Action of group A streptococcus extracellular product(s) on the connective tissue of the human heart valve

Summary The cultivation of a rheumatogenic strain of group A streptococcus in presence of human heart valve connective tissues leads to the release of substance(s) reacting with antistreptococcal polysaccharide and antihuman glycoprotein antibodies.     

Proteinuria in the rat: A comparison of tissue components in the voided and renal pelvic urine

Zusammenfassung Es wird gezeigt, dass bei gesunden männlichen Ratten nur Urin, der die unteren Harnwege passiert, Bestandteile der Geschlechtsdrüsen enthält. Somit ist die normale Proteinurie zum Teil auf die Ausscheidung extrarenaler Gewebskomponenten zurück-zuführen.     

Interaction of Co, Mn, Mg and Al with d(GCCCATGGC) and d(CCGGGCCCGG): a spectroscopic study

Spectroscopic study of the interactions of metal ions, Co, Mn, Mg and Al with d(GCCCATGGGC) and d(CCGGGCCCGG) revealed the following. Metal ions Mn, Al and Mg at the lowest concentrations enhanced the t _m of oligomers, whereas Mn and Mg at higher concentrations decreased the t _m . Co enhanced the t _m of oligomers at higher concentrations. The studies have also indicated that Mn at lower concentrations displaced EtBr fluorescence, Mg and Co at moderate concentrations and Al only at higher concentrations. Addition of Co, Mn, Mg and Al altered the bands of the circulars dichroism (CD) spectra of the oligomers in a concentration-dependent manner. The CD spectra of d(GCCCATGGGC) and d(CCGGGCCCGG) indicated B and Z forms of DNA, respectively, in contrast to the A form observed in the crystal structures. Mg and Co at different ionic strength induced Z–B transition in d(CCGGGCCCGG), while Al at higher concentrations induced a Z–A transition. Mn did not induce any transition. This is the first report to show that Al causes structural transitions in sequence-specific oligomers and has strong binding ability with GC-rich euchromatin oligomers. Received 22 December 1997; received after revision 16 March 1998; accepted 16 March 1998     

Upregulation of rat P23 (a member of the YjgF protein family) by fasting, glucose diet and fatty acid feeding

In a previous study, we identified and purified a 99-amino-acid rat liver-kidney perchloric-acid-soluble 23-kDa protein (P23) which displays 30% identity with a highly conserved domain of heat shock proteins (HSPs), as well as an AT-rich 3 untranslated region, which has also been described to play a role in H70 mRNA life span and protein expression. An identical perchloric-acid-soluble protein inhibiting protein synthesis in a rabbit reticulocyte lysate system was also found 2 years later by another group. More recently, the novel, the YjgF, protein family has been described, comprising, 24 full-length homologues, including P23, highly conserved through evolution, and consisting of approximately 130 residues each and sharing a common ternary structure. Independent studies from different laboratories have provided various hypothetical functions for each of these proteins. The high degree of evolutionary conservation may suggest that these proteins play an important role in cellular regulation. Although the function of none of these proteins is known precisely, we present experimental evidence which, combined with the relationship to glucose-regulating protein revealed here, and the relationship to fatty-acid-binding protein revealed by others, allow us to propose a role for P23. In rat liver, P23 expression is developmentally regulated and modulated by dietary glucose, and its mRNA is induced by starvation, in the presence of fatty-acids and in 3-MeDAB-induced hepatomas. The mRNA encoding mouse liver P23 is also hormonally modulated in a mouse line AT1F8. These data indicate that P23 protein might be a key controller of intermediary metabolism during fasting.Received 7 June 2003; received after revision 8 September 2004; accepted 10 October 2004     

Effect of experimental chronic renal failure upon the production of urea,as measured by the liver arginase activity in rats

Summary A significant diminution in liver arginase activity of chronic renal failure uremic rats is described, thus implying that the experimental finding of an increased urea production is not due to a depressed arginase activity.This work was supported by the Conselho Nacional de Desenvolvimento Cientifico e Tecnologico do Brasil's Grants. —Acknowledgments. We are indebted to Mr D'Arrochela Lobo for technical assistance, Mr Celso Chiarin for the statistical review and Dr C.E. Tosta and Dr Linda Caldas for helpful advice.     

