Prevention of enteral radiocesium absorption by hexacyanoferrates(II) in piglets

The efficacy of different hexacyanoferrates(II) in preventing the enteral absorption of 134Cs was studied in piglets. As compared to the controls, oral application of 134Cs together with KFe[Fe(CN)6], NH4Fe[Fe(CN)6], or Fe4[Fe(CN)6]3 resulted in a strong reduction of the 134 Cs-uptake by more than 97%. The decrease in enteral absorption depends on the dose of administered hexacyanoferrate(II), whereas differences between the compounds under study were small. The biological half-life of 134Cs in non-hexacyanoferrate(II) treated piglets was 21.6 +/- 3.3 days (mean +/- SD).     

Physical halflife of radiochemically pure (> 99.9999%) P59Fe and its metabolicturnover rate in man

Zusammenfassung Erstmalig wurde radiochemisch reines⁵⁹Fe (> 99,9999%) eingesetztg, um die radioaktive Halbwertzeit des⁵⁹Fe mit 44,52±0,016 (¯m _a ±SE) Tagen entsprechend einer Umwandlungskonstanten=0.015568±0.000 0056 [d^–1] zu bestimmen. Radiochemisch reines⁵⁹Fe wird im menschlichen Körper bei Männern mit einer Umsatzrate von 0,032%/Tag (=1,2 mg Fe/Tag) und bei menstruierenden Frauen mit 0,052%/Tag (=1,4 mg Fe/Tag) ausgeschieden. Diese Gesamtkörper-⁵⁹Fe-Eliminationsrate entspricht dem Eisenbedarf des Menschen.     

Role of calcium in the histamine release induced by D-galactosamine from rat mast cells

Summary Rat peritoneal mast cells were isolated and purified by differential centrifugation in Ficoll. Cells pooled from three to four rats were suspended at approximately 10⁶ cells/ml in a buffered salt solution and incubated for 1 h at 37°C in 300 l volumes in the absence or presence (9×10^–4 M) of calcium chloride. Addition of D-galactosamine hydrochloride (DGM; 2.8×10^–4 M) caused (in addition to basal release) a mean ±SEM percent histamine release of 15.7±5.2 in the presence of Ca⁺⁺ and 19±4.9 in the absence of Ca⁺⁺ (p>0.05). It is suggested that D-galactosamine does not require extracellular Ca⁺⁺ for the release of histamine from the rat mast cell.A preliminary analysis of these results was presented at the International Symposium on calcium entry blockers and tissue protection, Rome, 15–16 March 1984.     

Cytosolic free Ca2+ in insulin secreting cells and its regulation by isolated organelles

Summary The role of Ca²⁺ in secretagogue-induced insulin release is documented not only by the measurements of⁴⁵Ca fluxes in pancreatic islets, but also, by direct monitoring of cytosolic free Ca²⁺, [Ca²⁺]_i. As demonstrated, using the fluorescent indicator quin 2, glyceraldehyde, carbamylcholine and alanine raise [Ca²⁺]_i in the insulin secreting cell line RINm5F, whereas glucose has a similar effect in pancreatic islet cells. The regulation of cellular Ca²⁺ homeostasis by organelles from a rat insulinoma, was investigated with a Ca²⁺ selective electrode. The results suggest that both the endoplasmic reticulum and the mitochondria participate in this regulation, albeit at different Ca²⁺ concentrations. By contrast, the secretory granules do not appear to be involved in the short-term regulation of [Ca²⁺]_i. Evidence is presented that inositol 1,4,5-trisphosphate, which is shown to mobilize Ca²⁺ from the endoplasmic reticulum, is acting as an intracellular mediator in the stimulation of insulin release.     

Nest cell lining of the solitary beeHylaeus bisinuatus (Hymenoptera: Colletidae)

The nest cell lining ofHylaeus bisinuatus (Hymenoptera: Colletidae) was shown by high-resolution solidstate [¹³C]NMR to be composed of lipid polymer and protein. The lipid polymer was shown by reduction and subsequent GC/MS analysis to be comprised of -hydroxy fatty acids (C₂₀, C₂₂, C₂₄ and C₂₆) and fatty alcohols (C₁₆ to C₃₀). The protein portion of the lining had a silk-like amino acid composition.     

