Toshio Matsushita

Allergy to laboratory animals: an epidemiological study

A large cross sectional survey was carried out using a self administered questionnaire to examine the prevalence of laboratory animal allergy (LAA) and the factors associated with its development. Out of 5641 workers who were exposed to animals at 137 laboratory animal facilities in Japan, 23.1% had one or more allergic symptoms related to laboratory animals. The commonest symptom as rhinitis. About 70% of LAA subjects developed symptoms during their first three years of exposure. Atopy (past and family history), the number of animal species handled, and the time spent in handling correlated significantly with the development of LAA as did some types of job. A close relation between nasal symptoms and exposure to rabbits and between skin symptoms and exposure to rats were found. LAA subjects developed symptoms most quickly to rabbits.

Epidemiology of contact dermatitis from pesticides in Japan

An epidemiological study was made of 216 patients with contact dermatitis from pesticides in Japanese rural regions from 1968 to 1970. They were analyzed according to conditions of use, sex, age, occupation, exposure, and season. The pesticides most often responsible were captafol (Difolatan) (28.7%), sulfurs (18.5%), highly and moderately toxic organic phosphates (18.1%), and chlorinated hydrocarbons (9.7%). Complications, sites of dermatitis, prognosis and factors contributing to onset of dermatitis arc discussed.

Expression of cytokine mRNAs in mice cutaneously exposed to formaldehyde

In this study, we have investigated the expression of cytokine mRNAs in mice cutaneously exposed to formaldehyde using semiquantitative RT-PCR. We show that formaldehyde induced the long-lasting expression of IL-4 and IFN-gamma mRNAs and the transient expression of IL-13 mRNA in mouse spleen and draining lymph nodes. The transient increases in IL-2, IL-15, IL-12p40, IL-15 and IL-18 mRNAs, but long-lasting IL-15 mRNA were only seen in the formaldehyde-exposed mouse spleen. Moreover, a weak contact hypersensitivity (CH) and the significant increases in IL-4 and IFN-gamma mRNAs were detected in the ear skin of formaldehyde-cutaneously exposed mice when rechallenged mouse ears. Furthermore, CH as measured by mouse ear swelling response was positively correlated with IL-4 and IFN-gamma mRNA levels in the challenged ears. This study thus suggests that the induction of Th1 and Th2 cytokine mRNAs, particularly IL-4 and IFN-gamma, are a common immunological feature caused by contact allergens irrespective of strong or weak contact allergens. The analysis of IL-4 and IFN-gamma mRNAs may be useful markers in establishing the novel test for predicting chemical sensitizing potentials.

Immunological effects of toluene diisocyanate exposure on painters

Among the painters handling polyurethane varnish in two furniture manufacturing factories with high toluene diisocyanate (TDI) exposure (0.79 mg/m3 and 0.31 mg/m3), 26.3% and 15% subjects, respectively displayed asthmatic symptoms, lung function loss, and an increment in mast cell degranulation percentage specific to TDI. Some cases of TDI-linked contact dermatitis were also found among them, being elucidated by positive patch testing to TDI. However, the previous abnormalities could not be verified among the painters from another factory with TDI concentration below the TLV of it (0.11 mg/m3). It was concluded that both pulmonary hypersensitivity and contact sensitization to TDI had occurred in some of the painters included in this study, and that the immunologic effects of TDI was concentration dependent.

Provocation of respiratory allergy in guinea pigs following inhalation of free toluene diisocyanate

An animal exposure experiment which simulated a workplace exposure situation was made to compare toluene diisocyanate (TDI) concentrations which resulted in antibody production with those which elicited pulmonary responses. Groups of guinea pigs were exposed to inhaled TDI from 0.02 to 1.0 ppm (μg/g) for 3 h/day on 5 consecutive days. Three weeks later the animals were challenged with 0.02 ppm of free TDI for 15 min. TDI specific antibodies and pulmonary responses were evaluated. Specific antibody production showed a linear correlation to TDI concentration at induction. Most of the animals exposed to TDI levels above 0.2 ppm displayed significant pulmonary responses, but no correlation was found between TDI concentration at induction and the intensity of pulmonary response upon challenge to free TDI. These results indicated that there was a threshold concentration of 0.02 ppm TDI for antibody production and for the development of pulmonary response. It was also found that exposure to TDI at a level lower than its threshold concentration for sensitization may elicit a response in previously sensitized individuals.

Occupational dermatoses in farmers growing okra (Hibiscus esculentus L.).

By questionnaire survey, 32 out of 52 workers (61.5%) reported previous or current skin diseases from okra cultivation. The sites of skin lesions were mainly the‐ arms, lingers and fingertips. Positive patch test millions with preparations of okra leaves or immature pods in 111 workers, compared to 63 control subjects, wore significantly higher in okra workers than in controls (p<0.01), ranging from 9.8 to 30.0%, 37 out of 111 workers (33.3%) I were diagnosed as having allergic contact dermatitis (n= 17; 15.3%) and irritant contact dermatitis (n= 18; 16.2%) from okra cultivation.

Role of Fas/Fas ligand-mediated apoptosis in murine contact hypersensitivity.

