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  • 1
    Electronic Resource
    Electronic Resource
    Fin duplications and deletions induced by disruption of retinoic acid signaling (1998)
    Springer
    Development genes and evolution 208 (1998), S. 61-68 
    Details
    ISSN: 1432-041X
    Keywords: Key words Zebrafish ; Fundulus ; Homeotic duplication ; Citral ; Pectoral fins
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Retinoic acid (RA), a derivative of vitamin A, plays a critical role as a signaling molecule in axial patterning of vertebrates. Here we report that RA exposure of zebrafish (Danio rerio) and mummichog (Fundulus heteroclitus) embryos during gastrulation results in homeotic duplications of the pectoral fins in up to 94% of fish. We have observed three to four pairs of fins in an individual fish. Although some duplications are partial, many represent complete axial duplications of the pectoral girdle and fin and include coracoscapulae, proximal radials, and dermal fin elements. Fin duplications are observed only at a defined dose of RA. Inhibition of RA synthesis by exposure to citral during a narrow developmental window leads to fish which lack pectoral fins but can be rescued by addition of exogenous RA, suggesting that RA signaling is critical to fin specification during early development. The ability to consistently induce multiple fins in a large number of vertebrate embryos should contribute to the understanding of genetic regulation of the normal positioning of limbs during embryogenesis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004270050155
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  • 2
    Electronic Resource
    Electronic Resource
    Inhibition of glucose stimulated insulin secretion by neuropeptide Y is mediated via the Y1 receptor and inhibition of adenylyl cyclase in RIN 5AH rat insulinoma cells (1998)
    Springer
    Diabetologia 41 (1998), S. 1482-1491 
    Details
    ISSN: 1432-0428
    Keywords: Keywords Neuropeptide Y ; Y1 receptor ; insulin secretion ; insulinoma cells.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Neuropeptide Y (NPY) has been shown to inhibit insulin secretion from the islets of Langerhans. We show that insulin secretion in the insulinoma cell line RIN 5AH is inhibited by NPY. 125I-Peptide YY (PYY) saturation and competition-binding studies using NPY fragments and analogues on membranes prepared from this cell line show the presence of a single class of NPY receptor with a Y1 receptor subtype-like profile. Inhibition of insulin secretion in this cell line by NPY fragments and analogues also shows a Y1 receptor-like profile. Both receptor binding and inhibition of insulin secretion showed the same orders of potency with NPY 〉 [Pro34]-NPY 〉 NPY 3–36 〉 〉 NPY 13–36. The Y1 receptor antagonist, BIBP 3226, blocks NPY inhibition of insulin secretion from, and inhibits 125I-PYY binding to, RIN 5AH cells. Northern blot analysis using a Y1-receptor specific probe shows that NPY Y1 receptors are expressed by RIN 5AH cells. Y5 receptors are not expressed in this cell line. Neuropeptide Y inhibition of insulin secretion is blocked by incubation with pertussis toxin, implying that the effect is via a G-protein (Gi or Go) coupled receptor. Neuropeptide Y inhibits the activation of adenylyl cyclase by isoprenaline in RIN 5AH cell lysates, and the stimulation of cAMP by glucagon-like peptide-1 (7–36) amide (GLP-1). It also blocks insulin secretion stimulated by GLP-1, but not by dibutyryl cyclic AMP. Hence, we suggest that NPY inhibits insulin secretion from RIN 5AH cells via a Y1 receptor linked through Gi to the inhibition of adenylyl cyclase. [Diabetologia (1998) 41: 1482–1491]
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001250051095
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  • 3
    Electronic Resource
    Electronic Resource
    Use of the bomb radiocarbon chronometer for age validation in the blue grenadier Macruronus novaezelandiae (1997)
    Springer
