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SIR,-The Basle school health service has a legal obligation tosurvey tuberculin reactions in schoolchildren. While small childrenare tested with ’Moro-patch’, the 14-year-olds are offered BCGvaccination after intracutaneous testing. In 1972 the tine test

replaced the Mantoux test, mainly because some parents, who hadrejected vaccination, had protested against their children havingreceived an "injection" anyway. However, complications afterBCG vaccination were noted in tine-negative children and Mantouxtesting (with 10 IU PPD Berna) was again applied in children withnegative reactions to the tine test whose parents had given theirwritten consent to vaccination.In view of the poor results which Lunn and Johnson 1 obtained in

their studies with the tine test we did an analysis that confirmedtheir findings, with a sensitivity of 74% for the tine test.2 In a searchfor a better test we compared the tine test (Lederle Laboratories)with the Institut Merieux ’Mono-test’ (’Imotest’ in U.K.) in theschool year 1980-81. Children and examiners were systematicallyallocated to the two tests, to get a balance of school types andexaminers for each test. After a year we concluded that the mono-

_ test was no better than the tine test, but we realised that the two testscannot be applied serially by the same person because the mono-testneeds more pressure to penetrate the skin. Inadequate pressurewhen applying the mono-test might have been responsible for thelow sensitivity of the imotest found by Dr Rudd and colleagues.EXPERIENCE OF TINE AND MONO TESTING, FOLLOWED BY MANTOUX

WHERE INDICATED, IN BASLE SCHOOL HEALTH SERVICE

*Sensitiv1ty=A +(A + B+C)x 100. For assumpuons see text.

In the school year 1981-82 only the mono-test was used. Resultscan now be compared for large groups of children tested with tineand subsequent Mantoux and monotest and subsequent Mantoux,respectively. The table shows the resulting sensitivity, calculatedunder two assumptions-first, that the multipuncture tests do notproduce false-positive results and, secondly, that iri the group nottested further (because of lack of parental consent) the sameproportion of false-negative results would have been found as inthose which were retested.Our data do not support the conclusion that the imotest is less

reliable, but there seem to be fewer doubtful reactions with themono-test than with tine test, which makes its use for screeningmore practicable.In populations where tuberculosis is still present and where

complications of vaccinations have to be avoided double testing stillseems indicated.Institution of Social and Preventive Medicine,University of Basle,4052 Basle, Switzerland

HYPERLIPOPROTEINAEMIA TYPE V ANDAPOLIPOPROTEIN E4

SIR,-Dr Ghiselli and co-workers (Aug. 21, p. 405) reported ahigh frequency (74%) of the homozygous and heterozygous E4 apoEphenotype among type V hyperlipoproteinaemic patients. TheapoE4 allele frequency was 53% in contrast to 15% in normals.These workers concluded that apoE4 may predispose to a

disturbance in the catabolism of triglyceride-rich lipoproteins.We have apoE phenotyped twenty type V hyperlipidaemic

1. Lunn JA, Johnson AJ. Comparison of the tine and Mantoux tuberculin tests. Br Med J1978; i: 1451-53.

2. Ackermann-Liebrich U, Ritzel G, Liebrich F. Erfahrungen mit dem Tuberkulin Tine-Test bei Reihenuntersuchungen. Schweiz Med Wschr 1980, 110: 329-31.

URSULA ACKERMANN-LIEBRICH

E PHENOTYPE DISTRIBUTION AND E ALLELE FREQUENCY INNORMOLIPIDAEMIC AND TYPE V HYPERLIPIDAEMIC SUBJECTS

*No ofmdlviduals.

patients. All had severe hypertriglyceridaemia (over 10 mmol/l)associated with fasting chylomicronaemia and increase of very lowdensity lipoprotein (VLDL) triglycerides without evidence of post-heparin lipoprotein lipase deficiency or apoC-II deficiency. TypeIII hyperlipoproteinaemia and causes of secondary hyperlipidaemiaother than diabetes mellitus and obesity were excluded. Our methodfor isoelectric focusing of VLDL-apoproteins and other laboratorymethods have been described previously. The distribution of apoEphenotypes in our forty-nine controls (table) accorded with

previously reported population studies.2,3None of our twenty type V patients had the homozygous E4

phenotype and eight had the heterozygous E4 phenotype (table).The apoE allele frequency was similar in the control group and inthe type V patients. It seems unlikely that apoE4 is a majordetermining factor in the expression of this disorder.

