Skin lesions due to okra (Hibiscus esculentus L): proteolytic activity and allergenicity of okra

The present report describes experimental studies on the proteolytic activity of the secretion on the surface of okra pods and the allergenicity of okra components, to clarify the etiology of skin lesions due to okra. Proteolytic activity was detected on the surface of immature okra pods and seemed to be sufficient to cause the skin lesions. Further, in vivo, intradermal injection of the enzyme solution prepared from immature okra pods led to increased capillary permeability in guinea pigs, in contrast to heated preparations. The fraction purified by preparative paper chromatography from an ethyl acetate extract of okra pods showed moderate allergenicity in the guinea pig maximization test. The present experimental evidence supports our suggestions from previous surveys that the proteolytic enzyme of okra may be responsible for development of skin lesions, and that allergic contact dermatitis may also play a part in addition to irritant contact dermatitis.     

Does sodium cromoglycate have an effect on contact dermatitis?

Sodium cromoglycate was applied to the forearm of 9 subjects with known delayed hypersensitivity, and to the back of 14 dinitrochlorobenzene-sensitized guinea pigs before challenge with the allergen and sodium lauryl sulphate. Sodium cromoglycate did not decrease the intensity of allergic of toxic-irritant reactions in either humans or guinea pigs.     

Experimental nickel sensitization in the guinea pig: comparison of different protocols

3 different sensitization protocols were compared for inducing delayed-type nickel contact hypersensitivity in guinea pigs. Open epicutaneous sensitization (OE) induced nickel allergy in 11/22 (50%) guinea pigs. When intradermal injections of Freund's complete adjuvant into the nickel-painted skin was added to the same protocol. 4/13 (31 %) became sensitized. The guinea pig maximization protocol induced nickel allergy in only 7/31 (23%) of the animals. Compared with the 2 other methods, animals sensitized with open epicutaneous applications reacted more rapidly (maximum at 6 h) and strongly (2+ reaction in 12/22 of animals) in previous patch lest sites upon systemic (i p.) nickel challenge. Open epicutaneous sensitization of guinea pigs should he a useful model for studying cellular and immunological mechanisms in nickel contact sensitivity.     

Sunflower allergy On the constituents of the trichomes of Helianthus annuus L. (Compositae)

Sesquiterpene lactones (STL) of the sunflower, occurring in fragile multicellular capitate glandular hairs, have been shown to display a remarkable sensitizing capacity when investigated by experimental sensitization in guinea pigs. The strongest response was induced by the hemiketal form of 1-O-methyl-4,5-dihydroniveusin A. The STL content of 50 capitate glands was sufficient to elicit a remarkable response in the guinea pigs. Thus, touching a sunflower plant (with up to 1000 capitate glands per cm2) may lead to the release of sufficient STL to sensitize humans, and these substances can be considered to be responsible for the cases of allergic contact dermatitis described in sunflower growers since 1906.     

Cutaneous toxicity of chemical irritants on hairless Guinea pigs

To evaluate the toxicity of irritant chemicals on animal skin, investigators have frequently had to apply high concentrations, owing to the fact that its susceptibility is less than that of human skin. High concentrations are so damaging to tissue that specific effects are obscured on the various layers. The aim of the present study was to elucidate the effects of a variety of irritating chemicals on the skin of hairless guinea pigs. Graded concentrations of these irritating substances were applied to the back for varying periods. Histologic changes were analyzed by light and electron microscopy. The structural alterations varied greatly among the chemicals, reflecting quite different mechanisms of action. Hairless guinea pigs are quite susceptible to chemical injury, especially to their hair follicles and dermal components. The hairless guinea pig appears to be an advantageous model to assess the acute and chronic effects of chemical irritants.     

Allergic contact dermatitis to methylenelactones use of lymphocyte transformation test

Summary Seventeen guinea pigs were sensitized to alantolactone, a natural sesquiterpene lactone known for its sensitizing properties, using intradermal injections in Freund's complete adjuvant. Guinea pig skin protein extracts (SPE) were used to make conjugates with alantolactone and an isomer, isoalantolactone. Lymphocyte blastogenesis was observed with SPE-alantolactone conjugates, as well as with guinea pig albumin-lactone conjugates. In six cases, stimulation was noted with unconjugated haptens. These results do not show a high degree of hapten-carrier specificity in contact sensitivity to alantolactone, induced by unconjugated hapten injections. Cross-sensitivity with SPE-isoalantolactone conjugate was also observed.     

