Effect of estradiol-17ß and prostaglandins on rat myometrial gap junctions

The effects of estradiol-17ß and indomethacin on myometrial gap junction development, plasma estradiol levels and uterine PGF_2α content were evaluated in immature and/or ovariectomized, mature rats. High doses of estradiol stimulated the development of gap junctions in the myometrium of animals from both groups. Concomitant injections of estradiol and indomethacin to ovariectomized rats potentiated the estradiol stimulation of gap junctions. Plama estradiol levels were lower in ovariectomized rats treated with both estradiol and indomethacin than in animals treated with estradiol alone. Indomethacin also enhanced the uptake and retention of ³H-estradiol into uterine tissues. Uterine PGF_2α content of ovarectomized rats was stimulated with the initial injection of estradiol but thereafter, the PGF_2α content declined with repeated injections to values lower than that observed in controls. Prostaglandin F_2α content in tissues from rats treated with estradiol plus indomethacin were also higher than that observed in rats treated with indomethacin alone, however, the values obtained in both groups were significantly lower compared to those from control animals. These results are consistent with the hypothesis that steroid hormones and prostaglandins regulate myometrial gap junction formation. Regulation of myometrial gap junctions by prostaglandins is discussed with respect to down regulation of the steroid-receptor mechanism and effects on cyclo-oxygenase or lipoxygenase products.     

Microbial transformation of primaquine by Candida tropicalis

The microbial metabolism of primaquine, a 6-methoxy-8-aminoquinoline antimalarial agent, was investigated. The yeast Candida tropicalis was found to convert primaquine to the previously reported N-acetylated derivative. On continued incubation of C. tropicalis in the presence of the N-acetylated derivative, a minor dimeric metabolite was formed. The proposed structure of the metabolite was based primarily on the analysis of its spectroscopic properties (1H and 13C nuclear magnetic resonance spectra and field-desorption mass spectrum). The structure of the metabolite was proven by direct comparison with an authentic sample of the minor dimeric metabolite prepared by treatment of the N-acetylated derivative with formaldehyde in the presence of formic acid in methanol.     

A comparison of narcotic analgesics with neuroleptics on behavioral measures of dopaminergic activity.

Because of many practical difficulties which are encountered in obtaining direct evidence for the involvement of brain neurotransmitters in the action of narcotic drugs, several indirect procedures are often employed. One such method is to compare on the same measures of drug action the narcotic drugs with a non-narcotic drug having a known mechanism of action. Haloperidol is a prototype non-narcotic drug which blocks dopamine receptors and many of its actions are believed to be associated with this receptor blockade. In this paper we compare various actions of haloperidol or other neuroleptics with morphine or other narcotic analgesics using the same testing parameters. We hope that such a comparison would evaluate the role of dopamine receptors in narcotic action and narcotic dependence. This discussion is limited only to the behavioral measures as a comparison of neurochemical measures was recently reviewed in another paper (1).     

Formation of some monopositive and dipositive carbonium ions in chlorosulphuric acid. Part XV

Tetraphenyl-p-xylene-glycol, tetraphenyl-phthalein and Dipheno(3-10′)thiazinyl are shown to form dipositive carbonium ions, but triphenyl acetic acid, 2-3-5-6 tetramethyl benzoic acid, 2-3-4-5-6 pentamethyl benzoic acid, tert-butyl alcohol, triphenyl carbinol, tri-p-tolyl carbinol, tri-o-tolyl carbinol, tri-p-chlorophenyl carbinol and tri-p-nitrophenyl carbinol form monopositive carbonium ions in chlorosulphuric acid, as revealed by conductometric and u.v. spectral studies. Oxalyl chloride decomposes while ethylene glycol is sulphonated in chlorosulphuric acid. Dichloroethane behaves as a non-electrolyte but dibromomethane disproportionates in this medium.     

Thermodynamics of the binding of galactopyranoside derivatives to the basic lectin from winged bean (Psophocarpus tetrogonolobus).

The thermodynamics of the binding of D-galactopyranoside (Gal), 2-acetamido-2-deoxygalactopyranoside (GalNAc), methyl-alpha-D-galactopyranoside, and methyl-beta-D-galactopyranoside to the basic agglutinin from winged bean (WBAI) in 0.02 M sodium phosphate and 0.15 M sodium chloride buffer have been investigated from 298.15 to 333.15 K by titration calorimetry and at the denaturation temperature by differential scanning calorimetry (DSC). WBAI is a dimer with two binding sites. The titration calorimetry yielded single-site binding constants ranging from 0.56 +/- 0.14 x 10(3) M-1 for Gal at 323.15 K to 7.2 +/- 0.5 x 10(3) M-1 for GalNAc at 298.15 K and binding enthalpies ranging from -28.0 +/- 2.0 kJ mol-1 for GalNAc at 298.15 K to -14.3 +/- 0.1 kJ mol-1 for methyl-beta-D-galactopyranoside at 322.65 K. The denaturation transition consisted of two overlapping peaks over the pH range 5.6-7.4. Fits of the differential scanning calorimetry data to a two-state transition model showed that the low temperature transition (341.6 +/- 0.4 K at pH 7.4) consisted of two domains unfolding as a single entity while the higher temperature transition (347.8 +/- 0.6 K at pH 7.4) is of the remaining WBAI dimer unfolding into two monomers. Both transitions shift to higher temperatures and higher calorimetric enthalpies with increase in added ligand concentration at pH 7.4. Analysis of the temperature increase as a function of added ligand concentration suggests that one ligand binds to the two domains unfolding at 341.6 +/- 0.6 K and one ligand binds to the domain unfolding at 347.8 +/- 0.6 K.