THE BRITISH SOCIETY FOR CARDIOVASCULAR RESEARCH QUARTERLY BULLETIN

July 1991 Volume 4 Number 2

CONTENTS

BSCR Committee: 2 Letter from the Secretary Interesting Developments: 3 Chairman's Column: 3 BSCR Meeting Announcement Regulation of Blood Flow: 5 Meeting Announcement The Mammalian Myocardium: 6 BSCR Meeting Report Endothelium and Atherogenesis: 7 Readers' Views Power and Impedance in the Cardiovascular System: 8 Book Review Principles and Practice of Cardiovascular Imaging (Pohost & O'Rourke): 9 BSCR Abstracts Endothelium and Atherogenesis: 10

2

THE BRITISH SOCIETY FOR CARDIOVASCULAR RESEARCH

Quarterly Bulletin Edited by:

Dr Metin Avkiran Dr Michael J Curtis

BSCR Quarterly Bulletin Cardiovascular Research

The Rayne Institute St Thomas' Hospital

London SEl 7EH Tel: 071-928 9292 ext 3375

Fax: 071-928 0658

THE BRITISH SOCIETY FOR CARDIOVASCULAR RESEARCH

Committee Members Chairman:

Dr George Hart Cardiac Department

John Radcliffe Hospital Headington

Oxford 0 X 3 9DU Tel: 0865-220257 Fax: 0865-68844

Secretary: Dr Andrew C Newby Department of Cardiology

University of Wales College of Medicine Heath Park

Cardiff CF4 4XN Tel: 0222-742 338 Fax: 0222-761 442

Treasurer: Dr Mark Boyett

Department of Physiology University of Leeds Worsley Building

Leeds LS2 9JT Telephone: 0532-334 265

Fax: 0532-334 381

Sponsorship Secretary: Dr Paul J England

Smith Kline & French Research Ltd TheFrythe

Welwyn Hertfordshire AL6 9AR

Tel: 0707-325 111 Fax: 0707-7482

Committee: Mr Gianni D Angelini

Department of Cardiac Surgery Northern General Hospital

Sheffield S5 7AU Tel: 0742-434 343 Fax: 0742-560472 Dr Susan Coker

Department of Pharmacology & Therapeutics University of Liverpool

PO Box 147 Liverpool L69 3BX Tel: 051-794 5550 Fax:051-794 5540

Dr Peter Cummins Department of Physiology

The Medical School The University of Birmingham

Vincent Drive Birmingham B15 2TJ

Tel: 021-414 6906 Fax: 021-414 6924

Professor Keith A A Fox Cardiovascular Research Unit

University of Edinburgh Hugh Robson Building

George Square Edinburgh EH8 9XF

Tel: 031-667 1011 ext 2539 Fax: 031-667 9092

Dr Trevor Powell Department of Physiology

Oxford University South Parks Road Oxford 0X1 3QU Tel: 0865-272 467 Fax:0865-272 469

Dr Derek M Yellon The Hatter Cardiovascular Studies Unit

University College Hospital Gower Street

London WC1E6AU Tel: 071-3809888 Fax:071-388 5095

LETTER FROM THE SECRETARY 3

Interesting Developments The BSCR has grown over the last few years from a society narrowly concerned with cardiac muscle to one encompassing all aspects of the cardiovascular science. This change has reflected and at times, I hope, anticipated changes in the same direction by the ISHR, ESC etc. The result is a Society of over 500 members with now widely divergent interests. Hopefully, our strength will continue to grow from this breadth. It is equally true, however, that productive scientific interactions emerge from personal contacts and are best encouraged by small informal gatherings. There is therefore a current of feeling that BSCR meetings have become too formal and also that it is no longer possible stage a main meeting of interest to every member. Informal meetings should not be inconsistent with the Society's new standing, however, and are expressly catered for by workshops. Perhaps it is time to encourage the formation of "Interest Groups" within the Society and suggest that these groups organise (regular) informal workshops at which more of the membership can have the possibility of contributing. It is my view that the BSCR will have failed in its aim of promoting interchange of ideas unless such a development takes place. I am equally sure that British Cardiovascular Research will fail to keep up without the multi-group efforts that such contacts will foster. Without wishing to discourage the spontaneity or increase the burden of organising a workshop, I should remind prospective organisers of the main conditions which the BSCR attaches to the use of its good name and its contribution of £400. Prior approval must be obtained from the Committee, where a guiding principle will be the benefit of the proposed workshop the membership as a whole. Meetings must be open to all members, normally without any registration fee. Accounts must be kept and any residue returned to the Society. Finally, I should stress that sufficient time must be allowed for advertising to the membership and registration

Andrew Newby

CHAIRMAN'S COLUMN 1

Society Meetings The Spring meeting in Cardiff was very well attended and provided excellent reviews of recent developments in the endothelial world. We are very grateful to our Secretary for his hard work in organising this meeting. Future meetings are scheduled as follows: Winter 1991: 5-6 December in London, "Regulation of coronary and systemic blood flow", organisers Dr. Nicholas Flores and Professor Desmond Sheridan, Academic Cardiology Unit, St. Mary's Hospital. Spring 1992: Birmingham, "Myocardial receptors and innervation; therapeutic implications", organiser Dr. Peter Cummins, Department of Physiology, University of Birmingham. Winter 1992: London, "Cardiac Myofilaments", organiser Dr. John Kentish, Department of Pharmacology, St. Thomas' Hospital. Travel Bursaries for PhD Students At the last Committee meeting a proposal was warmly accepted to provide up to 20 travel grants of £50.00 for PhD students to help with their expenses in attending the 1991 Winter meeting of the Society in London. This level of sponsorship perhaps does not match up with that of other, much more wealthy societies but, given what student grants are worth these days, 1 anticipate that it will be welcomed. The aim is to encourage young researchers to attend and

