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  • General Chemistry  (4,294)
  • Analytical Chemistry and Spectroscopy  (3,254)
  • Cell & Developmental Biology  (1,486)
  • 1975-1979  (9,034)
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Year
  • 1
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 2 (1979), S. 153-162 
    ISSN: 0148-7280
    Keywords: spermatozoa ; cell surface ; epididymis ; surface labeling ; gel electrophoresis ; proteins ; membrane ; spermatozoa ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Differences in the exposure of spermatozoa surface components during epididymal passage have been examined using lactoperoxidase-catalyzed 125I-iodination or labeling with 125I-diazodiiodosulfanilic acid. Labeled surface proteins obtained from caput and cauda epididymides were solubilized in detergent, separated by sodium dodecylsulfate polyacrylamide slab gel electrophoresis, and identified by radiography. Densitometer scans of autoradiograms revealed increased amounts or exposures of surface proteins of ∼35,000, ∼39,000, ∼50,000, and ∼78,000 molecular weight on the cauda epididymal spermatozoa.
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  • 2
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 2 (1979), S. 177-185 
    ISSN: 0148-7280
    Keywords: multiple enzyme forms ; acid nitrophenyl phosphatase ; sea urchin ; development ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Acid nitrophenyl phosphatases from sea urchin eggs and embryos were investigated by gel filtration. Four different forms were found in Hemicentrotus pulcherrimus, and three forms in Anthocidaris crassispina and Pseudocentrotus depressus.The first and second forms (designated AcP-1 and AcP-2) had the highest activity in the range of pH 5.6-6.0. The third (designated AcP-3) had an apparent optimum pH between pH 4.3 and 4.8, and the fourth (designated AcP-4) showed the maximum activity at pH 3.0. AcP-1 was much more thermolabile than AcP-2 and AcP-3 at 56°C. NaF inhibited AcP-2, AcP-3, and AcP-4 but not AcP-1. AcP-1, AcP-2, and AcP-3 were observed in the three species, whereas AcP-4 was not detected in A. crassispina and P. depressus. AcP-1, AcP-2, and AcP-3 were separted by gel filtration.AcP-1 and AcP-2 of A. crassispina and H. pulcherrimus were studied in developing embryos. The behavior of these forms in gel filtration changed during development, from unfertilized eggs to the pluteus stage.
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  • 3
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 2 (1979), S. 187-192 
    ISSN: 0148-7280
    Keywords: zona isolation ; collagenase ; receptor for sperm ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Zonae pellucidae were collected from bovine ovaries by chopping, dispersing the chopped tissue with collagenase, sieving through nylon mesh screens, and pipetting. The zonae were free of corona cell processes when examined under the scanning electron microscope. Solutions of zonae obtained with collagenase exhibited the same antigenic and sperm receptor properties as those obtained without enzyme treatment.
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  • 4
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 2 (1979), S. 207-211 
    ISSN: 0148-7280
    Keywords: sperm ; capacitation ; acrosome ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Suspensions of nearly 100% viable golden hamster sperm were prepared by passing washed cauda epididymal sperm through a column of 0.25-0.3 mm glass beads. Incubations of these viable sperm under in vitro capacitation conditions in volumes of 0.1 or 1 ml (2-2.5 × 106/ml) resulted in 85-92% viable sperm after four hours and 45 minutes of incubation. More than 70% of these sperm were judged to have been capacitated after four hours and 45 minutes of incubation on the basis of their having undergone acrosome reactions and the presence of high numbers of sperm exhibiting the activated motility characteristic of capacitated hamster sperm.Thus, for the first time, procedures are available that will yield large numbers of viable capacitated sperm for biochemical analysis and that will also allow other studies of hamster sperm capacitation with minimum interference from molecules released from dead sperm.
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  • 5
    ISSN: 0148-7280
    Keywords: speramtozoon-copepoda (My tilicola intestinalis) ; external morphology ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The external structure of the male gamete of Mytilicola intestinalis is studied under a scanning electron microscope and compared with transmission electron micrographs of thin sections corresponding to the different parts of same. The cell in question is long and filiform, showing, along a significant part of its length, two ridges or expansions helicoidally arranged and diametrically opposed. Four different parts or segments can be identified in this spermatozoon: segment A, characterized by its screw-like aspect; segment B, the longest, provided with well-developed helicoidal expansions; segment C, showing an uneven surface and lacking expansions; and segment D, with a smooth surface and decreasing diameter. The significance of this original structure in a spermatozoon, considered immobile until now, is discussed, stating different hypotheses with regard to the possible mobility of the cell just before fertilization takes place.
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  • 6
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 2 (1979), S. 283-293 
    ISSN: 0148-7280
    Keywords: in vitro fertilization ; mouse ; second polar body formation ; second meiotic division ; spindle ; polarizing microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The second meiotic division and polar body formation in mouse eggs fertilized in vitro were observed by phase-contrast and polarizing microscopy, and recorded by time-lapse cinematography. Eggs were collected from oviducts of mice that had been superovulated by injections of PMS and HCG. Some eggs, inseminated with spermatozoa that had been collected from caudae epididymides of mature male mice and cultured for two to three hours before insemination, were observed continuously on a glass slide under a phase microscope. Other eggs were inseminated in Petri dishes in a 5% CO2 incubator and examined every 20 minutes for 180 minutes. Compatible results in both sets of eggs showed that formation of the second polar body began 25-40 minutes after fusion of spermatozoon with the vitellus; it was completed 40-60 minutes later; anaphase II lasted approximately five minutes before the appearance of the furrow abstricting the second polar body. It is suggested that the furrowing associated with second polar body formation is guided by the same kind of forces that divide a cell mitotically.
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  • 7
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 2 (1979) 
    ISSN: 0148-7280
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
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  • 8
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 2 (1979), S. 193-199 
    ISSN: 0148-7280
    Keywords: double spermatozoa ; human prolactin-secreting adenoma ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: In a man with a pituitary prolactin-secreting adenoma almost only double spermatozoa were produced. These cells were almost completely enveloped in a unique membrane, a common bilocular acrosome capped two paired nuclei, and all the other organelles were double. After 120 days of treatment with 2-brom-α-ergocryptine the prolactin level was corrected, and only normal, single spermatozoa were produced. The authors suggest that a high prolactin level inhibits cell division.
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  • 9
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 2 (1979), S. 201-206 
    ISSN: 0148-7280
    Keywords: zona pellucida ; antibody ; ovary ; calf ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Treatment of bovine ovary sections with rabbit antibovine zona serum followed by fluorescein-conjugated goat antirabbit IgG produced a specific fluorescent staining only of the zonae pellucidae. Fluorescence was greater near the inner and outer surface of the zona, suggesting that either the same antigen occurs in higher concentration in these regions or that there is more than one antigen, the most immunogenic being located peripherally. In some atretic follicles fluorescent material appeared to diffuse into the degenerating oocyte and into the intercellular spaces of the cumulus oophorus.
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  • 10
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 2 (1979), S. 213-222 
    ISSN: 0148-7280
    Keywords: urethan effect ; cleavage induction ; parthenogenesis ; sea urchin ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The effect of urethan on artificial induction of cleavage in eggs of the sea urchin, Hemicentrotus pulcherrimus, was studied. When the eggs were exposed for 20 minutes to seawater containing urethan (final concentration, 0.08 M) after butyric acid-activation and then treated with hypertonic seawater, the cleavage rate was enchanced by about 1.5 times as compared with the nontreated eggs. In the eggs exposed to urethan-seawater for over 70 minutes many clear spots appeared throughout the cytoplasm. Simultaneously, the pigment granules, which had been embedded within the cortex, migrated to the inner cytoplasm and encircled a monastral centrosphere and clear spots. The clear spots were composed of microtubules much like cytasters, and in the central region of them centrioles were not yet found. The eggs in which the pigment granules disappeared from the cortex may be more susceptible to cleavage induction by succeeding hypertonic treatment.
