Document G6yngEe96oRERk5wx5oBqgZw7

Industrial Hygiene Digest Auguel, tW y * u: In asan epithelioid granuloma. thus simulating tuberculosis or sarcoidosis. Silie* occur* *11 sorts of materials --from brick lo talc, from dirt to kaolin. The latent period for U.-v-u-^ went of granuloma averages 10 year* although a range from 6 month* to 59 year* ha* b*..,. K- reported. The preaence of anisotropic crystal* under polarising light Is the distinguUhiuj- r histological feature. The authors mads numerous Intradermal injections Into human vti!,ir.. tears of different types and concentrations of silica-containing materials. They found *b*t in man silica in a non-coltoldal form does not elicit an epithelioid granuloma* All fonr.j u; s' colloidal silica used in concentrations of l/lOQO or greator invariably produced an ~jppnuu. The authors postulate that chemical weathering reduces the large silica.eonia;i.n. < ..j-. i* . ;}lcidal state in the skin. They found no evidence that the process of ar.t <\`i :;.m -sa involved in any way. - Can. Med. Assn. J. i f A' 744 Free formaldehyde In Textiles: A Cause of Contact Ecsoma. G. Hovdlng* Acta Dermato-Venereol. 21* 2*7 (1959J. 1 i Contact ecsema due to formaldehyds-troatod textiles became of sufficient Ire. i quency in Norway to stimulate an investigation concerning the use of this chemical lr. Formaldehyde is used chiefly to impart anticrease and antishrink properties to rayon ar.i cotton fabrics. In addition, however, Us use stabilises casein fibers* improves the of nylon to ultraviolet light and renders wool thrlnkproof and mothproof. It la general!) on the fabric as a resin finish in the form of urea-formaldehyde or melamlno-formoldehy.. Of 250 different rayon and cotton samples of textiles studied for formaldehyde, 227 eeuuiu..; ' """formaldehyde, Of (Ms number* 200 showed free amounts of formaldehyde in excess ci A-*?'.; able standards. The author believes that these results bear out tho findings of Increaser. t.*v> quency of contact eesema from wearing apparel containing free formaldehyde used In fabric finishing. -- J. Occ. Med, Ab*t,. i > > j i.. 745 Value of Patch Tests in Dermatology. Special Study of Follicular Reactions. S. W. Beckei and M. P.O'Brien. A.M.A. Area. DucmatoL. 7V, 569-577 (May 19591. After partial recovery from extensive autosensitisation dermatitis 110 patients were tested with a series of 24 chemicals. Fifty-six similar patients were tested against i* 14 oleoreslns. In 69 patients eczematous or follicular reactions were given againet the chemicals* while 16 patients gave erythematous* edematous*.and sometimes vesicular re actions to the oleoresins. Serial biopsies on patients with follicular reactions showed the primary reaction to be dermal* (he folliculoporal epidermal vesiculation being a secondary phenomenon. Positive follicular reactions suggested dermal allergy, the primary dertr.iiitU being possibly constitutional in nature. Whore all tests were negative it was suggested that the primary dermatitis was also constitutional. Recurrent durmatltis after removal of con 3 tact with chromates, may also be constitutional in nature. - - Dull. Hyp. 746 Present Status of Skin Tested C. J. C, Britton, Practitioner 164, 427 (1960), 1 N 5 !i Skin testing is the must useful test w: have in the investigation of allergic di*r*4* A positive akin test indicates,rhlr liberation of histamine nr 11 substance at the situ. Tv*u performed during or just after m severe attack of jo allergic disease may fail to M;ow x p. *. ; f ! tive reaction, owing to oxheustlon of tho tkin-Sbiisitiaing substance. The intensity 01 a ; {1 skin reaction may be diiv.sni.ined by administration of antihistamine*. ephcdrlno and v' , spasmodic*. Corticosteroid* cause no tigi.ifiranc changr ir. mo skin reaction. As a * k rule it Is wise to avoid admimstcring medication for u period of 36 hours before testing. i tests may he positive in paiientt: wuo aro poln.-ti.illy sensitive own though they havu n.u <0 * / shown any symptoms; 25% of apparently normal siblings cf allergic children give positive i reaction* and those with a marked (.ensitivity develop hay fever for the first time severa> /*'* * later. The re;.sou ren..ilmi unexplained. Negative kin reactions may also >e found on r.r- f occasion* when lusting patumts who have a definite or even striking clinical scnsilivlty tf- f allergen, ilvrc itimist be remembered that we ore testing the skin, whereas the shock 0* ' f i; . 10.