The effect of diet on the hemolymph amino acid constituents of the larvae and pupae ofSarcophaga ruficornis (Fabricius): (Diptera)

Zusammenfassung Es werden zwei Zuchtgruppen vonSarcophaga ruficornis-Larven hinsichtlich ihres Aminosäuregchaltes des Blutes untersucht. Den auf Fleisch gezüchteten Tieren fehlt Lysin, Glutamin und Taurin, während diese Aminosäuren bei den auf Hundebisquit aufgezogen Larven vorhanden sind, ihnen dagegen Threonin fehlt. Der Aminosäuregehalt im Blut der Puppen beider Zuchtgruppen ist gleich.     

Effect of the type of diet on the distribution of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase in rat small intestine

Summary The jejunoileal gradient for the HMG-CoA reductase activity in the microsomal fraction of the epithelial cells of the small intestine of rats given commercial pellets was reserved within a few days after changing the ration to a semipurified diet. The response of the reductase was essentially the same in villus and crypt cells.     

English engineer John Smeaton's experimental method(s): Optimisation,hypothesis testing and exploratory experimentation

In this paper I provide a detailed account of eighteenth-century engineer John Smeaton's experimental methods, with the aim of bringing our understanding of his work into line with recent research in the history and philosophy of science. Starting from his use of the technique of parameter variation, I identify three distinct methodological aims in the research he carried out on waterwheels, windmills and hydraulic mortars. These aims are: optimisation, hypothesis testing and maxim generation. The main claim of this paper is that Smeaton did more than merely improve engineering methods by systematising earlier artisanal approaches, which is the classic view of Smeaton's method developed by historians of technology in the 1990s. I argue instead that his approach bridged the divide between science and technology, by integrating both hypothesis testing and exploratory experimentation. This is borne out, in particular, by the way that Smeaton emphasised the exploratory side of the work he published in the Philosophical Transactions, in contrast to his account of the construction of the Eddystone lighthouse, which was aimed at a broader, non-specialist public. I contribute to recent research on exploratory experimentation by showing – in line with other work on this topic – that exploratory experimentation is not incompatible with hypothesis testing. This new perspective on Smeaton's method will hopefully lead to further research and new insights into the relation between science and technology at the start of the Industrial Revolution.     

The early differentiation of the perinotochordal connective tissue. A scanning and transmission electron microscopic study on chick embryos (author's transl)]

The early differentiation of the connective tissue was investigated in the perinotochordal zone of 2-3 day-old chick embryos. After characterizing the different tissue components by transmission electron microscopy, their arrangement and distribution were examined by SEM. The results are discussed with regard to the role of the extracellular material in embryonic tissue interactions.     

Philosophy in the trenches: from naturalized to experimental philosophy (of science)

Recent years have seen the development of an approach both to general philosophy and philosophy of science often referred to as ‘experimental philosophy’ or just ‘X-Phi’. Philosophers often make or presuppose empirical claims about how people would react to hypothetical cases, but their evidence for claims about what ‘we’ would say is usually very limited indeed. Philosophers of science have largely relied on their more or less intimate knowledge of their field of study to draw hypothetical conclusions about the state of scientific concepts and the nature of conceptual change in science. What they are lacking is some more objective quantitative data supporting their hypotheses. A growing number of philosophers (of science), along with a few psychologists and anthropologists, have tried to remedy this situation by designing experiments aimed at systematically exploring people’s reactions to philosophically important thought experiments or scientists’ use of their scientific concepts. Many of the results have been surprising and some of the conclusions drawn from them have been more than a bit provocative. This symposium attempts to provide a window into this new field of philosophical inquiry and to show how experimental philosophy provides crucial tools for the philosopher and encourages two-way interactions between scientists and philosophers.     

Size ofTrichinella spiralis (nematoda) muscle cysts in the rat,mouse and guinea-pig

Zusammenfassung Bei Ratte, Maus und Meerschweinchen ist die Grösse der Muskelzysten vonTrichinella spiralis 60 Tage nach standardisierter experimenteller Infektion bestimmt worden. Die Grösse der Muskelzysten variierte bei jeder der 3 untersuchten Tierarten erheblich. Bei der Ratte wurden durchschnittlich grössere Muskelzysten vonT. spiralis gefunden als bei der Maus, bei der die Muskelzysten wiederum durchschschnittlich grösser waren als beim Meerschweinchen. Die Zystengrösse vonT. spiralis scheint demnach vom Stoffwechsel der jeweils als Wirt dienenden Tierart abhängig zu sein.