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  • 11
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 2 (1979) 
    ISSN: 0148-7280
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
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  • 12
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 2 (1979), S. 35-42 
    ISSN: 0148-7280
    Keywords: activated motility ; temperature dependence of motility ; sperm transport ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The motility of rabbit spermatozoa recovered from the vagina, endocervix, uterus, and four regions of the oviduct was assessed visually by phase-contrast microscopy at intervals from one minute to 16 hours after a single mating. The percentage of motile cells in each sample was dependent on the temperature of recovery, ie, 23° vs 37°C, but was not influenced by the temperature of observation. Spermatozoa in the lower isthmus of the oviduct were the most temperature sensitive population to recovery at 23°C. When all manipulations and observations were performed at 37°C, the percentage of spermatozoa with progressive motility varied according to the region sampled and interval after mating. Populations from the vagina, uterus and upper regions of the oviduct usually had a high proportion of progressively motile cells with vigorous flagellar activity. Fewer spermatozoa showed progressive movement on recovery from the endocervix and lower 2 cm of the tubal isthmus and their flagellar activity was generally depressed. The decrease in flagellar beat frequency noted in the latter regions may be a major factor limiting sperm ascent in the female tract. A unique pattern of “activated” motility was seen exclusively in populations taken from the oviducts at 6 to 16 hours after mating. This motility pattern, consisting of alternating episodes of linear progressive and vigorous nonprogressive movement, may be analogous to the activated motility described for capacitated rodent spermatozoa.
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  • 13
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 2 (1979), S. 75-87 
    ISSN: 0148-7280
    Keywords: acrosin ; activation ; inhibitor ; proacrosin ; spermatozoa ; zymogen ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The sperm-specific proteinase acrosin (EC 3.4.21.10) is found in spermatozoa as a zymogen. We have looked for different forms of this zymogen in testicular, epididymal, and ejaculated spermatozoa from ram and have compared total sperm extracts made immediately after cell disruption with extracts made later from isolated sperm heads. We have concluded that the autoactivatable zymogen form, known generally as proacrosin, is the only form of acrosin within intact mature ram spermatozoa; no other zymogen form was detected, although lower levels of proacrosin were found in some samples of testicular spermatozoa. From studies of the activation process, it appears that ram proacrosin is truly autoactivatable; no evidence could be found for the involvement of any auxiliary enzyme. Estimations of the molecular weight of proacrosin using gel chromatography (60,000) and SDS-polyacrylamide gel electrophoresis (51,300) indicated that the zymogen is monomeric. Comparison with the molecular weight of ram acrosin (44,000 or 40,000, using the two respective methods) indicated that a single acrosin molecule is derived from each zymogen molecule. The sperm acrosin inhibitor (molecular weight 11,000 or 8,000) was present in testicular spermatozoa as well as in ejaculated spermatozoa; there was no evidence that it was produced as a result of zymogen activation.
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  • 14
    ISSN: 0148-7280
    Keywords: spermatozoon-ostracoda (Heterocypris incongruens) ; external morphology ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: In various papers on the original spermatozoon of the Ostracoda, its helicoidal disposition has been indicated as the principle characteristic of this gamete, at cell structure level as well as in its external morphology. Through a combined study with scanning electron microscope (SEM) and transmission electron microscope (TEM), we have been able to establish the corresponding relationship between the cell architecture and the spermatozoon's external morphology. In the case of Heterocypris incongruens, the helicoidal relief of the gamete's external surface along the greatest part of its length, is the result of the twisting and undulating of a structure derived from the nucleus' external membrane, endoplasmic reticulum, and Golgi apparatus, called “feather-like organelle.” In keeping with the shape of this surface relief, the spermatozoon can be divided into three regions: An anterior one with a corkscrew form, a middle one showing a relief in the form of a screw with four threads, and a posterior or tail one without helicoidal relief. Finally, we discuss the different criteria existing on the possible orientation of this spermatozoon when it moves, as well as the functional advantages that the possession of a filiform, helicoidal, and mobile gamete represents.
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  • 15
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 2 (1979), S. 121-124 
    ISSN: 0148-7280
    Keywords: oocyte maturation ; LH ; ovum culture ; germinal vesicle breakdown ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Immature rats, aged 27 days, were stimulated to develop preovulatory follicles by subcutaneous injection of 15 IU of pregnant mare serum gonadotrophin (PMSG). Two days later their oocytes were collected. They were cultured under conditions that permitted continuous observation. Times of the initial stages of maturation were carefully noted, in the absence and the presence of 10 μg/ml of bovine luteinizing hormone (LH). LH did not accelerate germinal vesicle disappearance. It was concluded that the immature PMSG-treated rat was not an appropriate model for the study of LH action; it was speculated that persistence of PMSG mimicked LH in all the oocytes from such donors.
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  • 16
    ISSN: 0148-7280
    Keywords: lysin ; protease inhibitor ; sea urchin ; vitelline coat ; fertilization ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: To search the spermatozoa of sea urchins for their lysins, the eggs were inseminated in the presence of various protease inhibitors. Among them, two chymotrypsin-specific inhibitors, chymostatin and N-tosyl-L-phenylalanyl-chloro-methane, as well as p-nitrophenyl p′-guanidinobenzoate, inhibit fertilization of the sea urchins, Hemicentrotus pulcherrimus and Strongylocentrotus intermedius.A chymotrypsin-like protease is presumed to be a lysin of the sea urchins, since the inhibition of fertilization by chymostatin is remarkably diminished if the eggs are pretreated with trypsin or chymotrypsin to break the vitelline coat before insemination, and since N-tosyl-L-phenylalanyl-chloromethane, and p-nitrophenyl p′-guanidinobenzoate, as well as chymostatin, inhibit the fertilization.In all the sea urchins so far studied, elevation of fertilization envelopes is inhibited by leupeptin, antipain, soybean trypsin inhibitor, and p-nitrophenyl p′-guanidinobenzoate, all of which are potent trypsin inhibitors.Synthetic inhibitors have cytotoxic side effects on the eggs, but the microbial and plant inhibitors have no such effects.
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  • 17
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 2 (1979), S. 223-233 
    ISSN: 0148-7280
    Keywords: seminal plasma DNase ; nicked sperm DNA ; sperm decondensation ; DNA template ; DNA phosphorylation ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Ejaculated rabbit spermatozoa washed with buffer prior to decondensation by Triton X-100 and dithiothreitol were good templates for DNA synthesis by Escherichia coli DNA polymerase. This result agrees with the observations of Zirkin and Chang [1977], and implies that the sperm DNA is nicked. Template activity, however, was reduced if spermatozoa were extensively washed before decondensation, and if DNase inhibitors EDTA or Na2SO4 were present during decondensation. Template activity was also low if decondensation was induced with DNase inhibitors thioglycollic acid, Na2SO3 or sodium dodecylsulphate and dithiothreitol instead of with Triton X-100 and dithiothreitol. Calf thymus DNA was completely degraded when incubated with rabbit seminal plasma or buffer-washed spermatozoa, but much less degradation was observed if EDTA, Na2SO4, thioglycollic acid, Na2SO3 or sodium dodecylsulphate were also present, or if spermatozoa were extensively washed with buffer. Centrifugation of spermatozoa through 2.05 M sucrose completely removed contaminating DNase, and such spermatozoa were inactive as DNA templates after decondensation. The DNA template activity of swollen rabbit sperm nuclei thus parallels the activity of a contaminating seminal plasma DNase. This suggest that the nicks in sperm DNA enabling it to act as a template for DNA synthesis were generated by the DNase during decondensation and thus are not a natural structural feature of the DNA. The presence of breaks in the DNA of decondensed buffer-washed spermatozoa (DNase contaminated) was confirmed by their incorporation of phosphate from [γ-32 P] ATP in the presence of the enzyme polynucleotide kinase. These spermatozoa were found to contain as few as two breaks/mole of DNA, but sucrose-washed spermatozoa (DNase free) were free of breaks. The possible use of this enzymic procedure for the assessment of sperm genome damage and the evaluation of the quality of a sperm population are discussed.
