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  • 1
    Electronic Resource
    Electronic Resource
    Penetration of lidocaine and its active desethylated metabolite into cerebrospinal fluid in man (1983)
    Springer
    European journal of clinical pharmacology 25 (1983), S. 639-641 
    Details
    ISSN: 1432-1041
    Keywords: Lidocaine ; CSF penetration ; monoethylglycinxylidide ; glycinxylidide ; pharmacokinetics ; serum protein binding ; membrane permeability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Penetration into lumbar cerebrospinal fluid (CSF) of lidocaine and its active desethylated metabolite, monoethylglycinxylidide (MEGX), has been studied in 10 neurological patients after a single subcutaneous injection of 2 mg/kg prior to lumbar puncture. An HPLC method was used to assay lidocaine, MEGX and glycinxylidide (GX) in serum and CSF. The serum protein unbound fraction of lidocaine was determined by equilibrium dialysis. The mean peak serum lidocaine concentration was found 25 minutes after injection, and the corresponding peak CSF level occurred after 70 min. A similar slow penetration of MEGX into CSF was observed, which indicates low membrane permeability for these two agents. No GX was found. The steadily increasing CSF lidocaine/serum total lidocaine ratio throughout the period of study up to 120 min and the higher level in CSF than the corresponding unbound fraction of the total serum lidocaine indicate that serum protein binding is not the sole determinant of the penetration of lidocaine into lumbar CSF. Rapid accumulation in brain tissue and diffusion back into cerebral extracellular fluid and to lumbar CSF may also occur. The apparent slow membrane penetration of lidocaine and its desethylated metabolite may be one reason for the difficulty of controlling lidocaine infusion rates according to therapeutic effectiveness and side-effects.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00542352
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  • 2
    Electronic Resource
    Electronic Resource
    Muscle pathology in idiopathic cricopharyngeal dysphagia (1992)
    Springer
    European archives of oto-rhino-laryngology and head & neck 249 (1992), S. 216-223 
    Details
    ISSN: 1434-4726
    Keywords: Cricopharyngeal dysphagia ; Muscle biopsy ; Electron microscopy ; Enzyme histochemistry ; Myositis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The structural changes in the cricopharyngeal muscle (CM) were examined ultrastructurally and by enzyme histochemistry in five patients suffering from idiopathic cricopharyngeal dysphagia (ICD). Diagnosis was established by fiberoptic esophagoscopy, esophageal manometry and cineradiography. Cricopharyngeal myotomy was performed with marked improvement in all patients. Intraoperatively, a biopsy was taken from the CM. Additionally, all patients underwent neurological examination for possible generalized muscle disease, and a biopsy was taken from a limb muscle. CM from nine cadavers without known history of dysphagia served as control. The control samples disclosed structural changes which were considered to be pathological in other skeletal muscles, and required that the criteria for CM pathology we modified accordingly. In three patients changes in CM histology suggested specific pathogenesis: one patient had evidence for a generalized myositis but was only symptomatic for dysphagia. Another patient had muscle fiber atrophy and slight inflammation in her CM, possibly due to alcohol abuse. The third patient had loss of CM fibers with replacement by connective tissue enough to cause functional disturbances. In two patients no cause for dysphagia was found in either immunohistochemistry or electron microscopic studies. These results demonstrate the special structural features of the CM and indicate that ICD can have multiple etiologies.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00178473
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  • 3
    Electronic Resource
    Electronic Resource
    The vascular mechanism of action of betahistine in the inner ear of the guinea pig (1998)
    Springer
    European archives of oto-rhino-laryngology and head & neck 255 (1998), S. 119-123 
    Details
    ISSN: 1434-4726
    Keywords: Key words Cochlear blood flow ; Cochlear physiology ; Experimental vasodilatation ; Betahistine treatment
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The aim of this study was to investigate the mechanism and site of action of betahistine dihydrochloride in the inner ear of the guinea pig. Betahistine-evoked increases in cochlear blood flow (CBF) have been presumed to be due to the drug effect on the later wall capillary bed or larger feeding vessels in the cochlea vascular system. As such, the mechanism of action could be due to inhibition of H3 receptors. Betahistine may also have a direct effect on postsynaptic H1/H2 receptors and/or an effect modulated by other autonomic receptors. Betahistine-evoked CBF responses were assessed by laser Doppler flowmetry in the presence of an H3 agonist (α N-methylhistamine dihydrochloride), an H3 antagonist (thioperamide), an H2 antagonist (cimetidine) or an α2 antagonist (idazoxan). The effects of betahistine on circulation in the anterior