    Marine biology 128 (1997), S. 557-563 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Accelerator mass-spectrometry was used to measure radiocarbon in the earliest formed portions of selected blue grenadier, Macruronus novaezelandiae, otoliths to provide a validation of fish-age estimates based on the quantification of opaque and translucent zones in otolith thin-sections. Δ14C data from blue grenadier otoliths were compared with previous estimates of Δ14C in seawater-dissolved inorganic carbon at similar latitutes, longitudes, and depths to link variation in otolith Δ14C to time. Minimum otolith Δ14C was −76.9 ± 7.7‰, indicative of pre-bomb radiocarbon levels below the surface mixed-layer at latitudes where juvenile blue grenadier are found. When plotted versus fish age estimated from otolith sections, the majority of the Δ14C data combined to define a curve reflecting the increase in bomb radiocarbon in temperate oceans of the Southern Hemisphere, indicating that age-estimation procedures based on otolith thin-sections are satisfactory for determining blue grenadier age. If otolith-section age estimates were correct, peak otolith Δ14C of 106.8 ± 7.9‰ occurred during the late 1960s, i.e. earlier than expected. This may be a manifestation of an increase in the mixed-layer depth associated with increased frequency of zonal westerly winds at this time.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002270050121
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  • 4
    Electronic Resource
    Electronic Resource
    Seasonality of reproduction in the cushion star Odontaster validus at Signy Island, Antarctica (1998)
    Springer
    Marine biology 131 (1998), S. 479-487 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The reproductive and larval biology of the common Antarctic cushion-star Odontaster validus Koehler (Echinodermata: Asteroidea) were studied in a shallow-water population at Signy Island in the maritime Antarctic. The gonad index peaked in April/May, and injection with 1-methyladenine indicated that competence to spawn peaked in May/June. Gastrulae were first detected in May, and maximal water-column larval densities were measured in July. Reproduction was therefore highly seasonal, although not all individuals appeared to spawn each year. The pyloric caeca index increased in summer (typically November to March, but variable between years) and decreased during winter (June to October), suggesting that feeding activity was seasonal. All aspects of biology investigated showed significant interannual variability. Comparison with previous studies in the high Antarctic at McMurdo Sound indicated a similar if more pronounced seasonality at Signy, but the warmer seawater temperatures in the maritime Antarctic (particularly in late winter/early spring from September onwards) resulted in faster larval development at Signy.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002270050339
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  • 5
    Electronic Resource
    Electronic Resource
    Validation of otolith-increment age estimates for a deepwater fish species, the warty oreo Allocyttus verrucosus, by radiometric analysis (1995)
    Springer
    Marine biology 123 (1995), S. 29-38 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Otolith increment age estimates for a deepwater species, Allocyttus verrucosus, were validated by comparison with the results from 210Pb:226Ra radiometric analysis. Transverse sectioning and subsequent grinding of otoliths to a thickness of ≃ 0.2 mm revealed increments which provided age estimates for a range of fish sizes. Age estimates ranged from 7 yr for an immature fish of 15.2 cm total length (TL) to 130 yr for a female fish of 36.5 cm TL. Age at maturity was estimated as 28 yr for females and 24 yr for males. In comparison, radiometric analysis of whole otoliths, using a single linear otolith-mass growth-rate model suggested maximum ages of 130 to 170 yr for fish of 34 to 35 cm TL. Radiometric ages were also recalculated using a two-phase otolith-mass growth-rate model in which the growth rate was assumed to slow after maturity to 90% of the pre-maturity rate. This reduced the maximum age to 132±15 yr for a mean fish length of 34.5 cm. Age at maturity for females was estimated at 34 yr. The similarity between age estimates from otolith-increment counts and radiometric analysis strongly supports the accuracy of results from both methods, and encourages further use of such comparisons as an alternative to traditional validation techniques.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00350320
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  • 6
    Electronic Resource
    Electronic Resource
    Carotenoids in the tiger prawn Penaeus esculentus during ovarian maturation (1995)
    Springer
