Criteria for the appearance of post-tetanic potentiation of transmission at central synapses in Helix aspersa.

Long-lasting potentiation of inhibitory post-synaptic potentials occurs at 2 identifiable synapses in Helix brain. It appears only after tetanic stimulation and after a minimum of 20 impulses. Its amplitude and duration depends on the number of stimuli.     

Exchange of tritium from randomly tritiated taurocholate by microbial bile salt oxidoreductases.

Tritium distribution on randomly labelled taurocholate (TC) was estimated at 28%, 4%, 1% and less than 0.5% on the hydrogens opposite the 3alpha-, 7alpha- and 12alpha-OH groups and taurine moiety respectively. Anomalously, C. perfringens 3alpha-hydroxysteroid dehydrogenase (3alpha-HSDH) catalyzed tritium loss of 36% on formation of 7alpha-, 12alpha-dihydroxy-3-keto-5beta-cholanoate, implying additional losses of tritium at other sites by this enzyme.     

Effects of the antiprotease Trasylol on peripheral blood leucocytes.

Binding of the antiprotease Trasylol to human peripheral blood lymphocytes and polymorphonuclear leucocytes (PMNs) was demonstrated at the ultrastructural level using an indirect immunoperoxidase technique. This also revealed endocytosis of membrane bound Trasylol by PMNs. Trasylol inhibited PHA- and ConA-induced lymphocyte stimulation, and was cytotoxic to unstimulated cells.     

Positive after-image, PAI: early erasure by saccadic eye movement or Jendrassik manoeuvre

Positive after-images (PAIs) evoked by low intensity stroboscopic flash are erased by voluntary large amplitude saccadic eye movements. The duration of the PAI is shortened by a Jendrassik manoeuvre. The results suggest that muscle spindle afferent impulses conducted centrally are involved in the erasure phenomenon. The duration of the PAI is modifiable by drugs. The social implications of PAI are considered briefly.     

Effect of Tween 80 on lipids of Mycobacterium phlei ATCC 354

Addition of Tween 80 to the growth medium brings about qualitative and quantitative changes in the lipids of Mycobacterium phlei ATCC 354. The results suggest that Tween 80 itself may be a variant in the system.     

Isolation of the major toxic protein from the skin venom of the crested newt, Triturus cristatus

A new protein, of molecular weight 160,000, was isolated from the skin venom of the crested newt and partially characterized by bioassays and biochemical methods. This protein shows the same functional properties as the crude venom, which produces convulsions in mice and is cytotoxic.     

Sex related fibrinolytic activity in rat tissues

Histochemical study of many organs of male and female adult Wistar rats of the same age showed no difference in fibrinolytic activity (plasminogen activator activity) between the sexes.     

G-6PD loading of G-6PD-deficient erythrocytes

G-6PD-deficient erythrocytes were loaded during hypotonic hemolysis with G-6PD extracted from yeast. It was shown that enzyme was really trapped into red blood cells and remained functionally active.     

Effect of electroconvulsive treatment on serum dopamine-beta-hydroxylase activity in man

The activity of dopamine-beta-hydroxylase was measured in the serum before and immediately after electroconvulsive treatments. No significant difference was observed, suggesting that the seizures did not cause an increase in the peripheral sympathetic tone.