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  • 18
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 2 (1979) 
    ISSN: 0148-7280
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
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  • 19
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 2 (1979), S. 265-282 
    ISSN: 0148-7280
    Keywords: sperm chromatin ; nuclease digestion ; sperm decondensation ; chromatin structure ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The structure of rabbit, fowl, and Xenopus laevis sperm chromatin was explored by study of the reaction of their decondensed nuclei with DNase 1 and micrococcal nuclease. Those of rabbit and fowl were readily digested by DNase 1, and the polyacrylamide gel electrophoresis profiles of DNAs extracted from the digests were similar, each being polydisperse with a single discrete band of DNA smaller than 72 base pairs. There were differences, however, between the sperm chromatins in the course of their digestion by micrococcal nuclease. A limit digest at about 45% acid solubility was obtained with Xenopus sperm chromatin, while 90% of fowl sperm DNA was rendered acidsoluble by the enzyme. The gel profiles of the limit digests were polydisperse, but only those of rabbit and fowl sperm chromatins possessed a discrete band of DNA smaller than 72 base pairs. Bleomycin did not react with DNA of rabbit, fowl, or Xenopus spermatozoa. Since bleomycin reacts with somatic cell chromatin, and the course of DNase 1 or micrococcal nuclease digestion of sperm chromatin was different from that found for somatic cell chromatin, it would appear that sperm chromatin does not have the repeating nucleosometype structure of somatic cell chromatin. The nuclease digestion studies further suggest that the organization of rabbit and fowl sperm chromatins is similar, and is different from that of Xenopus sperm chromatin. The dependence of the structure of sperm chromatin on the composition of its basic proteins, and a possible structure for a protamine-type sperm chromatin, are discussed.
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  • 20
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 2 (1979), S. 295-304 
    ISSN: 0148-7280
    Keywords: in vitro fertilization ; mouse ; sperm penetration ; zona pellucida ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Sperm penetration through the zona pellucida and fusion of the sperm head with the vitellus were observed continuously and filmed under phase optics in cumulus-free living mouse eggs inseminated in vitro with capacitated epididymal sperm. Most spermatozoa penetrated the zona pellucida, traversed the perivitelline space, and fused with the vitellus at an angle nearly perpendicular to the surface. The mean duration required for sperm to penetrate the zona pellucida was 20 minutes with a range of 15-26 minutes. Sperm traversed the perivitelline space in less than one second. The initial contact of sperm with the vitellus generally took place at the tip of the sperm head. When the tip of the sperm head contacted the vitellus there was an immediate reduction in the rate of flagellation, followed by the gradual sinking of the sperm head into the vitellus.
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  • 21
    Electronic Resource
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    New York, NY : Wiley-Blackwell
    Gamete Research 2 (1979), S. 357-366 
    ISSN: 0148-7280
    Keywords: ova ; spermatozoa ; cryopreservation ; fertilization ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Mature unfertilized ova from superovulated hamsters were freed from all investments and frozen at -50°C. They were cooled at about 1°C/min to 0°C then at 0.8° to 0.6°C/min to -50°C. At 0°C, dimethyl sulfoxide was added to a final concentration of 1.25 M. The ova were stored at -50°C for up to four months. Thawing was performed at 2-4°C/min and followed by several washes with insemination medium. Approximately 90% of the ova were normal in appearance after thawing. The frozen and thawed ova with normal appearance could be penetrated by hamster or human spermatozoa at a rate comparable to unfrozen controls. The ability of hamster ova to tolerate storage at a relatively convenient temperature (-50°C) for long periods (tested for up to four months) makes possible their shipment at low cost to institutions lacking this resource. There they can be used for basic biological studies of sperm-egg interaction or in the clinical assessment of human sperm quality.
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  • 22
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 6 (1979), S. 173-178 
    ISSN: 0306-042X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A study of the effect of crystal size on the bioavailability of benoxaprofen, 2-[4-chlorophenyl]-α-methyl-5-benzoxazoleacetic acid, in man is reported. The technique utilized comparison of either the plasma concentrations or urine levels, resulting from administration of deuterium labeled (2H7) drug in solution coadministered with a test capsule formulation. Drug concentrations were determined by gas chromatography, and the ratio of labeled to unlabeled drug was obtained by gas chromatography mass spectrometry. Measurements following coadministration of labeled and unlabeled drug in solution established the absence of an isotope effect due to the presence of deuterium. The dry formulations consisted of either a 3.17-100 micron fraction (mean = 18.5 microns) or a 32-1000 micron fraction (mean = 610 microns) formulated with starch powder. The results in three subjects indicate an almost complete availability (0.95-0.98) of the small crystals as measured by comparison of either area under the plasma level curves or urine excretion (0.94-0.97) of labeled versus unlabeled drug measured to 168 hours. The larger crystals exhibited a lower availability as shown by plasma levels (0.41-0.46) or urine recovery (0.39-0.43). A higher dose of the large crystal formulation resulted in decreased relative availability with a fourfold dose dropping availability to 0.22 in a single subject.
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  • 23
    ISSN: 0306-042X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The synthetic prostaglandin analogue cloprostenol has been prepared radiolabelled with 14C. The isotopic abundance of 14C at position C-15 was greater than 90% of the theoretical maximum. We have utilized the high abundance of the 14C isotope for metabolism studies by preparing mixtures of [12C]:[14C]cloprostenol such that fragments detected by mass spectrometry contained characteristic isotope clusters analogous to those often obtained using stable isotopes.
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  • 24
    Electronic Resource
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    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 6 (1979), S. 392-395 
    ISSN: 0306-042X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A gas chromatographic mass spectrometric method has been developed to determine tyrosine and deuterium labelled tyrosine in biological samples using α-methyltyrosine (α-Me Ty) or m-hydroxyphenylalanine as internal standards. With the latter standard both labelled and unlabelled tyrosine as well as α-Me Ty can be determined simultaneously, in for example human blood, following administration of α-Me Ty to inhibit catecholamine synthesis. After isolation of the amino acids on an ion exchange column (Amberlite IR 120) the butyl ester pentafluoropropionyl derivatives were prepared. In human plasma the precision of the method was determined at a level of 80 nmol tyrosine ml-1 and found to be ±5% (coefficient of variation, n = 10).
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  • 25
    ISSN: 0306-042X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The t-butyldimethylsilyl derivatives of 1,2-dialkyl, 1-alk-1′-enyl-2-acyl, 1-alkyl-2-acyl and 1,2-diacyl glycerols were analysed with a gas chromatograph mass spectrometer system. The characteristic fragment ions were as follows. The molecular weight determining ion was [M - 57]+, which was formed by cleavage of the t-butyl radical from the molecular ion. The nature of the alk-1′-enyl residue could be determined by the presence of ions at [RCH—CH + 56]+ and [RCH=CH + 130]+ (RCH=CH=alk-1′-enyl), and the alkyl residue by the ion at [R + 130]+(R = alkyl group). Ions giving information about the acyl group, [RCO]+, [RCO + 74]+ and [M — RCH=CHO, —RO or —RCOO]+ were also observed. The mass spectra of pairs of trimethylsilyl and t-butyldimethylsilyl derivatives showed differences in several respects. The t-butyldimethylsilyl derivatives gave more effective information for elucidating the structure of phosphoglycerides.
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  • 26
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    Biological Mass Spectrometry 6 (1979), S. 415-421 
    ISSN: 0306-042X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The potential of chemical ionization mass spectrometry for the characterization of naturally occurring and semi-synthetic cardiac glycosides has been investigated. Methane, isobutane and ammonia were used as reactant gases. With the exception of ouabain, the ammonia chemical ionization mass spectra of the cardiac glycosides examined in this work contained abundant [M+NH4]+ ions and abundant fragment ions formed by cleavage of glycoside bonds. Ammonia chemical ionization mass spectrometry was found to provide a rapid and sensitive method for the characterization of the products of glycosidation reactions. In contrast, the methane and isobutane chemical ionization mass spectra of the cardiac glycosides, with the exception of ouabain, did not contain protonated molecular ions and did not contain abundant fragment ions above m/z 400.
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  • 27
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    Biological Mass Spectrometry 6 (1979), S. 431-434 
    ISSN: 0306-042X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A new procedure for the simultaneous measurement of prostaglandins E2 and F2α in human urine is described. Quantification was achieved by gas chromatography mass spectrometry with selected ion monitoring and deuterium labeled internal standards. The levels of measured prostaglandins ranged from 25 pg ml-1 of urine (PGE2) to 2500 pg ml-1 (PGF2α). The interassay coefficient of variation, determined by replicate analysis of four identical samples, was 1.9% for PGE2 and 0.8% for PGF2α. The procedure takes a fraction of the time needed with published methods and can be conducted with as little as one-tenth of the daily urinary output.