    Marine biology 123 (1995), S. 435-441 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Female Penaeus esculentus Haswell were collected by 15 to 20 min duration trawls during 1990. Carotenoids were analysed in the digestive gland, abdominal muscle, the remainder of the body (hereafter called “integument”) and ovary of prawns in Stage 2 through Stage 4 (fully mature) of maturation. The only oxycarotenoids (xanthophylls) identified were astaxanthins or astaxanthin esters; occasionally low levels of β-carotene were detected in the digestive gland. The concentrations of astaxanthin monoesters (AM) and diesters (AD) were highest, with only minor amounts of free astaxanthins (Ast), except in the maturing ovaries, where free astaxanthins predominated (up to 80% of the total carotenoid). Of the total carotenoid, 82 to 94% was in the integument, but at maturity the digestive gland contained 10.7±3.4% and the ovary 5.6±0.9% of the total carotenoid. Only the ovary increased in mass during maturation, reaching up to 5.2% of total prawn mass. During this period, digestive gland concentrations of AM, AD and Ast all increased (tota 20 to 120 μg g-1); levels in the muscle and integument varied little throughout maturation (total ∼0.4 and 100 μg g-1, respectively); ovary AM levels remained low throughout (1.5 to 1.2 μg g-1), AD increased from only 2 to 5 μg g-1, but Ast increased from 2 to 34 μg g-1. Apart from the ovary, AM concentrations were the most variable. In common with other decapod Crustacea, the maturing ovary of P. esculentus contained high levels of carotenoids, indicating that these may have an important role in early development. The natural diet of P. esculentus includes a variety of carotenoids, but except for a little β-carotene, the digestive gland, where absorption occurs, contained astaxanthins, with only an occasional trace of β-carotene. This suggests that the conversion of dietary carotenoids to astaxanthin occurs soon after ingestion.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00349222
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  • 7
    Electronic Resource
    Electronic Resource
    Is unilateral spatial neglect a single phenomenon? (1997)
    Springer
    Journal of neurology 244 (1997), S. 412-417 
    Details
    ISSN: 1432-1459
    Keywords: Key words Unilateral spatial ; neglect ; Frontal lobe ; Cerebrovascular accident ; Exploratory-motor tasks ; Perceptual-sensory tasks
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The aim of this study is to report the preliminary findings of a traditional battery of tests and our original battery capable of assessing the presence of components and extent of lesions in patients with unilateral spatial neglect. Thirty patients who had unilateral spatial neglect with a stroke in the right hemisphere were assessed for unilateral spatial neglect on exploratory-motor (E-M) tasks, visual-counting (V-C) tasks, and traditional neglect batteries at least 4 weeks after the onset. Other neuropsychological tests and computed tomography were also performed to investigate the relationship with neglect. A factor analysis showed that our tasks loaded significantly on three factors. E-M neglect was found in 16 patients, and V-C neglect in 22 patients with unilateral spatial neglect. There were high correlations between E-M neglect and motor paralysis, word fluency, backward digit span and motor impersistence. There were high correlations between V-C neglect and visual-field defect, line bisection, line cancellation and figure copying. Lesions in the frontal lobe, caudate, insula, and anterior portion of the paraventricular white matter were commonly associated with E-M neglect. Lesions in the occipital lobe were also associated with V-C neglect. We suggest that unilateral neglect is not a single phenomenon, but rather involves several different components. We propose that E-M and V-C tasks are useful methods for evaluating the extent of lesions in patients with unilateral spatial neglect.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004150050114
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  • 8
    Electronic Resource
    Electronic Resource
    Characterization of mechanosensitive channels in Escherichia coli cytoplasmic membrane by whole-cell patch clamp recording (1995)
    Springer
    The journal of membrane biology 144 (1995), S. 31-42 
    Details
    ISSN: 1432-1424
    Keywords: Escherichia coli ; Protoplast ; Mechanosensitive channels ; Whole-cell patch clamp recording ; Osmotic pressure ; K+ efflux system
