SLOW-RELEASE ASPIRIN AND PROSTAGLANDIN INHIBITION

1153 FREQUENCY OF FALSE POSITIVES

IN BLOOD DONORS AND

NONOXYNOL-9 AND HTLV-III

FREQUENCY

OF CORRECT RESULTS IN PANEL SERA

SIR,-Our letteron a collaborative project between the Mariposa Foundation and the Centers for Disease Control should have indicated that nonoxynol-9 concentrations in spermicides range from 1% to 12 - 507o (not 5%). We neglected to note that HTLVIII/LAV inactivation is very rapid (less than 60 s), an important consideration in evaluating the potential of nonoxynol-9 spermicides in reducing sexual transmission of HTLV-III. As evidence mounts that the virus may be sexually transmitted within host lymphocytes, and not just in free form, the importance of destruction of lymphocytes by 5% concentrations of nonoxynol-9 (present in some brands of spermicides) should not be overlooked. Mariposa Education and Research Foundation,

BRUCE VOELLER

Topanga, California 90290, USA

al. Inactivation of HTLV-III/LAV-infected cultures of normal human lymphocytes by nonoxynol-9 in vitro. Lancet 1985; ii: 1422.

1. Hicks

*Figures in parentheses are rates per 1000. t Doubtful results in parentheses.

The members of the SNTS study group who took part in this study were: F. Barin, Hopital Bretonneau, Tours; J. Baudelot, CTS Bobigny; M. Gueguen, CTS Rennes; C. Janot, CTS Nancy; J. M. Lemaire, CTS Montpellier; M. Maniez, CTS Lille; F. Mesnier, CTS Bordeaux; M. L. North, CTS Strasbourg; C. Rouzioux, Hopital Claude Bernard, Paris; W. Smilovici, CTS Toulouse.

Sanguine,

et

SLOW-RELEASE ASPIRIN AND PROSTAGLANDIN INHIBITION

calculated for each sample and the percentage of negative (ratio below 0 -90), doubtful (0 -90 or more but below I -00), and positive results (1 -00 or more) was established for the three categories in the panel (negative, positive, positive dilutions). The ’percentage of correct results is given in the table. The incorrect results found in the 17 negative samples of the panel related to single specimens only: no 46 for the Abbott (8 positive results/8, mean ratio 130) and Litton (1/8; 0 -60) tests; no 55for the Behring (8/8; 1 -32) and Organon (5/7; 1 -04) kits; and no 30 for the Dupont test (3/10; 0 ° 78). The negative and doubtful results found in the 25 positive samples in the panel were observed with the same specimen (no 23).* This study shows that the Wellcome kit followed by the two Pasteur kits are the most specific of the eight kits tested. Sensitivity is much more diifficult to compare. As judged by the recognition of undiluted and diluted positive samples of the panel, the most sensitive tests would seem to be the two Pasteur kits, then Wellcome, then Dupont, and then Abbott. But this evaluation, on only a few positive samples, is not rigorous since there are great qualitative and quantitative variations in anti-LAV/HTLV-III in different specimens.3,4 Western blot analysis showed, for example, that sample 25 recognised very clearly p25 and very poorly envelope proteins; the recognition pattern of sample 47 was the other way round. Since the first situation may arise more often than the second in blood donations-because antibodies to the major core protein appear first after exposure3-5-we are doing further comparisions of ELISA tests in individuals who have lately seroconverted.

Centre National de Transfusion 6 rue Alexandre Cabanel, 75739 Paris, France

DR, Martin LS, Getchell JP,

ANNE-MARIE COUROUCE, for the Retrovirus Study Group of the French National Society of Blood Transfusion (SNTS)

