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  • Polymer and Materials Science  (8)
  • subarachnoid haemorrhage  (4)
  • 1
    Electronic Resource
    Electronic Resource
    The effects of an intracellular calcium antagonist HA 1077 on delayed cerebral vasospasm in dogs (1988)
    Springer
    Acta neurochirurgica 90 (1988), S. 53-59 
    Details
    ISSN: 0942-0940
    Keywords: Calcium antagonist ; chronic cerebral vasospasm ; HA 1077 ; subarachnoid haemorrhage
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The effectiveness of calcium antagonists on a chronic cerebral vasospasm after an SAH is still under debate. Calcium channel blockers such as nimodipine, nefedipine etc. can dilate spastic arteries by intrathecal administration, but not by systemic (iv or po) use. HA 1077 is a novel and potent calcium antagonist vasodilator which is considered to act by employing different mechanisms from the usual calcium channel blockers since it inhibits 1. calcium ionophore A 23187 induced contraction in arterial strips and 2. phenylephrine induced contraction in calcium free media, suggesting that its site of action is in the intracellular space. HA 1077 is water soluble and relatively stable in light. In the present study, the efficacy of HA 1077 was evaluated on dogs by using the spiral arterial strips in vitro and by angiography in vivo. In the arterial strips from the control dogs, a 50% relaxation of KCl (15 mM) induced contraction was obtained by a 10−6 M HA 1077 for the “intracranial” basilar and middle cerebral arteries, while a 10−5 M was needed to obtain the same effect for the “extracranial” common carotid and vertebral arteries, indicating that HA 1077 is more effective for the intracranial arteries. A vasospasm was produced by the “two haemorrhage” model of Varsoset al. The average angiographic diameter of the basilar artery was reduced to 60% of the control on SAH day 7. Intravenous infusion of HA 1077 (0.5–3 mg/kg/30 min) significantly dilated the spastic basilar artery (up to 20–30%), for over 2 hours. A fall in the systemic BP remained less than 20% during this time. Such spasmolytic effects by intravenous administration could not have been obtained with the usual calcium channel blockers. HA 1077 may be suitable for the treatment of a vasospasm in humans as well.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01541267
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  • 2
    Electronic Resource
    Electronic Resource
    Vasodilation by intrathecal lipopolysaccharide of the cerebral arteries after subarachnoid haemorrhage in dogs (1996)
    Springer
    Acta neurochirurgica 138 (1996), S. 330-337 
    Details
    ISSN: 0942-0940
    Keywords: Angiography ; dog ; inducible nitric oxide synthase ; lipopolysaccharide ; subarachnoid haemorrhage ; tumour necrosis factor-α
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary To investigate the influence of inducible nitric oxide synthase on cerebral arteries after subarachnoid haemorrhage (SAH) in vivo, lipopolysaccharide (LPS), a major inducer of inducible nitric oxide synthase, was injected intracisternally into control and SAH model dogs. Intracisternal injection of LPS (0.5 mg) produced a long-lasting, submaximal vasodilation of the basilar artery of control dogs on angiography. This effect became significant at 4 hours after LPS injection and plateaued after 6 hours. This vasodilation was reduced by NG-monomethyl-L-arginine. Vasopressin slightly suppressed the vasodilation, while bradykinin increased it. The concentration of L-arginine in CSF decreased after LPS injection, while that of L-citrulline increased. In cytokines, the concentration of tumour necrosis factor-α (TNF-α) in CSF increased transiently at 4 hours after LPS injection, while interleukin-1β, interleukin-6, interferon-γ did not change. These data suggest that vasodilation by LPS is mainly due to nitric oxide predominantly synthesized by an inducible nitric oxide synthase, proximally induced by TNF-α. Our data make it unlikely that SAH itself induces the inducible nitric oxide synthase in vascular tissue, since isolated endotheliumdenuded basilar artery from SAH model dogs did not respond to L-arginine. In SAH model dogs, the degree of vasodilation by LPS differed with the severity of vasospasm. Vasodilation was much greater in mild than in severe vasospasm in dogs, and was increased by superoxide dismutase. These findings suggest that the induction of inducible nitric oxide synthase or its activity may be less effective in severe vasospasm.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01411745
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  • 3
    Electronic Resource
    Electronic Resource
    Alterations of monoamine metabolites and of tryptophan in the basal cisternal CSF of patients after subarachnoid haemorrhage (1987)
    Springer
    Acta neurochirurgica 87 (1987), S. 58-62 
    Details
    ISSN: 0942-0940
    Keywords: Homovanillic acid (HVA ; 5-hydroxyindoleacetic acid (5-HIAA) ; Tryptophan (TRP) ; subarachnoid haemorrhage
