Tolerance to cold and glucose homeostasis in adrenal demedullated dogs

Summary The rise in O₂ consumption and in glucose turnover, induced by acute cold exposure is not suppressed by adrenal demedullation in dogs. However, both at neutral and cold ambient temperature, the mean plasma glucose concentrations are higher in normal (N) than in adrenal-demedullated dogs (ADMX). In the cold, the fall in rectal temperature is larger in ADMX than in N dogs.This work was supported by a grant from Université Claude Bernard (U.E.R. Lyon Nord and U.E.R. Biologie Humaine).The authors thank D. Rougier and G. Dallevet for their excellent technical assistance and A. Brillant for secreterial assistance.     

Hibernation at moderate temperatures: a continuation of slow wave sleep

Summary Golden-mantled ground squirrels (Citellus lateralis) displayed virtually continuous electrophysiological states of sleep when hibernating at moderate ambient temperatures (22°C). Rapid-eye-movement sleep progressively diminished with the fall in body temperature so that at a body temperature of 23°C it was completely absent. At this temperature hibernation was characterized by slow wave sleep isomorphic with slow wave sleep episodes at non-hibernating (euthermic) body temperatures.Supported by National Institute of Health grants GM 23694 awarded to R.J. Berger and GM 23695 awarded to H.C. Heller.     

Pyruvate dehydrogenase kinase regulatory mechanisms and inhibition in treating diabetes, heart ischemia, and cancer

The fraction of pyruvate dehydrogenase complex (PDC) in the active form is reduced by the activities of dedicated PD kinase isozymes (PDK1, PDK2, PDK3 and PDK4). Via binding to the inner lipoyl domain (L2) of the dihydrolipoyl acetyltransferase (E2 60mer), PDK rapidly access their E2-bound PD substrate. The E2-enhanced activity of the widely distributed PDK2 is limited by dissociation of ADP from its C-terminal catalytic domain, and this is further slowed by pyruvate binding to the N-terminal regulatory (R) domain. Via the reverse of the PDC reaction, NADH and acetyl-CoA reductively acetylate lipoyl group of L2, which binds to the R domain and stimulates PDK2 activity by speeding up ADP dissociation. Activation of PDC by synthetic PDK inhibitors binding at the pyruvate or lipoyl binding sites decreased damage during heart ischemia and lowered blood glucose in insulin-resistant animals. PDC activation also triggers apoptosis in cancer cells that selectively convert glucose to lactate. Received 25 August 2006; received after revision 20 November 2006; accepted 20 December 2006     

Délimiation des voies ascendantes responsables de l'activités ponto-géniculo-occipitale chez le chat

Summary A ponto-geniculate system responsible for the PGO activity induced by Reserpine follows closely the topography of the intermediate catecholaminergic pathway which crosses the midlinie in the supra-optic decussation.

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Ce travail a bénéficié de l'aide de la D.R.M.E (No. 71.009), de l'I.N.S.E.R.M. (No. U52) et du C.N.R.S. (No. LA 162)     

Attenuation by carbocromen of cardiac metabolism alterations due to ischemia

Summary Carbocromen prevents to some extent, particularly in subendocardial layer, carbohydrate cardiac metabolism alterations induced by the ischemia obtained by intermittent occlusion of left coronary artery.Acknowledgments. Financial support from the U.E.R. of biologie Humaine is gratefully acknowledged.     

Myofibroblasts in hepatic schistosomal fibrosis

Summary Myofibroblasts were identified in liver portal spaces of patients with Symmers' fibrosis following infection by Schistosoma mansoni.Acknowledgments. This research was supported by a grant from U.E.R. (Human Biology) Claude Bernard University, Lyon (France), and by the Conselho Nacional de Pesquisas (Brazil). Thanks are due to Mrs Pavans de Ceccatty for her skillful technical assistance.     

Exocytosis of secretory granules — a probable mechanism for the release of neuromodulators in invertebrate neuropiles

Summary Presynaptic terminals typically contain secretory granules, usually 100–200 nm in diameter, in addition to the smaller synaptic vesicles. Evidence is presented that granule exocytosis is a widespread phenomenon in invertebrate neuropiles. Such secretory release is apparently associated with morphologically unspecialized regions of the plasmalemma, rather than synaptic thickenings.Acknowledgments. The authors gratefully acknowledge the assistance of Mr R. M. Hewit and Mrs. S. Al-Yousuf. Supported by research grant GR/A88743 from the S.E.R.C., U.K., to D.W. Golding.     

Systemic animal external parasiticidal activity of perfluoroalkylbenzimidazoles and their aminoanilide precursors

Summary In vitro and in vivo efficacy data indicate that chemical activity is optimized at the 2 carbon chain length and that these compounds have injectable potency and spectrum of activity against major animal external parasite species.Acknowledgments are due to R.O. Drummond, U.S.D.A., Kerrville, Texas; T.E. Elward, Stanford Research Institute and D.E. Weidhaas, U.S.D.A., Gainesville, Florida.     

