325

(3) Both groups have launched trials of similar design that will study different aspects of this problem. Their cumulative results will be of great value but will depend on recruiting sufficient numbers of patients to each trial. (4) Despite the overwhelming evidence supporting the need for such studies, most poor-risk early-breast-cancer patients in the U.K. are not entered into any trial where the value of adjuvant therapy can be assessed. We therefore ask clinicians in charge of eligible patients to give serious thought to collaborating

VASCULAR PROSTACYCLIN MAY BE REDUCED IN DIABETES IN MAN

SIR,-Vascular endothelium generates prostacyclin (P.G.I2), potent inhibitor of platelet aggregation.’ We have found that aorta2and renal cortex3 from streptozotocin-diabetic rats produce significantly less P.G.I2 than do tissues from control animals. To assess the clinical relevance of these findings, we have now estimated P.G.I2 release by vessels from diabetics and nondiabetics. a

with one or other of these studies. (5) Centres which enter a substantial number of patients will be provided with secretarial or other assistance to facilitate the conduct of the trial. Further information can be obtained from either of us regarding both trials, so that clinicians can choose which they would feel to be most appropriate for them to join.

Department of Radiotherapy, Royal Free Hospital,

F. SENANAYAKE

London NW3

Department of Surgery, King’s College Hospital Medical School, M. BAUM

London SE5

*,*A

note on

the latest U.I.C.C.

and other cancers appears

on

compendium of trials

in breast

p. 339.-ED. L.

SELF-TREATMENT OF COLD SORES WITH ICE

SIR,—Dr Zimmerman’ draws attention to the absence of a clinical trial of ice as a treatment for cold sores and points out that, in general, clinical trials to test non-pharmaceutical "household" remedies are seldom done. This is a valid criticism and reflects on the usual sources of drug-trial funds and on the low prestige attached to this type of investigation compared with studies with an aura of basic science. Another aspect-perhaps the most important one-is the difficulty in deciding which, if any, of these remedies is really likely to be successful and therefore warrants the major effort required to arrange and monitor a double-blind, controlled trial. If household remedies are extended to include the vast array of purportedly successful "traditional remedies" used in Asian medicine, the task of selecting those worthy of formal testing becomes staggering. I do not entirely envy Zimmerman his access to the medical views of 18 million women, for with such a group-as with any other-the strength of the placebo response must not be underestimated. The vast array of "simple" remedies now discarded but once heralded as successful in the treatment of rheumatoid arthritis2 is testimony to the importance of this factor. Similarly, several treatments thought to be effective against cold sores have, when tested in the correct format, proved of no significant value.3-7 In our own study 60% of patients experienced excellent response from placebo.7 While this may reflect a major role for psychogenic factors in this disorder, it sets a high standard for other potentially active agents to

improve on.

the ice therapy for cold sores, rather to emphasise the likelihood of a low yield after testing remedies of this type. Ice is safe, cheap, and relatively painless, and even though it may still be just a placebo, if Zimmerman’s women readers say "aye", who should say "nay"? I do

not mean to

decry

.

Patients A and B had been diabetic for 14 and 4 years respectively. B had been maintained on chlorpropamide, but this had been replaced by insulin 2 weeks preoperatively, and both patients were insulindependent at the time of surgery. Controls were not on any form of drug therapy. Vessels were removed during routine abdominal surgery (laparotomy for gallstones, inguinal hernia repair, and arteriovenous fistula) and immediately placed in Krebs’ buffer containing 200 mg/dl glucose at 4°C. Specimens were carefully dissected free of connective tissue, and pieces (3-31 mg wet weight) were cut into fine rings and incubated (10 mg in 100 µl) in Krebs’ buffer (22°C) with gentle agitation for 3 min. The incubations were performed within 10 min of biopsy. Supernatant (5-25 µl) was added to citrated human plateletrich plasma,’ 30 s before addition of a submaximal concentration of adenosine diphosphate (2 µmo1/1). The activity of the supernatant in inhibiting platelet aggregation’ was measured in a double-channel aggregometer (Payton). The presence of P.G.I2 was confirmed by complete loss of platelet inhibitory activity, after incubation with a specific antiserum raised in rabbits to 5,6-dihydro p.G.I2.5 The quantity of P.G.I2 was estimated from a standard curve using authentic P.G.I2 (sodium salt) and expressed as ng/mg wet weight of tissue.2 PROSTACYCLIN IN HUMAN VASCULAR TISSUES

by the inferior epigastric artery from three (0-26±003 ng/mg wet weight) was significantly (P

Self-treatment of cold sores with ice.

325 (3) Both groups have launched trials of similar design that will study different aspects of this problem. Their cumulative results will be of gre...
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