Myoepitheliom des Weichgewebes

Zusammenfassung Der Fall eines Myoepithelioms des tiefen Weichgewebes wird mit klinisch-pathologischen, ultrastrukturellen und genetischen Befunden vorgestellt. Bei einem 30-jährigen Patienten fand sich ein Weichgewebstumor am rechten Unterschenkel innerhalb der tiefen Wadenmuskulatur mit Ausmaßen von 13,2x8,2x9 cm. Histologisch lagen Strukturen eines Myoepithelioms mit lobulärer, teils trabekulärer und nestartiger Lagerung der blanden epitheloiden und spindeligen Tumorzellen in einer fibromyxoiden, teils chondroiden Matrix vor mit immunhistochemischer Expression von Panzytokeratinen, S100-Protein sowie Calponin, fokal auch GFAP und EMA. Ultrastrukturell fanden sich Glykogeneinlagerungen und subplasmalemmale Verdichtungsstrukturen, wobei eindeutige Myofilamente nicht zu sichern waren (bei immunhistochemisch fehlender Aktinexpression). Mit Hilfe der komparativen genomischen Hybridisierung (CGH) konnte ein Zugewinn am Y-Chromosom nachgewiesen werden. Ein 17p-Verlust war zwar nicht eindeutig zu detektieren, kann aber bei der geringen Auflösung der CGH auch nicht ausgeschlossen werden. Der Patient war 25 Monate nach vollständiger Tumorresektion krankheitsfrei.Myoepitheliome bzw. Mischtumoren des Weichgewebes stellen seltene Weichgewebsneoplasien dar, die — wie im dargestellten Fall — eine erhebliche Größe erreichen können und andere Weichgewebstumoren oder -sarkome klinisch-radiologisch imitieren können. Bei einer Lokalrezidivrate von 20% nach Angaben der Literatur ist eine vollständige chirurgische Entfernung mit Nachbeobachtung zu empfehlen.Gewidmet Herrn Dr. Heinrich Dickmans.     

Adenylate cyclase in human gastric mucosa: its activation by histamine in morphologically different biopsy specimens

Summary In morphologically different biopsy specimens from fundic, antral and duodenal mucosa of 134 persons, basal and histamine stimulated adenylate cyclase activity was studied: Basal and stimulated adenylate cyclase activities were log-normally distributed. Only in the fundic but not in the antral and duodenal mucosa adenylate cyclase was sensitive to histamine. The mean basal activity in the fundic gastric mucosa was 148, in response to 10^–5 mol/l histamine 292 pmol cAMP/mg protein/20 min. In human fundic biopsy specimens histologically identified as normal gastric mucosa, the stimulatory effect of histamine on adenylate cyclase decreased with the individual's age. In bioptic material from patients suffering from histologically proven chronic gastritis the histamine effect decreased with the degree of atrophy. A similar loss of histamine sensitivity was found in gastric mucosal biopsies of antrectomized individuals operated at least 5 years before by the Billroth I or II method, whereas in the mucosa of patients with gastric or duodenal ulcer no loss occurred. In contrast, the most pronounced stimulatory action of histamine was found in this latter group. Since a histamine sensitive adenylate cyclase is localized only in the glandular area of the fundic mucosa and the histamine sensitivity depends on a morphological intact structure of the mucosa, it can be concluded, that the effects of histamine on adenylate cyclase and on hydrochloric acid secretion have to be considered as a mechanism linked together.This study was supported by a grant from the Deutsche Forschungsgemeinschaft     

