Fluorometric detection of serotonin using o-phthaldialdehyde: An improvement

Résumé Dans la détermination fluorimétrique du complexe sérotonine-OPT, le lavage des spécimens avec un volume égal de chloroforme, avant de l'évaluation, réduit l'interférence des blancs et la dispersion primaire. Cela permet une évaluation plus exacte de la fluorescence de la sérotonine et, dans quelques cas, l'usage de spectres autrement illisibles.     

Presynaptic depolarization of olfactory afferent fibers in cat prepyriform cortex

Resumen El efecto de estímulos condicionantes sobre el potencial evocado del área prepiriforme fué estudiado en gatos. La estimulación del bulbo olfatorio y de la corteza prepiriforme contralateral provocan inhibiciones de larga duración (> de 100 mseg); estas pertenecen al tipo presináptico a juzgar por la depolarización aferente primaria (DAP) de los terminales axónicos y los efectos desinhibitorios de la picrotoxina.     

Biological degradation of TCDD in rats

Apart from its high toxicity, the chemical stability and persistence of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in the environment bring about additional hazards. However, until now there has been no evidence for degradation of this dioxin in biological systems, and it is considered unusual that a compound which is insusceptible to biological attack should be so extremely toxic. In in vitro studies with microsomal preparation from mouse, rat and rabbit liver, as well as in vivo, no metabolite of TCDD has been detected by several workers. Recent data, showing a lower toxicity of TCDD in rats after stimulation of the hepatic mixed-function oxidase, suggested possible metabolic transformation of this compound. In the present study, we used tritiated TCDD to search for metabolites in the bile of rats and found marked changes in lipophilicity and mobility in TLC of the excreted radioactivity. Treatment with diazomethane yielded at least two new compounds. These observations hinted at the formation of phenolic hydroxyl groups in the dioxin molecule.     

Transesterification reactions of ethylene glycol cyclic phosphate with 2-aminoalcohols

Résumé Il a été trouvé que l'éthylène glycol phosphate cyclique réagit en solution aqueuse avec plusieurs amino-2 alcools pour donner les phosphodiesters résultants d'une transesterification.     

‘Pitfalls’ in immune electron microscopy

Zusammenfassung Es werden die Fehlerquellen diskutiert, die bei der Untersuchung von Antigenen auftreten, wenn zu deren elektronenmikroskopischer Darstellung Antikörper, markiert mit Ferritin, verwendet werden. Durch geeignete Wahl der Fixierung können einige dieser Schwierigkeiten beseitigt werden.     

Chemische Sensibilisierung der Strahlenschädigung bei Rattenembryonen

Summary A combined treatment involving a radio-sensitizing chemical and low doses of X-rays was investigated. Small quantities of iodoacetamide can cause an increase in the radiation damages of rat embryos. The possibility of inhibition of postirradiation repair mechanisms is discussed.     

ISSR markers based on GA and AG repeats reveal genetic relationship among rice varieties tolerant to drought, flood, or salinity

Drought, flood, salinity, or a combination of these limits rice production. Several rice varieties are well known for their tolerance to specific abiotic stresses. We determined genetic relationship among 12 rice varieties including 9 tolerant to drought, flood, or salinity using inter-simple sequence repeat (ISSR) markers. Based on all markers, the nine tolerant varieties formed one cluster distinct from the cluster of three control varieties. The salt-tolerant varieties were closest to two flood-tolerant varieties, and together they were distinct from the drought-tolerant varieties. (GA)₈YG was the most informative primer, showing the highest polymorphic information content (PIC) and resolving power (Rp). The drought-, flood-, and salt-tolerant varieties grouped in three distinct clusters within the group of tolerant varieties, when (GA)₈YG was used. Sabita was the only exception. The two aus varieties, Nagina22 and FR13A, were separated and grouped with the drought- and flood-tolerant varieties, respectively, but they were together in dendrograms based on other primers. The results show that ISSR markers associated with (GA)₈YG delineated the three groups of stress-tolerant varieties from each other and can be used to identify genes/new alleles associated with the three abiotic stresses in rice germplasm.     

Seitenkettenabbau von Gallensäuren direkt zu Ketolen vom Typus der Nebennierenrinden-Hormone

Summary ^20;23-24, 24-Diphenyl-choladienes are easily brominated in 21-position by N-bromo-succinimide. The bromo-dienes obtained can be transformed into 21-hydroxy-, 21-acyloxy- or 21-alkoxy-dienes and the latter two split by oxidation into 21-acyloxy- or 21-alkoxypregnane-20-ones. This sequence of reactions, of which the last two may be exchanged, affords a new and simple degradation method, leading from bile acids directly to ketols of the type of the suprarenal cortical hormones.

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« Über Steroide », 62. Mitteilung (61. Mitt. siehe Helv. chim. acta30, 786 [1947]) sowie « Ein einfacher Abbau der Gallensäuren-Seitenkette », VI. (V. siehe Helv. chim. acta29, 627 [1946]).