SIR,-The use of low-dose, slow-release aspirin for the ideal antithrombotic effect has been widely proposed. 1-4 It has been suggested that the slow administration of low doses of aspirin may permit cumulative presystemic acetylation of platelet cyclooxygenase with resultant inhibition of the formation of the vasoconstrictor and platelet aggregating agent, thromboxane A2 - 2,3 6 Because of gut, liver,5 and extrahepatic metabolism,6 concentrations of aspirin reaching the peripheral blood after dosing with these formulations may be too low to inhibit vascular cyclo’oxygenase and reduce the formation of the vasodilator and platelet antiaggregating agent, prostacyclin.2,3 52 volunteers were used to examine the hypothesis of a selectivity from low-dose, slow-release aspirin formulations. They took one of three aspirin formulations for 10 days. The formulations were soluble aspirin (’Aspro Clear’; Nicholas), a 100 mg aspirin plus glycine tablet (’Cardiprin’; Reckitt & Colman), and a slow release formulation (Smith, Kline and French). Over 24 h the slow release formulation yielded relatively constant plasma aspirin and salicylate concentrations. Blood and urine were collected on days 0, 6, and 10. The blood (1ml) was incubated in a plain glass tube at 37°C for 1 h and the resultant serum was analysed by 125Iradioimmunoassay (New England Nuclear) for TXB2, the stable hydrolysis product of TXAz. The urine was analysed for the stable hydrolysis product of prostacyclin, 6-keto-PGFIa (relative to creatinine excretion), by column chromatography I radioimmunoassay (New England Nuclear). Validation for the analytical procedures was based on the consistency of control values (mean±SEM) for TXB2 (354 - 5-t27 -1 ng/ml) and 6-keto-PGFIa (146±7 ng/mg creatinine) with normal values reported using gas chromatography/mass spectrometry

and 25

(TXB2 300±40 ng/MI;7 6-keto-PGFIa 140±25 ng/mg creatinine8). Currently we are validating our assays directly by gas chromatography/mass spectrometry. The table summarises the results. The serum TXB2 generated is highly dependent on the aspirin dose (p<0 ’01, analysis of variance), TXBzbeing expressed as a % of control values. Urinary 6-ketoCOMPARISON OF SERUM TXB, AND URINARY

6-KETO-PGF,a

PRODUCTION AFTER DAILY DOSES OF ASPIRIN FOR TEN DAYS

*A table giving mean ratios for sample no 23 and for the dilutions of 4 positive samples may be obtained from The Lancet-ED. L. 1 Courouce

AM, et le groupe d’étude de la SNTS. Evaluation de 3 trusses immunoenzymatiques de dépistage des anticorps anti-LAV. Comparaison avec des tests de confirmation. Revue Fr Transf Immuno-hématol 1985, 28: 325-44. 2 Mortimer PP, Parry JV, Mortimer JY. Which anti-HTLV III-LAV assays for screening and confirmatory testing? Lancet 1985; ii: 873-77. 3 Lange JMA, Coutinho RA, Krone WJA, et al. Distinct IgG recognition patterns during progression of subclinical and clinical infection with lymphadenopathy associated virus/human T lymphotropic virus. Br Med J 1986; 292: 228-30. 4. Schupbach J, Haller O, Vogt M, et al. Antibodies to HTLV III in Swiss patients with AIDS and pre-AIDS and-in groups at risk for AIDS. N Engl J Med 1985; 312: 265-70. 5. Esteban JI, Shih JW-K, Tai C-C, et al. Importance of western-blot analysis in predicting infectivity of anti-HTLV-III/LAV positive blood. Lancet 1985; ii: 1083-86.

Values,

as mean

(and SEM), expressed as percentage of control values (day 0) (n=5-7). (SK&F); tsoluble aspirin (Nicholas); 4:Cardiprin (Reckitt &

*Slow-release aspirin

Colman)