(cont.) to contribute to our meetings (remember that if you submit a poster it will not be published, merely printed, if you so wish, in the Bulletin). The Society must remain, as it always has, an informal forum for exchange of results and ideas, and I hope that more contributions from young researchers will give us some freshness and vitality. The bursaries can be applied for on forms which will be issued with the Bulletin and which must be countersigned by the research supervisor. Awards will be given on a first-come, first-served basis but if the scheme is over-subscribed, preference will be given to applicants whose research is directly related to the areas covered by the meeting. Applicants need not be submitting an abstract but they must be, or must become, members of the Society. A BHF Award for the Bulletin The Education Committee of the British Heart Foundation have renewed their support for the Bulletin with another year's grant of £750.00. We are most grateful for their continued interest in this worthwhile publication. The Society Seeks Charitable Status The Liverpool office of the Charity Commission is presently considering the case of our Society and we look forward to their reply. Technically we are at the "questionnaire" stage which means that the Commission has been furnished with detailed responses to a standard set of questions and with a sheaf of documents concerning the activities of the Society. One of these is a draft constitution which involves the Chairman applying a cold towel to his head and marrying our (exceedingly brief and informal) set of rules with a model constitution for a voluntary society provided by the National Council for Voluntary Organisations. My aim has been to make the constitution as flexible and as unrestrictive as possible, while complying with the requirements necessary for safeguarding the good running of a society and the interests of the Commission. In fact most of the requirements are sensible and represent good practice, and the Committee voted to submit the draft at its last meeting. In drawing up the draft I have been greatly helped by the legal department of the NCVO and by a local barrister. The Commission looks at the submission in detail at this stage, making enquiries with the Inland Revenue and ensuring that the constitution is sound. When it is satisfied we may expect to be invited to submit a formal application. Hopefully we shall be in a position, at the AGM next December, for members to vote on accepting the new constitution. Benefits which the Society may expect from charitable status include tax relief on profits from meetings and on interest ftom our accounts, rules to ensure good practice in running the Society, and the production of an annual report and an audited statement of accounts. And maybe the minutes will be signed from now on!

An Insurance Policy I have been concerned that in these days of increasing litigation we should define and safeguard our position in the unlikely event of our being sued. At some but not all of our meetings local insurance cover is in place if, for example, a speaker falls off the podium, breaks his leg and wonders about taking legal action for failure to provide a handrail! The result is that the Committee have approved a liability insurance policy for the Society costing approximately £100 pa and covering us to a vast sum. But libel and slander are excluded, so do please be careful what you say! With that I hope these important housekeeping matters are at an end and next time I shall be able to write about cardiovascular research.. .

George Hart

BSCR MEETING ANNOUNCEMENT

5

Winter Meeting

REGULATION OF BLOOD FLOW Thursday 5th - Friday 6th December 1991

Royal Pharmaceutical Society of Great Britain London

Organisers: Dr Nicholas Flores and Professor Desmond Sheridan

SPEAKERS TO INCLUDE: Dr W.M. Chilian, Texas, USA (British Cardiac Society Lecture) Prof. C.C. Michel, London Prof. G. Heusch, Essen, Germany Dr B. Levy, Paris, France

Dr K. Parker, London

Segmental distribution and regulation of coronary microvascular resistance

Regulation of flow and permeability in capillaries Autonomic regulation of coronary arteriolar tone The structure and function of arteries in different experimental models of hypertension Wave transmission in large arteries

ABSTRACTS: Members of the Society are invited to submit abstracts (on any topic) for oral or poster presentation. REGISTRATION: Free to BSCR members and £25 to non-members. Registration forms and abstract instructions are included with this issue of the Bulletin. Further copies are available from:

Dr Nicholas A. Flores Academic Cardiology Unit

St Mary's Hospital Medical School QEQMWing

South Wharf Road London W2 INY

Tel: 071-725 6129 Fax: 071-725 6732

IF YOU WISH TO ORGANISE A MEETING OR WORKSHOP, PLEASE CONTACT THE SECRETARY OF THE BSCR, DR ANDREW NEWBY (ADDRESS ON PAGE 2 OF BULLETIN).

6

2nd International Symposium THE MAMMALIAN MYOCARDIUM

Biochemical and Physiological Mechanisms Underlying the Heartbeat Sunday 26th - Wednesday 29th July 1992

The University of Leeds Leeds, England

Organisers: Dr M. Boyett, Dr C. Orchard and Dr J. McCormack This meeting is being organized in conjunction with the British Society for Cardiovascular Research and is being held under the auspices of the British Heart Foundation. MAJOR TOPICS TO BE COVERED: Ion channels, pumps and exchangers of the sarcolemma; ion flux and contractility; the sarcoplasmic reticulum; intracellular Ca^* and excitation-contraction coupling; the myofilaments; cardiac metabolism and clinical aspects. SPEAKERS AND CHAIRMEN TO INCLUDE: B. Bean (USA), D. Bers (USA), E. Carafoli (Switzerland), R. Chapman (UK), M. Crompton (UK), D. Eisner (UK), P. England (UK), S. Fleischer (USA), H. Fozzard (USA), W. Giles (Canada), F. Hoffman (Germany), G. Isenberg (Germany), J. Kentish (UK), E. Lakatta (USA), W. Lederer (USA), G. Meissner (USA), D. Miller (UK), M. Morad (USA), D. Noble (Meeting Chairman, UK), M. Noble (UK), A. Noma (Japan), L. Opie (South Africa), H. Piper (Germany), J. Potter (USA), G. Radda (UK), B. Swynghedauw (France), H. ter Keurs (Canada), A. Williams (UK), D. Wray (UK). ABSTRACTS: There will be poster sessions. Abstracts of all lecture and poster communications will be published in a special issue of the Journal of Molecular and Cellular Cardiology. SPONSORS: British Heart Foundation, The Wellcome Trust, The British Society for Cardiovascular Research, The Biochemical Society, Glaxo, ICI Pharmaceuticals, Organon Laboratories, Pfizer Research, Smith Kline Beecham, Syntex Research. REGISTRATION: The conference fee will be around £200 and will include all accommodation, meals and coffee, conference materials and social events. The meeting is open to all interested and will be limited to about 250 participants. Further information can be obtained and preliminary registration can be indicated by writing to either Dr M. Boyett or Dr C. Orchard at:

Department of Physiology University of Leeds

Leeds LS2 9JT Tel: 0532-334265 Fax: 0532-334248

7

BSCR MEETING REPORT Spring Meeting

ENDOTHELIUM AND ATHEROGENESIS Cardiff, 10-11 April 1991

The symposium took place on 10-11 April 1991 at the University of Wales College of Medicine, Cardiff. The symposium attracted over 150 registrants, mainly from Britain, but with a contingent from Sweden and, of course, our guest speakers. Professor Russell Ross from the U. S. A. and Professor Arnold Herman from Belgium. The meeting was planned for 100, but last minute switching to a larger lecture theatre and flexibility on the part of the Residences Administration allowed us to seat and accommodate all those who applied to attend. There were 14 poster submissions, which we managed to reduce to our limit of twelve by some amicable (I hope) arm-twisting. Posters were on display throughout the meeting (abstracts reproduced on pages 10-12). The almost overwhelming response to a symposium outside the traditional area of the old Cardiac Muscle Research Group was most gratifying.