Influence of brown adipose tissue on deep cervical temperature during sleep in the young rabbit

Summary In young rabbits the slope of the temperature in the deep cervical region close to brown adipose tissue increased during desynchronized sleep at low ambient temperature. No increase occurred at neutral ambient temperature. In control rabbits (after disappearance of brown adipose tissue), the slope of deep cervical temperature did not increase during desynchronized sleep at low or neutral ambient temperatures.Preliminary data were reported at the Association des Physiologistes, Réunion de Poitiers, 20–23 June 1983.Acknowledgments. We wish to thank Giuseppe Mancinelli and Leonida Sabattini for technical assistance. This work was supported by a grant from the Consiglio Nazionale delle Ricerche, Rome. J.P.L. wishes to thank NATO for partial financial support during his stay at the Physiology Department in Bologna.     

Effect of ambient cold on urine concentration by the intact and denervated dog kidney

Summary In dogs transferred from room temperature to a low temperature of 1±(SD) 3.5°C, the plasma norepinephrine (NE) level increased significantly. Urine concentration decreased in the cold, in the intact and similarly in the chronically denervated kidney. After return to a warm environment urine concentration improved in both kidneys while plasma NE remained elevated. The data speak against an essential role of the renal nerves in the adaptation of renal function to ambient cold.Acknowledgments. We are greatly indebted to Dr J. Kurkus and Dr R. Gellert who performed the operations of surgical bladder division, and to Mrs W. Radziszewska for determination of plasma norepinephrine. The study was supported within the national research problem No. 10.4.     

Establishment of normal diploid and malignant heteroploid cell lines from non-treated and benzo(a)pyrene treated hamster embryo cell cultures

Summary Two normal diploid control cell lines and a heteroploid malignant transformed cell line from B(a) P treated hamster embryo cell cultures were established. The 14-month-old B(a)P transformed cell line grew 8-times faster than the 20-month-old control cell line. The control cell line showed normal diploid chromosome complement in 93% cells and heteroploidy in 7% cells while B(a)P treated line showed 83% heteroploid cells and only 17% diploid cells. This is the first report on the establishment of diploid hamster cell cultures grown for extended period. Acknowledgments. This work was supported by the French Ministry of Quality of Life, by the Institut National de la Santé et Recherche Médicale, by the S.E.I.T.A. and by Contract No. 12-14-7001-297 of the Agricultural Research Service, U.S. Dept. of Agriculture, Administered by the Athens, Georgia Area, Richard B. Russell Agricultural Research Center, Athens, Georgia 30604, USA. We thank Mr.B. R. Sharma, Mr.E. J. Radin, Dr.R. Hakim and Dr.Ved Brat for their help during this work.     

Biological activity of enantiomerically pure forms of insect juvenile hormone I and III inBombyx mori

Summary Biological activity of enantiomerically pure juvenile hormones was assayed by topical application on allatectomizedBombyx fourth instar larvae. JHs tested were (10R)-JH I [methyl (2E,6E,10R,11S)-10,11-epoxy-3,11-dimethyl-7-ethyl-2,6-tridecadienoate], (10S)-JH I [methyl (2E, 6E, 10S, 11R)-10,11-epoxy-3,11-dimethyl-7-ethyl-2,6-tridecadienoate], (10R)-JH III [methyl (2E,6E,10R)-10,11-epoxy-3,7,11-trimethyl-2,6-dodecadienoate] and (10S)-JH III [methyl (2E,6E,10S)-10,11-epoxy-3,7,11-trimethyl-2,6-dodecadienoate]. Among these compounds, natural (10R)-JH I was most active and the dose needed to induce 50% larval molting was 0.04 g/larva; it was approximately 12,000 times more active than unnatural (10S)-JH I. Though natural (10R)-JH III showed slight biological activity, it was only one three-thousandth of that of (10R)-JH I. Unnatural (10S)-JH III exhibited no biological activity at the levels assayed.     

Bromocriptine-induced removal of endoplasmic membranes from prolactinoma cells

Summary Adenomatous prolactin cells lose 39% of their cytoplasm volume within 7 days after the beginning of bromocriptine treatment. A simultaneous reduction of the rough-surfaced endoplasmic reticulum and the Golgi apparatus occurs. Their membranes are removed by rapid transport along the secretory pathway to the cell surface and to lysosomal destruction.We thank Prof. E. del Pozo, Sandoz Ltd, Basle, for the generous gift of injectable bromocriptine, Prof. E.R. Weibel, Dept. of Anatomy, University of Bern, for his technical advice, Dr U. Helfenstein, Institute of Biostatistics, University of Zürich, for his help in the statistical evaluation of the results and the EMDO-Foundation, Zürich, for financial support.     