Department of Internal Medicine,University of Nijmegen,6500 HB Nijmegen, Netherlands

P. M. J. STUYTA. F. H. STALENHOEFP. N. M. DEMACKERA. VAN’T LAAR

LEAD IN PETROL: THE ALTERNATIVES

SjR,—Dr Grandjean and Dr Andersen (Aug. 7, p. 333) correctlyconcluded that lead is not an ideal petrol additive from an environ-mental point of view. In the same paragraph, however, they omittedmention of the major octane extender additive and instead listedalternatives to lead which cannot be used on a large scale, at least inthe U.S.A., because of government prohibitions, technical

problems, or high costs.The manganese compound referred to was used commercially in

the U.S. in unleaded gasoline for a short time, but its use is nowprohibited by the Environmental Protection Agency because itincreases emissions of exhaust hydrocarbons. The other compoundslisted, which are either alcohols or ethers, have been or are beingused on a small scale, but all have drawbacks. Ethanol is veryexpensive: even with the current U.S.A. corn glut, its wholesaleprice is about$1.50 per gallon compared with$1.00 for gasoline(petrol), and it is used only where government subsidies make iteconomical. Methanol is a cheap relative to gasoline, but hasundesirable effects on gasoline quality and is used in very limitedvolumes in the U.S.A Methanol can be made from coal, and somecountries with large coal reserves are pushing methanol as analternative fuel, but not as an octane extender. ter-butyl ether andter-butyl alcohol are more expensive than gasoline and have somepoor quality features that prevent their use at high concentrations,but are used where local economics favour them. They are producedmainly as byproducts in chemicals manufacture and augment otherrefinery processing for octane improvement, but do not eliminatethem.

1. Stalenhoef AF, Casparie AF, Demacker PN, Stouten JT, Lutterman JA, van ’t Laar ACombined deficiency of apolipoprotein C-II and lipoprotein lipase m familialhyperchylomicronemia. Metabolism 1981, 30: 919-26.

2. Utermann G, Langenbeck U, Beisiegel U, Weber W. Genetics of the apolipoprotein Esystem in man. Am J Hum Genet 1980; 32: 339-47.

3. Zannis VI, Breslow JL. Human very low density lipoprotein apolipoprotein Eisoprotein polymorphism is explained by genetic variation and posttranslationalmodification. Biochemistry 1980; 20: 1033-41.

935

Grandjean and Andersen did not mention catalytic reforming,which is the major method of octane improvement used by all largerefineries. This improvement is more expensive than lead, and theprocess stream, called "reformate", consists mostly of aromatichydrocarbons, some of which have known health hazard potentials.

In summary, lead is not an ideal petrol additive, but neither are thealternatives. _

Standard Oil Co. (Indiana),Chicago, Illinois 60601, U.S A.

P. F. D. VAN PEENENT. O. WAGNER

HAIR ANALYSIS AND SELENIUM SHAMPOOS

SIR,-Mr Laker (July 31, p. 260) discusses the advantages of usinghair as a biopsy tissue to assess trace mineral status. He mentionsflameless atomic absorption spectrophometry, neutron activationanalysis, and electron microprobe analysis, but inductively coupledplasma emission spectroscopy can also be used in multi-elementanalysis ofhair. 1 doctors making use of hair mineral analysis shouldremember that, besides the influences of bleaching and tinting ontrace mineral levels in hair, cold waving ("perming") reduces zincand increases copper levels in hair.2 When untreated samples areused hair mineral analysis can be a clinically useful method ofscreening for the status of many trace minerals.3 The caveats andusefulness of the clinical application of this technique have beensummarised by the Hair Analysis Standardisation Board.4To add to knowledge of hair treatments that affect the trace

element content of hair, I would like to present evidence for hairselenium levels being increased by the use of selenium-containingshampoos.A retrospective analysis of the results of trace element analysis of

171 hair samples of patients seen in a general medical privatepractice was undertaken, irrespective of clinical diagnosis. Thesehair samples had been analysed by inductively coupled argonplasma emission spectroscopy for twenty-one elements, includingselenium, by Mineralab Inc., California. 1 g of hair was taken asclose to the scalp as possible from the nape and measured no morethan 5 cm. The samples were washed once in saturated free acidEDTA and then washed three times in de-ionised water, followed bydigestion in 70% nitric acid. 17 results were discounted because the hair had been dyed,

bleached, or permed during the three months before the sampleswere taken. Of the remaining 164, 156 had hair selenium in therange 0 - . 2-6 0 parts per million (ppm) and 7 had concentrations inthe range 18-160 ppm (table).The high hair selenium group (18-160 ppm) 7 patients gave a

history of using a shampoo (’Selsun’) which contains 2’ 5% w/v

1. Fassel VA. Quantitative element analysis by plasma emission spectroscopy. Science1978; 202: 183-91.

2. McKenzie J. Alteration of zinc and copper concentration of hair. Am J Clin Nutr 1978;31: 470.

3. Bland J. Diagnostic usefulness of trace elements in human hair. Department ofBiochemistry, University of Puget Sound, Tacoma, Washington 98416, U.S.A.,1981.

