The effect of 5-bromodeoxyuridine on mouse embryos during neurulation in vitro

Mouse embryos explanted at various stages during neurulation were cultured for 20-28 h in the presence of 25-900 micrograms/ml of 5-bromodeoxyuridine (BUdR). BUdR strongly inhibited closure of the cranial neural tube, which was found to be stage-dependent. When mouse embryos were exposed to BUdR after development of the concave curvature in the neuroepithelium of the midbrain to the upper hindbrain regions, they became insensitive to the drug-induced open cranial neural tube. Histological observations showed that BUdR interfered with interkinetic migration and cytokinesis of the neuroepithelial cells. These cellular abnormalities were not dependent on the morphological development of the cranial neural folds. The 3H-BUdR experiment confirmed that the label was mostly incorporated into the DNA fraction.     

Asscorbic acid portects against male infertility in a teleost fish

An animal unable to synthesize ascorbic acid uniquely minicks human and non-human primates. Therefore, in this study we used the rainbow trout, a teleost fish, as the model animal to study the importance of dietary ascorbic acid on the fertilizing ability of sperm. A high concentration of ascorbic acid in semen plays a key role in maintaining the genetic integrity of sperm cells, by preventing oxidative damage to sperm DNA. This study will show that the concentration of asorbic acid in seminal plasma refelcts the dietary fed either an ascorbate-free diet (from 4.74±0.9 to 0.16±0.08 g ml^–1) or an ascorbate-rich diet (from 37.9±4.7 to 17.7± 3.2 g ml^–1) during the sperimnation season. The relationship between ascrobate status and fertility was studied in six groups of fish fed graded levels of ascorbic acid, which sperimated over a 150-day-period. Sperm from individual males was used to fertilize several batches of eggs. When the seminal plasma ascorbate concentration decreased to 7.3 g ml^–1 a significant decrease of fertilization rate and the hatching rate of embryos resulted. This is the first evidence that dietary ascorbate level directly affected sperm quality and influenced male fertility in a scruvy-prone vertebrate.     

Inhibition of reduction in female mouse meiosis

Zusammenfassung Es wurde der Hemmungseffekt von Colcemid und Vincristin auf die Méiose bei Mäuseeiern in vitro und in vivo untersucht. Die in vitro wirksame minimale Konzentration für Vincristin wurde bei 4×10^–7 g/ml, für Colcemid bei 4×10^–3 g/ml gefunden. Die in vivo wirksame Minimaldosis von Vincristin war 1 g/g. Körpergewicht, von Colcemid 10 g/g Körpergewicht.

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Part of this data was presented in abstract in Clinical Research, vol. XV, No. 2, April 1967, p. 268.     

Temperaturabhängigkeit der elektrischen Leitfähigkeit einiger Tocopherole

Summary The electrical dark conductivity of several tocopherols has been measured and found to be analogous to that of organic semiconductors. Conductivity at 25°C varies between 10^–14 and 10^{–11 –1} cm^–1. The temperature dependence of the tocopherols yields a thermal activation energy of 1.6 ± 0.15 eV for most of the substances.     

Glutamate decarboxylase in barley aleurone and its relationship toα-amylase development during germination

Résumé L'enzyme glutamate décarboxylase se trouve dans les extraits d'eau de l'aleurone de l'orge. Au début de la germination, l'activité de cette enzyme augmente, mais après, quand apparait l'enzyme -amylase, elle diminue. Quoiqu'au dessous d'une concentration de 2×10^–6 M l'acide -amino butyrique (GABA) n'affecte pas l'activité de l'-amylase in vitro, la GABA à 5×10^–6 M peut provoquer une inhibition de 25% qui n'est pas modifiée par des concentrations de GABA comprises entre 5×10^–6 M et 10^–3 M.     

Antagonism by haloperidol of the suppression of exploratory locomotor activity induced by the local application of(−)3-(3-hydroxyphenyl)-N-n-propylpiperidine into the nucleus accumbens of the rat

Summary The injection of (–)3-PPP into the nucleus accumbens, 10 g/side, produced a suppression of exploratory locomotor activity without affecting treadmill locomotion. Furthermore, the suppression of exploratory locomotor activity produced by (–)3-PPP was antagonized by the administration of haloperidol, 25–50 g/kg i.p.Acknowledgments. The figures were prepared by M. Kröning at the Department of Psychology, University of Göteborg. This work was supported by Torsten and Ragnar Söderberg's Foundation, Magn. Bergvall Foundation and Åke Wiberg Foundation.     

