Effects of sympathetic stimulation on ventricular refractory periods in cats with acute coronary artery ligation

Ventricular refractory periods shorten in the ischemic area following acute coronary artery ligation. Subsequent bilateral sympathetic nerve stimulation reduces disparity in refractory periods across normal, border (peri-ischemic) and ischemic areas.     

Insensitivity of the ferritin iron core to heat treatment

Summary To test whether the reactivity of ferritin iron is affected by the heat treatment used in ferritin isolation, we prepared ferritin from the same horse spleen with or without heating. Both samples exhibited similar reactivity upon reduction or chelation of iron.Acknowledgments. We are indebted to George Rossman who brought this problem to our attention. Work was supported in part by NIH Grant HL20141 and by the Petroleum Research Fund.     

Meclofenamate does not reduce chronic hypoxic pulmonary vasoconstriction

Summary There was no reduction in the pulmonary pressor response to hypoxia following inhibition of prostaglandin synthesis in rats exposed to chronic hypoxia. A fall in left ventricular weight suggested that systemic pressure may have been reduced after inhibition of prostaglandin synthesis in normoxic rats.This work was supported by NIH grant No. HL14985.     

Electrical activity of the pectoral muscles during gliding and flapping flight in the herring gull (Larus argentatus)

Summary Electromyographic recording from the pectoral muscles of the herring gull during flight showed that very little muscle activity is associated with gliding flight. However, the integrated gliding potentials could be increased very considerably by loading the bird. The muscle activity during gliding and flapping flight are in accordance with the known energy requirements for these 2 types of flight.This work was supported by NIH Research Grant HL-02228 and NIH Research Career Award 1-K6-GM-21, 522 to Prof. Schmidt-Nielsen. G. Goldspink was in receipt of a Science Research Council (UK) Research Grant.     

Detection of factor VIII related antigens in long term cultures of rat endothelial cells

Summary Rat endothelial cells in culture can be distinguished from fibroblasts and epithelial cells by their reaction with antisera against human factor VIII (AHF) associated proteins.The data form part of the Ph.D. thesis submitted by A.T. Darnule to the Department of Biology, New York University. Supported in part by NIH USPHS Program Project grant HL15832.     

Lysozyme levels in tissues of iron-deficient rats

Summary Rats were fed either diets sufficient (300 ppm) or insufficient (5 ppm) in iron for 10 weeks. The iron-deficient animals had lowered hemoglobin and hematocrit levels and higher levels of kidney lysozyme activity than did control animals. There were no significant changes in serum and spleen lysozyme activity levels.Supported in part by grant HL18712-02, Heart and Lung Institute, NIH.     

Changes in Z-disc width of vertebrate skeletal muscle following tenotomy

Summary Results of unilateral Achilles tenotomy on male rats, after 2–6 weeks, showed conclusively that the Z-lines of tenotomized muscles are significantly wider than those of control, nontenotomized muscles.Acknowledgments. We would like to thank Paul Toselli, David Sack and Kathleen Finneran for their assistance with this project. This investigation was supported in part by NIH Grant No. HL 15462.     

Relaxation by glucagon of potassium contracture in cat ventricle

Summary Glucagon reduces K⁺-contracture, increases peak active force, but does not alter time to peak force and relaxation of the isometric twitch of cat ventricle.This study was supported by a grant-in-aid from the Florida Heart Association-Suncoast Chapter, National Institute of Health Research grant HL 19044 and NSRA Awards HL 05849 and HL 07188.The authors wish to thank Mr William Fitterman for his valuable technical and illustrative assistance.     

Catecholamines in adult iron deficiency patients

Summary Patients with iron deficiency whether uncomplicated or associated with other types of anemias, had plasma catecholamine levels which were significantly increased above normal controls. Patients with a variety of other anemias had no significant increase in catecholamine levels. Plasma catecholamine levels in uncomplicated iron deficient patients approached normal values as early as 3 h following oral FeSO₄.Acknowledgment. Funded in part by an NIH grant No. R01 HL 19933.     