Prof. Ross opened the meeting by giving the 5th Dame Honor B. Fell Memorial Lecture (organised jointly with the UWCM Tissue Culture and Cell Biology Club), and he acknowledged having spent formative years in Dame Honor's laboratory in Cambridge. Prof. Ross gave a pathologist's eye view of atherogenesis illustrated by quite splendid original micrographs. He laid stress on the sequence of events during atherogenesis in cholesterol fed monkeys, namely early ingress of monocytes and later generation of endothelial denudation and smooth muscle cell proliferation. He went on to describe important but differing roles for PDGF, TGFB, IGF-1 and FGF in the generation of plaques, which had been elucidated from both tissue culture and whole animal models.

The remainder of the afternoon was devoted to discussion of endothelial interactions with other vascular cells. Dr. R. F. G. Booth reviewed the mechanisms underlying monocyte adhesion to endothelium and presented data on the role of the protein kinase C pathway obtained with novel selective inhibitors. Dr. J. D. Pearson described the role of endothelial calcium and protein kinase C in regulating the production of prostacyclin, nitric oxide and von Willebrand factor all of which modulate platelet-endothel ium interactions. The role of nitric oxide production from endothelium and platelets themselves was

taken up by Dr. M. Radomski. Endothelial control of vascular smooth muscle cell proliferation was reviewed by Dr. A. A. Soyombo, who presented data on potentially novel proliferation enhancing activity produced by the endothelial cells in organ cultures of human saphenous vein. Dr. P. L. Weissberg completed the afternoon's programme by describing the action of endothelins to potentiate PDGF-induced vascular smooth muscle proliferation.

Wednesday morning opened with four papers related to lipoprotein interactions with endothelium. Dr. P. D. Weinberg described the localisation of transendothelial lipoprotein transport using novel fluorescence microscopy methods and related this to sites prone to atheroma formation. Prof. A. G. Herman described the influence of models of hyperlipidaemia-induced atherogenesis on the function of endothelium as measured by impaired release of nitric oxide. Dr. D. S. Leake discussed the mechanisms by which endothelium and other vascular cell can modify low density lipoproteins to increase their atherogenicity. Dr. M. Jacobs then described the dii'ect effects of normal and oxidatively modified LDLs to inhibit endothelial nitric oxide production.

The meeting was rounded off by a discussion of the importance of endothelium in clinically-encountered atherosclerosis from the cardiac surgeons point of view. In reviewing the literature and his own studies, Mr. G. D. Angelini achieved a perfect balance in conveying a serious message through the medium of a very light-hearted presentation.

Thanks are owing to Jill Allen, Gail Hughes and Wendy Simons, as well as many members of the Cardiff Cardiovascular Sciences Research Group, who bore the major burdens of organising the meeting. We are indebted to the British Heart Foundation for providing a visiting professorship to Prof Ross and to the British Cardiac Society for a lectureship to Prof Herman. The UWCM accommodated the meeting free of the usual charges. Finally, the meeting would have been impossible without the very generous financial support of Bayer (U. K.) Ltd.

Andrew Newby

8

READERS'VIEWS "Power and impedance in the cardiovascular system"

While not producing any firm conclusions that could be applied to the assessment of mechanical performance in small mammalian hearts, the recent workshop at Lambeth Palace was important for highlighting the polarisation of engineering and physiology principles.

In engineering, the physical properties of complex electromechanical systems are described by terms that are amenable to accurate mathematical formulations. Terms like power transfer function and load impedance are carefully defined and related by correctly dimensioned equations.

By comparison, cardiovascular physiology is a pseudo-science based upon ill-defined parameters such as 'myocardial contractility' and 'inotropic effect', and functional assessment that frequently embodies assumptions and approximations that can only be justified by generalisations. Empirical parameters, such as dP/dtmax, rate-pressure product and tension-time integral are obtuse and nebulous. They are subject to complex problems of methodology and interpretation and have weak theoretical bases. The paramount difference between systems analysis in engineering and physiology is the greater mathematical rigour and precision of the engineering techniques. Physiology protects itself from the demand for mathematical determination by the excuse of the biological diversity and variation.

Potential applications for engineering techniques in physiology are numerous. For the analysis of cardiovascular function, electrical transmission line theory provides the relevant mathematical basis. The heart is then analogous to a transducer that converts chemical energy stored in molecules of ATP into mechanical energy. With negligible losses due to the formation of heat, this energy is used to perform work. A variable proportion of this work is internal. That is, it is used to overcome the source impedance of the heart - in more familiar terms, the sliding viscoelastic resistance. The ratio of intemal to external work is a measure of myocardial efficiency.

External work results in the generation of blood flow and blood pressure in the proximal aorta and the rate of performing work is haemodynamic power. Power is a complex quantity in both conceptual and mathematical senses. The power spectrum consists of a frequency domain series of amplitude and phase relations. In this form, the external performance if the heart is comprehensively described, but the spectral data is difficult to interpret. A presentation that is easier to assimilate is to equate total haemodynamic power (W)^ to the interdependent sums of mean (W_̂ ) and pulsatile (Wp power, potential (W ) and kinetic (W^) power, and cospectral (C^ (pressure and flow in-phase) and quadrature ( D ^ power (pressure and flow out-of-phase). All of these parameters are easily computed from the Fourier components of the pressure and flow signals. The subscript's' = jw (j = / ^ l , w = 2 jcf, f = frequency) indicates that cospectral and quadrature power are dependent upon the heart rate. Haemodynamic power completely describes the external performance of the heart under any set of input and output loading conditions.

