Colchicine-estrogen interactions

Summary Colchicine does not block estrogen-induced recognition of uterine blood vessel surface by eosinophils, but interfers with their migration through endothelial lining and therefore blocks estrogen-induced uterine eosinophilia and edema.Acknowledgments. This work was supported by grant 4002 from the Servicio de Desarrollo Científico y Creación Artística of the University of Chile. Technical help of Mr D. Sáez is appreciated.     

Estrogen action in the male

Summary Estrogen administration induces a migration of eosinophil leukocytes to ductus deferens.Acknowledgments. This work was supported by grant No. 4002 from the Servicio de Desarrollo Científico y Creación Artística of the University of Chile. We thank Mr D. Sáez and Mr E. Astudillo for technical help.     

Potassium transfer from brain to blood during sustained hyponatraemia in the newborn calf

Summary The effect of dilutional hyponatraemia on cerebral blood flow and oxygen consumption, and net transfer of K⁺ to the circulation from brain tissue drained by the sagittal sinus was investigated in anaesthetized calves. Cerebral blood flow decreased, and net transfer of K⁺ to the circulation increased during hyponatraemia.Acknowledgments. The expert assistance of Miss B.N. O'Connor, Miss D. McNaughton and Mr P.M.M. Bircham is gratefully acknowledged.     

The chromosomes ofBufo rubropunctatus andBufo chilensis (Anura,Bufonidae) and other species of thespinolosus group

Summary The chromosomes ofBufo rubropunctatus andB. chilensis (on basis of adults) are described for the first time. These chromosomic sets are compared with the karyotypes ofB. spinolosus andB. variegatus and other species ofspinolosus group. The importance of the secondary constrictions applied to the phylogeny ofBufo are discussed.Supported by Proyecto N⁰ S-77-47, Dirección de Investigación, Universidad Austral de Chile.I would like to thank Dr J. M. Cei for collecting the Argentinian toads. Mr N. Diaz collected the specimens from Santiago, Chile.The technical assistence of Sonia Lacrampe is acknowledged with appreciation.     

Cerebral ammonia production during hypoglycaemia in the newborn calf

Summary The effect of insulin hypoglycaemia on cerebral blood flow, and cerebral metabolic rates of glucose, oxygen and ammonia was investigated in the unanaesthetized newborn calf. A net loss of ammonia from the brain occurred during hypoglycaemia, and was greater in convulsing than in comatose animals.Acknowledgments. The expert assistance of Mr P.M.M. Bircham and Miss B.N. O'Connor is gratefully acknowledged. This work was supported by the Medical Research Council.     

Chromosome aberrations in in vitro irradiated lymphocytes from human cord blood

Summary An in vitro dose effect curve of dicentric chromosome aberrations in human cord blood lymphocytes has been obtained for 250-kV X-rays. This is compared with a curve prepared in an identical manner using blood from adults. The comparison shows a marginally higher dicentric yield in blood of newborns at doses above about 250 rads.Acknowledgment. We wish to thank Miss P. Orledge of the John Radcliffe Hospital, Oxford, for samples of cord blood, Mr M.J. Corp of the MRC Radiobiology Unit, Harwell, for irradiating the samples and Mr A.A. Edwards of NRPB, for help with statistics. The work was partly supported by Euratom Contract No. 171-76-1 BIO UK.     

Differential effect of silybin on the Fe2+-ADP and t-butyl hydroperoxide-induced microsomal lipid peroxidation

Summary We have observed a differential effect of silybin dihemisuccinate on rat liver microsonal oxygen consumption and on lipid peroxidation induced by NADPH-Fe²⁺-ADP and t-butyl hydroperoxide. These results are ascribed to the antioxidant properties of the flavonoid. The differences observed in the effect of the catalysts may be a consequence of the different capacity of silybin to act as a scavenger of free radicals formed by NADPH-Fe²⁺-ADP or t-butyl hydroperoxide.This research was supported in part by grant B-2019-8412 from Dirección de Investigación y Bibliotecas, Universidad de Chile.     

The growth responses of hamster chondrocytes,dermal fibroblasts and embryo cells to whole blood serum and plasma-derived serum

Summary Autoradiographic studies with³H-thymidine demonstrated that the growth responses of hamster chondrocytes, dermal fibroblasts and embryo cells, respectively, differed in media containing whole blood serum (WBS) and plasmaderived serum (PDS). Dermal fibroblasts seemed to require a growth factor from platelets for growth, but chondrocytes did not. Embryo cells showed an intermediate pattern of growth response to this factor.This work was supported by a Grant-in-Aid for Cancer Research from the Ministry of Education, Science and Culture and the Ministry of Health and Welfare of Japan.We thank Miss M. Tanaka and Miss K. Kawana for technical assistance.     