科技政策、科研管理评论与报道

中美医学科学研究体系与管理有以下特点 :(1)资助和管理的政府机构 ,我国主要有国家科学技术部、国家自然科学基金委员会和国家卫生部 ;美国主要是国立卫生院 (NationalInstitutesofHealth ,NIH)。 (2 )项目的资助模式上 ,我国为“3+ 2”计划体系 ,即三大项目体系 (国家高技术研究发展项目计划 ,国家科技攻关计划和基础研究计划 )和两大科技平台条件建设体系 (研究开发条件建设计划和科技产业化环境建设计划 ) ,不同基金资助基础到产业化研究的不同阶段和类别 ;NIH基金按疾病领域、经费和院内、外研究机构 ,从基础、应用基础和平台条件建设以及产业化整体系统资助。 (3)管理和运行模式上 ,我国有两种模式 ,一是国家部委到地方科委再到高校和科研院所 ,二是国家部委直接到各高校和科研院所 ;NIH直接到高校和各科研院所。 (4)基金的构成特点上 ,我国医学科学研究来自三大项目和两大条件计划体系的每个部分 ,申请项目必须根据项目研究的不同性质和阶段找准计划体系中不同计划的特定资助方向 ;NIH基金系统支持医学研究的各个领域和不同研究阶段。 (5 )经费的投入上 ,我国医学科研经费投入约占总科研经费投入的 2 0 %左右 ,历年投入总和只相当于NIH一年经费的几十分之一。 (6 )规划计划上 ,NIH宏观和微观相结     

Effect of sulfated and non-sulfated gastrin and octapeptide-cholecystokinin on cat gall bladder in vitro

Summary This study demonstrates that for the isolated cat gall bladder a smaller molar dose of the sulfated form of OP-CCK and gastrin is required to produce contraction as compared to the respective non-sulfated forms. For OP the D₅₀ for the sulfated form versus the non-sulfated form was 1.94. For gastrin it was 1.10.This study was supported in part from NIH grant No. HL 15422 from the National Heart and Lung Institute.     

Prolonged vibration of cutaneous artery: Absence of persisting aftereffects

Summary 1–3 h after prolonged (3–16 h) vibration (120 Hz, 0.2–0.3 mm amplitude) of rings of canine saphenous arteries there was no significant change in the contractile response to electrical stimulation, exogenous norepinephrine or of neuronal uptake of tritium labeled norepinephrine. These results did not provide evidence for persistent aftereffects of prolonged vibration.Acknowledgments. Supported in part by NIH grant HL 05883 and the Swedish Work Environmental Fund.     

Liver esterase abnormalities in hereditary neurological diseases of mice

Zusammenfassung Alle von uns in Mäusen untersuchten vererblichen neurologischen Erkrankungen stellen entweder primäre oder sekundäre gesamtkörperliche Prozesse dar. Verschiedene allelische Substitutionen produzieren spezifische Leber-Esterase-Isozym-Defekte.

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This work was supported in part by NIH research grant No. NB 06448 from the National Institute of Neurological Diseases nad Stroke, a grant from the National Foundation for Neuromuscular Diseases, Inc., a grant from the Health Research Fund, United Fund of Schenectedy County, Inc., and an allocation from NIH General Research Support Grant No. RR 05545 from the Division of Research Resources to The Jackson Laboratory.

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The principles of laboratory animal care as promulgated by the National Society for Medical Research are observed in this Laboratory.     

Human plasma dopamine-β-hydroxylase: Oxygen and thermal stability

Summary There are wide individual variations in the thermal stability of human plasma dopamine--hydroxylase (DBH). Thermal stability variations have proven of value in biochemical genetic studies of many enzymes. The development of DBH thermolability depends on the exposure of plasma to oxygen. This observation may help to elucidate the biochemical basis of the genetic regulation of DBH.This work was supported in part by NIH grants HL 17487 and NS 11014.     

