Lymphocyte-stimulating activity of scarlet fever toxin

Zusammenfassung Das erythrogene Toxin stimuliert die Inkorporation von³H-Thymidin in Blutlymphocyten von normalen Kaninchen. Die Reaktion hat den Charakter einer Antwort auf ein nichtspezifisches Mitogen. Die in vivo erzeugte Toleranz führt zu einer Dosis-abhängigen Hemmung dieses Effektes.     

Polarographic activity of the antitumor drug cis-dichlorodiammineplatinum (II). The effect of hydrolysis and trans-isomerization of the drug

Summary Electrochemical activities of cis-dichlorodiammineplatinum(II) (cis-DDP) and its trans isomer were studied by classical and differential pulse polarography (d.p.p.). It was shown that both isomers yielded a polarographic step or peak at about –1.6V (vs. Ag/AgCl), which corresponded to electroreduction of the complex and to catalytic hydrogen evolution. This signal was easily measurable with the aid of d.p.p. and was suitable for investigation of the extent of hydrolysis and trans-isomerization of cis-DDP leading to the formation of toxic products. The detection limit for determination of cis-DDP and its trans isomer by d.p.p. was 1×10^–6 mol/l.Acknowledgment. This work was supported in part by Lachema n.e., Brno (Czechoslovakia).     

High-fat diet and the development of obesity in albino rats

Zusammenfassung Männliche, geschlechtsreife Wistar-Ratten wurden 44 Wochen lang mit isokalorischen Diäten gefüttert, die entweder einen erhöhten Fett- oder Kohlehydrat- bzw. Eiweissanteil enthielten. Zwischen den eine fettreiche und eine kohlehydratreiche Diät erhaltenden Tieren zeigten sich keine statistisch bedeutsamen Unterschiede in bezug auf ihre Gewichtszunahme und den Gesamtanteil des Körperfettes. Diejenigen Tiere, die eine Diät mit erhöhtem Kaseingehalt erhielten, nahmen in Übereinstimmung mit den Literaturangaben weniger an Gewicht zu und lagerten auch weniger Körperfett ab. Wie aus unseren Ergebnissen hervorgeht, muss ein hoher Fettanteil in der Diät von sich aus noch nicht zur Fettsucht bei Ratten führen.     

Komplex-Stabilität und tuberkulostatische Aktivität einiger 8-Oxychinolinderivate

Summary Based on polarographic viz. spectrophotometric determinations of the stabilities of several Cu⁺⁺- and Co⁺⁺⁺ hydroxyquinolin complexes it has been shown that a correlation exists between the quotient of complex-stabilitiesK _Co ⁺⁺⁺ /K _Cu ⁺⁺ and antitubercular activity (cf. table and graph). This supports the hypothesis that the 8-hydroxyquinolin derivatives and analogues act by competitive antagonism; the Cu⁺⁺-hydroxy-quinolates are able to replace Co in a prosthetic group of Mycobacterium-enzyme with Cu.

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Vorgetragen an der Organisch-Chemischen Konferenz des Vereines ungarischer Chemiker, 27. September 1953.

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III. Mitteilung: Acta chim. Hungarica (im Druck).     

The anti-tumour activity of 6-azauracil riboside

Zusammenfassung Es wird die cancerostatische Wirkung des 6-Azauracilribosids auf die subkutane Form des Ehrlich-Aszites-Tumors beschrieben und festgestellt, dass 6-Azauracilribosid ungefähr 6mal wirksamer ist als 6-Azauracil.     

The action of epinephrectomy on the toxicity of neomycin

Zusammenfassung Beiderseitige Exstirpation der Nebennieren vermindert die Toxizität von Neomycin undd-Tubocurarin.     

A strong decrease in Saturn's equatorial jet at cloud level

The atmospheres of the giant planets Jupiter and Saturn have a puzzling system of zonal (east-west) winds alternating in latitude, with the broad and intense equatorial jets on Saturn having been observed previously to reach a velocity of about 470 m x s(-1) at cloud level. Globally, the location and intensity of Jupiter's jets are stable in time to within about ten per cent, but little is known about the stability of Saturn's jet system. The long-term behaviour of these winds is an important discriminator between models for giant-planet circulations. Here we report that Saturn's winds show a large drop in the velocity of the equatorial jet of about 200 m x s(-1) from 1996 to 2002. By contrast, the other measured jets (primarily in the southern hemisphere) appear stable when compared to the Voyager wind profile of 1980-81.     

Hedgehog is an early and late mediator of pancreatic cancer tumorigenesis

Hedgehog signalling--an essential pathway during embryonic pancreatic development, the misregulation of which has been implicated in several forms of cancer--may also be an important mediator in human pancreatic carcinoma. Here we report that sonic hedgehog, a secreted hedgehog ligand, is abnormally expressed in pancreatic adenocarcinoma and its precursor lesions: pancreatic intraepithelial neoplasia (PanIN). Pancreata of Pdx-Shh mice (in which Shh is misexpressed in the pancreatic endoderm) develop abnormal tubular structures, a phenocopy of human PanIN-1 and -2. Moreover, these PanIN-like lesions also contain mutations in K-ras and overexpress HER-2/neu, which are genetic mutations found early in the progression of human pancreatic cancer. Furthermore, hedgehog signalling remains active in cell lines established from primary and metastatic pancreatic adenocarcinomas. Notably, inhibition of hedgehog signalling by cyclopamine induced apoptosis and blocked proliferation in a subset of the pancreatic cancer cell lines both in vitro and in vivo. These data suggest that this pathway may have an early and critical role in the genesis of this cancer, and that maintenance of hedgehog signalling is important for aberrant proliferation and tumorigenesis.     

N2 production by the anammox reaction in the anoxic water column of Golfo Dulce,Costa Rica

In oxygen-depleted zones of the open ocean, and in anoxic basins and fjords, denitrification (the bacterial reduction of nitrate to give N2) is recognized as the only significant process converting fixed nitrogen to gaseous N2. Primary production in the oceans is often limited by the availability of fixed nitrogen such as ammonium or nitrate, and nitrogen-removal processes consequently affect both ecosystem function and global biogeochemical cycles. It was recently discovered that the anaerobic oxidation of ammonium with nitrite--the 'anammox' reaction, performed by bacteria--was responsible for a significant fraction of N2 production in some marine sediments. Here we show that this reaction is also important in the anoxic waters of Golfo Dulce, a 200-m-deep coastal bay in Costa Rica, where it accounts for 19-35% of the total N2 formation in the water column. The water-column chemistry in Golfo Dulce is very similar to that in oxygen-depleted zones of the oceans--in which one-half to one-third of the global nitrogen removal is believed to occur. We therefore expect the anammox reaction to be a globally significant sink for oceanic nitrogen.