Different neuropathological effects of intrahippocampal injections of kainic acid and tetanus toxin

Behavioral and neuroanatomical effects of hippocampal injections of kainic acid (KA) and tetanus toxin (TT) were investigated in rats. Injections of KA resulted in both local and distant neuroanatomical damage, but not in clear signs of epilepsy; injections of TT on the other hand were followed (in some of the rats) by prolonged seizure attacks, but not by neuronal damage. Based on these results it is suggested that the widespread neuronal damage following KA lesions cannot be primarily attributed to orthodromic activation of epileptic discharges. Instead, specific properties of KA and their interactions with certain transmitters may provoke widespread neuroanatomical damage.     

Zur Charakterisierung der Siebröhren-Kallose

Summary Callose of sieve plates from the phloem ofVitis vinifera is characterized by a high density of 1.62 and a refraction index of 1.532±0.002. The X-ray diffraction pattern yields 5 diffuse rings, the strongest of which indicates a periodicity of 15.5 Å.     

Distribution of metals in annual rings of the beech (Fagus sylvatica) as an expression of environmental changes

Summary Annual rings of 140–160-year-old beeches (Fagus sylvatica) from St. Ingbert, Saarland (FRG) were prepared and analyzed for 14 metals by atomic absorption spectroscopy. According to the chronological variations of their concentrations, the elements could be divided into three groups: 1) Metals without any tendency for chronological changes. This was established for Na, K, Cu, Cr, Co, Ni, Pb, and Cd. 2) Metals with a recent decrease of their concentrations, appropriate for Ca, Mg, Mn, and Zn. 3) Metals with a recent tendency to increase, e.g. Fe and Al. These variations are discussed in connection with the industrial history of the Saarland region and the influence of acid immissions which may alter the soil and thereby the trace element metabolism of the trees with consequences for the vitality of the plants.     

Seasonal changes in the nitrate-reducing activity of a green alga

Zusammenfassung Trotz konstanter Kultur- und Versuchsbedingungen zeigt die Nitratreduktion intakter Zellen und zellfreier Extrakte der GrünalgeAnkistrodesmus braunii ausgeprägte jahresperiodische Schwankungen. Das Aktivitätsmaximum liegt in den Monaten Juni/Juli, das Minimum im Oktober/November.

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This work was supported by the Deutsche Forschungsgemeinschaft.     

In vivo conversion of corticosterone into aldosterone in rats treated with ACTH or submitted to stress

Zusammenfassung Es wurde die in vivo Konversion von Corticosteron zu Aldosteron in den Nebennieren der Ratte nachgewiesen. Wiederholte ACTH-Gaben verminderten die Konversion, während diese nach chronischer «Stress»-Einwirkung (Formol-Behandlung) unverändert blieb. Es wird angenommen, dass die Vergrösserung und Funktionsänderung der Nebennieren unter Stress-Einwirkung nicht nur durch vermehrte Abgabe von ACTH vermittelt wird.

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Supported by the Deutsche Forschungsgemeinschaft.