinesis occurs at boundaries of domains delimited by nuclear-based microtubules in sporocytes of Conocephalum conicum (Bryophyta) (1988)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 11 (1988), S. 139-146 
    Details
    ISSN: 0886-1544
    Keywords: phragmoplast ; sporogenesis ; indirect immunofluorescence ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Studies of the microtubular cytoskeleton during sporogenesis in the hepatic Conocephalum conicum (Bryophyta) have revealed several unusual phenomena that contribute to understanding the cytokinetic apparatus in plant cell division. Although a typical phragmoplast forms in the interzonal microtubules of the first division spindle and expands to the cell periphery, no cell plate develops. There is no evidence of predetermined division sites and the orientation of both first and second meiotic spindles is imprecise. Simultaneous division of the cytoplasm follows second nuclear division. Equal apportionment of the cytoplasm appears to be a function of the establishment of cytoplasmic domains in the coenocyte, the boundaries of which are delimited by interaction of postmeiotic microtubule systems radiating from the four nuclei. Primary phragmoplasts are initiated in phragmoplasts that are initiated between nonsister nuclei. Depending upon the arrangement of nuclei in the nonpolar sporocyte, from one to three secondary phragmoplasts develop in the zones of contact between opposing sets of microtubules. Except for the site and time of initiation, the two types of phragmoplasts are identical. Eventually the phragmoplasts become confluent and cell plates form in all second division phragmoplasts. It is clear that typical functional phragmoplasts can form in sites determined by interaction of postmeiotic microtubule systems as well as in interzonal spindles as is common in plant cell division.
    Additional Material: 18 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970110207
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  • 182
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    Optical approaches to the study of foraminiferan motility (1988)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 10 (1988), S. 126-136 
    Details
    ISSN: 0886-1544
    Keywords: microtubules ; Allogromia ; intracellular transport ; surface motility ; actin ; morphogenesis ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Microtubules are the major cytoskeletal component of foraminiferan reticulopodia. Video-enhanced differential interference contrast light microscopy has demonstrated that the microtubules serve as the intracellular tracks along which rapid bidirectional organelle transport and cell surface motility occurs. Microtubules appear to move, both axially and laterally within the pseudopodial cytoplasm, and these microtubule translocations appear to drive the various reticulopodial movements. F-actin is localized to discrete filament plaques form at sites of pseudopod-substrate adhesion. Correlative immunofluorescence and electron microscopy reveals a structural interaction between microtubules and the actin-containing filament plaques. Our recent data on reticulopodial motility are discussed in an historical context, and a model for foram motility, based on motile microtubules, is presented.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970100117
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  • 183
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    Biophysics of the leading lamella (1988)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 10 (1988), S. 164-171 
    Details
    ISSN: 0886-1544
    Keywords: motility ; lamella ; cytoskeleton ; membrane ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970100121
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  • 184
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    Regulation of the distribution of carotenoid droplets in goldfish xanthophores and possible implication to secretory processes (1988)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 10 (1988), S. 143-152 
    Details
    ISSN: 0886-1544
    Keywords: pigment organelle ; xanthophore ; microtubule ; F-actin ; intermediate filament ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: In goldfish xanthophores, the formation of pigment aggregate requires: (1) that a pigment organelle (carotenoid droplet) protein p57 be in the unphosphorylated state; (2) that self-association of pigment organelles occur in a microtubule-independent manner; and (3) that pigment organelles via p57 associate with microtubules. In the fully aggregated state, the pigment organelles are completely stationary. Pigment dispersion is initiated by activation of a cAMP-dependent protein kinase, which phosphorylates p57 and allows pigment dispersion via an active process dependent on F-actin and a cytosolic factor. This factor is not an ATPase, and its function is unknown. However, its abundance in different tissues parallels secretory activity of the tissues, suggesting a similarity between secretion and pigment dispersion in xanthophores. The identity of the motor for pigment dispersion is unclear. Experimental results show that pigment organelles isolated from cells with dispersed pigment have associated actin and ATPase activity comparable to myosin ATPase. This ATPase is probably an organelle protein of relative molecular mass ∼72,000, and unlikely to be an ion pump. Isolated pigment organelles without associated actin have 5× lower ATPase activity. Whether this organelle ATPase is the motor for pigment dispersion is under investigation. The process of pigment aggregation is poorly understood, with conflicting results for and against the involvement of intermediate filaments.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970100119
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  • 185
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    Abstracts (1988)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 11 (1988), S. 187-217 
    Details
    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970110307
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  • 186
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    Masthead (1988)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 2 (1988) 
    Details
    ISSN: 0886-9383
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180020101
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  • 187
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    Diary (1988)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 2 (1988), S. i 
    Details
    ISSN: 0886-9383
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180020102
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  • 188
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    Identification and substructure analysis of oligosaccharide chains derived from glycoproteins by computer retrieval of high-resolution 1H-NMR spectra (1988)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 2 (1988), S. 11-27 
    Details
    ISSN: 0886-9383