A simplified method for reading hemagglutinations on a flat-bottom microtitration plate in the mouse H-2 assay

Summary Kaliss' method for determining hemagglutination titer of mouse alloantiserum was modified to a simpler form. It became possible to read the hemagglutination directly on a flat-bottom microtitration plate using an inverted type microscope. Sensitivity of the modified method was almost the same as that of the original one. This method seems to be useful especially for the larger scale assay of H-2 specificities.Contribution from the National Institute of Genetics. Supported in part by grants-in-aid (No. 111510, 111504, 112105) from the Ministry of Education, Culture and Science, Japan.Acknowledgments. The excellent technical assistance provided by Miss M. Kuranou, Mr K. Sakakibara and Miss M. Tsuyuki is gratefully acknowledged.     

Effect of colchicine on long lasting synaptic modifications induced by hyperactivity

Resumen La facilitación de transmisión sináptica en un ganglio de cucaracha se puede inducir mediante hiperuso de reflejos anti-gravitatorios. La inyección intraganglionar de colchicina inhibe reversiblemente la modificación sináptica sin alterar la conducción nerviosa. Este resultado puede explicarse considerando que la colchicina bloquea el proceso de progresión axoplasmática.

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Acknowledgements. Supported by grants No. 76/72 and No. 2/73 from the Research Fund of the Catholic University of Chile. Colchicine was kindly supplied by Dr.Dalila M. Martines, Instituto Politécnico Nacional, México. We are greatly indebted to Dr.J. V. Luco, Catholic University of Chile, for helpful discussions and constructive criticism and to MissOfelia Fernández for excellent technical assistance.     

Types of response of insects on treatment with juvenile hormone active insect growth regulators

Summary The reactions of immature insects of more than 40 species placed in continuous contact with high doses of juvenile hormone active insect growth regulators were analyzed. 4 different types were recognized: Inhibition of both ecdysis and metamorphosis, defective metamorphosis, defective adult emergence and defective embryogenesis. The reactions are understood as a consequence of JH/ecdysone antagonism. The limits for the practical application of these substances are discussed.Acknowledgments. We wish to express our thanks to Miss M. Kälin, Miss M. Lehner, Mrs T. Mühle and Mr P. Müller for technical assistance and to Prof. G. Benz, Mr M. Gruber, Dr E. Günthart and Prof H. A. Schneiderman for helpful discussion and correction of the text.     

Metabolism of a biliary metabolite of phenacetin and other acetanilides by the intestinal microflora

Summary In vivo, rat intestinal micro-organisms mediate the metabolic hydrolysis of the biliary metabolite(N-acetyl-p-aminophenyl glucuronide) of phenacetin and related compounds.The authors acknowledge the financial support of the Medical Research Council and the technical assistance of Miss A. M. Pritchard, Miss J. A. Parr and Mr P. B. Wood.     

Evidence that superoxide radicals are involved in the hemolytic mechanism of phenylhydrazine

Summary Phenylhydrazine produces in the red blood cell the same effect as the enzymic system xanthine oxidase-xanthine, a superoxide radical generator system. Both effects are inhibited by the enzyme superoxide dismutase.This work was supported in part by grants Nos. 1045 and 3243 of Oficina Técnica de Desarrollo Científico y Creación Artística de la Universidad de Chile.     

Characterization of the estrogen receptors in the uterine and blood eosinophil leukocytes

Summary Estrogen receptors are found in the rat uterine and in the eosinophil-rich human blood leukocyte 24,000g fractions, but not in the low-eosinophil count human blood leukocyte 24,000g fraction. The total number of binding sites per blood eosinophil leukocyte is 7,400 sites per cell, and theK _d =5.6×10^–10 M.Acknowledgments. This work was supported in part by funds from the Unité de Recherches sur le Métabolisme Moléculaire et la Physio-Pathologie des Stéroïdes de l'INSERM, Hôpital de Bicetre, France, and by grant No. 2015 from the Oficina Técnica de Desarrollo Científico y Creación Artística of the University of Chile.     

