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Teratogenic effects of cadmium on Bufo arenarum during gastrulation   总被引:2,自引:0,他引:2  
Developing Bufo arenarum embryos were treated during gastrulation with cadmium chloride in concentrations ranging from 6x10(-7) to 1.5x10(-5)M Cd++ at 20 and 30 degrees C. Initial failures at gastrulation result mainly in axial incurvations, microcephaly, hydropsy and abnormal tail formation. The higher temperature has a dual effect: at high concentrations of Cd early malformations are significantly increased; whereas, at low concentrations the higher temperature prevents alterations.  相似文献   

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Summary Evidence was found that cornea in tail ectopic eyes of Xenopus tadpoles has the capacity to regenerate a new lens.Supported by an award from the Science Research Council.  相似文献   

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Zusammenfassung Leucin wurde in einer Dosis von 0,2 ml einer 1%igen Lösung im Amnion von 9 Tage bebrüteten Hühnereiern injiziert. Morphologische Anomalien mit abnormen Funktionen, meistens in den Beinen und der Nackenregion, wurden beobachtet, während Röntgen-Aufnahmen Stellungsanomalien in Gelenken der Extremitäten und der Halswirbel zeigten.

This work was aided by grants from Sigrid Juselius Foundation.  相似文献   

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Zusammenfassung Nach einmaliger i.p.-Injetion von 700 mg/kg Niridazol wurden männiiche Mäuse wiederholt mit unbehandelten Weibchen wöchentlich über 2 Monate hinweg gepaart und die Ova gesammelt. Es konnte eine starke Herabsetzung der Befruchtungsraten 3–4 Wochen nach Paarung festgestellt werden, was die Annahme einer Wirkung auf die meiotische Teilung der Spermatozyten und Spermatiden nahelegt. Nach der 7. Woche trat eine Normalisierung der Fruchtbarkeitsrate ein.

This work was supported by NIH Grants No. C-6516 and No. FR 05526 and by the Environmental Protection Agency Contract No. CPA-70-17.  相似文献   

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Zusammenfassung Die Michaelis-KonstanteKm der katheptischen Aktivität im Schwanzgewebe von Xenopuslarven wird durch das stark regenerationshemmende leucinanaloge Aminoketon E 9 nicht beeinflusst, obwohl nach 5 Tagenin vivo-Behandlung der Larven mit 3 · 10–3 M E 9 ein starker Anstieg der spezifischen Kathepsinaktivität im Schwanzgewebe zu beobachten ist. Das leucinanaloge-Bromallylglycin (BAG) hemmt die Regeneration wenig, erhöht jedoch dieKm deutlich. Es wird postuliert, dass E 9 eine Zunahme der Kathepsine im Schwanzgewebe bewirkt, ohne die kinetischen Eigenschaften dieser Enzyme zu beeinflussen, während BAG an den aktiven Zentren der Kathepsine wirkt und die Affinität zum Substrat herabsetzt.

With the aid of a grant from the Schweizerischer Nationalfonds zur Förderung der wissenschaftlichen Forschung. — Author's present address: Institut für experimentelle Gerontologie, Nonnenweg 7, Basel (Switzerland).  相似文献   

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Summary Reduction of DA receptor activity via depletion of DA stores does not seem to influence GABA turnover in the forebrain and in the DA cell body rich region of the midbrain.This work was supported by a grant (MH25504-03) from the National Institute of Health, USA, and by Magn. Bergvalls Stiftelse and Funds from the Karolinska Institute, Stockholm, Sweden.  相似文献   

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Male and female gametes of Drosophila were treated with various doses of ionizing radiations: X-rays at different energy, and gamma-rays from 2 sources given singly and in 2 temporal sequences. The induced lethality was assessed in successive developmental stages by scoring the number of eggs, larvae and adults. The results clearly show that the effects of various radiations appear in terms of difference among developmental stages and/or between treated sexes/genotypes. It is suggested that the various energies affect different gene functions which are not completely independent, as supported by the non-additive effects of the two temporal sequences.  相似文献   

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Résumé Des souris ayant subi un traitement journalier au PHA, entrepris 4 jours avant l'implantation de cellules leucémiques L1210 on survécu plus longtemps que celles qui furent traitées au sel. Le traitement journalier entrepris 24 h après l'inoculation de cellules leucémiques n'a pas eu d'effet sur la durée de survie. Par le traitement au PHA combiné à la 6-mercaptopurine, la durée de vie fut plus longue que par celui que l'on obtint avec d'autres agents employés isolément. Un mécanisme proposé pour l'effet antileucémique de PHA est discuté.