Thermal pleasantness sensation: an indicator of thermal stress

Summary The degree of pleasantness or unpleasantness of thermal sensation aroused by a particular peripheral thermal stimulus has been shown to be an indicator of thermal state of the body in relation to the thermoregulatory set point. This phenomenon is known as thermal alliesthesia. The quantification of thermal alliesthesia was possible using two methods: (1) A set of temperature stimuli (15, 20, 25, 30, 35, and 38 C) was applied, by means of a Peltier thermode 5.5×2.7 cm², on the back of the hand, the forehead, and the back of the neck. When each stimulus had been applied for 5 s the subjects voted their degree of thermal pleasantness/unpleasantness on a psychophysical scale ranging from +2.0 for very pleasant to –2.0 for very unpleasant. (2) The subjects were also asked to adjust the Peltier thermode temperature, without looking at the temperature scale, such that the temperature (on the back of the neck) was maintained at the level the subjects considered most pleasant. The subjects also rated their general thermal comfort sensation on a five point scale ranging from +2.0 for very comfortable to –2.0 for very uncomfortable. Rectal temperature and skin temperature at eight locations were continuously recorded. Passive thermal exposures (54) were made with nine passive subjects and 42 exposures were done with working (50 watt) subjects. All exposures were carried out in a climatic chamber at a constant temperature, relative humidity (45%), and air speed (0.3 m/s). Each subject underwent 6 exposures at six room temperatures of 15, 20, 25, 30, 35, and 40 C. The results of work exposures confirmed the findings of previous studies; namely, the effect of core temperature change overrides any effect due to mean skin temperature on alliesthesial response. A mathematical function to predict the mean slope of the thermal pleasantness rating/stimulus line (a measure of the alliesthesial response) was derived using the data obtained from the passive thermal exposures. The results indicate that alliesthesial response can be used as a quantitative indicator of thermal stress.Supported by the European Coal and Steel Community, Luxembourg     

Über die Umwandlung pathogener Bakterien beim Durchtritt durch die Schleimhaut der Verdauungswege

Ohne ZusammenfassungAus dem Institut Robert Koch [Abteilung Dr.Schiemann].Mit 4 Textabbildungen.     

Evidence that the different classes of relay cells of the cat's lateral geniculate nucleus terminate in different layers of the striate cortex

Summary Small electrophoretic injections of horseradish peroxidase (HRP) were made with recording microelectrodes in different layers of area 17 of the cat. The sizes and locations of labeled relay cells in the lateral geniculate nucleus (LGNd) were then studied. Layer I was found to receive inputs mainly from small LGNd cells (13–21 m). These cells were located in the parvocellular C laminae and the MIN. Layer II and the upper portion of layer III were not found to receive LGNd afferents. Lower layer III was found to receive inputs mainly from small to medium-sized relay cells. These cells were located in the A laminae and the parvocellular C laminae. Layer IVab and the layer III-IV border region were found to receive afferents from predominantly large LGNd neurons (> 20 m). These cells were located in laminae A, A₁; C, and the MIN. Layer IVc was found to receive inputs from mostly small to medium-sized cells (15–23 m). Nearly all of these cells were in the A laminae although some small cells in laminae C were observed following layer IVc injections which involved the layer IV–V border region. Layer V, away from the layer IV–V border region, was not found to receive LGNd afferents. Finally, layer VI was found to receive inputs from both large and small relay cells. These cells were all located in the A laminae.In the light of previous findings, these results suggest that the terminals of W, X, and Y cell axons are segregated within the cat's striate cortex: W cells projecting to layer 1, the deeper portion of layer III and the layer IV–V border region; X cells projecting heavily to layer IVc with a minor projection to layer VI and possibly also to lower layer III; Y cells projecting heavily to layer IVab and the layer III–IV border region with a smaller projection to layer VI.     

Mechanisms of compensation for vestibular deficits in the frog

Summary In hemilabyrinthectomized frogs excitatory responses of central vestibular neurons to electrical stimulation of the remaining vestibular nerve were recorded extra- and intracellularly at different stages (0, 3, and 60 days) after the operation.The output pattern of ipsilateral vestibular neurons sending an axon across the midline via the vestibular commissure to the deafferented nucleus did not change postoperatively.The synaptic efficacy of these commissural axons ending on partially deafferented vestibular neurons on the lesioned side increased with time. This enhanced synaptic potency was associated with a shortening in time to peak and duration and an increase in amplitude of the evoked EPSPs. As a result most vestibular neurons were readily excited by single shock stimulation of the contralateral vestibular nerve, a finding which was rarely observed in control animals.These plastic changes are explained by the assumption of reactive synaptogenesis. The consequences of this modification for the readjustment of static and dynamic vestibular reflexes are discussed.     

