Funktionelle Schluckaktuntersuchungen mit der Elektronenstrahl- computertomographie

Zusammenfassung Videofluorographie und Kinematographie gelten derzeit als Goldstandard für die Abkl?rung von Schluckst?rungen. Methodisch bedingt ist jedoch keine überlagerungsfreie Darstellung der anatomisch wichtigen Strukturen des Pharynx m?glich, so da? bei manchen St?rungen nicht unterschieden werden kann, ob diese pathoanatomisch oder funktionell-neurogen bedingt sind. Anhand von 3 Fallbeispielen wird dargelegt, ob und in welchem Umfang die Elektronenstrahlcomputertomographie mit ihrem hohen r?umlichen und zeitlichen Aufl?sungsverm?gen (Millisekundenbereich) diese Nachteile kompensiert. Es ist uns gelungen zu zeigen, da? die vollst?ndige und symmetrische nasopharyngeale Abdichtung durch den Passavantschen Wulst und den weichen Gaumen gew?hrleistet wird. Durch die EBT konnte die genaue anatomische Lokalisation und Ausbreitung eines lateralen hypopharyngealen Pouches dargestellt werden. Durch den Nachweis einer Kompression des oberen ?sophagussphinkters durch einen kleinen zervikalen Spondylophyten konnte eine scheinbar nur funktionell bedingte Dysfunktion weiter abgekl?rt werden. Diese Beispiele zeigen, da? die Elektronenstrahlcomputertomographie die sich funktionell ?ndernde Anatomie w?hrend des Schluckens in der Transversalschicht darstellen kann, und legen es nahe, ihre Wertigkeit auf der Basis systemischer interdisziplin?rer Untersuchungen zu evaluieren.      

Prolactin in patients with major depressive disorder and in healthy subjects. II. Longitudinal study of basal prolactin and post-TRH-stimulated prolactin levels

Longitudinal investigations of basal prolactin (PRL) and prolactin concentrations following thyrotopin-releasing hormone (TRH) stimulation (delta PRL) were conducted in 17 patients with major depressive disorder and healthy subjects. The patients were being treated with either clomipramine or maprotiline. Both basal and delta PRL increased significantly after clinical response during treatment with both drugs. However, these increases in basal and delta PRL were independent of each other. Surprisingly, elevations of basal PRL were significantly greater in responders than in nonresponders, whereas those in delta PRL showed no corresponding significant difference. These results suggest that the two drugs stimulate basal and delta PRL by different mechanisms. The increases in basal prolactin levels found in responders may possibly be due to weaker inhibition of prolactin due to "down-regulated" beta adrenergic receptors and/or enhanced activity of supersensitive serotonergic receptors. Neither basal PRL nor delta PRL proved to be a predictor of therapy response. The intraindividual retest reliabilities of both basal and delta PRL in healthy subjects was so good that a single blood sample would seem to be sufficient for investigating most issues involving PRL in psychiatric patients.     

Triperidin (Norakin): separation, stability and structure of stereoisomers

The antiparkinsonian triperiden (1; as hydrochloride Norakin) is a mixture of the stereoisomers 1a and 1b. Their identification and separation by chromatographic methods or fractional crystallisation of the tartrates is described. By means of IR- und 13C-NMR spectral data structures of 1a and 1b are proposed. Under proton catalysis 1b racemizes to 1a. In acidic solution (heating in 0.1 mol.1-1 HCl or storage in gastric juice at 37 degrees C) hydrolysis of 1 takes place and four isomeric products were observed (Z1-Z4), which arise by cleavage of the cyclopropyl moiety. The main product Z2 was identified as the 2"-hydroxy derivative. The solid drug is stable at least for 5 years.     

Thalamic connections of the vestibular cortical fields in the squirrel monkey (Saimiri sciureus).

The afferent thalamic connections to cortical fields important for control of head movement in space were analysed by intracortical retrograde tracer injections. The proprioceptive/vestibular area 3aV, the neck-trunk region of area 3a, receives two thirds of its thalamic projections from the oral and superior ventroposterior nucleus (VPO/VPS), which is considered as the proprioceptive relay of the ventroposterior complex (Kaas et al., J. Comp. Neurol. 226:211-240, 1984). The parieto-insular vestibular cortex (PIVC, area retroinsularis, Ri) receives its main thalamic input from posterior parts of the ventroposterior complex and from the medial pulvinar. Anatomical evidence is presented that the posterior region of the ventroposterior complex is a special compartment within this principal somatosensory relay complex. The parietotemporal association area T3, mainly involved in visual-optokinetic signal processing, receives a substantial input from the medial, the lateral, and the inferior pulvinar. Dual tracer experiments revealed that about 5% of the thalamic neurons projecting to 3aV were spatially intermingled with neurons projecting to areas PIVC or T3. This spatial intermingling was distributed over small but numerous, circumscribed thalamic regions, called "common patches," which were found mainly in the intralaminar nuclei, the posterior group of thalamic nuclei, and the caudal parts of the ventroposterior complex. The "common patches" may indicate a functional coupling of area 3aV with the PIVC or area T3 on the thalamic level. In control experiments thalamic projections to the granular insula Ig and the anterior part of area 7, two cerebral structures connected with the vestibular cortical areas, were studied. Some overlap in the thalamic relay structures projecting to these areas with those projecting to the vestibular cortices was found. A quantitative evaluation of thalamic regions projecting to different cortical structures was performed by constructing so-called "thalamograms." A scheme was developed that describes the afferent thalamic connections by which vestibular, visual-optokinetic, and proprioceptive signals reach the vestibular cortical areas PIVC and 3aV.     

