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Biomedical subjects

L D Scheel

Publications and source records attributed to L D Scheel.

4 recordsLinked to original sources
PubMed1975

A retrospective study of clinical, physiologic and immunologic changes in workers exposed to toluene diisocyanate.

A retrospective study was made of workers in a toluene disocyanate plant using an immunologic test procedure developed at the NIOSH laboratories. Case histories of 32 workers in seven response groupings are presented. Sensitization was found to correlate with the frequency and severity of significant exposures to TDI. Immunologic changes producing tolerance to TDI exposure also resulted in negative response to the antigen challenge tests. Some individuals exposed to TDI may have protective antibodies but still experience bronchoconstriction.

Adult↗
PubMed1975

An evaluation of the inhalation toxicity of one commercial proteolytic enzyme preparation.

The inhalation toxicity of a commercial proteolytic enzyme preparation containing 12% subtilisin Carlsberg was studied in experimental animals. Guinea pigs that had been pretreated by a series of intradermal injections of the enzyme preparation in saline solution died as a result of a single 6-hour exposure to the enzyme preparation at an air concentraion of 41.2 mg/m-3, while normal guinea pigs and pretreated guinea pigs that were dosed with an antihistamine immediately prior to exposure survived. The 6-hour LC50 for pretreated guinea pigs was determined as 24.7 mg/m-3. Normal rats, normal rabbits, and pretreated rabbits survived exposures to the enzyme preparation at concentrations as high as 36.8 mg/m-3. Pathologic examinations revealed changes only in the lungs of the exposed animals. These pulmonary alterations appear to be reversible. A histamine release is suggested as the primary effect of a secondary exposure to this proteolytic enzyme preparation.

Aerosols↗
PubMed1975

Histamine induction and release following proteolytic enzyme exposure.

The mechanism of biologic response from exposure to a 12% subtilisin Carlsberg preparation is shown to be one of histamine release in the guinea pig. Three groups of guinea pigs were pretreated by intradermal injections withsaline solution of (1) the commercial proteolytic enzyme preparation containing 12% subtilisin Carlsberg, (2) an alkaline protease preparation obtain from Aspergillus oryzae that was isolated from cotton dust, or (3) a nonproteolytic mixture of proteins and lipases obtained from cotton seeds. The histamine content of the ling, liver, and ear tissues of guinea pigs that were pretreated with any one of the three preparations showed an in untreated animals. Following challenge by intratracheal injection of a saline solution containing the subtilisin preparation, the guinea pigs pretreated with the same preparation showed a markedly reduced liver histamine level. Challenge by inhalation exposure to the subtilisin preparation of guinea pigs that were pretreated with any one of the above preparations resulted in a lower histamine concentration in the lungs and livers.

Aerosols↗