Peripheral and spinal components of the sensitization of spinal neurons during an acute experimental arthritis

In cats the injections of kaolin and carrageenan into the knee joint lead to an acute arthritis which develops within 1–3 hours. In parallel articular afferents (low, high threshold and unresponsive ones) are becoming (more) sensitive to movements in the working range of the joint and many show (enhanced) ongoing discharges. Consequently spinal nociceptive-specific and wide dynamic range neurons with afferent input from the inflamed knee develop (increased) responsiveness to gentle stimulation of the joint. But in addition most of these neurons display enhanced reactions to non-inflamed parts of their receptive fields, too, and some neurons show enlargement of their total receptive fields. These latter findings indicate that the sensitization of spinal neurons is not simply reflecting the increased afferent input from the inflamed knee but that intrinsic spinal mechanisms may participate in the sensitization process.     

Eye and neck motor signals in periabducens reticular neurons of the alert cat

The purpose of this work was to search for neurons in the ponto-medullary reticular formation which can carry horizontal eye position signals to dorsal neck muscles of the cat. The recordings were localized in an area of the ponto-medullary reticular formation which contains reticulo-spinal neurons projecting to the neck (Peterson et al. 1980). Experiments were performed on alert, head-fixed cats. Eye movements were measured by the search-coil technique. Neuronal activity was recorded extracellularly with glass microelectrodes. Neurons were localized both by stereotaxic coordinates and by their position with respect to the antidromic field potential profile of the abducens nucleus. EMG of longissimus capitis, obliquus capitis and splenius muscles were recorded. Vestibular stimulation was produced by a turn-table. Reticular cells were found below the abducens nucleus (1 to 3.5 mm below the center of the nucleus, A.P.:5.3 to 7.2 mm;L: 1 to 1.5 mm) showing a firing rate closely related to EMG during spontaneous saccades and, to a variable degree, to the ipsilateral horizontal component of eye position. 'Tonic' and 'burst-tonic' cells were found. During vestibular stimulation, the firing rate kept the same relationship with eye position and neck EMG. It is concluded that the analyzed reticular cells are good candidates to be reticulo-spinal neurons which mediate a signal allowing a synergistic movement of head and eye during orientation in the horizontal plane.     

Comparison of four methods for identification of gram-negative non-fermenters: Organisms less commonly encountered in clinical specimens

Four commercial kits - Oxi/Ferm (OF), API 20E (AP), Minitek (MT), Flow N/F (NF) were evaluated, without additional tests, for identification of 105 opportunistic Gram-negative non-fermentative rods. OF correctly identified 42% of strains, with 35% as part (but not first) of a spectrum of identifications (SI) and 23% incorrect identification. MT yielded 75% correct identification, with 12% SI and 13% incorrect. AP correctly identified 64% of strains, with 26% SI, 10% incorrect. NF correctly speciated 70% of strains, with 24% SI, 6% incorrect. All 4 methods show deficiencies in identification of these rare but increasingly clinically encountered organisms. Addition of new tests/modification of existing ones would render these systems more capable of identifying this organisms group.     

A “Stopper” mutant of Neurospora crassa containing two populations of aberrant mitochondrial DNA

Summary [E35], an extranuclear mutant of Neurospora crassa has all the phenotypic characteristics of the stopper mutants (De Vries et al. 1980). In the present work, the mitochondrial DNA as well as the mitochondrial translation products are characterized further. The primary mutational event appears to have been the deletion of about 4 kbp from the wild-type genome. Moreover, after prolonged vegetative growth the mutant accumulates an 8-m circular mtDNA, which was demonstrated both by electronmicroscopy and by restriction enzyme analysis. Hence, the mutant contains two populations of aberrant mitochondrial DNA, the smaller of which is an amplification of the rRNA-tRNA part of the larger. We propose that the primary deletion has generated a signal in the larger DNA which can cause premature termination of replication at the deletion site, and subsequent circularization of the unfinished daughter molecule. Finally, the deleted part may contain a determinant for synthesis of a protein of 11 kDal. The function of this protein, which is not a subunit of the F₀ ATPase, is not yet known.Abbreviations (k)bp (kilo)basepairs - kDal kilodalton - mt mitochondrial