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PNEUMOCYSTIS CARINII PNEUMONITIS

Sm,—Your editorial (Nov. 22, p. 1023) is timely becausethe disease seems to have become more frequent in Britain inthe past two years. For example, at the Royal Marsden Hospi-tal, from 1963 to 1973 there were not more than three casesproven or suspected. Within the past 15 months, however,eleven cases have come to light. This increase, which has alsobeen noted at other hospitals, may be partly attributable togreater diagnostic awareness, but a major factor, as stated inyour editorial, must be the more extensive use of immuno-suppressive drugs. Furthermore, when the organism is intro-duced to an environment where many patients are at risk itsspread among patients and staff may give rise to small epide-mics.’

Diagnosis can be difficult, but we have been impressed bythe value of fine-needle aspiration of the lung. The morbidity

Lung aspirate; P. carittii with characteristic bracket-shaped bodies.

(Gomori’s methenamine/silver-nitrate; x about 5000)

of this procedure is low and compares very favourably withopen lung biopsy.2 The aspirate usually provides the essentialinformation as to whether P. carinii is present and can also beused for standard bacteriological culture. One refinement oftechnique which we have developed is to aspirate and thenflush the needle and syringe with a small quantity of saline(1-2 ml). This is enough to make several cytocentrifuge prep-arations using about 0.25 ml fluid for each. Staining for 15min in 10% Giemsa shows the organism in mauve or purplespongy masses. The procedure can thus be used in an emer-gency situation, which is not uncommon, and the diagnosismade within 30 min. Methenamine/silver-nitrate stain may beused later, to confirm the diagnosis (figure).

Fine-needle aspiration was performed, without complica-tions, on nine patients. Six of these were positive, and anti-bodies were demonstrable in four from whom serum was avail-able. In addition, two out of three patients with negativeaspirates had serum antibodies. Thus evidence of P. carinii in-fection was found in eight out of nine patients in whom thecondition was suspected.Leukæmia Unit,Royal Marsden Hospital,Downs Road,Sutton,Surrey SM2 5PT.

H. MACD. CLINKP. F. HOWARDB. JAMESONH. E. M. KAY

1. Singer, C., Armstrong, D., Rosen, P. P., Schottenfeld, D. Ann. intern. Med.1975, 82, 772.

2. Hughes, J. R., Suika, D. P., Cooper, M. R., Shah, K. V., Bose, S. K. Pedia-trics, 1969, 44, 477.

OZONE, PARATHYROIDITIS, AND FEMORALFRACTURES

SIR,7-in our studies 01 the ettects 01 ozone mhatatton on the

parathyroid gland of rabbit and dogs, we found that this

strong oxidising gas caused significant cellular changes indica-tive of the specific cytological events of a parathyroiditis andincluding characteristic elements of immunologically mediatedinflammatory lesions. 1 2 It was assumed that these alterationsmight represent injury by the intervention of an autoimmuneprocess; and this interpretation was further supported by thepositive immunofluorescent localisation of antibodies againstparathyroid tissue of ozone-exposed rabbits by direct and in-direct Coon’s test.2 The mechanism of this autoimmune reac-tion is awaiting clarification. Preliminary data on serum cal-cium and phosphorus levels suggest that hypoparathyroidismmay well be a sequel to the glandular disturbance induced byozone exposure.

Burton et a1. have tried to predict the effect of an increasedozone layer in the atmosphere on the production of cholecalci-ferol which is formed by the irradiation of 7-dehydrocholes-terol in or on the skin by ultraviolet radiation. Their calcula-tions show that the increase in ozone would be expected tohave decreased the annual ultraviolet effect on the productionof cholecalciferol in the skin by about 20% over the past 20years. They suggest that a cholecalciferol deficiency due to anincreased ozone thickness might be related to the increasing in-cidence of fractured femoral neck in people over 65.

Parathyroid hormone (P.T.H.) and vitamin D are of majorimportance in the maintenance of extracellular calcium homoe-ostasis, and P.T.H. and vitamin D can usefully be considered asintegrated in the maintenance of plasma-calcium homreostasis.In a functional sense it could be argued that vitamin D playsa permissive role and enables P.T.H. to exert its normal actionupon bone resorption.Ozone-induced parathyroiditis,’ 2 with the possible resulting

hypoparathyroidism, and the data of Burton et a1. correlatingincreasing incidence of fractured femoral neck with atmos-pheric ozone thickness, if considered together, might enhanceour understanding of the increasing incidence of bone distur-bances in human populations of industrialised metropolitanareas.

Anatomical Laboratories,Department of Biomedical Sciences,University of Guelph,Guelph, Ontario, Canada N1G 2W2. O. S. ATWAL

99mTc-PERTECHNETATE SCANNING INCAPSULITIS

a amuy VI patients wim VI Luc auuumci,

we have carried out 99mTc-pertechnetate scanning of theabnormal and normal shoulder joints (the capsulitis being uni-lateral in all patients studied). Using the normal shoulder jointas control, we found increased uptake of the isotope in 4 outof 10 shoulders with capsulitis. Every patient had had painand limitation of movement at the shoulder joint for less than3 months, and none had received corticosteroid injections tothe shoulder. The 4 patients with positive scans all respondedrapidly to corticosteroid injections, as did 1 patient with anegative scan.

In a study of 99mTc-diphosphonate and 99mTc-pertechne-tate scanning in the shoulder-hand syndrome the isotopeswere localised primarily in the periarticular tissues, particu-larly 99mTc-diphosphonate.We think that further studies on isotope scanning in capsu-

litis of the shoulder and related conditions may help us to un-

1. Atwal, O. S., Wilson, T. Archs envir. Hlth, 1974, 28, 91.2. Atwal, O. S., Samagh, B. S., Bhatnagar, M. K. Am. J. Path. 1975, 80, 53.3. Burton, J. L., Ensell, F. J., Lench, J. F., Hall, K. A. Lancet, 1975, i, 795.4. Kozin, F., Genant, H. K., Sims, J., Bekerman, C., McCarty, D. J. Paper

read at the 39th annual meeting of the American Rheumatism Associ-ation. New Orleans. June, 1975.