This work was supported in part by Contract No. NIH-70-2001 from the Cancer Chemotherapy National Service Center, National Cancer Institute and by a grant from the Life Insurance Medical Research fund No. G-68-11.  相似文献   

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Summary Male and female gametes ofDrosophila were treated with various doses of ionizing radiations: X-rays at different energy, and gamma-rays from 2 sources given singly and in 2 temporal sequences. The induced lethality was assessed in successive developmental stages by scoring the number of eggs, larvae and adults. The results clearly show that the effects of various radiations appear in terms of difference among developmental stages and/or between treated sexes/genotypes. It is suggested that the various energies affected different gene functions which are not completely independent, as supported by the non-additive effects of the two temporal sequences.Acknowledgments. The authors wish to thank Prof. D.L. Palenzona for valuable discussion and criticism and Mrs C. Brunaleschi and Mr E. Boschieri for their technical assistance.  相似文献   

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Summary Young froglets ofRana breviceps do not possess the power to regenerate forelimbs after amputation through metacarpals. However, 5 min immersion of limb stumps in an oily solution of 150,000 IU vitamin A palmitate immediately after amputation, and once on each of the 3 subsequent days, induced definite though hypomorphic regeneration in 100% cases.Acknowledgments. This research was supported by a grant from the Council of Scientific and Industrial Research, India.  相似文献   

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Summary PGE1 increases cholesterolemia without lipemia modifications. In bile there are not modifications in cholesterol levels and total lipids appear diminished. PGE2 raise the lipemia and have no effect in cholesterolemia, moreover bile cholesterol and total lipids exhibit no changes. Both PGE1 and PGE2 decreased the bile volume.Acknowledgment. The authors wish to express their thanks to the Upjohn Laboratory for kindly furnishing the prostaglandins employed, with the relevant bibliography, and to Mr.F. A. Mori for the English translation.  相似文献   

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Summary In mice treated with mitomycin C, elimination of spermatocytes is observed during meiotic division, whereby an increase in number of the eliminated cells is closely related to an increase in the frequency of spermatocytes with chromosome aberrations at M-I.  相似文献   

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Zusammenfassung Nachweis adrenerger Synapsen an Zellkörpern der duodenalen submukösen Ganglien von Ratten nach 6-Hydroxydopamin-Behandlung.

Part of this work was done while I was on sabbatical leave in the Department of Anatomy, Monash University, in 1972, and I thank ProfessorG. C. Schofield for his kindness and encouragement during my stay there. Mr.H. L. Chan rendered invaluable technical assistance.  相似文献   

18.
D P Hanlon  V H Ferm 《Experientia》1989,45(8):767-770
A normally teratogenic dose of cadmium ions administered to hamsters late in gestation does not cross the placental barrier nor does it result in placental pathology. Our finding, which differs from data for other rodents, may be due to differences in the chemical status of cadmium in the placental cytosols.  相似文献   

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Summary A normally teratogenic dose of cadmium ions administered to hamsters late in gestation does not cross the placental barrier nor does it result in placental pathology. Our finding, which differs from data for other rodents, may be due to differences in the chemical status of cadmium in the placental cytosols.This project has been financed in part with Federal funds from the U. S. Environmental Protection Agency under grant number R 81 1078. The contents do not necessarily reflect the views and policies of the Environmental Protection Agency nor does mention of trade names or commerical products constitute endorsement of recommendation for use.  相似文献   

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L R Rodrigo  F Pozo  B Marin  O Schiaffin 《Experientia》1976,32(12):1604-1605
PGE1 increases cholesterolemia without lipemia modifications. In bile there are not modifications in cholesterol levels and total lipids appear diminished. PGE2 raise the lipemia and have no effect in cholesterolemia, moreover bile cholesterol and total lipids exhibit no changes. Both PGE1 and PGE2 decreased the bile volume.  相似文献   

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