Percutaneous absorption of 4 organic solvents in the guinea pig

Percutaneous absorption of 4 organic solvents (1,1,1-lrkhloroelhane, 1,1,2-trichloroethane, toluene and butanol) from various colloidal preparations in a surfactant-water-organic solvent system was studied in vivo in guinea pigs The preparations examined were binary solutions of organic solvents and surfactants, o/w emulsions and microemulsions. Phase diagram, birefringence microscopy and droplet size distribution analysis were used for characterization of the preparations. It was found that skin absorption of the solvents depends on the type of surfactant, type of preparation and also on phase equilibria in the systems studied. The presence of nonionic surfactants in the solvents and in a microemulsion with butanol caused skin absorption to decrease. A reduced uptake of solvents from o/w emulsions was observed. The absorption of butanol from a microemulsion with anionic surfactant was greater than from the pure solvent.     

Predictive evaluation in animals of the contact allergenic potential of medically important substances

Results of the optimization method and of other methods used to assess contact allergy in laboratory animals were compared with known epidemiological data on the occurrence of hypersensitivity reactions in man. Tests were performed with preservatives {formalin, ethylenediamine and sorbic acid), drugs (penicillin G, benzocaine and sulphathiazole) and other contactants belonging to widely different chemical classes (p-phenylenediamine, triclosan, pyrazole derivatives, nickel and chrome salts, eugenol, isoeugenol and mercaptobenzothiazole). The degree of sensitization achieved in guinea pigs by the optimized procedure (intradermal test with adjuvant combination) and the maximization procedure was invariably superior to that produced by the epidermal method using prior irritation of the site of application. Both the optimized procedure and the maximization test seem to be capable of identifying contact allergens that cause hypersensitivity reactions in as few as t in 10,000 of the human population as a whole. The optimization test merits consideration as a standardized and efficiently predictive procedure.     

The effect of the guinea pig maximization protocol on the irritant response to deodorized kerosene – the excited skin syndrome *

Deodorized kerosene in a concentration of 50g/100g in pet. did not cause cutaneous inflammation in 10 control guinea pigs. The proportion of 19 guinea pigs exhibiting inflammation following exposure to deodorized kerosene in the guinea pig maximization test increased, but the increase was not significant. The response in a group of 40 animals, half exposed to tetraethyleneglycol diacrylate and half to nonylphenol polyethoxylate-6, increased (z= 3.505, p=0.004). The inflammatory response was related to concentration in both groups of animals which exhibited inflammatory responses to deodorized kerosene. The relevance of this alteration and irritant response of the interpretation of predictive to tests animals for sensitization, routine patch testing and repeated insult contact dermatitis is discussed.     

UVB serum factor: suppression of allergic contact dermatitis in guinea pigs

Serum from guinea pigs exposed to a single high dose of UVB and from controls was injected into the spleen of normal animals 5 days prior to sensitization. When 1.0 ml was transferred 4.5 h after irradiation, immunosuppression was obtained. Transfer of 1.5 ml of serum 2.5 h after irradiation failed to induce immunosuppression. This experimental model in guinea pigs might be valuable in further studies investigating the effect of other modalities of ultraviolet exposure (e.g., PUVA or high-dose UVA) on the release of soluble serum factor(s) inducing immunosuppression in allergic contact dermatitis.     

The sensitizing capacity of helenin and of two of its main constituents, the sesquiterpene lactones alantolactone and isoalantolactone: a comparison of epicutaneous and intradermal sensitizing methods in different strains of guinea pig

The sensitizing capacities of helenin (an extract from a Compositae Inula helenium L.), alantolactone and isoalantolactone (two isomeric sesquiterpene lactones), were assessed by sensitizing guinea pigs of different strains: albino Himalayan spotted, Pirbright and Hartley. Both alantolactone and isoalantolactone are found to be sensitizers if injected intradermally. Only Pirbright guinea pigs showed a high sensitization rate by the open epicutaneous technique; with this method, alantolactone was the more potent sertsitizer.     