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Homovanillic acid (HVA), 5-hydroxyindoleacetic acid (5-HIAA) and tryptophan (TRP) were measured in the CSF obtained from the basal cistern of 20 patients, who had undergone surgical obliteration of bleeding aneurysms within 3 days after subarachnoid haemorrhage (SAH). The concentrations of these substances, which were assayed by high performance liquid chromatography (HPLC), were the highest on days 3 or 4, and thereafter showed a gradual decrease with an increase in time. The cisternal CSF in patients who had severe pre-operative clinical grades of SAH or vasospasm contained relatively higher concentrations of HVA, 5-HIAA and TRP than those contained in patients who did not. It is proposed that SAH stimulates the release of monoamines from the brain with the resultant extracellular accumulation of their metabolites and their diffusion into CSF during the acute stage. This stimulatory effect of SAH on the brain monoamine system may be consistent with those previously reported in cases of cerebral haemorrhage or infarction.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02076018
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  • 4
    Electronic Resource
    Electronic Resource
    The effects of HA1077 on the cerebral circulation after subarachnoid haemorrhage in dogs (1991)
    Springer
    Acta neurochirurgica 110 (1991), S. 185-188 
    Details
    ISSN: 0942-0940
    Keywords: HA1077 ; cerebral vasospasm ; subarachnoid haemorrhage ; cerebral blood flow ; calcium antagonist
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We examined the effects of the recently developed calcium antagonist HA1077 on cerebral haemodynamics during the chronic stage of the two-haemorrhage canine model system of vasospasm. Regional cerebral blood flow (rCBF), regional cerebral blood velocity and regional cerebral blood volume in the canine parietal cortex were measured by Laser-doppler flowmeter. On the 7th day after the initial injection of autogenous blood, subarachnoid haemorrhage (SAH) produced a significant decrease in rCBF (59% of control, p〈0.05) and Hood velocity (48% of control, p〈0.05), with no remarkable change in blood volume (108% of control). Bolus intravenous administration of HA1077 (0.1–0.3 mg/kg) dose-dependently increased the rCBF and blood velocity, without significantly changing the blood volume on Day 7 after SAH. HA1077 improves haemodynamic function manifested by an increase in rCBF and velocity in this SAH model, and may be suitable for the treatment of vasospasm in patients with SAH.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01400689
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  • 5
    Electronic Resource
    Electronic Resource
    XPS and SERS Studies of Cell Adhesion-controlled Polymer Modified by Ion Implantation (1996)
    Chichester [u.a.] : Wiley-Blackwell
    Surface and Interface Analysis 24 (1996), S. 252-256 
    Details
    ISSN: 0142-2421
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: X-ray photoelectron spectroscopy (XPS) of Ne ion-bombarded polymer has been carried out in order to examine the cause of HeLa cell adhesion control on polymers. Substrates used were polystyrene (PS) and oxygen plasma-treated polystyrene (PS-O). Neon bombardments into the patterned region of PS and PS-O were performed at an energy of 150 keV with fluences of 1×1014 and 1×1015 ions cm-2. The surface chemical bonding states were investigated by XPS. In HeLa cell adhesion measurements, the Ne-bombarded region of PS with a fluence of 1×1015 ions cm-2 exhibits higher adhesion and spreading of HeLa cells than the unbombarded region. On the contrary, it is found that the Ne-bombarded region of PS-O inhibits HeLa cell adhesion. The XPS results show that Ne bombardment to PS or PS-O destroys the original chemical bonds and consequently produces new functional groups. It is considered that the drastic change of surface chemical bonding states from the pristine states induced by Ne bombardment leads to a clear distinction between increasing and inhibiting HeLa cell adhesion.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Angle-dependent XPS Analysis of (NH4)2Sx-treated InP(001) Surfaces (1996)
    Chichester [u.a.] : Wiley-Blackwell
    Surface and Interface Analysis 24 (1996), S. 578-582 
    Details
    ISSN: 0142-2421
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: Angle-dependent high-resolution XPS spectra of S 2p, In 3d5/2 and P 2p have been measured on the InP(001) sample etched chemically, treated with (NH4)2Sx at room temperature (RT), exposed to air at RT and annealed at 400°C in a vacuum. Three kinds (S-I, S-II and S-III) of chemical states of sulphur on the (NH4)2Sx-treated InP(001) surface at RT are found. It is suggested that S-I, S-II and S-III correspond to sulphur in the bulk, sulphur bridge-bonded to indium on the surface and elemental sulphur, respectively. Chemical state of S-III is decreased for the treated sample exposed to air at RT for 1 month. It is removed upon annealing the sample at 400°C in a vacuum, while S-I and S-II remain on the surface. The thickness of the sulphide layer on the annealed surface is estimated to be about one monolayer. Angle-dependent XPS spectra of S 2p and In 3d5/2 are discussed.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Quantitative analysis by XPS using the multiline approach (1994)
