Sound-stimulated14C-glutamate release from the nucleus cochlearis

Summary The exogenous release of glutamate has been successfully studied in the cochlear nucleus of guinea-pigs after physiological sound stimulation of the ear (frequency 2000–20,000 Hz at 100 dBA).Acknowledgments. This study was supported by grants from the Swedish Medical Research Council (B80-12X-05666-01) and Torsten Söderbergs och Ragnar Söderbergs stiftelser.     

Esterase alterations in the liver of dystrophic mice

Zusammenfassung Esterase-Isozym-Verluste wurden in Leberzymogrammen von Mäusen mit hereditärer Muskeldystrophie gefunden.

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On leave of absence from the Department of Physiology, Wakayama Medical College, Wakayama, Japan.     

Cholesterin und Fettsäuren als Ersatz von Serum in der Kultur vonTrichomonas foetus

Summary In the presence of a minimal amount of a water-soluble growth factor from bovine serum, cholesterol together with an unsaturated fatty acid may replace the ethersoluble lipoid fraction of the same serum. The concentration of cholesterol and fatty acid, as well as the chemical structure of the latter, are relevant.     

Antiallergische Wirkung bakterieller Polysaccharide

Summary It is shown that certain bacterial polysaccharides possess marked antianaphylactic properties. These hitherto unknown effects, which are not due to a change in sensitivity to histamine, result from a complex and peculiar mechanism of action.     

Vergleichende Untersuchungen über die hypertensive Wirkung von Aldosteron und Desoxycorticosteron

Summary In the adrenalectomized and unilaterally nephrectomized rat an investigation has been carried out on the influence of a four weeks' treatment with aldosterone and desoxycorticosterone-acetate in doses which are equieffective concerning sodium retaining capacity. Desoxycorticosterone-acetate produced hypertension, perivascular granuloma and renal lesions, whereas under the influence of aldosterone the blood pressure remained normal and no histopathological alterations could be found. Towards the end of the experiment the animals treated with desoxycorticosterone-acetate took up twice as much drinking fluid as the animals treated with aldosterone. Although the results obtained so far are only of a preliminary character it is obvious that aldosterone in doses which are equieffective concerning sodium retention does not produce the same side effects as desoxycorticosterone-acetate.     

Functional improvement of dystrophic muscle by myostatin blockade

Mice and cattle with mutations in the myostatin (GDF8) gene show a marked increase in body weight and muscle mass, indicating that this new member of the TGF-beta superfamily is a negative regulator of skeletal muscle growth. Inhibition of the myostatin gene product is predicted to increase muscle mass and improve the disease phenotype in a variety of primary and secondary myopathies. We tested the ability of inhibition of myostatin in vivo to ameliorate the dystrophic phenotype in the mdx mouse model of Duchenne muscular dystrophy (DMD). Blockade of endogenous myostatin by using intraperitoneal injections of blocking antibodies for three months resulted in an increase in body weight, muscle mass, muscle size and absolute muscle strength in mdx mouse muscle along with a significant decrease in muscle degeneration and concentrations of serum creatine kinase. The functional improvement of dystrophic muscle by myostatin blockade provides a novel, pharmacological strategy for treatment of diseases associated with muscle wasting such as DMD, and circumvents the major problems associated with conventional gene therapy in these disorders.     

Structure of the SRP19 RNA complex and implications for signal recognition particle assembly

The signal recognition particle (SRP) is a phylogenetically conserved ribonucleoprotein. It associates with ribosomes to mediate co-translational targeting of membrane and secretory proteins to biological membranes. In mammalian cells, the SRP consists of a 7S RNA and six protein components. The S domain of SRP comprises the 7S.S part of RNA bound to SRP19, SRP54 and the SRP68/72 heterodimer; SRP54 has the main role in recognizing signal sequences of nascent polypeptide chains and docking SRP to its receptor. During assembly of the SRP, binding of SRP19 precedes and promotes the association of SRP54 (refs 4, 5). Here we report the crystal structure at 2.3 A resolution of the complex formed between 7S.S RNA and SRP19 in the archaeon Methanococcus jannaschii. SRP19 bridges the tips of helices 6 and 8 of 7S.S RNA by forming an extensive network of direct protein RNA interactions. Helices 6 and 8 pack side by side; tertiary RNA interactions, which also involve the strictly conserved tetraloop bases, stabilize helix 8 in a conformation competent for SRP54 binding. The structure explains the role of SRP19 and provides a molecular framework for SRP54 binding and SRP assembly in Eukarya and Archaea.