4. Hair Analysis Standardisation Board. Standardisation and interpretation of human hairfor elemental concentrations. P.O. Box 44, Trout Dale, Virginia, 24378, U.S.A.,1982.

ELEVATED HAIR SELENIUM IN 7 SUBJECTS

selenium sulphide in the three months before sampling. Patient VI(mild long-standing ulcerative colitis) did not use the shampoo onher own hair but had been using it twice a week for several months inwashing the hair of her mentally handicapped child. It is reasonableto assume that she was absorbing the selenium through her skin.Patient VII had a high hair selenium with no history of seleniumexposure. He had alcoholic cirrhosis. Aaseth et awl. noted a muchdecreased serum selenium in alcoholic cirrhotics and postulatedincreased urinary or faecal loss of this element. Hair, too, is an"excretory organ", and this may explain the abnormal value seen inpatient VII.

Little is known about the clinical significance of hair selenium,the most interesting work being evidence from China of low hairselenium levels in children with cardiomyopathy ("Keshandisease"). 6,79 Portland Road,East Grinstead,West Sussex RH 19 4EB T. STEPHEN DAVIES

MELANOMA, FLUORESCENT LIGHTS, ANDPOLYCHLORINATED BIPHENYLS

SIR,-Dr Beral and colleagues (Aug. 7, p. 290) have suggested alink between exposure to fluorescent lighting, office work, and anexcess of malignant melanoma. Beral et al. stated that no otherrelated causal factor known to be associated with melanoma couldaccount for their observation. May I propose a causal factor whichcould be important?Polychlorinated biphenyls (PCBs) have been associated with

melanoma and other cancers in man.8,9 PCBs are mainly used as adielectric fluid in "closed" electric components, such as the small

capacitors used in fluorescent light installations and other electricapparatus in offices such as air conditioners.In a recent investigation from Norway increased PCB

concentrations (56-81 ng/m3) were detected in the office

atmosphere and close to data screen terminals. 10 The concentrationof PCBs was 50-80 times higher than outdoor concentrations. Inthe United States higher PCB levels have been found indoors thanoutdoors. 11,12 z

Especially high PCB levels were detected in kitchens (0-31J..Ig/m3), offices (0-10 J..Ig/m3), and laboratories (0 - 21 J..Ig/m3).Outdoor concentrations were between 0 - 004 and 0 02 J..Ig/m3. On aday with burnout of a fluorescent light ballast, the PCB levels werefound to be over 50 times higher than normal (11-6 6 J..Ig/m3 vs 0’ 2pg/m3) for that room, and levels remained high for 3-4 months.The fact that fluorescent lighting fixtures in offices emit PCB was

reported in 1974.13These investigations show that PCB may escape from "closed"

electric systems, especially if the temperature is high. Indoor PCBexposure seems therefore to be of much greater importance thanpreviously recognised, and may be linked to malignant melanoma.

Danish National Institute

of Occupational Health,DK-2900 Hellerup, Denmark ALLAN ASTRUP JENSEN

5. Aaseth J, Thomassen Y, Real C, Alexander J, Norheim G. Decreased serum seleniumin alcoholic cirrhosis. N Engl J Med 1980; 303: 944-45.

6. Keshan Disease Research Group of the Chinese Academy of Medical Sciences,Beijung. Epidemiologic studies on the etiologic relationships of selenium andKeshan disease. Chin Med J 1979; 92: 477-82.

7. Editorial. Selenium in the heart of China. Lancet 1979; ii; 889-90.8. Finklea IF. Important developments regarding PCBs. Am Ind Hyg Assoc J 1976; 37:

17-18

9. IARC Monographs on the evaluation of the carcinogenic risk of chemicals to humans,vol XVIII: Polychlorinated biphenyls and polybrominated biphenyls. Lyon:International Agency for Research on Cancer, 1978.

10. Digernes V, Astrup EG. Are datascreen terminals a source of increased PCB-concentrations in the working atmosphere? Int Arch Occup Envir Health 1982; 49:193-97

11. MacLeod KE Sources of emissions of polychlorinated biphenyls into the ambientatmosphere and indoor air U.S. Environmental Protection Agency, Health EffectsResearch Laboratory, Research Triangle Park, North Carolina, 1979

(EPA-600/4-78-022).12. MacLeod KE. Polychlorinated biphenyls in indoor air Envir Sci Technol 1981; 15:

926-28.

13. Staiff DC, Quinby GE, Spencer DL, Starr HC. Bull Envir Contam Toxicol 1974; 12:455-63