Polarographic micro-electrodes (carbon fiber, o. d. 8 micron) implanted in the Rat caudate nucleus, allowed a practically continuous in vivo monitoring (one measurement every 5 sec.) of the extra-cellular concentration of dopamine released by striatal dopaminergic terminals. Administration of amphetamine produced a reproducible increase of the oxidation current. This effect was suppressed after the selective degeneration of the striatal dopaminergic terminals following the injection of 6-OHDA into the substantia nigra or after inhibition of the synthesis of the amine by alpha methyl-p-tyrosin. After 5 hrs. this drug produced a 70% decrease of the oxidation current.
The authors investigated basal levels of plasma immunoreactive growth-hormone in the rat (R-GH) after administration of 3 different anesthetic drugs: urethan, chloral hydrate and gamma-hdroxy-butyrate (GHB). Lowest R-GH concentrations (5 +/- 3 ng/ml) are observed after urethan; they are significantly higher (15 +/- 4 ng/ml) after chloral hydrate but this anesthetic also causes hyperglycemia (210 +/- 30 mg/100 ml). Normal blood glucose levels are observed under GHB narco-analgesia which elicits a clear-cut R-GH secretory episode (70 +/- 5 ng/ml); basal values (12 +/- 3 ng/ml) are maintained for several hours thereafter.
After 3H testosterone injection into castrated males of the Lizard Lacerta vivipara, the radioactive compound is detected by radioautography of epididymis, femoral glands, gut and liver. Between 1 hr. 30 min. to 12 hrs. of retention the 3H material concentrates progressively into nuclei of the glandular cells of epididymis and femoral organs although no particular concentration occurs in gut and liver cells. This submammalian model is consistent with those previously described for mammals.
The addition of exogenous histones to synchronous culture of Chlamydomonas reinhardtii, at the beginning of the cell cycle, leads to the death of the cells. The same amount of histones added in the middle of the cycle, only blocks the cell division. The mechanism of this inhibition effect of the histones could involve a block at the level of the chloroplast DNA replication.
Esterases of 62 Serratia marcescens, S. liquefaciens, S. plymuthica and S. marinorubra strains were analysed by electrophoresis in polyacrylamide-agarose gel. The comparative distribution of bands showed that the four Serratia species were characterized by distinct electrophoretic patterns of their esterases.
With the potassium ferricyanide method, the localization of the sites of 3 beta-hydroxysteroid dehydrogenase activity has been investigated in the glandular tissue cells, previously fixed, of the Pleurodeles testis. An abundant copper ferrocyanide precipitate, the final reaction product, is observed in the vicinity of the external faces of the membranes of the smooth endoplasmic reticulum, or in contact with them. A very weak reaction occurs in mitochondrial cristae.
Imazalil is a new fungicide effective against Penicillium molds on fruits after harvest. This compound inhibits ergosterol biosynthesis in mycelia of Penicillium expansum. The accumulation of 24--methylenedithydrolanosterol, obtusifoliol and 14 alpha-methyl-delta 8, 24(28)-ergostadienol in treated fungi suggests that imazalil blocks sterol C--14 demethylation.
Spectrin isolated from human erythrocytes has been spin-labeled with five maleimide nitroxides. The mobility of the labels is strongly dependent on their size, and on the temperature. A thermal transition of spectrin is shown to occur above 30 degrees C. Calcium and magnesium provoke a strong immobilization of the labels. This effect is yet more pronounced when spectrin is allowed to reassociate with the cytoplasmic surface of the membrane.
Anti-idiotypic sera were obtained in Rabbits immunized with Rh antibodies (isolated from the serum sample collected in 1974 from a Blood Donor). The sera agglutinate, at high titers, red cells coated with the immunizing antibodies and, at different titers, cells coated with antibodies from serum samples taken at other periods. Inhibition of hemagglutination of anti-idiotypic sera by different samples from the same Donor was complete with the immunizing serum and partial with other samples. These results show that idiotypes or idiotypic specificities appeared or disappeared during the period studied and represent the first observation on evolution of antibody idiotypy in Man.
Immunohistological investigations have been performed with Vertebrate neuropeptide antiserums in the subaesophageal ganglion of larval Thaumetopoea pityocampa (Lepidoptera). Positive immunoreaction was observed in two groups of cells only with an alpha-endorphin-antiserum. These cells are azocarmine ground positive earth and paraldehyde-fuchsin ground negative earth or Gomori ground negative earth. In the brain, immunohistological staining was completely negative.
Due to linear constraints over the nearest neighbour frequencies the order of the linear dependence of DNA CD spectra is 8. The computation of the CD signals of the 10 nearest neighbour configurations is therefore not possible if these signals are linearly independent. We show that the method proposed by Allen et coll. does not allow to obtain these signals.
The effects of peritubular salicylate for chloride substitution were studied in the isolated perfused Necturus kidney. This substitution resulted in changes of cell membrane p.d., varying from tubule to tubule; the withdrawal of the test-anion invariably produced a steep and prolonged depolarization. Exposure of the tissue to salicylate brought about, in addition, electrical uncoupling of junctional membranes, which was not related to concomitant changes of membrane p.d.
In the newborn female Rat, no transient LH and FSH serum surges were observed between 0 and 2 hrs., as compared with the newborn male. In the newborn female, a progressive increase in serum gonadotropins was observed between 2 and 6 hrs. These results indicate that, at birth, the pituitary-gonadal axis reacts in a different way in male and female Rats.
The cysteinyl peptides of monomeric and polymeric IgA were studied by comparative autoradiography. Autoradiographies of polymeric IgA (containing or lacking J chain) showed an extra cysteinyl peptide which was never found in the monomeric forms. A similar peptide was obtained when reduced IgA was cleaved by BrCN. The possible identity of this fragment is discussed.
Glycosidase and peptidase of non-treated Mouse peritoneal macrophages were characterized. The enzymatic activities of Corynebacterium parvum stimulated Mouse macrophages were compared to those of macrophages obtained from non-treated animals. All the enzymatic activities, but beta-C-galactosidase, were higher in stimulated Mouse macrophages.
HMBA induces differentiation in the whole population of some multipotential embryonic carcinoma cells. Morphological, biochemical and immunological changes can be observed even after short treatment. The cells lose the embryonal F9 antigen without acquiring H-2 antigens.
There exists a relationship between the chemical structure C--NO or N--NO and biological effects. p-nitrosomethylaniline, a C-nitroso compound, in contrast to its isomer, N-nitrosomethylphenylamine, a N-nitroso derivate, shows a marked action against microoganisms and is, alone, reduced enzymatically.
A new thiopyrimidine derivative has been synthesized. It can inhibit cell multiplication in Chick embryo fibroblasts, in Mouse Ehrlich ascites tumor cells and in Rat hepatoma cells (line Rueber) cultivated in vitro.
The purification of guanylate cyclase has been achieved. After electrophoresis on polyacrylamide gel only one protein band was observed. The low factor of purification must therefore be ascribed to the loss of an activator of guanylate cyclase. Stimulation of the activity by nitroprusside is also lost during purification. The purified enzyme follows Michaelis--Menten kinetics, it is activated by Mn++ ions and inhibited by triphospho nucleotides.
An optical polarizing microscope with a good coefficient of extinction permits the visualization of the cytoplasmic fibrillar body in living preparations and smears of leukemic cells (human leukemias and the L 5222 experimental leukemia). These inclusions are not visible by phase contrast microscopy nor in fixed and stained smears.
