Alkaloide ausSchizozygia caffaeoides (Boj.) Baill.

Summary FromSchizozygia caffaeoides (Boj.) Baill. (Apocynaceae), one major and ten minor new alkaloids have been isolated and characterised. Most of them are N-acylindoline derivatives, partly with the hitherto unknown 5,6-methylendioxyindoline system. Some possible correlations between these alkaloids are discussed.

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Den Herren Dres.H. Fritz, R. W. Schmid undH. Wagner und ihren Mitarbeitern danken wir für Spektren und Mikroanalysen.     

Morphologie und Bedeutung des ergastoplastischen Cisternen-Kollapses

Summary Acetyl salicycil acid, malonic acid and riboflavin deficiency produce characteristic changes of the endoplasmic reticulum called collapsed cisternae of rat and mouse hepatocyte probably as a consequence of a disturbed oxydative metabolism.     

浮体运动时域解的奇异性讨论

以推板造波的辐射问题为例，求出了线性时域解的解析表达式，并对线性时域解在造波板与自由面交线处的奇异特性进行了讨论，给出了奇异性的量阶。此奇异性结论对造波机的数值模拟有一定的指导意义。     

Ouabain--a link in the genesis of high blood pressure?

Hypertension or high blood pressure is a risk factor that increases risk of myocardial infarction, renal failure or cerebral stroke. The pathogenesis of hypertension is due to a variety of causes, including inherited predisposition, dietary habits, especially salt intake, smoking, and also 'general lifestyle'. But for the scientist interested in the complex interplay of physiological and molecular factors, the actual causes of high blood pressure remain uninvestigated. The following article is concerned with new reports that ouabain, a plant derivative, occurs in human beings, in whom it appears to have a hormonal function; ouabain may even play a key role in the pathogenesis of hypertension. We are thus brought a step closer to the background of cardiovascular disease; we may also be afforded a lead to a new therapeutic principle.     

Monomeric insulins obtained by protein engineering and their medical implications

The use of insulin as an injected therapeutic agent for the treatment of diabetes has been one of the outstanding successes of modern medicine. The therapy has, however, had its associated problems, not least because injection of insulin does not lead to normal diurnal concentrations of insulin in the blood. This is especially true at meal times when absorption from subcutaneous tissue is too slow to mimic the normal rapid increments of insulin in the blood. In the neutral solutions used for therapy, insulin is mostly assembled as zinc-containing hexamers and this self-association, which under normal physiological circumstances functions to facilitate proinsulin transport, conversion and intracellular storage, may limit the rate of absorption. We now report that it is possible, by single amino-acid substitutions, to make insulins which are essentially monomeric at pharmaceutical concentrations (0.6 mM) and which have largely preserved their biological activity. These monomeric insulins are absorbed two to three times faster after subcutaneous injection than the present rapid-acting insulins. They are therefore capable of giving diabetic patients a more physiological plasma insulin profile at the time of meal consumption.     

The role of proteolytic processing in the morphogenesis of virus particles.

Proteinases are encoded by many RNA viruses, all retroviruses and several DNA viruses. They play essential roles at various stages in viral replication, including the coordinated assembly and maturation of virions. Most of these enzymes belong to one of three (Ser, Cys or Asp) of the four major classes of proteinases, and have highly substrate-selective and cleavage specific activities. They can be thought of as playing one of two general roles in viral morphogenesis. Structural proteins are encoded by retroviruses and many RNA viruses as part of large polyproteins. Their proteolytic release is a prerequisite to particle assembly; consequent structural rearrangement of the capsid domains serves to regulate and direct association and assembly of capsid subunits. The second general role of proteolysis is in assembly-dependent maturation of virus particles, which is accompanied by the acquisition of infectivity.     

Quantification of the disorder in network-modified silicate glasses.

Local order in silicate glasses has been observed by many experimental techniques to be similar to that in crystalline materials. Details of the intermediate-range order are more elusive, but essential for understanding the lack of long-range symmetry in glasses and the effect of composition on glass structure. Two-dimensional 17O dynamic-angle-spinning nuclear magnetic resonance experiments reveal intermediate-range order in the distribution of inter-tetrahedral (Si-O-Si) bond angles and a high degree of order in the disposition of oxygen atoms around the network-modifying cations.     

Lactate dehydrogenase and glutamate dehydrogenase activities in the circumventricular organs of rat brain following neonatal monosodium glutamate

Glutamate (glu) an excitatory neurotransmitter amino acid, is present in high concentrations in the mammalian central nervous system and is the most abundant amino acid in our daily diet. In the present study the activities of lactate dehydrogenase (LDH) and glutamate dehydrogenase (GDH) were evaluated in the circumventricular organs (CVO) of the brain in 25-day-old rats following MSG administration at a dose of 4 mg/g b.wt during the first ten days of life. The results show the LDH activity increased to 265% of that in the control (p<0.001), whereas GDH activity was significantly decreased (p<0.05), The great elevation in LDH, a cytoplasmic marker enzyme, is apparently due to cytoskeletal changes brought about as a consequence of glu toxicity, whereas lowered GDH activity indicates altered glu homostasis in the blood-brain-barrier deficient areas following neonatal exposure to glu.