Localization of corticotropin- and endorphin-related peptides in the intermediate lobe of the rat pituitary

Summary The question is examined whether -melanocyte stimulating hormone (-MSH), adrenocorticotropic hormone (ACTH), met-enkephalin and -endorphin are detectable by enzyme immunocytochemistry in the cells of the intermediate lobe (PI) of the rat pituitary. By applying antibodies against MSH, ACTH and -endorphin on light microscopic sections, intense immunostaining was found in all PI-cells. At the ultrastructural level, after treatment of consecutive serial sections with these three antibodies the immunoreactivity was localized in the same secretory granules. No specific metenkephalin immunoreactivity could be detected in the cells of the intermediate lobe.Supported by Deutsche Forschungsgemeinschaft SFB 87/B2     

Ultrastructural aspects of early immune damage to Taenia crassiceps metacestodes

Siebert, A. E. Jr., Good A. H. and Simmons J. E. 1978. Ultrastructural aspects of early immune damage to Taenia crassiceps metacestodes. International Journal for Parasitology8: 45–53. Changes in the ultrastructure of the tegument and subtegumental cells of intraperitoneally implanted Taenia crassiceps metacestodes were studied by transmission electron microscopy over a 4-week period. Death of metacestodes without involvement of host inflammatory cells is indicated initially by vacuolization of the larval tegument followed by loss of the tegument and subsequent death of the larvae. Changes in the tegument involve loss of the glycocalyx, reduction in the numbers of mitochondria and microtriches present, and loss of secretory capacity. Subtegumental cells show an accumulation of secretory vacuoles and marked disruption of nuclear morphology. Tegument damage is attributed to a complement-mediated lysis of the outer tegument membrane and death of the larvae probably results from loss of tegument function.     

Strukturelle Grundlagen des Parasitismus beiOrobanche III. Die Differenzierung des Xylemanschlusses beiO. crenata

Zusammenfassung Innerhalb des Wirtsxylems wurden Haustorialzellen des WurzelparasitenOrobanche lichtund elektronenoptisch untersucht. Diese Zellen durchlaufen eine ungewöhnliche Differenzierung bis sie wasserleitendes Xylemanschlu\element sind. Von Haustorialzellen mit stark verdickten FrontwÄnden entwickeln sie sich bei Eintritt in das Wirtsxylem zu einer typischen Transferzelle mit polar zum Holzelement des Wirts angelegtem Wandlabyrinth. Erst durch einen zweiten Differenzierungsschritt wird die Transferzelle zum Wasserleitelement, indem die typischen SekundÄrwandverdickungen des Xylems in der Zelle angelegt werden. Diese entstehen teilweise innerhalb des Wandlabyrinths und sind stets gegenüber denjenigen des Wirtselements angelegt. Zuletzt wird das Labyrinth — bis auf gelegentliche Reststrukturen — abgebaut, der Protoplast degeneriert, und es entsteht ein haustoriales Wasserleitelement, das über kommunizierende Tüpfel an das Wirtselement angeschlossen ist.

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Structural features of parasitism ofOrobanche III. The differentiation of xylem connexion ofO. crenata

Summary Haustorial cells of the root parasiteOrobanche within the xylem of the host tissue were investigated by light- and electronmicroscopy. Coming into contact with the tracheary elements of the host these cells show an unusual differentiation before turning into a water conducting xylem element. From haustorial cells with thickened front walls they develop into typical transfer cells, bearing wall ingrowth in those parts of the wall orientated towards the tracheary elements of the host. During further differentiation the transfer cell changes into a water conducting element by developing the typical secondary wall thickenings of xylem elements within the cell. Partly these wall thickenings are formed inside the labyrinth structures of the transfer cell, always situated opposite those of the tracheary element of the host. Simultaneously the labyrinth disintegrates—some small remnants of wall ingrowths may persist. The protoplast degenerates, and finally a haustorial water conducting element results. Host- und parasitic tracheary elements are connected by pits.