The load that the heart works against is the vascular impedance. For the left ventricle, it is the aortic input impedance. Like power, impedance is also complex and can be described by the impedance spectrum (Z^, but the total impedance are the peripheral vascular resistance (Rp), characteristic resistance (Rc), arterial compliance (C) and inductance (L). By this process, parameters that are indeterminate by standard physiological techniques are revealed and the contributions of the arteries (Rc and C), arterioles (Rp) and blood volume (L) to the vascular load are distinguished.

Thus, cardiovascular function can be described by the computation of haemodynamic power and aortic input impedance. The technique is based upon elementary mechanics and electrical transmission line theory. It is equally applicable to isolated and in situ mammalian hearts, human patients and mechanical pumps. The measurement of blood pressure and flow can be made precisely and no assumptions concerning the relationships between cardiovascular function and the computed parameters are necessary. The specific relationships are:

Haemodynamic power Aortic input impedance W = -t- Z = sL -I- Rp

1 -I- sL/Rc 1 + sRpC W = W ^ - h D Zt = f (Rp ,Rc ,C ,L) w, = w^-^w,

9

Bibliography: 1. MilnorWR. Hemodynamics. Williams and Wilkins, Baltimore, 1982. 2. Nichols WW, O'Rourke MF. McDonald's blood flow in arteries: theoretical, experimental and

clinical principles. Third edit. Edward Arnold, London, 1990. 3. Wright G, Sum Ping JTS, Campbell CS, Tobias MA. Computation of haemodynamic power and

input impedance in the ascending aorta of patients undergoing open heart surgery. Cardiovasc Res 1988;22:179-84.

4. Wright G, Sum Ping JTS, Campbell CS, Tobias MA. Assessment of cardiovascular function in patients undergoing coronary artery bypass grafting. J Thorac Cardiovasc Surg 1988;96:400-7.

5. Wright G. The hydraulic power outputs of pulsatile and nonpulsatile cardiopulmonary bypass pumps. Perfusion 1988;3:251-62.

If you would like to set up a system for the computation of these parameters, the basic equations, recording and computation techniques can be found in the above references. If you have any problems, please contact me and I will do my best to help. Gordon Wright W. E. Dunn Unit of Cardiology, Dept of Biological Sciences, University of Keele, Staffs ST5 5BG Tel: 0782-621111 Ext.3105

BOOK REVIEW Principles and Practice of Cardiovascular Imaging

edited by Gerald M. Pohost and Robert A. O'Rourke

Churchill Livingstone 942 pages, 959 illustrations

£115.00 It is extremely refreshing to open a major review text and to discover that the editors have adopted a rational approach to their subject that makes it accessible and relevant to readers from a diverse range of subspecialities. Drs. Pohost and O'Rourke are to be congratulated on the organisation of their book which is divided into three sections. The first subdivides cardiovascular imaging by modality with subsections on echocardiography, nuclear medicine, radiology and MRI. I was a littie disappointed to discover that 'state of the art imaging' is given a disproportionate amount of space relative to its current clinical role (e.g. MRI covers 98 pages and angiography 40). Each subsection begins with a lucid and (mercifully) concise chapter on basic principles followed by chapters on the application of the modality to disease states. These chapters are (quite righUy) written by imaging experts rather than jobbing clinicians. Whilst this lends a quiet authority to the imaging aspects of the text, however, there are a number of controversial references to clinical practice, such as the assertion that cardiac catheterisation is essential for the differentiation of papillary muscle rupture and ventricular septal defect

following myocardial infarction. Each subsection ends with a consideration of future trends. In such a rapidly moving field no text can hope to be comprehensive, but I was again disappointed at the omission of any reference to angioscopy and the relatively short section on trans-oesophageal echocardiography.

Clinical integration of the various modalities is much better covered in the second section where clinicians consider the rational use of imaging by disease process. This approach inevitably leads to some duplication and contradiction between the sections but these disadvantages are far outweighed by the benefits of clarity and ease of reference. These chapters are authoritative but not comprehensive. There is no chapter on the clinical use of imaging in aortic disease although this is adequately covered within the first section. The rational use of imaging is further considered in the third section which covers the important and often ignored issue of cost.

The text is copiously illustrated and eight pages are devoted to colour plates. Photographic reproductions are of such high quality that I would defy even a non-clinician to miss their diagnostic implications. Similarly, line drawings are clear and well annotated.

The broad scope of this book and its authoritative execution commends it as a reference text to all with an interest in cardiac imaging. The separation of clinical and technical aspects makes it accessible to the basic scientist as well as the clinician. It would make a welcome occupant of the library shelves of any cardiac department.

Clive Lawson

10 Abstracts from Spring Meeting

ENDOTHELIUM AND ATHEROGENESIS Cardiff, 10-11 April 1991

L-GLUTAMINE TRANSPORT IN HUMAN UMBILICAL VEIN ENDOTHELIAL CELL MONOLAYERS AR Bavdoun , L M a d g e . JM MIot la . J D Pearson ' and GE Mann Biomedica l Sc iences Div is ion, K ing 's Col lege London , London W8 7AH and "Sec t ion o f Vascu la r Bio logy, MRC Clinical Research Cen t re , Ha r row , U.K.

T ranspor t of L-g lutamine, a pu ta t i ve inh ib i tor o f EDRF b iosyn thes is , w a s s tud ied in cu l tu red h u m a n venous endothe l ia l cel l mono laye rs . Up take w a s med ia ted via a saturable carr ier s y s t e m d e p e n d e n t upon ext racel lu lar s o d i u m and sens i t i ve to inh ib i t ion by subs t ra tes for amino acid t ranspor t s ys tems N (L-asparagine) and ASC (L-cyste ine) . By con t ras t , L-arginine (1 m M ) , l l -2 -amino-b icyc lo- (2 ,2 .1 )heptane-2-carboxYl ic acid (1 m M ) and 2 -methy lamino isobu ty r i c acid (1 m M ) , respect ive subs t ra tes for amino acid t ranspor t s y s t e m s y'^, L and A, w e r e ine f fec t ive inh ib i tors . In k inet ic expe r imen ts ca lcu la ted K,„ and V „ „ va lues for L-glutamine t ranspor t w e r e 0.14 m M and 2.5 pmo l /m in / / ;g p ro te in , respec t i ve ly .