    Chichester [u.a.] : Wiley-Blackwell
    Surface and Interface Analysis 21 (1994), S. 724-730 
    Details
    ISSN: 0142-2421
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: An efficient method for quantitative XPS analysis is the so-called multiline approach. This method does not require standards, it takes into account the instrumental and matrix effects and it derives quantitative information from statistical analysis of all photoelectron intensities visible in the spectra. One can expect the reliability of this approach to be better than the reliability of methods involving uncorrected relative sensitivity factors. This paper summarizes recent improvements in the multiline approach. In particular, a new expression for the universal energy dependence of the inelastic mean free path is currently used. Furthermore, the statistical analysis has been modified in order to account properly for the error in the countrates. Finally, a database with physical constants has been added (photoionization cross-sections, asymmetry parameters, binding energies, etc.) to avoid errors of polynomial approximations. The modified algorithm of the multiline approach was applied to photoelectron intensities measured for AuCu alloys in four laboratories. Surfaces of these alloys were sputtered with 2 keV Ar+ ions, because at this energy the selective sputtering effects are expected to be negliible. Very consistent results were obtained. The average deviation from the bulk surface composition was found to be equal to ±3.2 at.%. Extensive software implementing the described version of the multiline approach is presently being developed.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/sia.740211008
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  • 8
    Electronic Resource
    Electronic Resource
    Functionalized polyionenes bearing hydroquinone or catechol structure (1984)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Letters Edition 22 (1984), S. 129-133 
    Details
    ISSN: 0360-6384
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1984.130220301
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  • 9
    Electronic Resource
    Electronic Resource
    Surface chlorination of polypropylene film by CHCI3 plasma (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 51 (1994), S. 2131-2137 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Polypropylene films were treated with the CHCI3 plasma, and their chemical composition was analyzed with XPS and ART IR spectroscopy. The CHCI3 plasma irradiation made polypropylene films hydrophilic. The advancing contact angle decreases from 95° for the untreated to about 73° for the CHCI3 plasma-treated films. In the CHCI3 plasma irradiation, the chlorination occurs, and C—Cl, C—Cl2, and C—Cl3 units are formed in the polypropylene films. Simultaneously with the chlorination, unsaturated units (C=C and conjugated C=C units) are formed from dehydrogen chlorination of the chlorinated products, but the oxygen incorporation into the films is low. The CHCI3 plasma is preferred in chlorination of polypropylene films to the CCl4 plasma. © 1994 John Wiley & Sons, Inc.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1994.070511304
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  • 10
    Electronic Resource
    Electronic Resource
    Effect of crosslinking density on the viscoelastic properties of unsaturated polyesters (1965)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A: General Papers 3 (1965), S. 2637-2651 
    Details
    ISSN: 0449-2951
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Viscoelastic properties of unsaturated polyesters were investigated in the glass-rubber transition region in relation to the temperature dependence of specific volume. Polyesters which are homologous with respect to crosslinking density were prepared by using mixtures of succinic and fumaric acid as the dibasic acid component. The temperature dependence of the specific volume was determined by refractive index measurement, the specific refractivity being assumed to be independent of temperature. The temperature dispersion of dynamic viscoelasticity was measured at a constant frequency. Results are summarized as follows. Specific volume and glass temperature are linearly related to the logarithm of crosslinking density. The thermal expansion coefficient and steepness of viscoelastic dispersion decrease with increasing crosslinking density. Fractional free volume and expansion coefficient of free volume, both of which were calculated by WLF equation, are in good agreement with the temperature dependence of specific volume. The results indicate that the effect of crosslinking is largely attributable to the change in amount and distribution of free volume in polymer networks.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1965.100030719
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