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Wir danken FrauChristl Glockmann für ihre stets verantwortungsvolle Mitarbeit. Den GÄrtnern des Botanischen Gartens in Kiel sei Dank für die oft schwierige Anzucht des Pflanzenmaterials. Die Untersuchungen wurden durch Mittel der Deutschen Forschungsgemeinschaft gefördert.     

Ein Modell zur örtlich-zeitlichen Signalübertragung im visuellen System des Menschen auf der Basis der linearen Systemtheorie kontinuierlicher Medien

Zusammenfassung Als Modell für die Übertragung örtlich-zeitlich variabler Helligkeitsmuster durch das visuelle System des Menschen wird ein dreidimensionales, homogenes neuronales Geflecht betrachtet. Die Ausbreitung der neuronalen Erregung erfolgt anisotrop in afferenter und lateraler Richtung und wird durch eine modifizierte Wärmeleitungsgleichung beschrieben, deren Hauptmerkmal ein regenrativer Signalanteil ist. Die zeitabhängige Lösung beschreibt u.a. die zeitliche Übertragungscharakteristik für flimmernde Gitter im gesamten Frequenzbereich. Die stationäre Lösung beschreibt die örtliche Übertragungscharakteristik für Gitter, wobei auch die Struktur rezeptiver Felder mit inhibitorischem Umfeld deutlich erkennbar ist. Die Struktur der Lösung läßt verstehen, wie sich mit zunehmender Tiefe im neuronalen Geflecht der Übergang von der Ortsselektivität zur Ortsfrequenzselektivität vollzieht.

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A model for the spatial-temporal signal transmission properties of the human visual system based on the linear system theory of continuous media

In this paper, a three dimensional homogeneous neural web serves as a model for the transmission of spatial-temporal luminous pattern by the human visual system. The propagation of neuronal excitation in afferent and lateral direction is assumed to be anisotropic. It is described by a modified heat conduction equation a main feature of which is a regenerative signal component. The time-dependent solution describes f.e. the temporal transmission characteristics for flickering grids in the whole frequency range. The stationary solution contains the spatial transmission characteristics for grids as well as the structure of receptive fields with inhibitory surrounds. The structure of the solution makes it under-standable how the transition from spatial selectivity to spatial-frequency-selectivity develops with growing depth of the neuronal web.

     

Die Kommunikation von Sialis (Megaloptera) durch Vibrationssignale

A newly discovered system of communication used by Sialidae while mating is described here. By means of this system males and unmated females of Sialis lutaria and S. fuliginosa are able to find each other and to communicate. Three kinds of signals are to be distinguished: (a) Rhythmic vibrations of the abdomen (♂+♀) allow mutual approach and recognition of species and sex; (2) prolonged, unstructed vibrations (♂ only), and (3) tapping of abdomen and wings on the ground is used by ♂♂ of S. lutaria as feedback for ♀♀ after their approach and by ♂♂ and ♀♀ of S. fuliginosa in the first step of their approach. The vibrations caused by movements of the abdomen are passed on via legs on to the ground and transmitted there only. The receptor is located within the legs. Observations in nature are being tested by experiments in the laboratory.     

Derivative chromosomal structures from a ring chromosome 4

Summary This report describes the results from cultured lymphocytes studied at metaphase, anaphase, and interphase from an individual with a ring chromosome 4. A ring was present in 90.1% of metaphases. Special attention was directed towards the occurrence of derivative chromosomal structures, such as partially duplicated and triplicated rings, tricentric rings, chains of 3 interlocked rings, rod-shaped chromosomes, pulverized rings, and others.The clinical features of the individual (small stature and impaired mental development, hypoplastic thumbs, ptosis palpebrae hypoplastic external male genitalia, abnormal dermatoglyphic pattern) did not conform to a specific phenotype.