EXPRESSION OF FIBROBLAST GROWTH FACTOR mRNA AND PROTEIN IN THE DEVELOPING BOVINE HEART. P. Cummins, S. Beestone, D. Chilton. Molecular Cardiology Unit, Department of Physiology, The Medical School, University of Birmingham, Binningham, B15 2TJ, UK.

Basic (bPGF) and acidic (aFGF) fibroblast growth factors have been implicated in several growth processes in the heart, including myocyte proliferation and angiogenesis. The aim of this study was to establish the characteristics of the respective mRNA's, level of protein expression and cellular localisation of these factors. Total cell RNA was isolated from 20-30 v\/eek gestation bovine fetal ventricles and probed with cDNA's specific for aFGF and bFGF. Despite these mRNA's being present at low copy number and normally undetectable in the heart, bFGF mRNA was detected at 7.1Kb and aFGF at 3.8 Kb. These are compatible with mRNA sizes in other organs. ELISA of bFGF indicated levels of 380 to 520 pg/kg in the developing ventricle, considerably higher than previously determined.Immuno-cytochemical investigations using a polyclonal anti-recombinant bovine bFGF localised bFGF not only in blood vessels but also the cardiac myocytes. These results have important implications for the role of FGF's in myocyte proliferation.

BALLOON CATHETER DE-ENDOTIIELIALISATION OF T H E N U D E R A T CAROTID: RESPONSE TO INJURY IN T H E ABSENCE OF F U N C T I O N A L T LYMPHOCYTES. G.A.A.Ferns, M.Reidy, R.Ross. Dept of Pathology SM-30, University of Washington, Seattle WA 98195, USA.

We have studied the intimal proliferative response to balloon catheter de-endothelialization in congenitally athymic 'nude rats', that lack functional T cells. Significant intimal thickening was observed in both homozygous (nu/nu) and euthymic heterozygous (nu / + ) animals by six days after injury, with further thickening occurring over the next four days. There were no significant differences in mean intimal: medial cross-sectional area, nor thymidine labeling of intimal and medial cells between the nu/nu and n u / + animals at any time point. Approximately 1% of neo-intimal cells in both groups were leukocytes (OX-1 positive); 0.7% were macrophages (ED-1 positive). In neither group did T cells (OX-19 positive cells) constitute more than 0.1% of the neo-mtimal population. These data suggest that T lymphocytes do not play a major role in the accumulation of neo-intimal cells. The presence of macrophages within the lesions raises the possibility that they may be involved in the recruitment and proliferation of smooth muscle cells. To aid in the interpretation of our in-vivo data, we have also characterized the medial smooth muscle cells from nu/nu rat carotids with regard to their chemotactic and mitogenic responses to PDGF, TGF-beta and basic FGF. CORONARY VASCULAR ENDOTHELIUM RELEASES FACTORS WHICH ACTIVATE MYOCARDIAL POTASSIUM CHANNELS S Fort & M J Lewis, Department of Phannacology & Therapeutics and Cardiology, University of Wales College of Medicine, Heath Park, Cardiff, CF4 4XN

We have investigated the role of the coronary vascular endothelium in the regulation of myocardial contractile performance by the inlra-coronary infusion of substance P (SP) and bradykinin (BK) in isolated Langendorff-perfused ferret hearts. The results are expressed in mean ± scm.

Following pentobarbitone anaesthesia the hearts were excised and perfused with Krebs Henseleit solution (1.25 mM Ca; 95% 02/5% CO2) at ZTC, containing 0.01 M acebutolol and indomethacin. Left ventricular pressure was recorded via a fluid-filled latex balloon. SP and BK, both 10-6 M, continuously infused into the coronary circulation via an aortic root cannula produced a significant transient (<2 mins) reduction in peak pressure (16.2±3.6% and 27.0±4.2% respectively) and a fall in maximum rate of development of pressure (14.7+2.5 and 27.1±3.0% respectively). The SP- and BK-induccd mechanical effects were not blocked by N-o)-nitro-L-arginine. The effects of BK were completely inhibited following removal of the endothelium by prior injection of a single bolus of Triton X-100. The BK-induced changes in mechanical performance were also inhibited by the prior infusion of glibcnclamide, but not by tetrapentylammonium bromide (TPA). The SP-induced effects were blocked by TPA, but not by glibcnclamide.

The present results indicate that the coronary vascular endothelium can modulate myocardial contractile performance tlirough the release of one or more factors acting via myocardial K channels.

MODULATION OF ENDOTHELIAL ADHESION MOLECULE EXPRESSION BY PLATELET DERIVED IL-1 CM. Hawrylowicz, G.L. Howells, and M. Feldmann. Charing Cross Sunley Research Centre, Lurgan Avenue, Hammersmith, London W6 8LW.

Interleukin 1 (IL-1) plays a critical role In the body's defense to infectrous and inflammatory stimuli. Recent evidence has demonstrated the rapid cell associated expression of IL-1 by human platelets following activation (1). Since one of the earliest events in inflammation is the adhesion of platelets to injured endothelium, we have addressed whether platelet derived lL-1 Is present In a functionally relevant fomfi that can alter expresston of the IL-1 inducible adhesion molecule intercellular adhesion molecule 1 (ICAM-1) on cultured endothelial cells.

Thrombin activated platelets enhanced expression of ICAM-1 antigen by both umbilical vein and saphenous vein endothelial cells. Unstimulated platelets induced much lower Increases, whilst thrombin alone or supematant harvested from preparations of thrombin activated platelets stimulated no increase In ICAM-1 antigen expression. Pretreatment of thrombin activated platelets with antibodies specific for IL-1 a and IL-ip, but not irrelevant antibodies, abrogated their capacity to enhance ICAM-1 expression. These results suggest that platelets may initiate and regulate some of the earliest events in the inflammatory response via the delivery of proinflammatory cytokines such as IL-1 to injured vascular endothelium. 1) C M . Hawrylowicz, S.A. Santoro, P.M. Platts, and E.R. Unanue. 1989. Activated platelets express IL-1 activity. J. Immunol. 143:4015 - 4018.

