Non-viraemic transmission of tick-borne encephalitis virus: a mechanism for arbovirus survival in nature

The vectors of arthropod-borne viruses (arboviruses) become infected by feeding on the viraemic blood of an infected animal. This theory is based on transmission studies involving artificial infection of vertebrate hosts by syringe inoculation. To reproduce natural conditions of virus transmission, infected and uninfected vectors (ticks) of tick-borne encephalitis virus, the most important arbovirus in Europe, were allowed to feed together on uninfected wild vertebrate hosts. The greatest numbers of infected ticks were obtained from susceptible host species that had undetectable or very low levels of viraemia. The results suggest that nonviremic transmission is an important mechanism for the survival of certain arboviruses in nature.     

Differentiation of the epithelium in early grafts of the mouse müllerian vaginal region

Zusammenfassung Die Resultate dieser Untersuchung unterstützen die Auffassung, dass das Epithel im kranialen Teil der Vagina ein Derivat des Müllerschen Epithels ist. Seine Differenzierung erscheint durch Zusammenwirken von Mesenchym und Epithel verursacht.     

Formation of cardiovascular tubes in invertebrates and vertebrates

The cardiovascular system developed early in evolution and is pivotal for the transport of oxygen, nutrients, and waste products within the organism. It is composed of hollow tubular structures and has a high level of complexity in vertebrates. This complexity is, at least in part, due to the endothelial cell lining of vertebrate blood vessels. However, vascular lumen formation by endothelial cells is still controversially discussed. For example, it has been suggested that the lumen mainly forms via coalescence of large intracellular vacuoles generated by pinocytosis. Alternatively, it was proposed that the vascular lumen initiates extracellularly between adjacent apical endothelial cell surfaces. Here we discuss invertebrate and vertebrate cardiovascular lumen formation and highlight the possible modes of blood vessel formation. Finally, we point to the importance of a better understanding of vascular lumen formation for treating human pathologies, including cancer and coronary heart disease.     

Neue lokalanästhetisch wirksame Analoga des Diperodons

Summary Highly active, and relatively little toxic local anaesthetics were developed from the group of 3-alkoxy substituted monophenylcarbamates of piperidino-and dialkylamino-2,3-propanediol.     

Cytostatic activity of organic compounds and their average quasi-valence number

Summary It is found that the average quasi-valence numbers of alkylating cytostatics lie in the region of potential carcinogens, while the average quasi-valence numbers of antimetabolites predominantly cover the region of noncarcinogens. Implications of this finding on the design of new drugs are discussed.     

Effects of ovarian steroids on superoxide dismutase activity in the rat brain

The levels of manganese superoxide dismutase (MnSOD) and copper-zinc superoxide dismutase (CuZnSOD) were determined in appropriate subcellular fractions prepared from whole brain homogenates of cycling and long-term (3 week) ovariectomized (OVX) Wistar rats, and were compared to the levels found in corresponding samples prepared from OVX rats treated with progesterone (P) or estradiol 17B-benzoate (EB). The activity of both SODs was steady during the estrous cycle, except at proestrus, when MnSOD activity was elevated significantly. Bilateral ovariectomy resulted three weeks later in an increase of the MnSOD activity even higher than that recorded at proestrus. High post-castration MnSOD activity was lowered profoundly by exogenous P (2 mg) or EB (0.5 g), given s.c. to OVX animals 2 h or 24 h before sacrifice. Neither removal of the ovaries nor the hormone treatments affected the activity of CuZnSOD. These results suggest suppressive effects of ovarian steroids on MnSOD activity in the rat brain.     

Determination of adenine in hydrolyzates of ribonucleic acids with the aid of comparative titration

Zusammenfassung Auf dem Prinzip der Komparationstitration wird eine schnelle oszillographische Methode für quantitative Adeninbestimmung in saurem Hydrolysat der RNS entwickelt.