1154

PGF I levels also varied with aspirin dose (p<0 - 05). The urinary 6-keto-PGFla levels after the 50 mg slow-release formulation did

from the levels after 0, 5, and 10 mg doses on days 6 and 10 significantly greater than for the 50 (soluble), 100, and 300 mg doses on day 6. Thus 50 mg soluble and slow-release aspirin formulations produced a similar, almost complete inhibition of serum TXBzproduction but the slow-release formulation produced less inhibition of urinary 6-keto-PGFla’ at least on day 6. Although these results are consistent with the hypothesis that a low-dose, slow-release aspirin may provide the ideal antithrombotic effect, we recognise the difficulty of assessing vascular cyclooxygenase activity by measuring urinary 6-keto-PGFla concentrations. The degree of suppression of this production is small, possibly due to the rapid recovery of vascular cyclooxygenase after aspirin.7Furthermore analytical procedures for 6-keto-PGF in biological fluids have been criticised. Our data do show that a 50 mg dose of soluble aspirin or of this slow-release formulation will produce an antithrombotic effect. not differ

but

was

M. S. ROBERTS R. M. JOYCE L. J. MCLEOD J. H. VIAL

School of Pharmacy and Department of Physiology and Medicine, University of Tasmania, Hobart, Tasmania 7001, Australia

Smith, Kline & French (Aust),

Sydney,

P. R. SEVILLE

NSW

1. Editorial. Aspirin: what dose? Lancet 1986; i: 592-93. 2. Roberts MS, McLeod LJ, Cossum PA, Vial JH. Inhibition of platelet function by a controlled release acetylsalicylic acid formulation: single and chronic dosing studies. Eur J Clin Pharmacol 1984; 27: 67-76. 3 Pedersen AK, Fitzgerald GA. Dose-related kinetics of aspirin. N Engl J Med 1984; 311: 1206-1211. 4. Eastham RD. The low dose aspirin controversy solved at last? Br Med J 1985; 291: 738-739. 5. Harris PA, Riegelman S. Influence of the route of administration on the area under the plasma concentration-time curve. J Pharm Sci 1969; 58: 71-75. 6. Roberts MS, Cossum PA, Kilpatrick D. Implications of hepatic and extrahepatic metabolism of aspirin in selective inhibition of platelet cyclooxygenase. N Engl J

Med 1985; 312: 1388-89. 7.

Heavey DJ, Barrow SE, Hickling NE, Ritter JM. Aspirin causes a of bradykinin-stimulated prostacyclin production in man.

short lived inhibition Nature 1985; 318:

186-88. 8. Fischer S, Scherer B, Weber PC. Prostacyclin metabolism in adults and neonates. and 2,3-dinor-6 keto prostaglandin Urinary profiles of 6-keto-prostaglandin studied by gas chromatography-mass spectrometry. Biochim Biophys Acta 750: 127-33.

F1&agr;

F1&agr; 1983;

DISSEMINATED CRYPTOCOCCOSIS DIAGNOSED IN AIDS PATIENT BY SCREENING FOR SOLUBLE SERUM ANTIGENS

SIR,-Cryptococcosis is one of the most common mycotic infections encountered in AIDS patients.l When the clinical presentation is meningitis or pneumonia, the diagnosis is made on the basis of Cryptococcus neoformans found in cerebrospinal fluid (CSF) or in broncho-alveolar lavage (BAL) fluid. Sometimes, however, cryptococcosis is asymptomatic or masked by the symptoms and signs of other adventitious infections; in these cases, the diagnosis can only be reached at necropsy. We report here the diagnosis of disseminated cryptococcosis by screening for soluble cryptococcal antigens in serum.‘ A 34-year-old homosexual man had had AIDS with Kaposi’s sarcoma since January, 1984. In March, 1985, he was admitted to hospital for dyspnoea and fever; BAL revealed Pneumocystis carinii. Treatment with co-trimoxazole was started. As part of a prospective study, screening for serum soluble cryptococcal antigen using latex agglutination was performed: this test was positive at 1/2048. Even though no clinical anomalies indicative of cryptococcosis could be identified, a systematic mycological investigation was carried out. Although biochemically and cytologically normal, the CSF contained numerous encapsulated yeasts (indian ink); C neoformans was isolated on Sabouraud culture. The fungus was also found in blood and urine cultures. Both the urine and the CSF were also positive for soluble cryptococcal antigen. Antifungal treatment with intravenous amphotericin B and 5-fluorocytosine was added to the co-trimoxazole therapy. 1 month later, CSF and urine culture were negative. The patient died of multiple Kaposi’s sarcomas in

September,

1985.