Involvement of tissue monoamine and plasma FFA concentrations in the responses of the pigeon to changes of photoperiod

Summary A deviation of the length of photophase from the rhythm of 12L12D induced monoamine accumulation in diencephalon and pancreas. A short photophase increased plasma FFA. The results suggest that photoperiodism is a stronger modulator of catecholamines and lipid metabolism than changes in ambient temperature (Ta).Acknowledgment. The support of Emil Aaltonen foundation (to E.H.) and the Finnish Ministry of Education (to A.H.) is gratefully acknowledged.     

Starvation-induced adaptation of rat liver tyrosine transaminase and serine dehydrase

Résumé Les activités de la tyrosine transaminase et de la sérine déhydrase sont augmentées dans le foie de rats normaux ou surrénalectomisés soumis au jeûne. Ces augmentations, qui sont supprimées par la puromycine ou le glucose, ne sont dues ni à une sécrétion d'hormones surrénaliennes ni à une accumulation des substrats des enzymes.

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This work was supported by a grant (AM 07 249 02) from the U.S. National Institutes of Health. Technical assistance of MmeYveline Van Heijenoort and MileCristiane Portemer (C.N.R.S.) is gratefully acknowledged.     

Evoked release of 5-HT and NEFA from the hypothalamus of the conscious monkey during thermorégulation

Zusammenfassung Unterkühlungsexperimente mit Affen zeigen einen Anstieg des 5-HT-Gehaltes in der Durchströmungsflüssigkeit des vorderen Hypothalamus. Erwärmung der Tiere ergab 2–4fachen Anstieg eines NEFA-ähnlichen Stoffes.

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Supported in part by U.S. Office of Naval Research Contract No. N00014-67-A-0226-0003, Grant No. GB 7906 from the National Science Foundation and a grant from the Wallace Laboratories. The authors are indebted to P.Cuezon, J. E.Evans and R. B.Holman for their valuable assistance.     

Evaluation of participation of glucose in elevation of glycemia of scorpion (Heterometrus fulvipes) caused by the hyperglycemic principle of the scorpion and crab

Summary A single injection of the hyperglycemic principle obtained from scorpion cephalothoracic ganglionic mass causes an elevation of glycemia in the scorpionH. fulvipes in which little glucose is involved (10.8%). With the crustacean hyperglycemic principle, the elevation of glycemia is initially almost exclusively contributed by glucose (glucose is 92% of total carbohydrate at 2 h post injection); 6 h after treatment, non-glucose carbohydrates appear to participate in the elevation of glycemia.Acknowledgments. We wish to express our gratitude to CSIR, New Delhi for providing financial support to P.S.R., Reprint requests should be addressed to Prof. R. Ramamurthi.     

Interaction of diltiazem with propranolol on atrioventricular conduction and refractoriness in the dog

Summary Propranolol pretreatment (0.1 mg·kg^–1) significantly increased the lengthening induced by diltiazem (0.15 mg·kg^–1+0.01 mg·kg^–1·min^–1, 20 min) of the A-H interval of His bundle potential recordings in the dog. In the presence of propranolol, diltiazem also significantly increased the atrioventricular effective refractory period. The results suggest the possible occurrence of AV blocks as a result of the use of a diltiazem-beta blocker combination in clinical practice.Acknowledgments. Financial support from the U.E.R. Biologie Humaine is gratefully acknowledged.     

Freeze tolerance in the frog,Rana sylvatica

Summary Wood frogs survive extracellular freezing at moderate subzero temperatures (–4°C) for at least 11 days. Freezing survival is aided by the accumulation of high concentrations of glucose as a cryoprotectant in blood and tissues. Glucose production was accompanied by a rapid decline in liver, but not muscle, glycogen levels suggesting that liver is the organ controlling cryoprotectant synthesis.Acknowledgments. This study was supported by grants to L.M.G. from the Kroc Foundation (Santa Ynez, California) and from the National Institute of Dental Research (Grant No. DE-03987). The authors wish to thank K. Yorko, M. Shakin, J. Finan and Mrs N. Manivannan for their technical and secretarial assistance.Acknowledgments. I thank Dr J. Ballantyne, Dr F. Schueler and I. McMurray for help with frog collections and Dr. W. Schmid, Dr J. Bogart and Dr F. Cook for helpful discussions. Supported by an N.S.E.R.C. operating grant and by a grant from the Atkinson Charitable Foundation.     

Infrared spectrum of strontium hydroxyapatite

Zusammenfassung Es wird über eine Methode berichtet, die es erlaubt, Apatide zu unterscheiden, in denen anstelle des Calciums Strontium eingetreten ist.

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This investigation was supported by Research Grant DE-02102-02 of the U.S. Public Health Service. I thank Prof.N. Fuson for his interest, encouragement and many helpful suggestions throughout apatite investigation. The IR-spectrum of the sample was run by Mr.K. E. Stine at Beckman Instruments Inc., Fullerton, California, and the X-ray diffraction pattern was done by Dr.R. L. Collin of the University of Rochester, Rochester, New York. The sample was prepared at the Infrared Spectroscopy Institute, Fisk University, Nashville, Tennessee, and the results and discussion parts were completed at Kentucky State College, Frankfort, Kentucky.