The comparative metabolism of ethylene dimethanesulphonate and ethylene dibromide

Zusammenfassung Äthylenglykol-dimethansulfonat (EDS) wird von der Ratte zu N-Acetyl-S-(-hydroxyäthyl)-cystein (V), N-Acetyl-S-(-hydroxyäthyl)-cystein-S-oxyd (VI), und Methansulfonsäure abgebaut. Äthylendibromid (EDB) gibt ausser V und VI, S-(-Hydroxyäthyl)-cystein (III) und wird weiter zu Kohlendioxyd und anorganischem Sulphat via S-(-Hydroxyäthyl)-cystein-S-oxyd (IV) abgebaut. Keine der erwähnten Stoffwechselprodukte sind gegen Tumoren oder gegen Spermatogenese wirksam.

---

---

This work was supported by grants from the Ford Foundation and the Wellcome Trust (A. R. J.) and the British Empire Cancer Campaign for Research (K. E.).     

Reduction in number of immunostained GABAergic neurones in deprived-eye dominance columns of monkey area 17

The primary visual cortex (area 17) of the Old World monkey is divided into alternating right- and left-eye dominance columns that are highly modifiable by visual experience during a critical period in development but display little morphological or physiological plasticity during adult life. However, changes in immunocytochemical staining for a calcium/calmodulin-dependent protein kinase occur in visual cortical neurones of adult monkeys after brief monocular deprivation and concentrations of putative neurotransmitters or their related enzymes can be altered with changes in neuronal activity in other systems. We therefore examined the effects of monocular deprivation on the immunocytochemical staining for gamma-aminobutyric acid (GABA) and its synthetic enzyme, glutamic acid decarboxylase (GAD), in adult monkey area 17. The staining for GABA and GAD in neuronal somata and terminals was markedly reduced within ocular dominance columns associated with a removed or a visually deprived eye, suggesting that the GABA concentration in cortical neurones may depend on their levels of activity. Thus area 17 of adult monkeys may retain a greater degree of plasticity than previously recognized and sensory experience can profoundly affect transmitter levels, in the cortex, apparently by regulating levels of a synthetic enzyme.     

Effect of benzo[a]pyrene on friend virus leukemogenesis,CFU-S viability,and induction of humoral immunity

Summary Benzo[a]pyrene (BP) potentiated the induction of leukemia by low doses of Friend virus in SJL/J mice if injected 2 days before the virus. BP also reduced the viability of hematopoietic stem cells (CFU-S) within this time interval but had little effect on the induction of humoral immunity (the PFC response).This work was supported by Department of Energy Contract No. EP-78-S-02-4800.     

Pathological changes in the liver of mice given 2,3,7,8-tetrachlorodibenzo-p-dioxin.

In C57BL/6 mice a single oral dose of 2,3,7,8-tetrachlorodibenzodioxin (LD50 126 mug/kg) results in loss of body weight and death with an enlarged fatty liver after ca. 21 days. A progressive necrotic centrilobular liver lesion is also seen.     

Alkylating esters VIII. The action of the isomers of dimethylmyleran on spermatogenesis

Zusammenfassung Als Antifertilitätsmittel haben dasmeso-Isomer und die (±)-Isomere von Dimethylmyleran eine synergistische Wirkung auf die Spermatogenese von Ratten. Bei Mäusen und Wachteln hat ein 50% iges Gemisch der Isomere eine niedrigere Toxizität als die einzelnen Isomere, was bei höherer Dosis des Gemisches zu längerdauernder Sterilität führt.     

Identification of comet Hyakutake's extremely long ion tail from magnetic field signatures

Observations of the varying orientations of comet tails led to the suggestion of the existence of the solar wind--a continuous outflow of ionized material from the Sun. It is now well established that gas from comets is ionized by several processes and joins the solar wind, forming an ion (plasma) tail that points away from the Sun. The plasma environments of three comets have been measured in situ, but only in the upstream direction or less than 8,000 km downstream of the nucleus. Here we report a fortuitous crossing by a spacecraft of the plasma tail of comet Hyakutake (C/1996 B2), at a distance of more than 3.8 astronomical units (550 million kilometres) from its nucleus. This surpasses the tail length of 2 AU determined for the Great March Comet of 1843 (C/1843 D1). Our measurements reveal that, at this distance, the tail of comet Hyakutake was a structured entity at least 7 million kilometres in diameter.