Apoptosis plays an important role in immune responses, but little is known about its involvement in contact hypersensitivity (CH). In this study, we have investigated the role of Fas/Fas ligand (FasL)-mediated apoptosis in the pathogenesis of CH. Mice were sensitized by one topical application of 100 microl of 3% oxazolone to shaved skin of the abdomen. Six days later, CH was provoked by challenging both sides of sensitized mouse right ear with 15 microl of 1% oxazolone. Using a DNA ladder assay, we found that apoptosis was induced in the skin of oxazolone-sensitized mice 24-96 h after allergen challenge. Annexin V-fluorescein isothiocyanate (FITC)-propidium iodide (PI) apoptosis flow cytometric assay showed that early apoptotic CD4(+) T cells (annexin V-FITC(+)PI(-)), but not late apoptotic CD4(+) T cells (annexin V-FITC(+)PI(+)), increased in the inflamed skin of mice with CH. Moreover, the expressions of mRNAs for T helper (Th2) cytokine (interleukin (IL)-4), Th1 cytokine (interferon (IFN)-gamma) and proapoptotic molecules (Bax, Fas, FasL and IL-1beta-converting enzyme (ICE)/caspase-1) were significantly elevated in the oxazolone-sensitized mouse skin 6-72 h after allergen challenge. Dramatic increase in IL-10 mRNA was only observed in the sensitized mouse skin 6 and 12 h after allergen challenge. Furthermore, CH was significantly inhibited with decreased apoptosis and early apoptotic CD4(+) T cells in inflamed skin in Fas mutant lpr/lpr mice compared to wild-type mice, whereas there were no significant differences in IL-4, IFN-gamma, IL-10, Bax and ICE mRNAs in the inflamed skin of CH between lpr/lpr and wild-type mice. Our results thus suggest that Fas/FasL pathway partially contributes to apoptosis in murine CH and that Fas/FasL-mediated apoptosis plays a partial role in the development of CH. The contribution of Fas/FasL-mediated apoptosis to CH appears independent of Th1 and Th2 cytokines.

EXPRESSION OF CYTOKINE mRNAS IN THE DRAINING LYMPH NODES FOLLOWING CONTACT SENSITIVITY IN MICE

To clarify in vivo cytokine profiles during the afferent phase of contact sensitivity, balb/C mice were sensitized by topical applications of 2.5% 1-chloro-2,4- dinitrobenzene (DNCB) and 3% 4-ethyoxymethylene-2-phenyloxazol-5-one (OXAZ), respectively. On day 6 of contact sensitization, total RNA was extracted from the draining lymph nodes. Expressions of Th1 and Th2 cellrelated cytokine mRNAs were detected by semiquantitative reverse transcription polymerase chain reaction (RT-PCR). Among the 8 cytokine mRNAs observed in naive mice, the mRNAs for IL-2, IL-4, IL-10, IL-12p35, IL-12p40, and IFNwere constitutively expressed weakly, whereas IL-5 and IL-13 mRNAs were undetectable. Contact sensitization with DNCB or OXAZ significantly up-regulated the expressions for Th1 cell-related cytokine mRNAs such as IL-2, IL12p35, IL-12p40, and IFN-, in particular IL-2 and IFN- genes. Moreover, in Th1 cytokine cases, the Th2 cytokines including IL-4, IL-5, IL-10, and IL-13 mRNAs were significantly induced or augmented in...

RT-PCR Analysis of in Vivo Cytokine Profiles in Murine Allergic Contact Dermatitis to DNCB

To elucidate an in vivo cytokine pattern in allergic contact dermatitis, the mRNAs for IL-2, IL-4, IL-10, IL-12p35, IL-12p40, and IFN-gamma were detected in the skin and spleens of mice with allergic contact dermatitis responses to DNCB using reverse transcription-polymerase chain reaction (RT-PCR). The mRNAs for IL-2, IL-4, IL-10, and IFN-gamma and IL-12 were constitutively expressed in the spleens from control and allergic contact dermatitis mice. Among these cytokines, the mRNAs for IFN-gamma and IL-12p40 were upregulated in mice with allergic contact dermatitis. On the other hand, the mRNAs for IL-2, IL-4, and IFN-gamma were detected only at diseased skin sites of allergic contact dermatitis mice, but not the skin from the control mice. Moreover, both IL-12p35 and IL-12p40 mRNAs were highly expressed in the skin of mice with allergic contact dermatitis responses to DNCB compared with control mice. Therefore, the present study indicates that, in vivo, allergic contact dermatitis mice appear to have a d...

Evaluation of contact allergy to chemicals using laser Doppler flowmetry (LDF) technique.

Skin blood flow in allergic contact reactions and cross‐sensitivity were evaluated using laser Doppler flowmetry (LDF) to study the dose‐response relationships in phases of induction and challenge in guinea pigs. Guinea pigs were sensitized with different doses of 1‐chioro‐2,4‐dinitrobenzene (DNCB) and challenged with different doses of DNCB and 2,4‐dinitrobenzene sulfonic sodium salt (DNBS). The skin reactions were evaluated by LDF and visual reading score. The results indicated that there were dose‐response relationships between the doses of DNCB and LDF measure‐men is in both phases of induction and challenge, that there was a cross‐reaction between DNCB and DNBS. and that the reactions at 24 h were greater than that at 48 h after removal of the patches. LDF may discriminate between positive patch test reactions and negative or doubtful reactions, but not between weak positive and strong positive reactions. This is because vascular dilatation and increase of flow already reaches a maximum in weak reactions. The more advanced phases are dominated by oedema formation. This is simply the nature of the inflammatory reaction, rather than a methodological error. The important point is that LDF, can separate positive reactions from negative/uncertain reactions. The results indicated that LDF, as a non‐invasive technique, may objectively und quantitatively evaluate the dose‐response relationships of contact sensitivity of sensitizers.