Effectiveness of phosphocitrate and N-sulpho-2-amino tricarballylate,a new analogue of phosphocitrate,in blocking hydroxyapatite induced crystal growth and calcium accumulation by matrix vesicles

Summary Phosphocitrate and its analogue N-sulpho-2-amino tricarballylate were compared with ethane-1-hydroxy-1, 1-diphosphonate for inhibition of calcium phosphate crystallization in hydroxyapatite induced crystal growth and⁴⁵Ca uptake by matrix vesicles. Phosphocitrate (1 M) was the most potent inhibitor followed by ethane-1-hydroxy-1, 1-diphosphonate and N-sulpho-2-amino tricarballylate, the latter requiring a high concentration (100 M) to be equally effective as an inhibitor.Acknowledgments. We wish to thank Mr J. Jordan and Miss L.C. Ward for the excellent technical assistance and Mr R.J. Tennant for the transmission electron microscopy. We also thank the Golden Poultry Farming Industries Ltd., Hobart, Tasmania for their generous supply of broiler strain chickens.     

Chromosomal homology in southern Akodon

Summary Differential staining (G and C) of southern South AmericanAkodon are presented.A. olivaceus, A. longipilis andA. sanborni all have the same karyotype (2n=52, NF=58). A virtually identical band sequence is observed. This situation is interpreted using the canalization model of chromosomal evolution which stresses an optimum karyotype for each adaptive zone. Despite the high degree of conservation of the chromosome structures, the specific status of these species is supported by maintenance of distinctness when they occur in areas of sympatry.The research was partially supported by Proyecto de Investigación I-78-86, Dirección de Investigación, Universidad Austral de Chile and Programa Especial de Citogenética, U. de Chile sede Norte, Santiago, Chile.     

Contractile filaments in cells of regenerating tendon

Summary An extensive cytoplasmic fibrillar system has been observed in fibroblast-like cells of regenerating tendon. It consists of bundles of actin filaments, which often show a cross-striated appearance due to electron dense bodies occurring throughout their length. The functional role of this contractile apparatus seems to be related to the process of movement and orientation of the newly formed cells and to the retraction of the regenerating tendon.Work was supported by grant C. N. R. n. 75.01224.04–115.5479 from Consiglio Nazionale delle Ricerche, Italy.The authors are grateful to Dr G. F. Bottazzo, Dept. Immunology, Middlesex Hospital, London, for carrying out the absorption experiments with purified actin and to Miss M. Rita Nicotra, Miss Laura M. Vassallo and Mr Mario Termine for their technical assistance.     

The effect of Valium® anaesthesia on the radiosensitivity of the skin of the mouse foot

Summary Valium^® anaesthesia significantly reduces the effect of large single doses of X-rays on the mouse foot skin as compared with Nembutal^® anaesthesia. The radioprotective action of Valium may be attributed to a direct effect on the cells of the skin.Supported by the Swiss National Science Foundation (Grant no. 3.682-0.75).Acknowledgments. The authors wish to thank Miss F.T. Josuran, Miss U. Schärer and Mr P.P. Binz for their excellent technical assistance with the experiments.     

Variations in the Golgi complex of mouse somatotrops at different times in a 24-hour period

Resumen El aparato de Golgi de las células somatotropas de la pars distalis de la hipofisis del ratón, presenta importantes diferencias ultraestructurales en distintos momentos de un período de 24 horas. Es pequeño a mediodia y marcadamente hipertrófico a mediodía y 6 de la tarde.

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This investigation was supported with a grant from the Comisión de Investigación de la Universidad Nacional de La Plata. Thanks are due to Miss A. C.Nessi for the technical assistance.     

Biotin-binding proteins in eggs of oviparous vertebrates

Summary Biotin-binding was found in the egg whites and yolks of all 23 avian species studied, and in a turtle, but the amount varied considerably even in related species. There was no clear correlation in biotin-binding between egg white and yolk in various species. Antigenic determinants of avidin in different species have changed in the course of evolution as compared with those of chicken egg white avidin.We thank Mr Jukka Peltonen and Mr Antti Karlin for the collection of the avian eggs with permission obtained from the Ministry of Agriculture, and Mr Reino Saarinen for the turtle eggs. The authors are indebted to Mrs Outi Kurronen Miss Riitta Mero and Miss Tiina-Maija Mattila for technical assistance. This work was supported by the Ford Foundation Grants No. 760-0526 and No. 790-0665.