Rauwolfia alkaloids XXVI. Stereochemistry at C-17

Zusammenfassung Bei der Behandlung von 3-epi--Yohimbin mitp-Toluol-sulfochlorid in Pyridin bei 5° wird mit grosser Leichtigkeit und ausgezeichneter Ausbeute ein quaternäres Tosylat erhalten. Dieser Befund, zusammen mit der bekannten sterischen Beziehung zwischen 3-epi--Yohimbin und Deserpidin, stützt die Annahme dertrans-Konfiguration der Substituenten in 16- und 17-Stellung auch im Deserpidin. Ein Vergleich der optischen Drehungen von Reserpinderivaten spricht für analogen räumlichen Bau des Kohlenstoffatoms 17 im Reserpin.     

Phaeomelanic pigments from a human melanoma

Summary The pigments in melanomas from 2 patients were studied with regard to solubility and chemical composition. Melanoma pigment from a patient with red-blonde hair was alkali-soluble and contained 9 or 10% sulfur and was thus of phaeomelanic type. Melanoma pigment from a patient with red-brown hair was insoluble in 0.2N NaOH. Its sulfur content was 6%. This pigment was eumelanic with regard to solubility characteristics but the sulfur content was higher than previously observed for eumelanin.Supported by grants from the Swedish Cancer Society (No. 626-B75-04XA), the Swedish Medical Research Council (No. B76-04X-00056-12), and the Walter, Ellen, and Lennart Hesselman Foundation for Scientific Research. ProfessorProta was a visiting scientist of the Swedish Cancer Society (No. 626-B75-04U).     

Application of Teleonic Principles in the Search for Systemic Causes of Accidents in Anesthesia

Safety of patients in anesthesia has always been one of the major concerns of the anesthetist. It is clear from studies of safety in general that many accidents and critical incidents occur as the result of latent systemic failures to which a great number of factors contribute (Reason, 1990). An ideal way to approach this problem would be within a systemic framework, such as teleonics, developed by Járos and his co-workers (Cloete, 1999; Járos and Cloete, 1987, 1993). In this framework the events and procedures in anesthesia are considered to be part of a very complex network of process systems (teleons). It is postulated that teleonic uncertainty (telentropy) in this complex network is a factor that might lead to accidents. In a previous paper presented to the World Congress at Toronto in 2000, the principles of teleonics were described in a mathematico symbolic way (Horváth et al., 2000). This paper contains selected examples of application of these principles to the identification of possible systemic causes of accidents in anesthesia.     

Ultrastructural localisation of substance P and choline acetyltransferase in endothelial cells of rat coronary artery and release of substance P and acetylcholine during hypoxia

Substance P and choline acetyltransferase have been localised in a small proportion of endothelial cells of rat coronary arteries using electron microscopic immunocytochemistry. During a hypoxic period of 1 min, coronary vasodilatation was produced in the Langendorff heart preparation and increased levels of substance P and acetylcholine were released into the perfusate. The possibility that these substances are released from endothelial cells during hypoxia and contribute to the hyperaemic response is discussed.     

Malarial parasites complete sporogony in axenic mosquitoes

Summary To obtain sporogonic stages of malaria free from microbial contaminants for in vitro studies,Anopheles stephensi were reared under sterile conditions using a mosquito cell line as larval food. The adult females, kept in sterile humidified containers and allowed to engorge on parasitemic hamsters, supported the sporogonic development of the rodent malarial parasitePlasmodium berghei. In 10 experiments, the proportion of infected mosquitoes varied from 0 to 92%, and the geometric mean number of oocysts per female mosquito from 2.5 to 58,6, with a range of 1 to 548. The average number of salivary gland sporozoites per infected mosquito was determined by direct sporozoite counts in the pooled homogenate of the thoraces of all female mosquitoes. In five experiments, it varied from 2.7×10³ to 9.0×10³. The sterile sporozoites, harvested on day 19 or 20 after the infective blood meal, were as infective for rodents as nonsterile ones.Supported in part by Public Health Service research grant AI 18345 from the National Institute of Allergy and Infectious Diseases, by a grant from the Agency of International Development DSPE-5542-G-SS-3042-00, and by a Charles and Johanna Busch award.     

Nonspecific reaction of a thiol:Protein disulfide oxidoreductase with the disulfide bonds of insulin

Summary A thiol:protein disulfide oxidoreductase from bovine liver was isolated after separation from protein disulfide isomerase. The enzyme, after activation (reduction) with glutathione, was reacted with stoichiometric amounts of insulin and the sulfhydryl groups of the partially reduced hormone were labeled with iodo (l-¹⁴C)acetamide. After separation of the insulin chains, the radioactivity was found in both the peptides, with a ratio A-chain/B-chain equal to 2/1.     

Androstenedione or corticosterone treatment during pregnancy alters estrous cycle of adult female offspring in mice

Summary Female offspring from mice injected with androstenedione during late pregnancy showed lengthened vaginal cycles, persistent estrus and decreased incidence of pro-estrus and dïestrus, whilst offspring from mice injected with corticosterone showed increased incidence of dïestrus. These observations give qualified support to the hypothesis that stress during pregnancy alters the female offspring reproductive system through the action of adrenal steroids.