Responses of retinal ganglion cells to eyeball deformation: a neurophysiological basis for "pressure phosphenes"

By means of microelectrodes, the activity of single neurons (on-center, off-center ganglion cells, latency class I and class II neurons) was recorded from the optic tract of anesthetized cats. Eyeball deformation in total darkness led fairly consistently to an activation of the on-center ganglion cells, while off-center ganglion cells were inhibited. The latency and strength of this activation or inhibition seemed to be mainly dependent on the strength of eyeball indentation and the location of the neurons relative to the point of eyeball indentation. Some on-center neurons (mostly latency class I) also exhibited a short activation at "deformation off". For comparison, the responses of retinal ganglion cells to eyeball deformation in a hydrostatically open system and to a sudden increase in the intraocular pressure (closed system) are described. The neurophysiological data are explained by the assumption that eyeball indentation leads to a nonuniform tangential stretch of the retina, which exerts a locally variable depolarization of horizontal cells. This horizontal cell depolarization leads either directly or via a feedback loop through cone pedicles to a depolarization of on-bipolars and a hyperpolarization of off-bipolars. These effects determine in turn the responses seen at the ganglion cell level. It is emphasized that eyeball deformation can be used as an independent tool in transmitter studies of the retina.     

Trichophyton eboreum sp. nov. isolated from human skin

An unusual dermatophyte was isolated from the plantar scales of a human immunodeficiency virus-positive man with tinea pedis. Morphology, physiology, and molecular data provided evidence to support the new species Trichophyton eboreum. This dermatophyte is characterized by rapid growth on common mycological media, a flat powdery off-white colony, formation of clavate microconidia, smooth- and thin-walled cylindrical or club-shaped macroconidia with two to nine cells, the presence of hook-shaped hyphae, the production of cleistothecium-like structures and spiral hyphae in older cultures, positive hair perforation, the absence of pigmentation on potato glucose agar, the absence of a requirement for vitamins, a weak positive urease reaction, no growth at 37 degrees C, resistance to 5% NaCl, resistance to fluconazole, good growth on human epidermal keratin, and the production of various enzymes on different media by the API-ZYM test. More than 5% divergence from any known species of dermatophyte was revealed by sequence analysis of the internal transcribed spacer of the rRNA gene.     

The influence of surface roughness of titanium on beta1- and beta3-integrin adhesion and the organization of fibronectin in human osteoblastic cells

Mechanisms of cell adhesion and extracellular matrix formation are primary processes in the interaction with the material surface of an implant which are controlled by integrin receptors. The aim of our study was to find out whether beta1- and beta3-integrins of osteoblastic cells sense the surface topography of titanium, and if structural alterations of integrin adhesions were involved in the organization of fibronectin. Pure titanium surfaces were modified by polishing (P), machining (NT), blasting with glass spheres (GB), and blasting with corundum particles (CB) resulting in increasing roughness. Confocal microscopic investigations revealed fibrillar adhesions of beta1- and alpha5-integrins on P, NT, and GB, but on CB with its sharp edges these integrin subunits did not form fibrillar adhesions. beta3 generally appeared in focal adhesions. We observed aligned fibrillar structures of fibronectin on NT not only on the basal site but interestingly, also on the apical cell surface. In contrast, on CB, fibronectin appeared apically clustered. We suggest that this alignment of fibronectin fibrils depends on the directed actin cytoskeleton and in particular, on the capability of the beta1-integrins to form fibrillar adhesions, which is affected by the surface roughness of titanium.     

The effect of stimulus velocity on the response of movement sensitive neurons of the frog's retina

Summary 1. By means of metal-filled micropipettes the action potentials of 4 different classes of optic nerve fibers were recorded in Rana esculenta. The relationship between the angular velocity of the stimuli and the neuronal response was determined.2. If an object smaller than the excitatory receptive field (ERF) was moved through the receptive field of the different classes of retinal units the response depended on the angular velocity, contrast and size of the stimulus. The response was measured as the average impulses frequency (R) during the traverse of the ERF. Between R and the angular velocity (v) the equation R=k·v ^c [impulses · sec^–1] was found. The exponent c was 0.5 for class 1 neurons, 0.7 for class 2 neurons, and 0.95 for class 3 neurons. In class 4 neurons the response to large stimuli increased linearly with the increase of the angular velocity, while no systematic relationship between R and v was valid for small moving stimuli (<5°)3. If the contrast or the size of the stimuli was changed the exponent c was not changed; but k depended on both parameters and on the direction of the contrast against the background. The power function was no longer valid if stimuli considerably larger than the ERF were used. The exponent c was independent of the type of the movement (linear, non-linear, irregular movement); it was also independent of the direction of the motion.4. A model of the receptive field is demonstrated. In this model an RC-filter function within the bipolar cells is assumed. The bipolar cells with different filter function activate different classes of ganglion cells. Different time constants of the bandpass filter at the bipolar cell level are the main cause for the different exponents of the power function between angular velocity and neuronal response.