INTIMAL PROLIFERATION IN A N ORGANj:ULTURE OF H U M A N INTERNAL MAMMARY ARTERY C M Holt, S E Francis, C Clelland, G D Angelini, S Rogers, P Gadsdon. Department of Cardiac Surgery, University of Sheffield, Clinical Sciences Centre, Northern General Hospital, Sheffield

Arterial intimal proliferation is an early feature of atherosclerosis. However its progression in humans is difficult to study. We therefore attempted to develop an organ culture model of intimal proliferation using segments of human internal mammary artery (IMA). Segments of IMA were dissected free from adventitia, carefully opened out and cultured, intimal surface uppermost for 14 days at 37°C in RPMI 1640 containing 30% foetal calf serum. In a separate experiment segments of IMA were de-endothelialized, prior to culturing. Tissue viability was assessed by A T P / A D P ratio, endothelial coverage by scanning electron microscopy and immunostaining for von Willebrand factor antigen and cell proliferation by autoradiography of histological sections. The A T P / A D P ratio of IMA did not significantly alter following 14 days in culture, 1.6 + 0.2 (Mean±SEM) vs 2.0 + 0.2 (n = 10) indicating that tissue viability was maintained. Intimal proliferation was observed in histological sections of cultured IMA. Immunostaining revealed that these neointimal cells were weakly positive for oc-actin, suggesting a differentiation towards a type of smooth muscle cell. Autoradiography showed proliferating cells in the neointimal layer with few dividing cells in the media. De-endothelialized IMA showed less neointimal thickening when compared with intact IMA, 21±2|jm vs 36±7 )im (n = 6,p<0.05) as well as a reduced number of dividing cells per mm intimal length, 4.1±0.6/mm vs 6.7±1.3/mm (n = 6). Thus, an organ culture model of human arterial intimal proliferation has been established. De-endothelialization results in diminished neointimal thickening, providing evidence for an endothelial derived proliferation enhancing factor. Inhibitors of this factor may therefore present new possibilities for therapy. D I S T R I B U T I O N OF MATURE IMMUNOREACTIVE E N D O T H E L I N S AND T H E I R PRECURSORS I N HUMAN VASCULAR T I S S U E . P . G . H o w a r d , C . P l u m p t o n , a n d A . P . D a v e n p o r t . C l i n i c a l P h a r m a c o l o g y U n i t , U n i v e r s i t y o f C a m b r i d g e , C a m b r i d g e U . K . CB2 2 Q Q .

We h a v e r a i s e d f i v e p o l y c l o n a l a n t i b o d i e s i n r a b b i t s t o c o m p a r e t h e d i s t r i b u t i o n o f m a t u r e E T s , b i g E T - 1 , b i g E T - 2 , a n d b i g E T - 3 i m m u n o r e a c t i v i t y i n h u m a n v a s c u l a r t i s s u e . V e s s e l s t e s t e d i n c l u d e : s a p h e n o u s v e i n ( n = 7 ) , m e s e n t e r i c v e i n ( n = - 3 ) , m e s e n t e r i c a r t e r y ( n = ^ 4 ) , a n d i n t e r n a l m a m m a r y a r t e r y ( n = 4 ) . E L I S A s h o w e d t h a t t h e C - t e r m i n a l h e p t a p e p t i d e o f E T - 1 c r o s s - r e a c t s w i t h E T - 1 , E T - 2 , a n d E T - 3 b u t n o t w i t h t h e B i g E T s . A n t i s e r a d i r e c t e d t o C - t e r m i n a l s o f b i g E T s ( p r o e n d o t h e l i n s ) o n l y r e c o g n i s e d t h e c o r r e s p o n d i n g b i g ET p e p t i d e . M a t u r e ET a n t i s e r a a n d b i g E T - 1 a n t i s e r a s t a i n e d t h e c y t o p l a s m o f e n d o t h e l i a l c e l l s a n d t h e v a s a v a s o r u m i n a l l v e s s e l s w h i l e i m m u n o r e a c t i v e b i g E T - 3 c o u l d n o t b e d e t e c t e d a t c o n c e n t r a t i o n s a s h i g h a s 1 : 1 0 0 . H o w e v e r , B i g E T - 2 i m m u n o r e a c t i v i t y s h o w e d a m o r e i n t e n s e s t a i n i n g a s c o m p a r e d t o c o n t r o l s u s i n g p r e - i m m u n e s e r a o r n o r m a l r a b b i t s e r a . T h e s e r e s u l t s p r o v i d e e v i d e n c e f o r a s o u r c e o f E T - l i k e p e p t i d e s i n v a s c u l a r t i s s u e . (We t h a n k t h e BHF f o r c o n t i n u e d s u p p o r t ) . EFFECT OF PENTOSAN POLYSULPHATE, HEPARIN AND A HEPARIN CORTICOSTEROID COMBINATION ON INTRACELLULAR LEVELS OF tPA AND P A I - 1 IN HUMAN ENDOTHELIAL CELLS. N . B . M a r t i n , A. J a m i e s o n , and D . P . T u f f i n . ICI P h a r m a c e u t i c a l s , M e r e s i d e , A l d e r l e y P a r k , M a c c l e s f i e l d , C h e s h i r e SK104TG. I n a d d i t i o n t o t h e i r w e l l r e c o g n i s e d a n t i - c o a g u l a n t e f f e c t s , h e p a r i n - l i k e compounds a r e a l s o r e p o r t e d t o i n d u c e p r o - f i b r i n o l y t i c a c t i v i t y . T h i s r e s p o n s e may c o n t r i b u t e t o t h e a n t i - a n g i o g e n i c a c t i o n s r e p o r t e d f o r t h e s e c o m p o u n d s , and i s p a r t i c u l a r l y e v i d e n t w i t h h e p a r i n c o r t i c o s t e r o i d c o m b i n a t i o n s . The a im o f t h i s s t u d y was t o f u r t h e r i n v e s t i g a t e t h e p r o - f i b r i n o l y t i c a c t i o n o f t h e s e compounds b y m e a s u r i n g i n t r a c e l l u l a r l e v e l s o f tPA a n d P A I - 1 a n t i g e n f o l l o w i n g a 3 - 6 d a y t r e a t m e n t o f human u m b i l i c a l v e i n e n d o t h e l i a l c e l l s . P e n t o s a n p o l y s u l p h a t e ( l O O u g / m l ) , h e p a r i n ( 9 0 u g / m l ) a n d a h e p a r i n ( 9 0 u g / m l ) + h y d r o ­c o r t i s o n e ( l O O u g / m l ) c o m b i n a t i o n ( b u t n o t h y d r o c o r t i s o n e a l o n e ) s i g n i f i c a n t l y i n c r e a s e d i n t r a c e l l u l a r l e v e l s o f tPA a n t i g e n . T h i s e f f e c t was m o s t d r a m a t i c w i t h t h e h e p a r i n s t e r o i d c o m b i n a t i o n . A p a r a l l e l r e d u c t i o n i n i n t r a c e l l u l a r l e v e l s o f P A I - 1 was a l s o o b s e r v e d . I f m i r r o r e d i n v i v o . t h i s r e s p o n s e w o u l d l e a d t o i n c r e a s e d p l a s m a f i b r i n o l y t i c c a p a c i t y w h i c h i n t u r n c o u l d c o n t r i b u t e t o t h e a n t i - a n g i o g e n i c a c t i o n o f t h e s e c o m p o u n d s .