Hydrolysis of isoprenyl diphosphates with the acid phosphatase fromCinnamomum camphora

Direct observations of the enzymatic hydrolysis of C₁₀ acyclic allylic isoprenyl diphosphates by an acid phosphatase from the leaves ofCinnamomum camphora (camphor tree) were made using¹H and³¹P NMR spectrometers. The measurements indicated that the allylic primary diphosphates, geranyl diphosphate and neryl diphosphate, were hydrolyzed to their corresponding alcohols in a sequential manner via their corresponding monophosphates, whereas the allylic tertiary diphosphate, linalyl diphosphate, was hydrolyzed only to its corresponding monophosphate.     

1-(Substituted)benzyl-5-aminoimidazole-4-carboxamides are potent orally active inhibitors ofTrypanosoma cruzi in mice

Summary 1-(Substituted)benzyl-5-aminoimidazole-4-carboxamides are potent orally active inhibitors ofTrypanosoma cruzi infections in mice. The most active compounds are the 1-(4-chlorobenzyl)- and 1-(3,4-dichlorobenzyl)-analogs (L-153,094 [2] and L-153,153 [4], resp.) which are approximately 7-fold more potent upon oral administration than nifurtimox (Lampit) in suppressing parasite levels in the blood of mice with acuteTrypanosoma cruzi infections.     

Effect of 15(R)-15-methyl-prostaglandin E2 on iron absorption in the rat

Summary The administration of 15(R)-15-methyl prostaglandin E₂ (15(R)-15-M-PGE₂) in vivo significantly diminished the uptake of⁵⁹Fe into blood, spleen, liver, femur and dried intestine of rats, whereas acetylsalicylic acid (ASA) increased the counts significantly. This effect of ASA was counteracted by 15(R)-15-M-PGE₂. It is suggested that prostaglandins (PGs) might play an important role in inhibiting iron absorption at the intestinal level.This work was supported by grant No.6638 from CONICET (Argentina). The technical assistance of Mrs María E. Castro and Norma Rizzo is gratefully acknowleged.     

Biomimetic synthesis of cannabispiran

Summary Total synthesis of cannabispiran (1) was accomplished by a biomimetic-type cyclization of the bibenzyl2, using K₃Fe(CN)₆ or MoOCl₄.Acknowledgment. Supported in part by the Research Institute of Pharmaceutical Sciences, School of Pharmacy, University of Mississippi.     

Invertebrate neuropeptides resembling vasotocin and some analogues: Synthesis and pharmacological properties

Summary The solid phase synthesis of three invertebrate vasopressin-oxytocin homologs: AVP-like factor, F₁ ¹, ([Leu², Thr⁴] AVT)² isolated from subesophageal and thoracic ganglia ofLocusta migratoria ³, Arg-conopressin-S⁴. ([Ile², Arg⁴] AVT), Lys-conopressin-G⁴ ([Phe², Arg⁴] LVT), both isolated from the venom of fish-hunting marine snails of the genusConus and six of their analogues is reported. These analogues are: [Arg⁴] AVT, [Ile²] AVT, [Leu²] AVT, [Phe², Arg⁴] AVT, [Arg⁴] LVT and [Ile², Arg⁴] LVT. All peptides were tested for antidiuretic and vasopressor activities.     

The effect of a phorbol ester upon the cholinergic regulation of potassium permeability in the rat submandibular gland

Acetylcholine releases calcium from cytoplasmic stores and permits an influx of calcium in salivary acinar cells. The resultant rise in [Ca²⁺]_i causes an increase in potassium permeability which is an important part of the secretory response. We have investigated the effects of 12-0-tetradecanoyl phorbol-13-acetate, a potent activator of protein kinase C, upon this regulation of potassium permeability in superfused pieces of rat submandibular salivary gland. This compound inhibited the initial [Ca²⁺]_o-independent component of the response of acetylcholine but had no effect upon the subsequent [Ca²⁺]_o-dependent phase. This compound does not, therefore, appear to inhibit receptor-regulated calcium influx.     