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  • 28
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Twin male infant siblings who presented in Harrow, UK, with a Reye's-like syndrome associated with profound hypoglycaemia, vomiting, diarrhoea, coma and death in one child, with dicarboxylic aciduria, and similarities to Jamaican vomiting sickness (hypoglycin toxicity) have been shown to excrete large amounts of a previously unrecorded urinary organic acid. This has been identified as 5-hydroxyhexanoic acid by gas chromatography mass spectrometry using a synthesized standard. Concentrations observed were 340 and 330 mg g-1 creatinine in the two patients. The metabolic precursor of the urinary acid is suggested to be hex-4-enoic acid, a probable chemical toxin closely related to the active organic acid metabolite of hypoglycin. The possibility of ω - 1 oxidation of hexanoic acid to 5-hydroxyhexanoic acid in these and other patients with dicarbocylic acidurias is also discussed.
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  • 29
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A method is described for the quantitative determination of terbutaline in 2 ml human plasma. The drug is extracted from plasma as the terbutaline tetraphenylboron ion pair and determined by gas chromatography mass spectrometry of its t-butyldimethylsilyl ether. Salbutamol is used as internal standard. Quantification is achieved by selected ion monitoring of the ion m/z 482 derived from t-butyldimethylsilyl terbutaline and m/z 495 from t-butyldimethylsilyl salbutamol. The detection limit was estimated to be 250 pg terbutaline ml-1 plasma. The coefficient of variation at the level of 1 ng terbutaline ml-1 was 4.1% (n = 5).
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  • 30
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A quantitative gas chromatographic mass spectrometric method using a deuterated analogue as internal standard was developed for the analysis of 5-methoxytryptamine in brain. The internal standard was synthesized in two steps and possessed high isotopic purity. The analytical procedure involves the addition of the internal standard to the homogenizing medium containing the tissue, followed by homogenization, extraction with chloroform and derivatization with pentafluoropropionic anhydride. The identification and quantitation of 5-methoxytryptamine is based on monitoring the ions at m/z 306, 319 and 482 for the pentafluoropropionyl derivative of 5-methoxytryptamine and m/z 308, 322 and 486 for the internal standard. Using this procedure 5-methoxytryptamine was identified and quantitated in the sheep pineal gland. The mean 5-methoxytryptamine level (N=12) was 545±180 pmol g-1.
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  • 31
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    Biological Mass Spectrometry 6 (1979), S. III 
    ISSN: 0306-042X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 32
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    Biological Mass Spectrometry 6 (1979), S. 447-452 
    ISSN: 0306-042X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The biotransformation products of shikimate in the rat have been identified by electron impact mass spectrometry. Analysis of the metabolites produced after oral administration of shikimate resulted in the identification of hippurate, 3,4,5,6-tetrahydrohippurate, hexahydrohippurate, benzoyl and cyclohexylcarbonyl-β-D-glucuronides and two isomeric 3,4-dihydroxycyclohexanecarboxylates. Results showed that shikimate itself is not metabolized by rat tissues and that all metabolites produced were dependent upon initial metabolic transformations by gastrointestinal microgranisms. The various hippurate derivatives and glucuronide conjugates appear to arise via a conversion of shikimate to cyclohexanecarboxylate, which is then further metabolized by the rat tissues.
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  • 33
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The mass spectra of a number of 2-trifluoromethyl-3-oxazol-5-ones, prepared from protein amino acids, have been recorded. The compounds have been separated by gas chromatography using binary column techniques. Analysis of the mass spectra has identified major fragmentation processes which, directly or indirectly, yield the nature of the amino acid sidechain. These fragmentations would be considered advantageous in the identification of unknown α-amino acids.
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  • 34
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Clinical studies were conducted by gas chromatography mass spectrometry selected ion monitoring of urinary dicarboxylic acids as dicyclohexyl esters. The dicyclohexyl esters of the dicarboxylic acids give characteristic electron impact mass spectra suitable for selected ion monitoring. The mass spectra exhibit a prominent acid + 1H ion and an (acid + 1H)- H2O ion for use as quantitating and confirming ions. The cyclohexyl esters are stable for days at room temperature and have excellent chromatographic properties. Dicarboxylic acid quantitation is performed within one hour using only 50 μl of unpurified urine. A rapid method specifically for methylmalonic acid quantitation is described which has assisted physicians in the diagnosis of pernicious anemia and methylmalonic aciduria. This procedure is applicable for screening urinary organic acids for detection of inborn errors of metabolism. The detection of a child with elevated medium length dicarboxylic acids in the terminal urine specimen is reported. This condition, previously described as an inborn error, is attributed to a terminal event. Finally, an increase in urinary succinic acid paralleling putrescine levels is described during a response to cancer chemotherapy.
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  • 35
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Methyl stearate was tested as an internal standard for the mass spectrometric quantitation of six structurally different compounds because of the limited availability of sample-like standards (labelled analogues, etc.). Based on the selected ion monitoring and integrated ion current techniques, satisfactory (correlation coefficient 〉0.99) calibration curves were obtained in all cases by plotting the log ratio of evaporated weights vs the log ratio of integrated ion currents (sample to standard). This indicates that the use of sample-independent standards instead of compounds closely related to the sample, provides a versatile and generally applicable quantitation technique with a precision better than ± 15% at the ng level.
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  • 36
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  • 37
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The mass spectra of the tristrifluoroacetyl derivative of α-methyldopamine and the bistrifluoroacetyl derivative of 3-O-methyl-α-methyldopamine contain important ions which can be rationalized by two alternative fragmentation pathways. These ambiguities were resolved by means of a simple chemical derivatization technique. The labile phenolic ester groups were hydrolyzed and subsequently re-esterified by reaction with chlorodifluoroacetic anhydride in the presence of ethyl acetate thereby labeling ions containing ester group(s) in the mass spectra with the diagnostic chlorine isotope ratio. This resulted in the addition of 16/18 mass units to the weights of the ions for each fluorine atom replaced by chlorine. Since it was easy to distinguish loss of the mass of a neutral molecule of trifluoroacetamide (113 mass units) from the ions of a chlorodifluoroacetoxy radical (129 mass units), the elimination of trifluoroacetamide was distinguished from that of trifluoroacetoxy radical. Derivatives were also prepared in which the chlorine label was located on the N-acyl function. The mass spectra of the chlorine labeled compounds showed that the major fragmentation pathway of tristrihaloacetyl-α-methyldopamine and bistrihaloacyl-3-O-methyl-α-methyldopamine is by loss of a neutral molecule of trihaloacetamide.
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  • 38
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Picogram amounts of underivatized chlorophenols and chlorocresols are analysed by gas chromatography mass spectrometry using high resolution selected ion monitoring. Deactivation by pretreatment of columns with 2,4-dichlorophenoxyacetic acid gives long-term improvement in sensitivity and reproducibility.
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  • 39
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    Biological Mass Spectrometry 6 (1979), S. 149-156 
    ISSN: 0306-042X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The 5-dimethyl-, diethyl-, dibutyl-, and dipentyl-aminonaphthalene-1-sulfonyl (dansyl, ethansyl, propansyl, bansyl and pentansyl resectively) derivatives of tyramine and other biogenic amines were prepared and their mass spectra recoded. The relative intensity of the largest unique ion increased with increasing length of the alkyl group. Several O-alkyl-N-propansyl- and N,O-dialkyl-N-propansyl-, bansyl- and pentansyl-tyramines were also synthesized and their mass spectra recorded. Dimethylbansyl- and dimethylpentansyltyramines exhibited the largest unique ions in their mass spectra and the greatest sensitivity in quantitation by the integrated ion current method. Procedures for preparing these derivatives in amounts ranging from nanograms to milligrams are presented and their thin-layer chromatographic behavior in three solvent systems is described.
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    Biological Mass Spectrometry 6 (1979), S. 162-164 
    ISSN: 0306-042X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The electron impact mass spectra of a number of androsterones and androsterols as their formate ester derivatives are discussed; these ester derivatives are in common use for routine assay of 17-oxosteroids and 17-oxogenic steroids in biological samples.
