Karyotype and chromosome banding in the reed frogHyperolius viridiflavus ommatostictus (Amphibia,Anura, Hyperoliidae)

Summary C-banding and mithramycin staining were used to characterize the karyotypes of 10 specimens of the African reed frogHyperolius viridiflavus ommatostictus from Tanzania. The diploid chromosome number is 2n=24. Although no heteromorphic sex chromosomes were present in the mitotic karyotypes, in many diakineses of male meiosis one or two bivalents exhibited an end-to-end arrangement. In the laboratory 7 out of 24 females changed sex spontaneously. This indicates that an XY/XX system of sex determination operates inH. viridiflavus ommatostictus.This study was supported by the Deutsche Forschungsgemeinschaft (Schm 484/2-4). We thank K. E. Linsenmair and C. M. Richards for helpful comments on an earlier draft.     

Detection of caprine arthritis-encephalitis- and maedi-visna viruses using the polymerase chain reaction

Summary The polymerase chain reaction (PCR) was used to demonstrate proviral DNA of lentiviruses of small ruminants in cultured cells. Primers for the Taq polymerase were selected in the GAG gene of Icelandic maedi-visna virus and POL gene of caprine arthritis-encephalitis (CAE) virus. Using PCR, proviral DNA of CAE virus was detected at 1 day post infection, 4 days beforeviral protein could be demonstrated using a sensitive immunoblotting protocol and 6 days before the appearance of syncytia. Primers derived from the published sequence of CAE virus successfully primed for the synthesis of homologous virus and Icelandic maedi-visna viruss but not for maedi-visna virus isolated in The Netherlands. In contrast, primers derived from the GAG region of Icelandic maedi-visna virus allowed the amplification of DNA of homologous virus, maedi-visna virus isolated in The Netherlands as well as CAE virus.     

Enantiomeric cannabinoids: stereospecificity of psychotropic activity

The 1,1-dimethylheptyl homolog of (-)-(3R,4R)-7-hydroxy-delta-6- tetrahydrocannabinol (compound II) is highly psychotropic in mice, rats and pigeons. The (+)-(3S,4S) enantiomer (III) was found to be psychotropically inactive at doses up to several thousand times those of the ED50 of (II).     

Distribution of contractile proteins and adrenergic nerves in the adrenal gland of guinea-pig,rat and ox as revealed by immunofluorescence and the glyoxylic acid technique

Summary Myosin and actin were localized in the adrenal gland, using antibodies against these proteins which were isolated from chicken gizzard. Myosin and actin were preferentially located in vascular walls including endothelial cells and in the capsule. In rat and guinea-pig adrenal cortex, the amount of contractile elements in vascular walls corresponded well to the density of adrenergic nerves as revealed with the glyoxylic acid method.Supported by grants from Deutsche Forschungsgemeinschaft.     

Studies on the toxic effects of mouse submaxillary gland extracts

Riassunto È stata studiata l'azione tossica di estratti di ghiandola sottomascellare di topo. La tossicità dell'estratto totale appare la risultante di varie componenti alcune delle quali di natura proteica. Mediante gel-filtrazione, è stata isolata e parzialmente purificata una frazione che a dosi subletali provoca una marcata atrofia del timo in topolini neonati ed adulti.     

A new technique of recording cortical blood flow in cats,suitable for measurement of arterio-venous concentration differences

Zusammenfassung Der Blutstrom in der Hirnrinde der Katze wurde mit einer neuen Methode quantitativ gemessen und die Resultate mit früheren Untersuchungen über die Durchblutung eines nervös isolierten Rindenlappens verglichen. Bei normalen Druckverhältnissen war die Strömungsgeschwindigkeit 0,17 bis 0,50 ml/g/min. Selbststeuerung des Strömungswiderstandes war deutlich vorhanden. Die Aufnahme von Glykose, die aus Durchblutung und arteriovenöser Differenz berechnet wurde, betrug 30 bis 70 µg/g Hirngewebe/min.