ACTH: Differential effects on avoidance and discrimination

Zusammenfassung Andauernde ACTH-Behandlung beeinflusst sowohl Vermeidungs- als auch Fehlerkomponenten im Zweiwahl-Y-Labyrinthtest. Die Einwirkungen waren von der Intensität des Elektroschocks wie auch von der Reaktionsfähigkeit der Tiere abhängig.

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This work was supported by Medical Research Council Grant No. MA 1746. Some of the work was done while the first author held a pre-doctoral terminal year grant from the USPHS and while the second author held a Research Career Award from the Canadian Association for Retarded Children. We are indebted toSusanna Kertesz for help in running the subjects in these studies. Requests for reprints should be sent to Dr.J. A. Corson, Allan Memorial Institute, 1033 Pine Avenue West, Montreal 112 (P.Q., Canada).     

SEM observation of cultured,mitogen-stimulated leukocytes. Cells obtained from patients with acute myeloblastic and chronic lymphocytic leukemias

Summary SEM observation of acute myeloblastic leukemia cells, incubated for 20 h with the mitogens pokeweed and phytohaemagglutinin, showed these to have elongated structures that were either smooth or partially covered by thumblike figures. By contrast, the chronic lymphocytic leukemia cells possessed more compact shapes and some were covered with blebs of varying sizes.Supported by grant No. A3624 from the Natural Sciences and Engineering Research Council of Canada.We would like to acknowledge the help of Mr Jean-Luc Verville and Mrs Diane Keating from this Department. Our thanks also go to Dr J.F. Perdue, Lady Davis Institute for Medical Research of the Jewish General Hospital, Montreal, Canada, for the very generous use of his equipment and also to Mr Pierre Daigneault from M. E. C. A. Laboratories.     

Relationship of specific granules to the natriuretic and diuretic activity of rat atria

Summary The isolation of several fractions from rat atrial homogenates, by the use of differential and sucrose gradient centrifugation, indicates that the diuretic and natriuretic activity is restricted to the fractions rich in specific granules. Our preliminary results suggest that the active substance is a small peptide which is probably different from the natriuretic substance(s) already known.Supported by a group grant given by the Medical Research Council of Canada to the Multidisciplinary Research Group on Hypertension of the Clinical Research Institute of Montreal.Acknowledgments. The authors thank Suzanne Diebold for technical assistance.     

Effect of cortisol and norethandrolone on inflammation and tumor growth

Résumé Le norethandrolone administré chez le rat intact ou surrénalectomisé se montre très efficace à prévenir la perte de poids causée par le cortisol. Cet antagonisme, toutefois, n'est pas démontrable en ce qui concerne l'effet anti-inflammatoire, la diminution de la croissance tumorale et l'atrophie du thymus et de la surrénale dus au cortisol. En outre, le norethandrolone présente à lui seul des propriétés anti-inflammatoires et thymolytiques, plus spécialement chez l'animal intact.

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This work was supported by grant from the National Cancer Institute of Canada. The authors wish to thank Pfizer Canada, Montreal, and G. D. Searle & Co., Chicago, U.S.A. who graciously supplied cortisol acetate and norethandrolene.

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Medical Research Associate of the National Research Council of Canada.

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Work done under tenure of a summer fellowship from the Fondation Rhéaume of Montreal (Canada).     

On the contamination of the Murphy-Sturm lymphosarcoma with a pleuropneumonia-like organism

Résumé La terramycine et la néomycine ne parviennent pas à décontaminer le lymphosarcome de Murphy-Sturm infecté par un «pleuropneumonia-like organism». Il a été constaté que ce microorganisme est transmissible à d'autres tumeurs transplantables. Le rat porteur d'une tumeur infectée devient résistant à l'induction d'arthrite par l'exsudat d'une tumeur homologue. L'exsudat d'un lymphosarcome de Murphy-Sturm provenant d'un autre laboratoire est également doué de propriétés arthritogènes.

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This work was supported by a grant from the National Cancer Institute of Canada. The authors also gratefully acknowledge generous gifts of terramycin from Pfizer Canada, Montreal, and neomycin from The Upjohn Co., Kalamazoo, U.S.A.

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Medical Research Associate of the National Research Council of Canada.     

Enhanced production of aggregation pheromones in four stored-product coleopterans feeding on methoprene-treated oats

Summary Production of aggregation pheromones by maleOryzaephilus surinamensis, O. mercator, Cryptolestes ferrugineus, andTribolium castaneum was enhanced by feeding on methoprene-treated oats, implicating juvenile hormone in control of pheromone production. Methoprene application to control insects in stored food products may cause enhanced pheromone production by these insects, thus drawing additional beetles into the treated product.Acknowledgments. We thank Dr. G. B. Staal of Zoëcon Corp. for a generous gift of methoprene. Particular thanks are due to J. Dodic for technical assistance. Research funded by the Natural Sciences and Engineering Research Council of Canada and the Science Council of British Columbia.     