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  • 41
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    Biological Mass Spectrometry 6 (1979), S. III 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
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  • 42
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    Biological Mass Spectrometry 6 (1979), S. III 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
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  • 43
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
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    Topics: Chemistry and Pharmacology
    Notes: Deuterated methadone, 2-ethylidene-1,5-dimethyl-3,3-diphenyl pyrrolidine, 2-ethyl-5-methyl-3,3-diphenyl-1-pyrroline, 1,5-dimethyl-3,3-diphenyl-2-pyrrolidone and 4-dimethylamino-2,2-diphenylpentanoic acid have been synthesized for application to metabolic studies of methadone and as potential internal standards for selected ion monitoring methods. Mass fragmentation patterns are described based upon comparisons between labeled and unlabeled derivatives.
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    Biological Mass Spectrometry 6 (1979), S. 191-193 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In water soluble substances obtained by water extraction from human skin surface, free glycerol was detected by gas chromatography mass spectrometry. A selected ion monitoring method was employed to measure low concentration of free glycerol and the mean amounts were found to be about 0.7 μg cm-2 on the cheek and 0.2 μg cm-2 on the forearm and sole.
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    Biological Mass Spectrometry 6 (1979), S. 205-207 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Field desorption mass spectrometry was applied to the screening of aquatic environments for herbicides. The standard field desorption mass spectra of these compounds are also presented. The spectra of standard herbicides showed molecular and isotope ions, but fragment ions were not observed. The molecular ion was observed as the base peak. The spectra of the extracts of water showed positive responses at m/z 257 and m/z 344 corresponding to molecular ions of benthiocarb and oxadiazon. These herbicides were simultaneously confirmed when present in mixtures.
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  • 46
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    Biological Mass Spectrometry 6 (1979) 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
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  • 47
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
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    Topics: Chemistry and Pharmacology
    Notes: Several data reduction procedures have been used for converting isotope ratios, determined using gas chromatography mass spectrometry, into mole ratios for the purpose of quantitating organic compounds. In this report, these procedures are shown to be related under certain limiting approximations of original sample and internal standard isotope ratios. With the understanding that some of the procedures involve approximations, the incorporation of related systematic errors into calculated mole ratio values was investigated. The results indicate that certain data reduction procedures allow quantitation over wider mole ratio ranges and with internal standards which contain a significant quantity of unlabeled impurity.
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  • 48
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
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    Topics: Chemistry and Pharmacology
    Notes: A novel application of selected ion monitoring was used for a mixture of non-acid glycosphingolipids of one rabbit small intestine. Earlier studies of permethylated and permethylated-reduced (LiAlH4) derivatives of model compounds have revealed a specificity and abundance of saccharide ions (terminal monosaccharide(s), disaccharide, trisaccharide, etc., and all sugars plus fatty acid) and of ceramide fragments that permit a conclusive detection of separate glycolipid species in a mixture. The sample (50-200 μg) was evaporated slowly (1-5°C min-1 form 150-350°C) from the direct inlet probe of an MS 902 mass spectrometer (electron ionization). Mass spectra with fragments up to about m/z 2000 were collected on-line by a computer system. A successive partial separation was obtained for glycolipids with from one up to seven sugars. The structures of eight different compounds were identified. They all had 16:0, 22:0 and 24:0 2-hydroxy fatty acids and 18:0 trihydroxy base (phytosphingosine) as major ceramide components. The dominating complex glycolipid was a hexaglycosylceramide with a blood group B type of sequence. A blood group A type sequence was found in a second hexaglycosylceramide. In support of this, the native mixture showed blood group A and B activity. An intense peak, m/z 182, collected from methylated derivatives was evidence for a dominating type 2 carbohydrate chain of the core tetrasaccharide.
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  • 49
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    Biological Mass Spectrometry 6 (1979), S. 260-265 
    ISSN: 0306-042X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Fragmentation studies of the mass spectra of 15 high purity compounds of the 1-(5-ethyl-2-thienyl)-1-thiaalkane series are presented. The molecular weight range covered is from 158 to 284. These substances are of importance to those utilizing fossil fuels which contain them and also to those studying natural products. The molecular ion intensities are moderately strong and easy to verify due to the presence of two sulfur atoms in the molecule. Prominent ions occur in all spectra at m/z 144 and 129. A total of six different ion species are base peaks for the compounds reported, including alkyl and alkenyl ions. The methyl and ethyl compounds are exceptions to the correlations developed in this work and are discussed in detail. Metastable and low ionization voltage data are presented in support of the suggested mechanisms of fragmentation. Those using only three to four peaks in selected ion monitoring should anticipate experiencing difficulties with positive identification of these types of molecules due to the plethora of alkylions. An integration of the correlations developed with those of other sulfur containing moieties is presented.
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A simple gas chromatographic mass spectrometric determination of the impurity 3-quinuclidinyl benzilate in the anticholinergic agent clidinium bromide (3-hydroxy-1-methylquinuclidinium bromide benzilate) is not feasible because clidinium bromide decomposes to 3-quinuclidinyl benzilate in the injection port of the gas chromatograph; the trimethylsilyl derivative of clidinium bromide also decomposes to the trimethylsilyl derivative of 3-quinuclidinyl benzilate. Therefore, a quantitative thin-layer chromatographic gas chromatographic mass spectrometric method has been developed for determining 3-quinuclidinyl benzilate in clidinium bromide, using β-piperidylethyl benzilate as an internal standard. A band containing only 3-quinuclidinyl benzilate and β-piperidylethyl benzilate can be eluted from the thin-layer chromatographic plate. The samples are analyzed by single ion monitoring of m/z 255 produced by the trimethylsilyl derivatives of 3-quinuclidinyl benzilate and β-piperidylethyl benzilate which are separated by gas chromatography. A level of 0.03% of 3-quinuclidinyl benzilate can be determined with a precision of about 6%; the lower limit of detection of 3-quinuclidinyl benzilate alone is about 1 ng on the thin-layer chromatographic plate. Analysis of a reference standard of clidinium bromide by the thin-layer chromatographic gas chromatographic mass spectrometric procedure showed that it contained no detectable 3-quinuclidinyl benzilate. One commercial bulk sample of clidinium bromide contained about 0.018% of 3-quinuclidinyl benzilate, while a formulated sample of clidinium bromide contained no detectable 3-quinuclidinyl benzilate. Commercial samples of clidinium bromide containing chlordiazepoxide can be analyzed for 3-quinuclidinyl benzilate only with difficulty using this method.
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Five hydroxyoctachlorodiphenyl ethers present in technical pentachlorophenol have been isolated and tentatively identified. Electron impact mass spectrometry and electron capture negative ion chemical ionization mass spectrometry were used to assist in the identification.
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Two abnormal metabolites, 3-keto-2-methylvaleric acid and 3-hydroxy-2-methylvaleric acid, have been identified and quantitated in the urine of a child with propionic acidemia. These metabolites may be produced as a result of the self-condensation of propionyl-CoA. Data are presented to show that the unusual ketone, 3-pentanone, which has been observed previously in the urine of patients with propionic acidemia, is produced as a result of the decarboxylation of 3-keto-2-methylvaleric acid.
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    Biological Mass Spectrometry 6 (1979), S. 315-316 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
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    Biological Mass Spectrometry 6 (1979), S. 325-330 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A gas chromatographic chemical ionization mass spectrometric assay has been developed to measure carprofen in blood. The method features the addition of either a structural or stable isotope analog internal standard to plasma prior to a simple benzene extraction at pH 4.5. The residue, after removal of the benzene, is methylated with ethereal diazomethane. Following evaporation of the methylating solvents, a portion of the reconstituted residue is analyzed by gas chromatography mass spectrometry. The mass spectrometer is set to monitor in the gas chromatographic effluent the [MH]+ions of carprofen methyl ester and the methyl ester of internal standard generated by isobutane chemical ionization. Assay sensitivity is 5 pmol ml-1. When 200 pmol ml-1 samples are analyzed using a stable isotope analog as the internal standard, the precision and accuracy are both 4%. Using a structural analog as the internal standard, the assay was neither as precise nor as accurate.
