Temperature and acidity for maximal fluorescence of serotonin and serotonin-O.P.T.

Résumé Dans la détermination fluorimétrique de la sérotonine elle-mÊme et du complexe sérotonine-O.P.T. (o-phthaldialdéhyde) un maximum de fluorescence a été atteint pour des normalités de HCl de 3.25–3.50 et 6.25–6.50, respectivement. Pour les deux procédés, on a noté des rapports en sens inverse entre la fluorescence produite et la température de l'échantillon, pour des températures comprises entre 5 à 35 C. Entre la température ambiante (de 20 C) et 5 C, la fluorescence s'est accrue de 30% environ.     

Sporeless mutants of Bacillus thuringiensis. II. mutants derived from var. thuringiensis and var. sotto.

Three sporeless mutants of Bacillus thuringiensis, 2 derived from var. thuringiensis and 1 from var. sotto were selected after mutagenic treatment. They were completely lacking in ability to form spores, yet maintained intact insecticidal activity.     

The effects of age and nutritional state on m.e.p.p. amplitude

Summary A quantitative restriction of food intake for 7 days reduced the amplitude of spontaneous miniature endplate potentials by about 1/3 in rats aged 30 days but not in rats aged 110 days.I would like to thank Dr D. V. Roberts for encouragement and advice and the Medical Research Council and the Muscular Dystrophy Group of Great Britain for financial support.     

Ultrastructure of cell-mediated immunity. I. Comparison between E and EA rosettes.

The ultrastructural comparison between E and EA rosettes showed that, in the former, the rosetting lymphocytes are mostly round in shape and their interaction with sheep erythrocytes only consists of limited areas of membrane contact, in the latter, rosetting lymphocytes are mostly in the shape of uropods and surrounding ox red cells show pseudopods protruding towards the lymphocyte and coming into contact with it.     

Epilepsy in women. Oestrogen and progesterone plasma levels.

Comparison is made between numbers of fits and estrogen, progesterone plasma values during the menstrual cycle of women with epilepsy. All six cycles in women with ovulation had a significant positive correlation between estrogen/progesterone ratio and scores of fits. Three periods without ovulation all showed a significant correlation to estrogen variations.     

Corticotropin and nonshivering thermogenesis.

Chronic treatment with corticotropin led to reduced calorigenic effect of norepinephrine in cold acclimatized rats, but potentiated its effect in controls. This inhibitory effect was not due to the observed decrease in corticosterone plasma level, as it was shown by metopirone administration. It is concluded that corticotropin could have a competitive action on receptor sites mediating the calorigenic effect of norepinephrine in nonshivering thermogenesis.     

Naloxone and intestinal motility.

It was supposed that the inhibition of intestinal peristalsis seen in animals and humans after abdominal surgery might be related to the release of endorphins, endogenous opiate receptor agonists, caused by the surgical stress and pain. However, naloxone, a potent morphine and endorphin antagonist, failed to block this peristaltic inhibition in rats, which leaves the mechanism of this inhibition, and thus the function of intestinal endorphins, still very much in doubt.     

Nuclear apparatus and binary fission inSpirostomum dharwarensis n. sp.

Résumé Dans cet article on a décrit l'appareil nucléaire et la fission binaire dans le cilié d'eau douceSpirostomum dharwarensis. La division micronucléaire est de type synchrone. En ce qui concerne le mode de division micronucléaire, on a étudié également le déplacement graduel du type sélectif au type synchrone dans le genreSpirostomum.