12 THE USE OF L-ARGININE HYDROCHLORIDE AS AN ACUTE HYPOTENSIVE AGENT DURING ANAESTHESIA. A. J.Petr O S ,A.M.Hewlett,R.Bogle,J.D.Pearson. Depts of A n a e s t h e s i a , Northwick Park H o s p i t a l & V a s c u l a r B i o l o g y , C l i n i c a l R e s e a r c h C e n t r e , Watford Road, Harrow, Middlesex HAl 3UJ.

We a r e e v a l u a t i n g t h e use of L - a r g i n i n e as an h y p o t e n s i v e agent i n a n a e s t h e t i c p r a c t i c e and whether i t s r e p o r t e d h y p o t e n s i v e a c t i o n ' - ^ can be e x p l o i t e d c l i n i c a l l y .

Two male p a t i e n t s have been s t u d i e d ; mean a r t e r i a l blood p r e s s u r e (MAP) and c a r d i a c output (CO) were measured and s y s t e m i c v a s c u l a r r e s i s t a n c e (SVR) c a l c u l a t e d . The f i r s t was a 6 2 - y e a r - o l d normotensive man and t h e second a 71-year-old-man both r e q u i r i n g e l e c t i v e s u r g e r y f o r abdominal a o r t i c aneurysm r e p a i r . They r e c e i v e d an i n f u s i o n of L-a r g i n i n e h y d r o c h l o r i d e a t 8.3mg/kg/min a f t e r commencement of s u r g e r y and when t h e a o r t a had been clamped.

MAP, CO and SVR a l l f e l l w i t h i n 5 minutes of g i v i n g L - a r g i n i n e and r e c o v e r e d 10 minutes a f t e r s t o p p i n g t h e i n f u s i o n . No s i g n i f i c a n t changes o c c u r r e d i n a r t e r i a l oxygen t e n s i o n o r blood g l u c o s e l e v e l s .

L - a r g i n i n e a p p e a r s t o reduce s y s t e m i c blood p r e s s u r e i n a g e n t l e and c o n t r o l l a b l e f a s h i o n and i s an a t t r a c t i v e a l t e r n a t i v e t o o t h e r a g e n t s a s i t may be i n c r e a s i n g endogenous l e v e l s of EDRF t h e r e b y c o n t r o l l i n g v a s c u l a r tone i n perhaps a more p h y s i o l o g i c a l f a s h i o n . 1. V a l l a n c e P, C o l l i e r J , Moncada S. E f f e c t s of endothelium d e r i v e d n i t r i c o x i d e i n

p e r i p h e r a l a r t e r i o l a r tone i n man. Lancet 1989; i i : 997-1000. 2. Nakaki T, H i s h i k a w a K, S u z u k i H, S a r u t a T, Kato R. L - a r g i n i n e - i n d u c e d h y p o t e n s i o n .

Lancet 1990; i i : 696. THE EFFECT OF APROTININ ON PLATELET-ENDOTHELIAL CELL REACTIONS B. D . R o y s t o n , D . R o y s t o n , R. B o g l e * , S . B . C o a d e * & J . D . P e a r s o n - ' , D i v i s i o n s of A n a e s t h e s i a and " ' V a s c u l a r B i o l o g y , C l i n i c a l R e s e a r c h C e n t r e , H a r r o w .

We have shown p r e v i o u s l y t h a t t h e s e r i n e p r o t e a s e i n h i b i t o r A p r o t i n i n w i l l d r a m a t i c a l l y r e duce blood l o s s a f t e r open h e a r t s u r g e r y and i s a s s o c i a t e d w i t h a r e d u c t i o n i n template b l e e d i n g t i m e . The p r e s e n t s t u d i e s i n v e s t i g a t e d t h e e f f e c t s of A p r o t i n i n (30yM) on normal and s t i m u l a t e d human u m b i l i c a l v e i n e n d o t h e l i a l c e l l s (HUVEC) w i t h r e s p e c t t o ( 1 ) t h e adherence of p l a t e l e t s and ( 2 ) r e l e a s e of pro- and a n t i - a g g r e g a t o r y s u b s t a n c e s . The mean b a s a l adherence of p l a t e l e t s to u n s t i m u l a t e d HUVEC was 3 . 3 Z + 0 . A(n = 1 2 ) w h i c h i n c r e a s e d to 8.5%±1.l(n=12) f o l l o w i n g p r e t r e a t m e n t of HUVEC w i t h lU/ml thrombin ( p = 0 . 0 0 1 ) . A p r o t i n i n caused s i g n i f i c a n t d e c r e a s e s i n b a s a l adherence to 2 . 5 % + 0 . 4(n = 1 2 ) p = 0 . 0 0 8 and s t i m u l a t e d adherence to 6 . 3 Z + 1 . 1(n = 1 2 ) p = 0 . 0 0 9 . L-methyl a r g i n i n e enhanced s t i m u l a t e d adherence to 1 2 . 5 Z + 2 . 5 (n= A ) and t h i s was n o t a l t e r e d s i g n i f i c a n t l y by A p r o t i n i n . The e f f e c t of A p r o t i n i n on r e l e a s e o f p r o s t a c y c l i n (PGI2) and v o n W i l l e b r a n d f a c t o r (vWF) from HUVEC was a l s o i n v e s t i g a t e d . PGI2 r e l e a s e was i n c r e a s e d f o l l o w i n g s t i m u l a t i o n w i t h thrombin, h i s t a m i n e , and p o l y - L - l y s i n e ( 6 , 1 0 and 2 f o l d r e s p e c t i v e l y ) , vWF r e l e a s e was i n c r e a s e d f o l l o w i n g s t i m u l a t i o n w i t h thrombin, h i s t a m i n e , p o l y - L - l y s i n e and phorbol m y r i s t a t e a c e t a t e ( 3 , 2 , 5 and ^ f o l d ) . . A p r o t i n i n had no s i g n i f i c a n t e f f e c t s on t h e s e r e l e a s e r e a c t i o n s .