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    Biological Mass Spectrometry 6 (1979), S. 345-346 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A total of 26 monomethyl branched saturated fatty acids was identified in baboon liver lipids; these included a novel anteiso component with an odd number of carbon atoms in the chain (13-methylpentadecanoic acid).
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    Biological Mass Spectrometry 6 (1979), S. 347-349 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Mid-chain ethyl substituted fatty acids with chain lengths ranging from 10 to 16 carbon atoms were identified in a concentrate of branched chain fatty acids isolated from the triacylglycerol fatty acids of the subcutaneous adipose tissue of barley-fed lambs. The acids were identified by gas chromatography in combination with mass spectrometry and their mass spectral features are discussed.
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    Biological Mass Spectrometry 6 (1979), S. 356-358 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Vaporization of a ornithine-containing polar lipid from Thiobacillus thiooxidans has been accomplished by thermolysis in a chemical ionization source. The thermolysis has been shown to be more extensive than previously thought. It occurs in at least two steps, the first being dehydration of the ornithine to produce a substituted piperidone. This fragment undergoes a facile elimination to produce two neutral lipid components: a long chain fatty acid and piperidone-containing fatty amide. The results demonstrate the utility of chemical ionization for developing an understanding of a thermolysis process.
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    Biological Mass Spectrometry 6 (1979), S. iii 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
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    Biological Mass Spectrometry 6 (1979) 
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    Notes: A survey has been made of about 120 papers appearing in the food literature in which mass spectrometry has been employed to measure toxic contaminant levels. The areas covered are, mycotoxins, nitrosamines, polyhalogenated hydrocarbons and other industrial contaminants. All the essential analytical details have been collected and the limitations of the present day methods are discussed. The reader may conclude that sometimes there is a lack of essential information and that a more standard reporting procedure for quantitative assays is needed.
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    Biological Mass Spectrometry 6 (1979), S. 414-414 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
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    Biological Mass Spectrometry 6 (1979) 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
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    Topics: Chemistry and Pharmacology
    Notes: A methane chemical ionization quantitative assay for methylphenidate and its major metabolite, ritalinic acid, is described. Methylphenidate and the internal standard, ethylphenidate, were extracted from plasma samples and derivatized to prevent thermal decomposition in the gas chromatograph. Ritalinic acid was esterified with diazomethane and extracted as methylphenidate. The intensity of the protonated molecular ion of the derivatized drug and internal standard was measured by selected ion monitoring. Calibration curves were prepared from drug standards dissolved in drug-free plasma, and the lower limit of the curves extended to 0.5 ng methylphenidate per ml plasma. The method was used to generate plasma decay curves for pediatric patients undergoing methylphenidate therapy.
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    Biological Mass Spectrometry 6 (1979), S. 439-443 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Eleven biologically interesting N-acylglycines have been synthesized and the gas chromatographic and mass spectrometric properties of their trimethylsilyl derivatives studied. A sharp and reproducible gas chromatographic peak could be obtained for each N-acylglycine as the N, O-bis-(trimethylsilyl)-N-acylglycine. By the use of these derivatives a sensitive and specific selected ion monitoring method for the determination of N-acylglycines in human urine has been developed.
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    Topics: Chemistry and Pharmacology
    Notes: The urinary extract of a child investigated because of strabismus was found to contain large amounts of a compound which was identified using gas chromatography/mass spectrometry as 2-deoxyerythropentono-1,4-lactone. This lactone has not been observed previously in urinary extracts. When ion-exchange chromatography was used to isolate the organic acids from urine, the major peaks obtained by gas chromatography were shown to be 2-deoxyerythropentonic acid, 2-deoxyerythropentono-1, 5-lactone and 2-deoxyerythropentono-1,4-lactone. Another abnormal metabolite, 2-deoxyribitol, was also excreted by the patient although this compound could not be detected in the urine of normal children. It is proposed that these unusual compounds accumulate in the urine of this child as a result of a defect in the catabolism of 2-deoxyribose.
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    Biological Mass Spectrometry 6 (1979), S. 467-468 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
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    Biological Mass Spectrometry 6 (1979), S. 472-475 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The mass spectral characteristics of a group of 1[(2-benzyl-4-thiazolyl)methyl]-4-phenylpiperazines are discussed, and the information used to determine the structure of an impurity, degradation product and aid the characterization of compounds synthesized for metabolic purposes.
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    Biological Mass Spectrometry 6 (1979), S. 467-471 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The identification of carpronium chloride and a metabolite in human urine has been performed by means of field desorption mass spectrometry using deuterium labelling. Essential points in this study are the simultaneous administration of a deuterium labelled drug ([2H9]carpronium chloride), a purification procedure by ion pair extraction with an iodine reagent, and the use of paper electrophoresis to examine the degree of clean-up. The field desorption mass spectra of the purified extracts obtained from sample urine gave a characteristic pattern resulting from the carpronium cation (m/z 160, m/z 169) and a metabolite of the N-(3-carbohydroxypropyl)trimethyl ammonium cation (m/z 146, m/z 155).
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    Biological Mass Spectrometry 6 (1979), S. 491-498 
    ISSN: 0306-042X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Differentiation of normal human cells has been accomplished by pyrolysis gas chromatography mass spectrometry. Normal cells from human kidney, spleen, liver and brain tissues have been pyrolyzed and the products chromatographically separated and characterized by mass spectrometry. Molecular pyrolysis products giving rise to the characteristic pyro-mass chromatograms include, but are not limited to, alkenes, alkanes, nitriles and various ring compounds. Single ion mass chromatograms as well as multiple ion mass chromatograms have been used to explore the characteristic differences between various tissue materials. A dynamic computer methodology for comparing pyro-mass chromatograms has been developed for use in automatic identification and classification of the human cellular material.
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    Biological Mass Spectrometry 6 (1979), S. 502-507 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: After appropriate sample pretreatment and derivatization, uremic serum was investigated by combined high resolution gas chromatography and mass spectrometry, using both electron impact and chemical ionization methods. Electron impact and chemical ionization spectra of a number of identified (trimethylsilylated) carbohydrates and organic acids are compared. The utilization of chemical ionization mass spectrometry, with isobutane as the reagent gas, is discussed in detail. The influence of the reagent gas pressure on the total ion current and on the spectral appearance was studied. The identification of compounds, based on electron impact mass spectral data, was confirmed and often aided appreciably by using this technique. The chemical ionization spectra of trimethylsilylated alditols and aldonic acids, as well as of other organic acids showed protonated molecular ions, whereas aldoses did not. Differences with electron impact spectra are found mainly in the high mass region. The loss of one or more trimethylsilanol groups becomes the predominating fragmentation route at higher reagent gas pressure.
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    Biological Mass Spectrometry 6 (1979), S. 515-545 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The first biennial updated compilation, for the period 1977-1978, of slected references to the use of 2H, 13C, 15N, 18O and 34S in biochemical, pharmacological, clinical and environmental applications is presented. Author and subject indices for this information are compiled to enable the reader to make further use of these references.
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    Notes: The α-and β-forms of permethylated 1,3-, 1,4- and 1,6-linked N-acetylglucosaminyl-N-acetylglucosaminitol disaccharides have been analysed directly (without hydrolysis or further modifications) by combined gas-liquid chromatography mass spectrometry. Gas-liquid chromatography facilitated the separation of the α- and β-isomers of each disaccharide pair. In every case, the respective α-form was slower than the β-form. While, additionally, the α- and β-forms of the 1,6-linked glucosamine disaccharide could be separated from those of the 1,3- and 1,4-linked disaccharides, the α- and β-forms of the latter two could not be resolved from each other with the liquid phases used. All three disaccharides could be readily differentiated and characterized by mass spectrometry, however. Specific fragments for each glucosamine disaccharide could be defined. Therefore, combined gas-liquid chromatography mass spectrometry allowed an unequivocal determination of the anomeric configuration and the position of the glycosidic linkage in the glucosamine disaccharides.