Tomato contact dermatitis

The tomato plant (Solanum lycopersicum) is an important crop worldwide. Whereas immediate‐type reactions to tomato fruits are well known, contact dermatitis caused by tomatoes or tomato plants is rarely reported. The aims of this study were to present new data on contact sensitization to tomato plants and review the literature on contact dermatitis caused by both plants and fruits. An ether extract of tomato plants made as the original oleoresin plant extracts, was used in aimed patch testing, and between 2005 and 2011. 8 of 93 patients (9%) tested positive to the oleoresin extracts. This prevalence is in accordance with the older literature that reports tomato plants as occasional sensitizers. The same applies to tomato fruits, which, in addition, may cause protein contact dermatitis. The allergens of the plant are unknown, but both heat‐stable and heat‐labile constituents seem to be involved. The fruit contains fragrance compounds that are also present in Myroxylon pereirae (balsam of Peru), possibly accounting for cross‐reactivity. The proteins in pulp and peel may contribute to protein contact dermatitis. Until more is known about the allergens, the diagnosis of contact dermatitis caused by tomato plants and fruit may be established with the use of ether extracts and fresh fruits, respectively.     

Propolis allergy

As shown in the preceding paper, propolis or bee-glue is the cause of an increasing number of allergic reactions in persons using it in external preparations and cosmetics. Propolis and its main contact allergen, 1,1-dimethylallyl caffeic acid ester, designated LB-1, show strong sensitizing properties in patients as well as in guinea pig experiments. 9 patients have been patch tested with this compound, 8 of whom reacted strongly. Chemical separation of different propolis samples and poplar bud extracts reveal that LB-1 is always present. Poplar bud secretion is the bee's major source for propolis and hence the origin of LB-1. A warning is indicated, in agreement with several other authors, that propolis should not be used in topical products because of its strong sensitizing properties.     

Topical application of artesunate on guinea pig allergic contact dermatitis

Artesunate is derived from the Chinese medicinal herb qinghao. Many animal studies suggest that systemic artesunate has immunoregulatory activity. We investigated the effect of topical artesunate on contact sensitivity in guinea pigs sensitized with DNCB. Female hairless guinea pigs were used and the contact reaction graded by visual (5 point) score and erythema measured with a color analyzer. Topical artesunate inhibited the elicitation reaction of contact hypersensitivity when given at the 1st and 12th h after challenge ( p < 0.05), but showed no effect when given from day 3 to day I before challenge ( p > 0.05). Artesunate had no effect on toxic (irritant) contact dermatitis from 20% croton oil ( p > 0.05). The results indicate that topical application of artesunate may offer a novel treatment of allergic contact dermatitis and other cutaneous immune-mediated disorders.     

复方昆明山海棠颗粒剂治疗豚鼠光变应性接触性皮炎的药效学研究

目的对复方昆明山海棠颗粒剂(CTHHG)治疗豚鼠光变应性接触性皮炎(PACD)的药效学进行研究,以期为CTHHG的临床开发应用提供更深入的理论依据。方法将豚鼠随机分为8组:CTHHG高、中、低剂量组、昆明山海棠颗粒剂组(THHG)、氢化可的松组、羟基氯喹组、模型组、正常对照组。以6-甲基香豆素(6-MC)为光敏剂,通过长波紫外线(UVA)的诱导和激发,建立起豚鼠PACD动物模型。通过27天连续灌胃给药,评价豚鼠背部皮肤红斑反应,观察激发后皮损病理特征,再对真皮内浸润的单一核细胞进行计数。结果与模型组相比,CTHHG高、中、低剂量组均能明显改善PACD模型豚鼠背部皮肤红斑、水肿等炎症反应(红斑抑制率达8 0%以上),减少其皮损处单一核细胞的浸润(P(0.01)。其中高、中剂量组作用优于THHG组(P(0.05),与羟基氯喹的疗效相当(P>0.05),但几组均不及氢化可的松(P(0.01)。结论CTHHG具有显著的抗炎及免疫抑制作用,作为治疗PACD的药物,具有良好的开发前景。     