    Keywords: Oligosaccharides ; Glycoproteins ; Identification ; Substructure analysis ; High-resolution ; 1H-NMR spectra ; Computer retrieval ; Reproducibility ; Chemical shifts ; Similarity index ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Based on a statistical model of the reproducibility of NMR spectral features, a system for computer retrieval of high-resolution 1H-NMR spectra of glycoprotein carbohydrates has been developed. For corresponding peaks in an unknown and a reference spectrum, a similarity index based on the reproducibility of the chemical shifts is calculated. In addition, a second similarity index, based on the probability distribution of the percentage of non-matching peaks, has been developed. From these two similarity indices, a combined similarity index using the recall-reliability function as the optimizing criterion has been derived.First results indicate that the ‘1H-NMR reproducibility-based retrieval’ (‘1HRR’) system offers good perspectives for both identification and substructure analysis.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180020104
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  • 189
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    Chance classifications by non-parametric linear discriminant functions (1988)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 2 (1988), S. 1-10 
    Details
    ISSN: 0886-9383
    Keywords: Linear discriminant functions ; Pattern recognition ; Monte Carlo simulations ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In applications of pattern recognition techniques to problems in chemical fingerprinting, only limited knowledge about the underlying statistical distribution of the data is generally available. This means that non-parametric methods must be used. Non-parametric discriminant functions have been used to provide insight into relationships contained within sets of chemical measurements. However, classification based on random or chance separation can be a serious problem. Monte Carlo simulation studies have been carried out to assess the probability of chance classification for non-parametric linear discriminants. The level of expected chance classification is a function of the number of observations (the number of samples), the dimensionality of the problem (the number of independent variables per observation), class membership distribution and the covariance structure of the data being examined. An approach for assessing the level of significance of classification scores obtained from real training sets will be presented. These simulation studies establish limits on the approaches that can be taken with real data sets so that chance classification are improbable, and provide information necessary for integrating the data analysis into the overall experimental design.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180020103
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  • 190
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    Taxonomy based on chemical constitution: Differentiation of Africanized honey-bees from European honey-bees (1988)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 2 (1988), S. 29-37 
    Details
    ISSN: 0886-9383
    Keywords: Pattern recognition ; Principal component analysis ; Linear discriminant analysis ; Classification ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Gas chromatography and pattern recognition methods have been used to develop a potential method for differentiating between European and Africanized honey-bees based on chemical constitution. 243 European, African and Africanized honey-bees were characterized by 40-peak GCs of cuticular hydrocarbon extracts. Discriminants were developed that correctly classified the bees, and these discriminants were used successfully to classify bees of unknown origin, including hybrids.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180020105
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  • 191
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    Expert system for knowledge-based modelling of analytical laboratories as a tool for laboratory management (1988)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 2 (1988), S. 49-65 
    Details
    ISSN: 0886-9383
    Keywords: Laboratory organization ; Expert systems ; Digital simulation ; Decision support ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: An expert system (LABGEN) is presented for decision support in analytical laboratories by means of digital simulation. In an interactive manner, LABGEN constructs simulation models of laboratory organizations. It makes use of a database of model fragments and applies rules in order to prevent the user providing redundant information and to prevent inconsistent models being constructed. The models are written in the dedicated simulation language SIMULA. After compilation they can be used for simulation experiments. LABGEN can be applied to a wide range of laboratory organizations. An example of the application of LABGEN is presented.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180020107
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  • 192
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    Selection of optimal regression models via cross-validation (1988)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 2 (1988), S. 39-48 
    Details
    ISSN: 0886-9383
    Keywords: Regression modelling ; Cross-validation ; Bootstrap ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A general problem arising in the development of regression models is the selection of the optimal model. Whenever a feature selection procedure, such as step forward, backward elimination, best subset or all possible combinations, or when a data compression approach, such as principal components or partial least-squares regression, is used, the question of how many regression terms to include in the final model must be addressed.This work describes the evaluation of four different criteria for selection of the optimal predictive regression model using cross-validation. The results obtained in this work illustrate the problems which can arise in the analysis of small or inadequately sampled data sets. The common approach, selecting the model which yields the absolute minimum in the predictive residual error sum of squares (PRESS), was found to have particularly poor statistical properties. A very simple change to a criterion based on the first local minimum in PRESS will provide a significant improvement in the cross-validation result. A criterion based on testing the significance of incremental changes in PRESS with an F-test may provide more robust performance than the local minimum in PRESS method.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180020106
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    The effect of interferences and calbiration design on accuracy: Implications for sensor and sample selection (1988)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 2 (1988), S. 67-79 
    Details
    ISSN: 0886-9383