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    Biological Mass Spectrometry 6 (1979), S. 27-30 
    ISSN: 0306-042X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A gas chromatography mass spectrometry method has been developed and evaluated for the quantitative analysis of tiamenidine in plasma. Tiamenidine and internal standard are extracted from basified plasma, converted to dibenzyl derivatives by reaction with benzyl bromide and potassium t-butoxide in the presence of 18-crown-6 ether prior to analysis by selected ion monitoring. The method can be used over the range 0.2-10 ng ml-1 with a coefficient of variation of better than 20% at 1 ng ml-1.
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
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    Topics: Chemistry and Pharmacology
    Notes: A highly sensitive and specific assay is described for the bronchodilator drug terbutaline in human plasma and urine, based on single ion monitoring gas chromatography mass spectrometry and employing a homologue of the drug as internal standard. Recovery of terbutaline and internal standard into ethyl acetate is effected at pH 9.8, while back-extraction into dilute acid serves to purify the initial extract. Following preparation of O-TMS, N-TFA derivatives, the drug and its homologue are detected by selected ion monitoring of their common base ion at m/e 355. The limit of detection of terbutaline by this procedure is 0.3 ng ml-1 from a 4 ml sample of plasma.
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    Biological Mass Spectrometry 6 (1979), S. 47-56 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A method has been developed for qualitative screening of carboxylic acids in human urine. The method uses direct chemical ionization mass spectrometry with isobutane as reagent gas. The carboxylic acids are separated from the urine samples by ion exchange. Normal carboxylic acid profiles have been determined and are compared with the profiles of patients suffering from certian metabolic disorders.
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    Topics: Chemistry and Pharmacology
    Notes: The gas chromatographic mass spectrometric properties of the dimethylisopropylsilyl ether derivatives of 27 hydroxysteroids have been studied. The retention times of the dimethylisopropylsilyl ether derivates were close to those of the dimethyl-n-propylsilyl ether derivatives. The mass spectra were characterized by their marked simplicity and the molecular ion cluster, [M]+·, [M-15]+ and [M-43]+. The [M-43]+ ion, corresponding to loss of the isopropyl group from the molecular ion in these derivatives, was very intense and was frequently observed as a principal ion. In particular, it was found as a principal ion in the DMiPS ether derivatives of pregnanediols.
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    Topics: Chemistry and Pharmacology
    Notes: The electron impact mass spectra of permethylated aldohexopyranosyl-(1 - x)-aldohexoses, where x = 1-6, are given. A scheme is presented to discriminate between the various types of glycosidic linkages. Moreover, their fragmentation mechanisms and mutual differences are examined with the aid of labelled compounds, high resolution measurements and information derived from metastable ions.
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    Biological Mass Spectrometry 6 (1979), S. 91-97 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A new technique is reported resulting in the direct, instantaneous analyses of trace compounds in breath. The analyses were performed using a commercial atmospheric pressure chemical ionization mass spectrometer (TAGA TM 2000 APCI mass spectrometer). A known flow of breath sample is introduced into the ionization region of the mass spectrometer. The study includes the measurement and monitoring in real-time, of breath ammonia during a 24 hour and a 48 hour period. The ammonia profiles indicate a personalized daily pattern associated with each subject. This method appears to be of potential value in routine detection and treatment of hyperammonemia patients. Results also show that it is possible to obtain instantaneous analyses of several naturally occurring metabolites and other substances on breath in the ppm to ppt range, suggesting a number of diagnostic research applications.
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    Biological Mass Spectrometry 6 (1979), S. 109-112 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The antimalarial drug primaquine was analysed in plasma and urine by gas chromatography mass spectrometry, using a deuterated internal standard. After freeze-drying and extraction with trichloroethylene the sample plus internal standard was reacted with Tri Sil TBT (a) 3:3:2 by volume mixture of trimethylsilylimidazole, N,O,-bis-(trimethylsilylacetamide and trimethylchlorosilane) and an aliquot injected into the gas chromatograph mass spectrometer. The gas chromatographic effluent was monitored at m/z 403 and m/z 406, the molecular ions of the bis-TMS ethers of primaquine and 6-trideuteromethoxy primaquine. Calibration curves were prepared from standards made up in plasma and urine. Data from the analysis of plasma and urine samples from a volunteer who ingested the equivalent of 45 mg primaquine are presented.
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    Biological Mass Spectrometry 6 (1979), S. 124-128 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The mass spectrometry of eight valepotriates and their derivatives has been investigated. Mass spectral fragmentation schemes have been proposed as well as the use of this fragmentation for structural elucidation. Structures of two valepotriates, acevaltrate and homoacevaltrate, have been clarified.
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    Biological Mass Spectrometry 6 (1979), S. 129-134 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A potent toxin isolated from Penicillium islandicum Sopp was found to have the composition C24H31N5O7Cl2. Mass spectrometric investigation of a partial acid hydrolzate showed that it has the structure of cyclochlorotine. The mass spectral characteristics of polyamino alcohol-related derivatives of peptides containing β-phenyl-alanine, α-amino butyric acid and dichloroproline were determined in the course of this work.
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    Biological Mass Spectrometry 6 (1979), S. 169-172 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A quantitative method is reported for the determination of n-hexane, 2-hexanone and 2,5-hexanedione in biological tissues by stable isotope dilution using gas chromatography mass spectrometry. n-[2H14]Hexane, 2-[2H5]hexanone and 2,5-[2H10]hexanedione are used as the isotopic diluents. After tissue homogenization and extraction of the three compounds in the presence of the deuterated internal standards, analysis is carried out in a single gas chromatographic injection by selected ion monitoring. Principal advantages of the technique are the ease of sample handling, rapidity of analysis and low limits of detection. The methodology is used to determine the organ distribution, pharmacokinetics and metabolism of n-hexane to 2-hexanone and 2,5-hexanedione in rats following inhalation exposure.
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    Biological Mass Spectrometry 6 (1979) 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
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    Biological Mass Spectrometry 6 (1979), S. 187-190 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Quantification of low levels of psychotropic drugs (10-7 to 10-9 g ml-1) in small volumes of plasma requires sensitive and accurate methods. Validation of these methods is best achieved by comparing results obtained using several techniques. In this study, amphetamine levels in plasma were measured using gas chromatography mass spectrometry and radioimmunoassay. Correlation of the results obtained by the two methods was found to be positive and high (R = 0.9822). The average coefficient of variation between assays for gas chromatography mass spectrometry was 5.8% and for radioimmunoassay was 12.3%, while the average coefficient of variation within assays for gas chromatography mass spectrometry was 4.9% and for radioimmunoassay 6.9%. Although gas chromatography mass spectrometry was 1.9 times more sensitive than radioimmunoassay, for most purposes, the convenience of the radioimmunoassay method outweighs the technical superiority of gas chromatography mass spectrometry.
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    Topics: Chemistry and Pharmacology
    Notes: A quantitative method has been developed to measure plasma concentrations of warfarin and warfarin alcohol. The analytical procedure uses deuterated analogues as internal standards, and the technique of selected ion monitoring following gas chromatography methane chemical ionization mass spectrometry of the 4′-methyl ethers of warfarin and warfarin alcohol. Concentrations of warfarin and warfarin alcohol have been measured in plasma samples from 43 patients maintained on chronic warfarin therapy and compared with the ‘apparent warfarin’ concentration as measured by a fluorometric procedure. The study demonstrated a high degree of correlation between the gas chromatographic mass spectrometric derived sum of the individual concentrations of warfarin and warfarin alcohol, and the ‘apparent warfarin’ concentration determined from a spectrofluorometric assay.
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
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    Topics: Chemistry and Pharmacology
    Notes: The methoxime derivatives of N-acyl prostaglandin E2 carboxamides (PG imides), when analyzed in the presence of excess N,O-bis(trimethylsilyl)trifluoroacetamide by gas chromatography, were converted to nitriles and trimethylsilyl esters. For example, the methoximetrimethylsilyl (MO-TMS) derivative of N-acetyl PGE2 carboxamide was converted to the MO-TMS derivative of 9-keto-11,15-dihydroxy-prost-5,13-dienonitrile and the MO-TMS derivative of PGE2. The ratio of rearrangement products was found to be dependent upon the nature of the N-acyl group, and the rearrangement apparently took place in the vapor phase after silylation of the imide moiety.