CHARACTERIZATION OF NITRIC OXIDE SYNTHASE IN CULTURED ENDOCARDIAL CELLS J.A. Smilhl, R. Schulz. MJ. Lewis^, S. Moncada. Wellcome Research Laboratories, Beckenham, Kent, BR3 3BS; Departments of Cardiology^ and Phannacology & Tlierapeutics^, University of Wales College of Medicine, Cardiff, Wales, CF4 4XN, UK

Ttie endocardial cells lining the interior chambers of the heart have recently been shown to release a humoral agent with properties indistinguishable to tliose of endothelium-derivcd relaxing factor (EDRF). Since nitric oxide (NO) accounts for the biological activity of EDRF wc have now examined porcine endocardial cells for the presence of NO synthase, the enzyme which synthesizes NO from L-arginine (L-arg). In bioassay experiments, perfusate from a column of endocardial cells grown on microcarrier beads caused relaxation of a segment of cndothelium-denudcd pig coronary artery. This effect was potentiated in the presence of superoxide dismuta.se and catalase and abolislicd by haemoglobin (0.5 |iM) or N^'-monomcthyl-L-argininc (L-NMMA) (50 nM). Cytosol was prepared from endocardial cells by sonication and ultracenuifugation and the rate of NO synthesis was measured spcctrophotomcuically. Addition of L-arg (0.3-30 )iM) in tlic presence of NADPH (100 (iM) and CaCl2 (200 (iM), caused a concenfration-dependent increase in the rate of NO formation to a maximum of 5.67±0.80 pmol/min/mg protein (n=3). In the absence of added L-arg, or if D-arg (30 (iM) was substituted for L-arg, or if NADPH was omitted from the reaction mixture, the rate of NO synthesis was below ilie limit of detection (<0.1 pmol/min/mg protein). L-NMMA but not D-NMMA (30 |iM), abolished NO formation, which was partially reversed by addition of L-arg (300 |iM) (41.7±4.1 %, n=3). Release of NO was not detectable in the presence of EGTA (1 mM). Readdition of calcium stimulated NO synthesis in a concentration-dependent manner (EC50 0.65±0.I0 nM, n=3). Thus we have shown for tlic first time that endocardial cells have a constitutive NO synthase which is L-arg, calcium and NADPH dependent, similar to that found in vascular endothelial cells. Tlie physiological role of endocardial-dcrivcd NO remains to be investigated.

Autoradioqraphical localization and characterization of calcitonin gene-related peptide (CGRP) receptor in porcine cgronary artery (CA): higher specific finding density jn small coronary artery (5CA) Binq Sun, Anthony P Davenport and Horns J Brown. Clinical Pharnacology Unit, University of Caobridqe, Caabridge, UK CGRP is a 37-residue peptide and has potent vasodilating effect on CA. A correlation between decreasing vessel diameter and increasing vas9dilative response to CGRP in pig heart was reported. In the preseilt study, specific binding s i tes for huioan l̂pha-(;GRP m porcine CA wefe localized and characterized using quantitative autpradiograpfiy. Fresh porcine hearts (n=5) were obtained fron a local slaughter house and snap frozen. Tissue sections (10 ua thicl() froB ventricles were cut on a cryostat and thaw-mounted onto gelatin-coated s l ides . Receptor autoradiography was carried out as described previously. Tissue sections were incubated in the presence of 0.34 nH [1251] alpha-fiCGRP (AmershaD, UK) ?t 4 C for 2 hr, Hon-specifi9 binding was defined by coincubating an adjacent section with 1 uK alpha-hCGRP. A displaceiaent experiiient was carried.out with 0.1 nH to 1 uH alpha- or beta-RCGRP in the presence of 0.2 nH [1251 alpha-hCGEP. CGifP bindina was guantified in autoradiograas using a computer-assisted iiaqe analysis system by

com] ano

laris on with a series of redioactive tissue paste standards. The average density of binding was expressed as /sq m. TRe bindinq to CGRP receptor in the CA was time-dependent and saturable. Specific bindinq was higher to SCA [internal diameter (ID) < 1 mm, 61 amol/sq Bin] than to larqe a (La 1.5 mm < ID < 5.5 mm, 28 amol/sq mm, p < 0.0001, unpaired two tailed student's t t e s t ) . Host of the bindinq in LCA appeared to be associated with the inti ia and media. In one experiment, similar displacement curves with alpha- or beta-hCGRP were obtained in both LCA and SCA. alpha-hCGRP showed less affinity (IC50 2.3 nH) than beta-hCGRP (IC50 1.3 nH) m both LCA and sa . The Bmax for CGRP receptor in the LCA was 114 fmol/mq protein, whereas the Bmax in the SCA was 255 fmol/mg protein. . Our results haye demonstrated a higher density of specific ^)indinq s i tes for CGRP existed in small porcine CA, which i s consistent with previous phafmacoloqical studies. CGRP miqht play a more important role in the regulation of blood supply to the myocites throuqh i t s receptor m the small CA.