This case illustrates the possibility of an asymptomatic disseminated cryptococcosis;3 it demonstrates the possibility of screening for cryptococcal antigen as a method for the early diagnosis and it shows that early initiation of antifungal treatment might improve the prognosis of cryptococcosis in AIDS patients. PATRICIA ROUX

JEAN-L. TOUBOUL Laboratory of Parasitology and Chest Diseases Department, Hôpital Tenon, 75020 Pans, France;

Laboratory of Parasitology and Dermatology Department, Hôpital Creteil-Henri-Mondor, Creteil

MARTINE FEUILHADE DE CHAUVIN THIERRY DELACOUR JEAN REVUZ DIDIER BASSET CHARLES MAYAUD FÉLIX LANCASTRE

1. Kovacs JA, 2.

Kovacs AA, Polis M, et al. Cryptococcosis in the acquired immunodeficiency syndrome. Ann Intern Med 1985; 103: 533-38 Bloomfield N, Gordon MA, Elmendorf DF. Detection of Cryptococcus neoformans antigen of body fluids by latex particule agglutination. Proc Soc Exp Biol Med 1961,

114: 64-67. 3. Roux P, Basset D, Delacourt T. Problèmes diagnostiques posés parla cours du SIDA. Bull Soc Fr Mycol Med 1985, 14: 255-59.

cryptococcose au

HEART DISEASE PREVENTIVE STRATEGIES

SIR,-Professor Lewis and his colleagues (April 26, p 956) state that "the causal role of the four major risk factors [for coronary heart disease (CHD)]-hypercholesterolaemia, cigarette smoking, hypertension, and diabetes-is now established beyond reasonable doubt". I agree about the first three but have questioned a causal role for non-insulin-dependent diabetes (NIDDMi’zand have yet to be struck by a thunderbolt or have my arguments refuted. Furthermore, although Lewis et al do not include obesity among the cardinal risks, they do imply elsewhere that its reduction would prevent CHD; Barrett-Connor’s comprehensive review3 concluded that "inconsistent results with regard to the nature, strength and linearity of the association between obesity and atherosclerosis do not support the hypothesis that obesity causes atherosclerosis, despite its biological plausibility". I would not disagree, but would add that there is no experimental evidence that weight reduction reduces CHD incidence. On hypercholesterolaemia and CHD risk, I do agree with Lewis et al that it is wrong to regard a population strategy and a high-riskgroup strategy as necessarily mutually exclusive. However, their advocacy of both strategies in relation to hypercholesterolaemia and the consequent need, with the second, for screening/case finding and the establishment of more specialised lipid clinics ignores the reality of the figures in their table 11. Thus, using a cut-off at 6-55 mmol/1 serum cholesterol, they find that 23% of the UK population aged 25-29 exceed this value, reducing to 10-13% with a "realistic" estimate of dietary induced reduction in serum of known cholesterol of 7-9%. Compare this with the diabetes in the total population (about 1’ 1%) in the UK, note the inadequacies of the long-established diabetic services shown in the British Diabetic Association inquiry,5remember the competing calls on NHS resources, throw in a few doubts about very long-term hypolipidaemic drug therapy (safety and cost)-and then try and get a proposal for a new lipid clinic past your fellow consultants, let alone the district general manager. It could be a testing question for part I of the membership examination of the Faculty of Community Medicine. Apart from the economic and logistic problems of the suggested high-risk strategy, there is also an ethical consideration. Thus symptomless people would be advised of their increased risk of coronary disease, possibly as early as their third decade of life, with the consequent "need" for long-term supervision and treatment and potential emotional distress at the knowledge of the risk and of economic distress (eg, by loading of insurance premiums) without the compensating assurance or guarantee of substantial risk reduction. If the strategy were confined to members of families where high risk had already identified itself by premature CHD, it might be more acceptable. The report of the European Collaborative Trial (April 19, p 870) at first sight offers more scope for preventive action by doctors and

prevalence