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    Biological Mass Spectrometry 6 (1979), S. 249-252 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A new very sensitive method of ketoprofen [(benzoyl-3-phenyl)2-propionic acid] determination in various biological fluids using selected ion monitoring is described. After ether extraction in acidic medium, ketoprofen and (benzoyl-4-phenyl)-2-butyric acid used as internal standard are methylated and their concentrations determined by monitoring the m/z values corresponding to their respective molecular ions. Standard deviation is below 5% at 100 ng ml-1. Detection limits range from 10 ng ml-1 for urine and serum samples to 50 ng ml-1 for maternal milk specimens. This method has been applied successfully to various biological studies: pharmacokinetic profiles, bioavailability and transfer of the drug through physiological barriers.
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    Biological Mass Spectrometry 6 (1979), S. 242-248 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Chemical ionization spectra of permethylated aldohexopyranosyl-(1-x)-aldohexoses (x = 1-6) with methane, isobutane, methanol and ammmonia as the reagent gases were studied. The chemical ionization methane spectra showed more pronounced differences related to different glycosidic linkages than the corresponding electron impact spectra. In contrast to the electron impact spectra, a reliable differentiation between (1-2) and (1-4) linked disaccharides could be achieved as well as a more detailed characterization of the stereoisomers in case of the (1-4) and (1-6) linked disaccharides. The chemical ionization isobutane spectra showed somewhat higher abundances for the [M+H]+ ions than with methane. It also methane. It also allows an easy differentiation of the various glycosidic linkages but its capability with respect to the discrimination of stereoisomers is inferior to that of methane. The base peak in chemical ionization ammonia spectra is [M+NH4]+, but the spectra are less characteristic than the above, although discrimination of the glycosidic linkages remains possible. Mass analysed ion kinetic energy and collisional activation spectra of selected ions of the chemical ionization spectra showed no characteristic differences, which excludes the possibility of using them as a means of differentiation for these compounds.
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A series of synthetic, semisynthetic and naturally occurring aporphine alkaloids were converted to the O-trimethylsilyl derivatives, and analyzed by gas chromatography mass spectrometry. A discussion of discussion of structurally informative fragment ions along with gas chromatographic data is presented. Their applicability to the analysis of biological metabolites of apomorphine, a CNS active structural analog of dopamine, is discussed.
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    Biological Mass Spectrometry 6 (1979) 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A method for quantitative analysis of protein amino acids by a gas chromatography mass spectrometry computer system is described. Amino acids were analysed as their N-trifluoroacetyl n-butyl ester derivatives. Isotope ratio determination was used as the quantitating technique via multiple internal standards. The exact composition of a deuterated amino acid mixture was determined against a standard amino acid calibration mixture and in turn the protein amino acid composition was determined against the deuterated amino acid mixture. The amount of protein taken for analysis was 100 μg and the procedure, excluding hydrolysis, could be performed within 21/2 hours. The introduction of the internal standards prior to protein hydrolysis provides a method with good precision (mean coefficient of variation less than 5%). The method, tested on insulin, gave results which agreed well with the known composition of the protein and with simultaneous analysis on ion exchangers.
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The free urinary metabolites, homovanillic, indoleacetic and 5-hydroxyindoleacetic acid were measured in 24 h urines obtained from seven highly selected drug-free chronic schizophrenic patients and seven mentally normal control subjects on a low amine diet. Gas chromatography selected ion monitoring of silylated extracts was used to assay each metabolite using its own deuterated form as an internal standard. In the electron impact mode the positive ion fragments used to quantitate the amount of each metabolite in the urine were, respectively, m/z209/211 for homovanillic acid, 319/321 for indoleacetic acid and 290/292 for 5-hydroxyindoleacetic acid. It was found essential that each compound be assayed using its own deuterated derivative as the internal standard. When expressed per mg creatinine, the homovanillic and 5-hydroxyindoleacetic acid levels of the chronic schizophrenic patients were in the normal range, but indoleacetic acid was slightly and statistically significantly higher, p = 0.01.
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  • 94
    ISSN: 0306-042X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The technique of mass analysed ion kinetic energy spectroscopy has been applied to the structural determination of five different substituent sidechains from five steroids of similar ring anatomy. A mass spectrometer of reversed geometry, which permits ion selection according to its mass-to-charge ratio before the ions enter the electric sector, was used to isolate the ion corresponding to the mass of each particular sidechain. Subsequent mass analysed ion kinetic energy spectra of the selected ion demonstrated daughter ions whose compositions were compatible with the structures of the model compounds. This ability to determine the structure of a specific portion of a large molecule and to permit differentiation of minor structural features in a series of compounds, whose major framework is similar, adds a new dimension to the powerful mass analysed ion kinetic energy spectroscopy technique for structural analysis of complex biological molecules.
    Additional Material: 3 Ill.
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  • 95
    ISSN: 0306-042X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 96
    ISSN: 0306-042X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Breath tests that measure the oxidative utilization of 13C labeled substrates have been shown to be clinically useful, but have failed to gain wide acceptance because of the slow and costly isotopic analysis of the breath samples. Therefore we have developed a fully automated, microprocessor controlled CO2 purification and isotopic analysis system. The breath CO2 is cryogenically purified by passage through cold traps of -94°C and -196°C to condense water and CO2, respectively. The CO2 is introduced into a dual inlet, peak-stepping mass spectrometer and analyzed for isotopic content by comparison with a known standard. Thirty samples can be analyzed without operator intervention. Analysis time averages 14 minutes per sample, and the analysis has a precision of 0.3‰ which corresponds to 3 parts excess 13C per 106 parts CO2. The speed of analysis is comparable with scintillation counting and permits next day reporting of clinical breath test results. The precision is sufficient for clinical applications as it is less than the 0.7‰ isotopic variation in basal breath CO2.
    Additional Material: 3 Ill.
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  • 97
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 6 (1979), S. 374-380 
    ISSN: 0306-042X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The electron impact mass spectra of a series of natural anthraquinone, anthrone, dianthrone aglycones and their ‘O’ and ‘C’ linked glycosides have been studied. Electron impact mass spectrometry failed to provide molecular weight information for the dianthrone aglycones and for the ‘O’ linked glycosides. Ammonia chemical ionization and field desorption mass spectra were studied as techniques to overcome this deficiency. A combination of electron impact and field desorption mass spectrometry proved to be most effective for structural studies of the dianthrone aglycones and the ‘O’ linked glycosides.
    Additional Material: 12 Ill.
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  • 98
    ISSN: 0306-042X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 2-Bis-(chlorodifluoromethyl)-4-substituted-1,3-oxazolidin-5-ones, a new type of α-amino acid derivative for gas chromatographic separation, have been studied by low resolution mass spectrometry. These derivatives are obtained by reacting α-amino acids with dichlorotetrafluoroacetone. Their structure has been established or confirmed for most protein amino acids and several non-protein α-amino acids. The mechanisms responsible for the mass spectral pattern have been rationalized. An interesting feature of this derivatization procedure is that it distinguishes aspartic and glutamic acid from the respective amides. The structure of asparagine and glutamine derivatives has been established. A survey of oxazolidinone mass spectra has provided a list of diagnostically useful ions. Each amino acid can be identified by one or two of its most abundant fragments.
    Additional Material: 30 Ill.
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  • 99
    ISSN: 0306-042X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: We have developed a successive direct inlet system which allows us to introduce multiple samples in succession into an evacuated ion source of the mass spectrometer. The applicability of this system was examined by determining the reproducibility of the measurement, memory effect in the ion source and sample loss prior to the mass spectral measurement. This successive direct inlet system makes it possible to shorten the measurement intervals of mass spectra as compared with the presently available commerical instruments.
    Additional Material: 7 Ill.
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  • 100
    ISSN: 0306-042X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Deuterium labelled analogues of the major zeatin derived cytokinins have been synthesized to serve as internal standards for mass spectrometric quantitation. A procedure for the isolation, high performance liquid chromatographic purification and direct probe mass spectrometric analysis of these cytokinins has been devised and applied to the analysis of Zea mays kernels where the levels of endogenous zeatin, zeatin-9β-riboside and zeatin-9β-glucoside were estimated by isotope dilution. Additionally, the deuterated compounds have been utilized to confirm the identity of the in vitro enzymic glucosylation products of zeatin.
    Additional Material: 1 Ill.
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