Physicochemical studies of indocyanine green (ICG): absorbance/concentration relationship,pH tolerance and assay precision in various solvents

Summary Indocyanine green (ICG) obeyed the Beer-Lambert law within the concentration range 1.25 g/ml–10.0g/ml in distilled water, methanol, dimethylformamide (DMF), 1.2-propanediol and aqueous buffers (pH 9.0), but only up to 7.5 g/ml in human bile and 0.5% human albumin, and only to 5.0 g/ml in human duodenal fluid. ICG was rapidly (<1 h) decomposed to a colorless derivative at pH<5 and >11, but remained relatively stable for 48 h at pH 8–10. ICG is an indicator and a weak acid with a pKa of 3.27. In bile stabilized with 25% methanol, the precision of the method (CV) is 5% and the accuracy is 106–127%.     

The effect of insulin on the electrophoretic mobility of rat hepatocytes

Summary The addition of insulin (10 U) to a suspension of isolated hepatocytes in Krebs-Ringer bicarbonate solution. causes an increase in the negative electrophoretic mobility of the cells from –1.68 m sec^–1 V^–1 cm to 2.26 m sec^–1 V^–1 cm. This observation supports the findings by other workers that the binding of insulin to its receptor leads to a marked change in the membrane.Acknowledgment. We wish to thank the Medical Research Council for the provision of the microelectrophoresis apparatus and initial running costs of the project.     

Über «therapeutische» und «toxische» Digitoxigeninwirkungen auf elektrophysiologische Messgrössen des Meerschweinchenvorhofs

Summary Therapeutic concentrations of digitoxigenin (10^–7–3× 10^–7 g/ml), producing positive inotropic effects, did not alter resting and action potentials of electrically driven guinea-pig auricles. However, toxic concentrations of digitoxigenin (5 × 10^–7–10^–8 g/ml), producing arrhythmias and contracture of the myocardium, had a marked influence upon resting and action potentials and conduction velocity.     

Effect of pulsing electromagnetic fields on DNA synthesis in mammalian cells in culture

Summary DNA synthesis in Chinese hamster V79 cells was significantly enhanced when they were exposed to weak, pulsing electromagnetic fields generated by specific combinations of the pulse width (25s), frequency (10, 100 Hz) and magnetic intensity (2×10^–5 8×10^–5T). Conversely the DNA synthesis of cells in the fields at 4×10^–4 T was repressed to 80% of that in controls not exposed to the fields.This work was supported by Kaken Pharmaceutical Co., Ltd, Tokyo, Japan, and in part by a Grant-in-Aid from the Ministry of Education, Science and Culture of Japan and from the Foundation for Life Science Promotion Tokyo, Japan to I.K.     

Studies on hydrogen,halides and thiocyanate ions in dioxane-water mixtures at various temperatures

Summary The free enrgies of transfer (G _t ⁰ ) of H⁺, Cl^–, Br^–, I^– and SCN^– ions from water to 10, 20, 30 and 40% dioxanewater mixtures have been studied from potentiometric measurements. For anions the G _t ⁰ values are in the order Cl^–>Br^–>SCN^–>I^–.     

The uptake of iodinated protein by spleen cells of guinea-pigs in vitro

Zusammenfassung 6×10^–10 g bis 10^–4 g J 125 Rinderserum-Albumin (BSA) bzw. 1,0×10^–7 bis 1,0×10^–6 g J 125 Rinderserum--Globulin (BGG) werden 3 × 10⁷ Milzzellen normaler Meerschweinchen in vitro angeboten. Unabhängig von der Höhe des Angebotes beträgt die Menge des aufgenommenen BSA 1%, die des aufgenommenen BGG 10% des Angebotes. Durch 4C Inkubations-temperatur wird die Aufnahme z.T. behindert. Die Aufnahme findet nach wenigen Sekunden Inkubationszeit statt und ist nach etwa 2–3 min abgeschlossen.

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The work was supported by a grant of the Stiftung Volkswagenwerk and of the Deutsche Forschungsgemeinschaft.     

Effects of selective dopamine D1 and D2 antagonists on male rat sexual behavior

Summary The effects of selective dopamine (DA) D₁ and D₂ antagonists on male rat sexual behavior were investigated. The D₁ antagonist (+)SCH-23390, 25–100 g kg^–1 s.c. –20 min, and the D₂ antagonist raclopride, 0.1–1.6 mg kg^–1 s.c., –20 min, decreased both the number of mounts and intromissions preceding ejaculation. No statistically significant effects in the time up to ejaculation or in the time up to the first intromission were noted, whereas both compounds produced a statistically significant increase in the post-ejaculatory interval. The effect can generally be characterized as psychomotor inhibition, and no evidence was obtained for a specific role of DA D₁ or D₂ receptors in the mediation of male rat sexual behavior.The expert technical assistance of Ms Elisabeth Wallin is gratefully acknowledged. The figures were skilfully prepared by Ms Madelene Kröning at the Department of Psychology. This study received support from the Bank of Sweden tercentenary Foundation, The Swedish MRC and Wilhelm and Martina Lundgren Foundation.     