    Keywords: Experimental design ; Multivariate calibration ; Variable selection ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Methods of multivariate calibration use models that relate spectral data or sensor array responses to the concentrations of analytes. The goal is to insure that the calibration model can accurately estimate analyte concentrations in unknown samples not contained in the calibration set. The sensors or spectral channels (e.g. wavelengths) selected for incorporation in the model, as well as the samples selected for the calibration step, are known to have an effect on the accuracy of analysis for unknown samples. This work provides a fundamental treatment of this effect and derives criteria for optimal selection. Additionally, a proof is given for the advantage of having more sensors and calibration samples than analytes - the overdetermined case.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180020108
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  • 194
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    Monte Carlo studies of non-parametric linear discriminant functions (1988)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 2 (1988), S. 85-89 
    Details
    ISSN: 0886-9383
    Keywords: Linear discriminant functions ; Pattern recognition ; Monte Carlo simulations ; Chance classification ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Classification rules using non-parametric linear discriminant functions are often developed from training sets that are not linearly separable. In these situations it is a common practice among inexperienced workers to use many different pattern recognition methods and then select the results that look the best. However, this practice will only increase the risk of spurious results. To document this, we recently carried out a series of Monte Carlo simulation studies to assess the level of chance classification for two different classification algorithms. The level of chance classification for a given dichotomy is found to vary with the choice of the non-parametric linear discriminant function employed. Although previous workers have indicated that the degree of separation in the data due to chance is only a function of the object-to-descriptor ratio, the results of this study suggest otherwise.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/cem.1180020110
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  • 195
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    Principal component variable discriminant plots: A novel approach for interpretation and analysis of multi-class data (1988)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 2 (1988), S. 81-84 
    Details
    ISSN: 0886-9383
    Keywords: Multiclass analysis ; Covariance correlation display ; Variable Discriminant plots ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Principal component analysis is a useful method for analysing data-matrices. By analysing separate class models, i.e. disjoint principal component modelling as in the SIMCA or FCVPC programs (developed for supervised and unsupervised principal component analysis respectively), the principal component variance/covariance decomposition (class models) may be used to investigate and interpret the data-structure of separate classes. The potential of comparing the loadings of variables on subsequent eigenvectors in two class models where the same variables have been used will give information for determining how the variance/covariance in the two datasets differ. This information may then be used either to formulate a hypothesis or to select variables which are specific for the different classes.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180020109
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  • 196
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    Announcements (1988)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 2 (1988), S. 91-92 
    Details
    ISSN: 0886-9383
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180020111
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  • 197
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    Announcement (1988)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 2 (1988), S. i 
    Details
    ISSN: 0886-9383
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180020202
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  • 198
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    Masthead (1988)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 2 (1988) 
    Details
    ISSN: 0886-9383
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180020201
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  • 199
    Electronic Resource
    Electronic Resource
    Estimation of prediction error for multivariate calibration (1988)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 2 (1988), S. 93-109 
    Details
    ISSN: 0886-9383
    Keywords: Multivariate calibration ; Error estimation ; Confidence intervals ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: When arrays of non-selective sensors or overlapping spectra are used for chemical analysis, multivariate calibration must be used to relate the instrument responses to individual analytes. Using a set of carefully selected calibration samples, a multivariate mathematical model is constructed for one or more analytes. If this step is successful, the model can be used to predict the concentrations of these analytes in prospective samples. Previously, the equations required to estimate the errors in the predicted concentrations, and from these the confidence intervals, were not available because the three sources of error (measured responses from calibration data, concentrations of the analytes in the calibration set and measured responses from the unknown sample) propagated in a non-linear manner not amenable to statistical analysis. A new theory for error propagation is developed. The theory developed herein does not require estimates of the actual three sources of errors mentioned above and therefore is easy to implement. Data from near-infrared reflectance spectrometry of wheat samples were used to test the equations derived from the theory. Complete agreement between the true prediction errors and those estimated from the theory is demonstrated.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180020203
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  • 200
    Electronic Resource
    Electronic Resource
    The application of submatrix analysis to disordered spectroscopic data (1988)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 2 (1988), S. 111-119 
    Details
    ISSN: 0886-9383
    Keywords: Oscillating reactions ; Rank determination ; Submatrix analysis ; Principal component analysis ; Spectroscopy ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Submatrix analysis has been extended to systems in which the values of adjustable parameters are not known. The technique is illustrated by application to phosphoric acid and to the chlorite-iodide oscillating reaction.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180020204
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