Studies on the hydrolysis of bradykinin by angiotensin-converting enzyme (kininase II)

Summary Arg-Pro-Pro-Gly-Phe, the N-terminal pentapeptide of bradykinin, is not an inhibitor of angiotensin-converting enzyme and is not hydrolyzed by the enzyme. Arg-Pro-Pro, the N-terminal tripeptide is a relatively potent (IC₅₀=2.3×10⁶ M) inhibitor but its higher homolog, Gly-Arg-Met-Lys-Arg-Pro-Pro is not an inhibitor of angiotensin-converting enzyme.This work was supported in part by grants from the US Public Health Service (HL 18415, HL 15691, HL 19764) and the John A. Hartford Foundation, Inc., and by the Medical Research Service of the Veterans Administration.     

Cerebrovascular reactivity to CO2: Modulation by arterial pressure

Summary Cerebrovascular reactivity to CO₂ (CO₂R), measured in halothane-anesthetized rabbits, decreased as arterial pressure was increased either pharmacologically or mechanically. On the other hand, hypotension, induced by bleeding, led to an increase in CO₂R. These responses were unaffected by denervation of baroreceptors.This work was supported by grants from NIH (HL 17903) and American Heart Association — Greater Los Angeles Affiliate (437IG). To whom requests for reprints should be sent.     

Coxsackievirus B4 infection of spinal sympathetic ganglion

Summary Coxsackievirus B₄ infection of a spinal sympathetic ganglion of a squirrel monkey is described. Chromatolysis and neuronophagia were extensive. It is suggested that such viral sympathetic ganglial infections may be responsible for dysfunction of organ systems.Supported by the Cardiovascular Research Fund, the Rowell A. Billups Fund for Research in Heart Disease, the Feazel Laboratory and grant No. RR-00164-17 from the Animal Resources Branch, Division of Research Resources of NIH.     

Inhibition of liver fructose 1,6-bisphosphatase activity by Zn2+: Reversal by imidazole pyruvate

Summary Imidazole pyruvate was found to be a very potent natural chelating agent in reversing the inhibition of liver fructose 1,6-bisphosphatase activity by Zn²⁺. This metabolite may play a physiological role in gluconeogenesis.This work was supported by grant RR-8006 from the General Research Branch, Division of Research Resources, NIH, USA.     

Effect of substrates on the mechanical performance of rhesus monkey papillary muscle

Summary This study examines the effect of different substrates on mechanical performance of excised papillary muscles from rhesus monkeys which had been divided into a control group and an experimental group fed a high fat diet for 5 months prior to sacrifice. The results show that performance is affected by available substrate for both groups. The performance of the experimental group was depressed relative to control with the short chain fatty acid, butyrate (C4), producing a monotonically decreasing force-frequency response. Relative to other mammals, isolated rhesus papillary muscles exhibited a protracted treppe which was sensitive to -adrenergic blockade with propranolol.Acknowledgments. I would like to thank Dr R.M. Larson, Dr R.L. McCann and Dr O.F. Hagan for making available the papillary muscles used in this study. Support for this work was provided in part by a grant from the Walker P. Inman Fund and grants from the NIH HL 17391 and HL 15448.     

Functional consequences of treating turkey liver fructose-1,6-bisphosphatase with penicillin G

Summary Treatment of turkey liver fructose-1,6-bisphosphatase with penicillin G progressively inactivated the enzyme and desensitized the enzyme toward high substrate inhibition. The treatment also led to reduced sensitivity to AMP inhibition and the loss of cooperative interaction among AMP-binding sites. These altered properties were not reversed by dialysis, but were prevented when treatment with penicillin G was performed in the presence of substrate.This work was in part supported by grant RR-8006 from the General Research Branch, Division of Research Resources, NIH (USA) and in part by Faculty Research Grant from Southern School of Pharmacy, Mercer University, Atlanta (Georgia, USA).