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Zusammenfassung Die Lymphocyten eines Patienten mit Ringchromosom 4 wurden in der Meta-, Ana-und Interphase beobachtet. 90,1% der Metaphasen wiesen einen Ring auf. Besondere Aufmerksamkeit wurde abnormen, aus dem Ring entstandenen Chromosomen zugewandt. Es fanden sich u. a.: partielle Doppel-und Dreifachringe, Ringe mit 3 Zentromeren, Ringe aus 3 miteinander verketteten Ringen, stabförmige Chromosomen und pulverisierte Ringe.Die Symptome des Patienten (Minderwuchs, Schwachsinn, Hypoplasie der Daumen, Ptosis palpebrae, Hypoplasie des äußeren genitale, abnorme Dermatoglyphen) waren zum größten Teil unspezifish.

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This work was supported in part by grants from the Deutsche Forschungsgemeinschaft and is part of a thesis by R.N. for a medical doctorate.     

Plasma normetanephrine: A biochemical marker of sympathetic nerve function in man

The concentration of the catecholamines in plasma are regarded by many investigators as biochemical markers of sympathoadrenal activity in man. This study was designed to: 1) assess the relationship of normetanephrine (NMN), the metabolite of norepinephrine (NE) most likely to represent degration of newly synthesized and released “active” norepinephrine, to that of norepinephrine in plasma of normal volunteers and 2) to determine regional variations in plasma normetanephrine concentrations at venous and arterial sites of patients undergoing cardiac catherization. The findings suggest that 1) plasma normetanephrine reflects sympathoadrenal activity and neurotransmitter production at both peripheral neuronal and adrenal medullary sites and 2) there is net removal of normetanephrine by liver and kidney. Plasma normetanephrine should provide assistance in the biochemical assessment of sympathoadrenal tone in man and in patients with various autonomic disorders.     

Possible Causes of a Harbour Porpoise Mass Stranding in Danish Waters in 2005

An unprecedented 85 harbour porpoises stranded freshly dead along approximately 100 km of Danish coastline from 7–15 April, 2005. This total is considerably above the mean weekly stranding rate for the whole of Denmark, both for any time of year, 1.23 animals/week (ranging from 0 to 20 during 2003–2008, excluding April 2005), and specifically in April, 0.65 animals/week (0 to 4, same period). Bycatch was established as the cause of death for most of the individuals through typical indications of fisheries interactions, including net markings in the skin and around the flippers, and loss of tail flukes. Local fishermen confirmed unusually large porpoise bycatch in nets set for lumpfish (Cyclopterus lumpus) and the strandings were attributed to an early lumpfish season. However, lumpfish catches for 2005 were not unusual in terms of season onset, peak or total catch, when compared to 2003–2008. Consequently, human activity was combined with environmental factors and the variation in Danish fisheries landings (determined through a principal component analysis) in a two-part statistical model to assess the correlation of these factors with both the presence of fresh strandings and the numbers of strandings on the Danish west coast. The final statistical model (which was forward selected using Akaike information criterion; AIC) indicated that naval presence is correlated with higher rates of porpoise strandings, particularly in combination with certain fisheries, although it is not correlated with the actual presence of strandings. Military vessels from various countries were confirmed in the area from the 7th April, en route to the largest naval exercise in Danish waters to date (Loyal Mariner 2005, 11–28 April). Although sonar usage cannot be confirmed, it is likely that ships were testing various equipment prior to the main exercise. Thus naval activity cannot be ruled out as a possible contributing factor.     

Effects of superoxide radicals on transport (Na+K) adenosine triphosphatase and protection by superoxide dismutase

Membrane (Na+K)ATPase isolated from rat brain was preincubated in a medium in which superoxide radicals were generated enzymatically. Exposure to superoxide radicals caused an irreversible inactivation, which could be prevented by further addition of superoxide dismutase. (Na+K)ATPase was also protected by addition of allopurinol, a xanthine oxidase inhibitor, during preincubation. The K-activated nitrophenylphosphatase associated with (Na+K)ATPase was also found to be inactivated by preincubation with superoxide radicals, which could be prevented by superoxide dismutase.