The relationship of myocarditis to dilated cardiomyopathy

Three patients with congestive cardiomyopathy are reported inwhom high neutralizing antibody titres to Coxsackie B viruseswere detected. At post-mortem examination, all three had histologicallydemonstrable chronic inflammation of the myocardium. The heartsof ten patients dying in cardiac failure due to other causesshowed no comparable inflammatory infiltration. This providesfurther evidence that Coxsackie B viral myocarditis is involvedin the pathogenesis of some cases of dilated cardiomyopathy. One patient also had pulmonary veno-occlusive disease. Thishas been reported in association with myocarditis once previouslyin an infant. A viral aetiology has been postulated. It seemslikely in this patient to have also been due to a CoxsackieB virus.     

The Translocation of Inhaled Silicon Dioxide: An Empirically Derived Compartmental Model

The Translocation of Inhaled Silicon Dioxide: An EmpiricallyDerived Compartmental Model. VACEK, P. M., HEMENWAY, D. R.,ABSHER, M. P., AND GOODWIN, G. D. (1991). Fundam. Appl Toxicol.17, 614–626. The movement of inhaled silicon dioxide particleswas studied by measuring the amounts in alveolar fluid and cells,lung tissue, and lymphoid tissue during the 6 months followingshort-term aerosol exposure of Fischer 344 rats. A variety offirst-order compartmental models were fit to data from nineexposure experiments to identify the most feasible biologicpathways for the transfer of material among these sites andout of the body. A multivariate least-squares approach was usedto simultaneously fit the data from several compartments. Theresults indicate that transfer between alveolar cells and lungtissue occurs in both directions, suggesting that silica canreenter the alveolar space from the lung tissue. This featurehas not been included in previously published models. The resultsalso indicate that transfer from lung tissue to the mediastinallymph nodes and thymus is indirect; there are one or more unidentifiedextrapulmonary compartments that receive silica from the lung.Rates of transfer among compartments were dependent on mineraltype (quartz or cristobalite), heat treatment, and exposuredose. There was no evidence for direct clearance from the alveolarspace via the tracheobronchial tract.     

Two decades of atrial tumour

We have reported 19 patients with atrial tumour. The long follow-up(5–19 years, mean 10 years) of the 17 patients with leftatrial myxoma has been described. No patient showed evidenceof recurrence of the tumour, although three patients have unexplainedshadows—probably artifactual—on echocardiography.The limitations ofechocardiography and importance of clinicalindicators are stressed. One patient had a rhabdomyosarcoma of the left atrium and diedone year after operation. Certain features differentiated thispatient from those with myxoma. It is concluded that true atrial myxoma does not metastasize.Reports in the literature of metastasizing left atrial myxomaprobably refer to malignant tumours simulating myxoma. Variationsfrom the typical clinical and haemodynamic picture of atrialmyxoma should arouse suspicion of malignancy. Careful microscopicexamination of the tumour is essential.     

Bacillus subtilis Enzymes: a 7-year Clinical, Epidemiological and Immunological Study of an Industrial Allergen

A survey of 1642 workers in a factory producing enzyme washingpowders from 1968 to 1975 has shown that reduction of totaldust and enzyme dust levels, combined with full implementationof the Soap and Detergent Industry Association recommendations,have eliminated detectable respiratory illness.Previous findings,that atopic subjects were more likely than non-atopies to becomeskin prick-test positive (PT+) to a standardized enzyme reagent,have been confirmed. After excluding atopies from such workthe percentage converting to PT+ has steadily fallen. Individualswith only a PT+ have no clinical symptoms and do not react inany way to the working environment. Of all employees workingthroughout this period, 82 per cent (1354 out of 1642 tested)have remained prick-test negative. It is shown that repeatedprick testing with the same allergen does not induce allergicskin reactivity. There is a good correlation between prick-testresults and the results of serological tests for enzyme specificIgE. There is no evidence of any difference in changes in theventilatory capacities of prick-test positive as against prick-testnegative employees, or that positivity alone is a contraindicationto working with these products.Varying degrees of contact orlengths of exposure to enzymes do not produce any statisticallysignificant differences in changes in lung function. The surveydoes not reveal any evidence of longer-term obstructive bronchialdisease. Requests for reprints should be addressed to: Dr C.P. Juniper, Medical Centre, Lever House, Port Sunlight, Merseyside.