3′–5′-cAMP and lysosome membrane labilization

Zusammenfassung Es wird gezeigt, dass 3–5-cAMP (10^–3 M) und Theophyllin (10^–4 M) die Permeabilität derjenigen Lysosmen-Membranen steigern, die aus Rattenleberzellen in bezug auf saure Phosphatase and in bezug auf -Glucuronidase-Enzyme präpariert wurden.     

Influence of environmental conditions on the amount of N2O released from activated sludge in a domestic waste water treatment plant

Waste water purification is characterized by intensive mineralization and nitrification processes. Because of the high O₂ demand, temporarily anaerobic conditions may be produced, and denitrification by nitrifying organisms as well as heterotropic denitrification may contribute to N₂O release. In situ measurements (1993–1994) suggest that N₂O is released from activated sludge in a domestic waste water treatment plant at an average rate of 1040 g m^–2h^–1 with a range between zero and 6198 g m^–2h^–1. The production of N₂O seems to be related to the concentration of NO ₂ ^– and NO ₃ ^– as well as to the pH. In the waste water about 75–200 g N₂O l^–1 is dissolved. This N₂O is released after discharge into the receiving waters. The N₂O is produced essentially by nitrification rather than by heterotropic denitrification. On a long-term scale the increasing use of mechanical-biological waste water purification plants world-wide may add increasingly to the anthropogenic production of N₂O, although the present amount of N₂O produced is negligible compared to its global terrestrial production.     

Effect of the calmodulin inhibitor R24571 (calmidazolium) on rat embryos cultured in vitro

Summary The possible effects of inhibition of the calcium-binding protein, calmodulin, on mammalian morphogenesis have been investigated by culturing rat embryos in vitro from 9 1/2 to 11 1/2 days of development in the presence of R24571 (calmidazolium), a specific inhibitor of calmoldulin. Embryos cultured in 10^–2 mM R24571 for 48 h show inhibited development and exhibit a range of morphogenetic abnormalities including assymetry and neural tube defects. Embryos exposed to R24571 for the first 24 h of a 48 h culture are more severely affected than embryos exposed to R24571 for the last 24 h.Acknowledgments. We wish to thank Mr C. Veltkamp and Mr B. lewis for their expert help with the scanning electron microscopy and photography.     

Dopamine and cerebral cortical blood flow in the rat

Summary Dopamine topically applied to the cerebral cortex (1–20 g/ml) or administered i.v. (0.5–64 g/kg/min) has no effects on cerebral cortical blood flow in the rat.     

Relationship between chlorophyll a content and protein content of invertebrate symbioses with algae or chloroplasts

Summary The chlorophyll a and protein contents of invertebrates containing autotrophic symbionts are indices of symbiont and host biomass, respectively, and the chlorophyll a content per unit protein is a good measure of symbiont: host ratio. For three different associations, the chlorophyll a content per unit protein is 0.01–0.02 g g^–1.The hydra andE. viridis were provided by M. H. Christopher and J. R. Turner. I thank Professor D. C. Smith, Dr J. B. Searle and Dr T. A. V. Rees for the valuable comments on drafts of this paper. This work was supported by research grants from S.E.R.C.     

Reinforcement with naloxone of N-n-propylnorapomorphine (NPA) capability for stimulating male rat copulatory behavior

Summary Naloxone at a dose of 2 mg·kg^–1, which per se did not significantly alter the copulatory pattern of sexually active adult male rats, did significantly reduce the intromission frequency as well as latency to ejaculation when administered before a low and inactive dose of N-n-propylnorapomorphine (0.5 g·kg^–1).     

Influence of cyclic nucleotides on protein synthesis in vascular smooth muscle

Summary The incorporation of leucice-¹⁴C into protein in bovine mesenteric arteries was augmented by cyclic GMP (10^–3 M) and decreased by cyclic AMP (10^–3 M). There was no effect of 5 AMP (10^–3 M). The phosphodiesterase inhibiting drugs theophylline (10^–3 M) and papaverine (5×10^–5 g/ml) both decreased the leucine-¹⁴C incorporation.We are indebted to Mrs.Lena Burlin for hear assistance. Finacial support has been provided by the Swedish State Medical Research Council (No. 04X-101X-4498).