Metabolic restoration in rat liver after partial hepatectomy

Zusammenfassung Es zeigt sich während des frühen Regenerationsstadiums bei der teilweise hepatektomierten Rattenleber, dass ein Anstieg im Galaktose-Metabolismus mit gleichzeitiger Abnahme seiner Hemmung durch Ethanol einhergeht. Nach vollständiger Geweberegeneration kehrt der normale Metabolismus zurück.

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I wish to thank ProfessorJ. H. Quastel for providing me with the facilities and for his encouragement during my work at McGill University, Montreal (Canada).     

Effect of the juvenoid methoprene on the hemolymph composition of the cabbage maggotDelia radicum (Diptera: Anthomyiidae)

Summary Treatment of post-feeding larvae of the cabbage maggotDelia radicum with methoprene did not affect the capacity of the insect to pupate, but suppressed eclosion to the adult stage. The concentration of hemolymph trehalose was significantly decreased by methoprene treatment, although hemolymph protein and amino nitrogen levels were unaffected.19 December 1986The authors are grateful to D. C. Read of the Research Centre, Agriculture Canada, Charlottetown, P.E.I., Canada for supplying eggs ofD. radicum for the stock colony. TheD. radicum colony was maintained at the Agriculture Canada Research Station, St. John's West, Newfoundland, Canada. The sample of methoprene was donated by Zoecon Corp., Palo Alto, California, U.S.A. This research was supported by a grant from the Natural Sciences and Engineering Research Council of Canada (Operating grant A6679).     

Effect of blood pH on anionic ferritin transport through rat aortic endothelium

Summary Acute lowering of blood pH between 7.4 and 6.9 in rats by ventilation with 10 or 20% CO₂ does not increase the passage of ferritin molecules across the aortic endothelium. These results do not rule out alteration of endothelial permeability to anionic macromolecules in local circulatory disturbances when blood pH drops to levels much lower than 6.9.Supported by The Medical Research Council of Canada grant No. MA-5958.Dr J.R. Fraser was a recipient of a Summer Research Scholarship from McGill University during the completion of this study.The authors thank Colin Bier for the statistical analysis.     

Persistence of infradian body weight cycles in castrated dormice (Glis glis)

Summary Male dormice were castrated at 2 phases of their infradian body weight cycles. No consistent changes were found in cycle period, amplitude, or absolute weights of the dormice following castration. Unlike other mammals, body weights of dormice appear unaffected by castration. Although both body weight and reproductive condition vary on an infradian basis, the changes in body weight appear to be programmed independently from changes in gonadal function.Acknowledgments. I would like to thank R. Melnyk, N. Mrosovsky, and J. D. Hallonquist for much helpful criticism and K. Lang and J. Kenyon for invaluable technical help. Research support was provided by a National Sciences and Engineering Research Council of Canada grant to N. Mrosovsky.     

Anti-myosin stains chromaffin cells

Summary The presence in fixed chromaffin cells of antigenic sites for a myosin antibody was demonstrated using immunofluorescence techniques. Tests on viable cells showed that at least some of the antigenic sites seem to be localized on or close to the cell surface and explained the cell agglutination that occurred with the addition of the myosin antibody to cells isolated by a method described in this paper.Acknowledgments. This work was supported by grants from the Medical Research Council of Canada. We thank Dr B. G. Livett for advice in the preparation of isolated cells, Drs J. Lowenthal and B. Collier for comments and Mrs J. Ritchie for technical assistance.     

Induction of deoxyribonucleic acid degradation inEscherichia coli by ozone

Summary Cell survival and deoxyribonucleic acid (DNA) degradation were measured for wild-typeEscherichia coli B251 cells after exposure to different concentrations of ozone. The results show that extensive breakdown of DNA occurs after ozonation and that the extent of ozone-induced DNA degradation generally correlates with the colony-forming ability of the cells.We thank Dr M.J. d'Aoust for supplying laboratory facilities. This work was jointly sponsored by the National Research Council of Canada, the Ministère de l'Education du Québec, and funds from the Université de Montréal. One of us (C.H.) acknowledges a postgraduate scholarship from the NRC of Canada.     

The anticonvulsant effects of propranolol and β-adrenergic blockade

Summary The anticonvulsant activity of racemic and (+)-propranolol was studied in rats. Neither drug changed the current to produce a minimal seizure in 50% of animals. Both drugs were effective in the maximal electroshock seizure test, the (+) isomer being more potent than the racemic form. Since the (+) isomer is practically devoid of -adrenergic blocking activity, the anticonvulsant effects of propranolol do not result from -adrenergic blockade.We wish to thank Hana Boucek for skilful technical assistance. Propranolol and (+)-propranolol were obtained through the courtesy of Ayerst Laboratories Ltd, in Montreal. This research was supported by the Medical Research Council of Canada, grant MA-4754.     