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Whole-cell patch clamp recordings were done on giant protoplasts of Escherichia coli. The pressure sensitivity of the protoplasts was studied. Two different unit conductance mechanosensitive channels, 1100 ± 25 pS and 350 ± 14 pS in 400 mm symmetric KCl solution, were observed upon either applying positive pressure to the interior of the cells or down shocking the cells osmotically. The 1100 pS conductance channel discriminated poorly among the monovalent ions tested and it was permeable to Ca2+ and glutamate−. Both of the two channels were sensitive to the osmotic gradient across the membrane; the unit conductances of the channels remained constant while the mean current of the cell was increased by increasing the osmotic gradient. Both of the channels were voltage sensitive. Voltage-ramp results showed that the pressure sensitivity of protoplasts was voltage dependent: there were more channels active upon depolarization than hyperpolarization. The mech anosensitive channels were reversibly blocked by gadolinium ion. Also they could reversibly be inhibited by protons. Mutations in two of the potassium efflux systems, KefB and KefC, did not affect the channel activity, while a null mutation in the gene for KefA changed the channel activity significantly. This indicates a potential modulation of these channels by KefA.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00238414
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  • 9
    Electronic Resource
    Electronic Resource
    Serum screening for Down's syndrome between 8 and 14 weeks of pregnancy (1996)
    Oxford, UK : Blackwell Publishing Ltd
    BJOG 103 (1996), S. 0 
    Details
    ISSN: 1471-0528
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Objective To determine the value of serum screening for Down's syndrome at 8–14 weeks of pregnancy using seven potential serum markers (alpha-fetoprotein, unconjugated oestriol, total human chorionic gonadotrophin (hCG), free α-hCG, free P-hCG, pregnancy associated plasma protein A (PAPP-A), and dimeric inhibin A).Design Stored blood samples collected from women at about 10 weeks of pregnancy, prior to having a chorionic villus sampling procedure on account of advanced maternal age, were retrieved from pregnancies associated with Down's syndrome and from matched unaffected pregnancies.Setting Twenty-one obstetric centres in nine countries.Subjects Seventy-seven pregnancies associated with Down's syndrome each matched with five controls (except in two cases that were matched with four controls) for maternal age (same five year age groups), duration of storage of the serum sample (same calendar year), and gestational age (usually same week of pregnancy).Results The levels of two potential markers differed between affected and unaffected pregnancies sufficiently to be of value in screening—free β-hCG and PAPP-A. The median free P-hCG level in affected pregnancies was 1.79 times the median level for unaffected pregnancies, and the median PAPP-A level was 0.43 times the normal median. These two markers were combined with maternal age to estimate a woman's risk of having a fetus with Down's syndrome. A screening programme that used a risk cutoff level of 1:300 would detect 63 % of affected pregnancies and also classify 5.5% of unaffected pregnancies as screen positive. None of the other five markers added more than 2 % detection for the same false-positive rate.Conclusion The performance of screening using maternal age and serum-free β-hCG and PAPP-A at 10 weeks of pregnancy was better than the double test (alpha-fetoprotein and hCG with maternal age) and similar to the triple test (alpha-fetoprotein, unconjugated oestriol and hCG with maternal age) at 15–22 weeks.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1471-0528.1996.tb09765.x
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  • 10
    Electronic Resource
    Electronic Resource
    Milk Alkaline Phosphatase Purification and Production of Polyclonal Antibodies (1999)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of food science 64 (1999), S. 0 
    Details
    ISSN: 1750-3841
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Purification was by electroelution from native polyacrylamide gels or by sequential use of three columns. Electroelution was faster and resulted in a higher yield (23.4 vs 1.6%) than column purification. The enzyme had a molecular mass of 187 kDa, and the isoelectric point ranged from 5.4 to 6.0. ALP purified by electroelution was used as the antigen to immunize rabbits for polyclonal antibody (PAb) production. Western blot analysis showed that PAbs cross-reacted with bovine milk and placenta ALP, but did not cross-react with ALP from calf or bovine intestinal mucosa, Escherichia coli or with other milk proteins.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2621.1999.tb15093.x
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