Influence of hydroxyurea,ellman's reagent and potassium ferricyanide on the radiosensitivity ofEscherichia coli

Zusammenfassung Zwei thiolbindende Agentien, K₃Fe(CN)₆ undEllmans Reagens wie auch der die DNA-Synthese hemmende Oxyharnstoff wurden als mögliche bakterielle Sensibilisatoren für Röntgenstrahlen untersucht. K₃Fe(CN)₆ und Oxyharnstoff im Medium können die Bakterien für die Inaktivierung durch Röntgenstrahlen besonders sensibilisieren (stärker mitE. coli B/r als mitE. coli B _s-1).     

Microbial influence on the sorption of137Cs onto materials relevant to the geological disposal of radioactive waste

Summary A major concern in the geological containment of radioactive wastes is the speed of movement of radionuclides from the repository, after their eventual leaching and release, into the geosphere and finally into the biosphere. Radionuclide sorption onto the host rock is an important retarding mechanism. Experimental evidence shows that the presence of microbes in this environment influences the sorption capabilities of the host rock. Their presence can decrease the amount of retardation of¹³⁷Cs, a common radionuclide in radioactive waste, by the solid phase. Sorption methods and data analysis procedures are presented and the implications for radioactive waste disposal assessments are discussed.     

Molecular compounds without chemical bonding

Zusammenfassung Die Infrarotspektren der Einschlussverbindungen [Ni(CN)₂(NH₃)(C₆H₆)] und [Ni(CN)₂(NH₃)C₄H₅N] wurden untersucht und mit den Spektren von gasförmigen und flüssigen C₆H₆ bzw. C₄H₆N verglichen.

---

---

Clathrate work was carried out under a research grant by University of Western Australia. Nickel cyanide-ammonia clathrates were further investigated by the author at the Punjab University (Chandigarh, India), University of Rome (Rome, Italy) and Fisk University (Nashville, Tennessee, USA).     

Fatty acid modulation of antiestrogen action and antiestrogen-binding protein in cultured lymphoid cells

Summary Nonsteroidal antiestrogens reversibly and specifically inhibited the proliferation of two estrogen receptornegative lymphoid cell lines (EL4 and Raji) in a dose-dependent manner. [³H]Thymidine incorporation of concanavalin A-stimulated primary splenocytes was also inhibited by 10^–6 M clomiphene (1-[4-(2-diethylaminoethoxy)phenyl]-1,2-diphenyl-2-chloroethylene). The antiproliferative effect could be prevented by the simultaneous presence in the growth medium of 10^–5 M linoleic acid or 10^–5 M arachidonic acid but not by 10^–6 M estradiol. Both lymphoid cell lines had high affinity antiestrogen-binding sites whose affinity could be altered by conditions of growth. Growth of EL4 cells in RPMI 1640 medium supplemented with charcoal-pretreated 5% fetal calf serum (charcoal-stripped medium) resulted in significantly higher affinity (K_d 0.54 nM±0.11 nM; n=6) than growth in medium supplemented with untreated serum (complete medium) (K_d=1.68 nM±0.48 nM; n=6) (p<0.001). This change in affinity was partly due to removal of fatty acids from the growth medium by charcoal pretreatment, since addition of 10^–5 M linoleic acid or 10^–5 M gamma-linolenic to charcoal-stripped medium decreased the affinity of the antiestrogen-binding protein. In contrast, growth in 10^–5 M stearic acid or 10^–5 M oleic acid did not significantly alter the affinity of the antiestrogen-binding protein, whereas 10^–5 M palmitic acid significantly increased its affinity. The same fatty acids were also tested for their intrinsic effects on EL4 cell proliferation. Oleic, linoleic and gamma-linolenic acids were growth stimulatory while stearic and palmitic acids were not. Thus linoleic and gamma-linolenic acids whose presence in the growth medium was associated with decreased affinity of [³H]tamoxifen (1-[4-(2-dimethylaminoethoxy)phenyl]-1,2-diphenylbut-1(Z)-ene) binding to the intracellular antiestrogen-binding protein were also growth stimulatory. Unsaturated fatty acids have previously been shown to inhibit binding of [³H]tamoxifen to the antiestrogen-binding protein in a cell-free system. The present observations demonstrate that unsaturated fatty acids also modify the affinity of the antiestrogen-binding protein in intact cells.     