Allergic contact dermatitis to plant extracts in patients with cosmetic dermatitis

Cosmetic contact allergy is commonly seen in patients undergoing patch testing, with fragrance one of the most frequently implicated ingredients. Many cosmetics contain plant extracts either as a fragrance or for medicinal properties. With a vogue for natural products there is an increase in their use. We have performed a prospective study over a 2-year period looking at the prevalence of contact allergy to plants in patients diagnosed with cosmetic dermatitis. In addition, we have performed a review of the products of two popular cosmetic companies, examining product labelling and the prevalence of use of plant extracts. We suggest that patients allergic to fragrance be advised to avoid plant extracts, which are separately labelled, in their personal care products.     

An animal model for altering the irritability threshold of normal skin

Theory behind conditioned hyperirritability (autoeczematization) predicts the lowering of the irritation threshold in the presence of a pre-existing dermatitis. We have attempted to develop an animal model that parallels the syndrome seen in man. Groups of 10 guinea pigs were shaved and depilated; irritation thresholds to benzalkonium chloride and trichloroacetic acid were determined using 1 cm diameter open patches. Reactions were scored 24 h later on the basis of erythema and induration. Animals having as little as 1.56 cm2 of skin acutely inflamed with a known irritant had lowered irritation thresholds to the same irritant on normal skin at remote sites (p less than 0.01). Mild irritation of a much larger surface area produced the same effect (p less than 0.01). More extensive, severe dermatitis did not lower the irritation threshold further. Acute dermatitis induced by a contact allergen (DNCB) lowered the irritation threshold of normal skin to the same level as that obtained with irritants (p less than 0.01). Induction of chronic cutaneous ulcers 3-4 cm in diameter lowered the irritation threshold of normal skin to the same point defined by the acute studies (p less than 0.01). These results indicate that an acute irritant or contact dermatitis, as well as chronic skin ulceration, may alter the reactivity of unaffected normal skin to exhibit a heightened response to irritation. This model appears to differ from that seen in humans, in that a more extensive or chronic dermatitis did not further heighten the susceptibility to irritation.     

Alantolactone sensitivity in chrysanthemum contact dermatitis

A case of occupational chrysanthemum contact dermatitis is reported. Patch tests showed the patienttobe sensitized to Chrysanthemum morifolium (Chr M) leaves, flowers, and stems (alcoholic extracts) and to alantolactone. An attempt at desensitizalion appears to have been successful.
Gas chromatography indicated the presence of alantolactone in all the various parts of Chr M, mostly in the flowers.
The "maximization test" succeeded in sensitizing guinea pigs to alantolactone.     

Allergic contact dermatitis to tulips: An example of enantiospecificity

Summary Allergic contact dermatitis (ACD), an immunological reaction of the skin resulting from contact with reactive compounds occurring in plants was shown to the enantiospecific (animals sensitized to a compound do not react to its nonsuperimposable mirror image). Thus, when guinea pigs were experimentally sensitized to (+)-tulipalin B (a compound present in tulip bulbs) they did not react to its enantiomer, (-)-tulipalin B. This was also true for (+)- and (-)--hydroxy--methyl--methylene--butyrolactones.     

Sensitizing potential of acetaldehyde and formaldehyde using a modified cumulative contact enhancement test (CCET)

The contact allergenic activity of acetaldehyde was investigated with a modified cumulative contact enhancement test (CCET) method in guinea pigs. Possible cross-reactivity between acetaldehyde and formaldehyde was also studied. In contrast to the original CCET protocol, we used sham-treated controls and the chemicals were tested with closed epicutaneous application at 1st challenge. The suitability of the method was verified with formaldehyde and the results were comparable with those previously found with the guinea pig maximization test (GPMT). For the 1st time, acetaldehyde was shown to be a contact allergen in predictive tests. No cross-reactivity was observed between acetaldehyde and formaldehyde. Acetaldehyde seems to be a rare sensitizer in man. However, its allergenic activity should be considered, since it might be present as an impurity in ethoxylated surfactants. As the CCET protocol involves topical induction and challenge, we regard the modified version as well suited to evaluation of the contact allergenic potential of chemicals.