Uptake of exogenous protein by supraependymal cells of the feline area postrema

Summary Supraependymal cells occurring on the surface of the feline area postrema were examined for phagocytic ability. It was shown that they could ingest exogenous horseradish peroxidase that was experimentally introduced into the brain ventricular system. The cells thus bear functional as well as ultrastructural attributes of macrophages, similar to those found in the third ventricle and subarachnoid space.We thank J. Stevens and A. Fenton for technical assistance. Supported by the Medical Research Council of Canada.     

The oxygen consumption of some tissues from hypophysectomized goldfish,Carassius auratus L.

Summary Hypophysectomy has no effect on the O₂ consumption of minced brain and white muscle tissue, while liver tissue shows a marked reduction. This reduction in liver O₂ consumption is attributed to the increased glycogen content that follows hypophysectomy which has the effect of increasing the nonmetabolizing dry weight component of the cells.Supported by the National Research Council of Canada, Grant Number A-3744 to P. H. J.     

On the origin ofd-aminoacid residues in microbial peptides

Zusammenfassung Ein Gemisch von Angolid und seinen drei valinhaltigen Homologen ausl-valinhaltiger Kultur vonPithomyces sacchari enthielt gleiche Mengen zweier Isomere mit nur einem Valinrest, was wahrscheinlich macht, dass Angolid durch Umkehrung einesl-Rests aus einem zyklisch-symmetrischen Vorläufer entsteht.

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This investigation was supported by a grant No. MA 2480 from the Medical Research Council of Canada. We are most grateful to Dr.J. A. Verpoorte for the aminoacid analyses.     

Effect of norepinephrine and vasopressin on carotid sinus baroreceptor activity in the anesthetized rabbit

Summary Norepinephrine (NE) 10^–6 M or vasopressin (VP) 12.5 U/ml were injected into the isolated carotid sinus of anesthetized rabbits. The sinus was exposed either to the arterial pressure or to a pressure controlled reservoir. Multifiber and single fiber recordings were made. Both NE and VP increased baroreceptor activity at all sinus pressures but decreased activity in a few fibers. The results are consistent with the drugs having their effects on smooth muscle fibers in the adventitia.Acknowledgments. This work was supported by grants from the Medical Research Council of Canada and the B.C. Heart Foundation. The authors are grateful to J. Sharp and D. Morton for their excellent assistance.     

Lamprin: A new vertebrate protein comprising the major structural protein of adult lamprey cartilage

Summary Chemical analysis of lamprey cartilage showed that its major constituent was a newly defined structural protein termed lamprin. Amino acid analysis of lamprin revealed that it has a unique composition which is distinct from previously identified structural proteins.Acknowledgment. This work was supported by grants U0105 to G.M.W. and A5945 to J.H.Y. from the Natural Sciences and Engineering Research Council of Canada.     

Solid phase synthesis and some pharmacological properties of 8-glutamine-oxytocin: a possible intermediate in the evolution of the neurohypophysial hormones

Zusammenfassung Die erstmalige Synthese des Peptidhormons 8-Glutamin-Oxytocin wird beschrieben. Das synthetische Peptid ist mit einem anderen Peptid des Dornhaies von noch ungeklärter Struktur nicht identisch.

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(a) This work was supported in part by a Studentship (to J.W.M.B.) and a Grant (to M.M.) from the Medical Research Council of Canada, an award (to T.C.W.) from the Banting Research Foundation, a National Science Foundation Grant No. GB 4932 and a General Research Support Grant to Columbia University from the National Institutes of Health. (b) An abstract of this work was presented at the 5th Annual Meeting of the Federation of European Biochemical Societies, July, 1968; M.Manning, T. C.Wuu, J. W. M.Baxter and W. H.Sawyers, FEBS 1968 Meeting, Prague, Abstr.824, p. 206.     

Analysis of vasodilatation in the submaxillary gland using potentiators of acetylcholine and kinins

Zusammenfassung Nachweis, dass bei Reizung des N. chorda lingualis der Katze ein Blutdruckeffekt ausbleibt, wenn ein Bradykinin potenzierender Faktor (Präparat BPF) zuvor gegeben wurde.

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Acknowledgments. We are greatly indepted to Dr.J. Stewart of the University of Colorado and to Dr.L. Greene of Brookhaven National Laboratories, New York, for kind gifts of synthetic bradykinin potentiators.

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This work was supported by grants from the Medical Research Council of Canada and the Alberta Heart Foundation.