Cu(CH3CN) 2 + , ein Mittel zum Studium homogener Reaktionen des einwertigen Kupfers in wässriger Lösung

Summary The quantitative acidimetric investigation (Bjerrum's method) of Cu^I coordination reactions in homogeneous aqueous medium is feasible by application of the easily accessible, well crystallized stable complex Cu(CH₃CN)₄ClO₄ in 0.1 to 1 molar CH₃CN aq., the stability of particles present in the system Cu^I, CH₃CN, H₂O being previously established polarographically. The advantage of the new acidimetric method lies in the possibility of investigating Cu^I in absence of Cu^II.     

Synthesis and contractile activity of the C-terminal heptapeptide of substance P with N5-dimethyl glutamine in the 6-position. Active site studies

Summary The synthesis and testing of [N⁵-dimethyl-Gln⁶]-SP_5–11 showed 37±12% contractile activity relative to SP, and intrinsic efficacy 98±4%. This finding indicates that the carboxamide groups of the dual Gln⁵-Gln⁶ moiety are not equally related with the contractile response of the C-terminal heptapeptide of SP.The authors wish to express their deep appreciation to Professor H. Niedrich and Dr J. Bergmann of the Institute of Drug Research, Academy of Sciences of DDR, Berlin, for their valuable help in providing the biological data.     

Effect of xanthurenic acid on P-450-dependent biotransformation by molting glands in vitro

Incubation of molting glands from the crayfishProcambarus clarkii (Y-organ) and the silkwormBombyx mori (prothoracic gland) with 23,24-[²H₄]-2-deoxyecdysone resulted in the production of deutero-ecdysone; this biotransformation was inhibited in the presence of xanthurenic acid. When the experiments were performed under an¹⁸O₂ atmosphere, the¹⁸O atom was introduced into ecdysone, as confirmed by mass spectrometry. We therefore suggest that xanthurenic acid inhibits P-450-dependent hydroxylation of 2-deoxyecdysone. However, deutero-2-deoxyecdysone was not converted to 3-dehydroecdysone when using Y-organs in vitro, although it is a major product. We therefore conclude that the biosynthetic pathway of ecdysteroids inP. clarkii branches at an early step.     

Displacement activity of some natural cularine alkaloids at striatal3H-SCH 23 390 and3H-raclopride binding sites

Five natural cularines isolated from the aerial parts ofSarcocapnos crassifolia (Fumariaceae) and a cularioid isolated from the bark ofGuatteria ouregou (Annonaceae) were tested for their ability to displace³H-SCH 23 390 and³H-raclopride from their striatal binding sites. Celtisine, breoganine and cularidine were able to inhibit the binding at D-1 and D-2 dopaminergic sites at nanomolar concentrations. Other alkaloids were active at micromolar concentrations. These data suggest that the presence of an oxepine system in the isoquinoline skeleton could lead to compounds which would be very active and possibly selective at dopaminergic receptor sites.     

Lipid characterization and14C-acetate metabolism in catfish taste epithelium

Summary The catfish,Ictalurus punctatus is an important model system for the study of the biochemical mechanisms of taste reception. A detailed lipid analysis of epithelial tissue from the taste organ (barbel) of the catfish has been performed. Polar lipids account for 62±1% of the total, neutrals for 38±1%. Phosphatidyl-cholines, serines and ethanolamines are the major constitutents of the polar fraction. Plasmalogen concentration is high relative to that of non-neural tissues. [¹⁴C]-Acetate is incorporated into cell lipid fractions after incubation of barbel tissue at 37°C for 60 min. Percentage amounts of most lipids change with time during this in vitro incubation. The phospholipids are the most metabolically active fractions. This work yields information for continuing reconstitution experiments and indicates that the taste epithelium of this important model system is a metabolically active tissue capable of supporting lipid turnover/synthesis.This work was supported in part by NIH Research Grant No. NS-23622, NS-22620, and by the Veterans Administration.