Effect of the lymphocytosis-stimulating factor from Bordetella pertussis on murine lymphoid and hemopoietic cells

Effect of B. pertussis lymphocytosis-promoting factor (LPF) on the lympho-hematopoietic system of mice was studied. The injection of LPF was shown to sharply enhance endogenous colony formation and to induce a severe depletion of thymus cells, reaching its maximum of day 4. Thymocytes obtained on day 2 or 3 after the injection of LPF produced a suppressive effect on endogenous colony formation. The proliferative activity of hematopoietic stem cells sharply increased under the influence of LPF, though it had no radioprotective action. On the following day after the injection of LPF a steep rise in the number of hematopoietic stem cells was observed in the blood of mice: their content increased 20-fold in comparison with the control level. These data may be important for the evaluation of the side effects of pertussis vaccine on the lympho-hematopoietic system.     

Ethoxyformylation of histidine residues in equine growth hormone

Reactivity of histidine residues in equine growth hormone to ethoxyformic anhydride was studied. The existence of two kinetically different sets was demonstrated: one of them including only the slow reacting histidine 169 (k = 0.164 min-1) and the other containing fast reacting histidines 19 and 21 (k = 0.892 min-1). A correlation between the decrease in the capacity to compete with 125I-labeled hormone for rat liver binding sites and the degree of ethoxyformylation of the fast group was found. Circular dichroism studies indicated no significant conformational changes in the protein with all three residues modified. These results fully agree with those obtained for bovine growth hormone which is further evidence supporting the vinculation of histidines 19 and/or 21 with the binding site of these hormones to their specific receptors.     

Aromatization of androstenedione by normal and neoplastic endometrium of the uterus

The ability of human uterine endometrium to aromatize androstenedione to estrogens was investigated using 10 normal and neoplastic tissues. Normal and neoplastic endometrial homogenates were incubated with [6,7-3H]androstenedione (A) and NADPH. Estrone (E1) and estradiol (E2) were subsequently isolated in amounts ranging from 0-17600 fmol/h/g and 0-377 fmol/h/g, respectively, from the incubates after purifications by using Bio-Rad AG1-X2 column, thin layer chromatographies and co-crystallization. The conversion of A to E1 and E2 was significantly higher in neoplastic tissues.     

Properties of purified colchicine-binding protein from a cultured carrot cell extract

Colchicine-binding protein (CBP) was purified from a cultured carrot cell extract by DEAE-Sephacel, phosphocellulose and Sephadex G200 column chromatographies. The purified CBP separated into three bands on SDS-polyacrylamide gel electrophoresis. One of them reacted with a monoclonal antibody against chick brain alpha-tubulin and the other two with that against beta-tubulin. Colchicine-binding activity of the purified protein was enhanced by tartrate and inhibited little by an excess of podophyllotoxin. It decayed following first order kinetics, but was more stable than the CBP in the crude extract. The binding constant of the purified CBP for colchicine was 0.57 microM-1 and the number of binding sites of colchicine per mg protein was about 2 nmol. This binding constant is about ten times lower than that of porcine brain tubulin under identical conditions.     

D-2 dopamine receptors in the frontal cortex of rat and human

D-2 dopamine receptors and serotonin receptors in the frontal cortex of rat and human were labelled with 3H-spiroperidol. The D-2 receptors were then distinguished in 4 ways. Dissociation of spiroperidol was biphasic, indicating two populations of sites. Cinanserin in competition with 3H-spiroperidol exhibited high (75%) and low (25%) affinity sites. Dopamine and LY 141865 in competition with 1.25 nM 3H-spiroperidol exhibited high (20-25%) and low (80-75%) affinity sites in the absence of cinanserin, while in the presence of 300 nM cinanserin only the high affinity sites remained. Lesioning of the dopaminergic meso-cortical pathway increased the number of cinanserin-resistant sites by 26%. Thus 3H-spiroperidol binding in the presence of cinanserin can be used to selectively label D-2 receptors in the frontal cortex.     

Changes in the size and shape of the synaptic vesicles in the sensorimotor cortex of the rat brain in the initial phases of kindling

The sensorimotor area of rat cerebral cortex was subjected to repeated electrical stimulation at 10-min intervals, with resultant formation and progressive lengthening of self-sustained after-discharges (SSAD). One and 60 min after the third SSAD ended, we carried out an electron microscopy morphometric analysis of the agranular synaptic vesicles in type I synapses (after Gray) in the second cortical layer of the homotopic area of the unstimulated hemisphere. One minute after the seizure ended, 5.8% enlargement of the synaptic vesicles compared with the control was demonstrated in zone II of the synapse (0.1-0.2 micron from the active zone of the synapse). Neither the size nor the shape of the synaptic vesicles in the other parts of the synaptic apparatus altered. Sixty min after the seizure ended, a 5.5% enlargement of the synaptic vesicles in zone I (0.0-0.1 micron) and a 5.4% enlargement of those in zone II was found. The synaptic vesicles in zone I in the experimental animals were more oval than in the controls. Our findings support the vesicular theory and testify that hyperfunction, up to temporary exhaustion of the synaptic apparatuses, produces a change in the transmitter content of the synaptic vesicles. A raised amount of transmitter in the synaptic vesicles near the active zone could be one of the factors responsible for continued hyperexcitability of the tissue one hour after the seizure had ended. The results likewise support the concept of two mechanisms of synaptic vesicle formation, and hence of the existence of two different vesicle populations.