inferior cerebellar artery (AICA) and ipsilateral stria vascularis (SV) were assessed using intravital microscopy (IVM). Findings showed that betahistine increased CBF and reduced systemic blood pressure (BP). In contrast, α N-methylhistamine dihydrochloride had no effect on baseline CBF or BP and did not influence betahistine-induced increases in CBF. Thioperamide reversed the effects of betahistine on CBF, but had no effect on baseline CBF or BP. Cimetidine had no marked effect on baseline CBF or betahistine-induced increases in CBF Idazoxan had no consistent effects on baseline CBF, but abolished the effect of betahistine on CBF. The mean increase of red blood cell velocity in SV capillaries was 15% and occurred without a demonstrable change in capillary diameters. In contrast, the diameter of the AICA increased by 17–20%, indicating that betahistine-evoked increases in CBF resulted primarily from vasodilatation of the AICA. We suggest that this effect may be mediated via presynaptic H3 heteroreceptors and autonomic α2 receptors.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004050050025
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  • 4
    Electronic Resource
    Electronic Resource
    Audiovestibular findings and location of an acoustic neuroma (2000)
    Springer
    European archives of oto-rhino-laryngology and head & neck 257 (2000), S. 237-241 
    Details
    ISSN: 1434-4726
    Keywords: Key words Acoustic neuroma ; Auditory brainstem ¶response ; Electronystagmography ; Topodiagnosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Forty-one patients with unilateral acoustic neuroma (AN) were diagnosed by magnetic resonance imaging (MRI) between 1992 and 1997. All cases were analyzed with respect to tumor location and the results of audiometric examinations, auditory brainstem response (ABR) testing, and electronystagmography (ENG). Tumor location was determined by MRI and cases were divided into intracanalicular and extracanalicular sites. Intracanalicular tumors were significantly smaller than the extracanalicular ones The pure-tone hearing thresholds were better in ears with intracanalicular lesions than in those with extracanalicular ones. Respectively, speech reception thresholds were 33 dB and 45 dB, and speech discrimination scores 79% and 65%. ABR was abnormal in 98% of ANs, but was insufficient for determining tumor location. The ENG pursuit test was more frequently normal and the caloric side difference was smaller in ears with intracanalicular than extracanalicular AN. These findings show that the results of pure-tone and speech audiometry and ENG are better in ears with intracanalicular AN, while ABR results are similar regardless of tumor location.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004050050230
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  • 5
    Electronic Resource
    Electronic Resource
    Simulation of the apparent anomalies of the galactic structure (1984)
    Springer
    Astrophysics and space science 107 (1984), S. 85-107 
    Details
    ISSN: 1572-946X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract In the maps of the galactic structure based on the kinematical method, several systematic heliocentric anomalies are found: in the northern galactic hemisphere the spiral arms are more tightly wound and the extent of neutral hydrogen is smaller than in the southern hemisphere; with separate rotation curves for the north and the south the arms become anomalously circular with a consequent discrepancy to the stellar distribution; there are straight portions in the arms pointing towards the Sun, as well as systematic strong curvatures and knee-like features; the inner arms affect the structure of the outer arms; with the northern rotation model, Hii-regions and Hi avoid the southern tangential circle; in the rear of the Galaxy, at symmetric longitudes, enhanced Hi-densities are found; the Perseus arm is displaced atl=180°. All of these anomalies can be explained with a simple model involving a non-velocity redshift field within the Galaxy, with an enhancement within the spiral arms. This is demonstrated by numerical simulations of the structural anomalies. Reducing the redshift effect from the kinematic data, the Galaxy's structure and kinematics appear symmetric. The significance of the result for the redshift problem is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00649616
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  • 6
    Electronic Resource
    Electronic Resource
    On the existence of cosmological evolutionary effects (1985)
    Springer
    Astrophysics and space science 109 (1985), S. 111-122 
    Details
    ISSN: 1572-946X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Parameters of the distant galaxy clusters of 3C295 (z=0.46) and Cl 0024+1654 (z=0.39) are compared with the predictions made using galaxies of the local clusters Coma (z=0.023) and DC 0329−52 (z=0.057) taking theK-effect into account. The distributions of colour and morphological type, and the amplitudesF +/F− of the λ0 4000 discontinuity are examined and no evidence for evolution of the galaxies and the clusters can be seen.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00651018
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