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Hands & Feet
Published in Richard Ashton, Barbara Leppard, Differential Diagnosis in Dermatology, 2021
Richard Ashton, Barbara Leppard
Eczema here can be due to: Atopic eczema. Eczema affecting the dorsum of the big toe in a child aged 7–10 years is one of the patterns of atopic eczema. Note tinea pedis affects the fourth and fifth toes not the big toe.Allergic contact dermatitis. A rash up to the level of the shoe and sparing the toe webs is usually due to an allergic contact dermatitis to chrome in the leather of the shoe uppers, or azo dyes in nylon socks/stockings. A rash at the site of contact with flip flops is due to mercaptobenzothiazole (MTB), a rubber additive.Endogeneous eczema. Symmetrical eczema on the dorsum of the foot can be due to endogeneous eczema. Patch testing is negative.Discoid eczema presents as a well-defined round or oval red scaly plaque with obvious vesiculation and crusting (see p. 175).
Animal Models for Percutaneous Absorption
Published in Rhoda G. M. Wang, James B. Knaak, Howard I. Maibach, Health Risk Assessment, 2017
Ronald C. Wester, Howard I. Maibach
Table 8 compares the in vivo percutaneous absorption of cortisone in guinea pig with that in Rhesus monkey and man.8 The data indicate that skin absorption, at least for cortisone, is greater in the guinea pig. Absorption of the PCB aroclor 1242 is greater in guinea pig than in the rhesus monkey (Figure 1).27 El Dareer et al.28 compared in vivo percutaneous absorption study of 2-mercaptobenzothiazole (MBT) and 2-mercaptobenzothiazole disulfide (MBTS) in guinea pig and rat. The absorption of MBT was actually higher in guinea pig (33.4 ± 8.2%) than in rat (male 16.1 ± 2.8%; female 17.5 ± 1.9%). Absorption of MBTS was slightly higher in guinea pig (12.2 ± 2.2%) than rat (male 5.9 ± 1.8%; female 7.8 ± 0.7%).
Anogenital region
Published in Robin Lewallen, Adele Clark, Steven R. Feldman, Clinical Handbook of Contact Dermatitis, 2014
Monica Huynh, Michael P. Sheehan, Michael Chung, Matthew Zirwas, Steven R. Feldman
Diaper dermatitis affects the area covered by the diaper and is most often irritant in nature. A secondary infection with candida should also be considered. A clue to ACD secondary to diaper components is an eczematous dermatitis that spares the skinfolds and is refractory to conventional therapies for diaper dermatitis. Allergens to consider in this setting include fragrances utilized to provide a pleasant odor to the diaper, coloring dyes, glues, and rubber-related allergens; it is also important to consider wet wipes, which are often used during the diaper-changing process.5,6,7 If the pattern of dermatitis favors the hips and lateral buttock, rubber accelerators such as mercaptobenzothiazole should be considered. This pattern has been referred to as the “Lucky Luke” dermatitis and is a subset of allergic contact diaper dermatitis in which the child is reacting to the elastic bands found in disposable diapers.8,9
Design, synthesis, and biological evaluation of benzoheterocyclic sulfoxide derivatives as quorum sensing inhibitors in Pseudomonas aeruginosa
Published in Journal of Enzyme Inhibition and Medicinal Chemistry, 2023
Shen Mao, Qiaoqiang Li, Zhikun Yang, Yasheng Li, Xinyi Ye, Hong Wang
To verify the above hypothesis, we referred to 2-mercaptobenzothiazole disulphide with the excellent P. aeruginosa quorum-sensing activity to design the new candidate compounds.23 We retained the core part of the benzothiazole and replaced the disulphide bond with sulfoxide to synthesise a series of benzoheterocyclic sulfoxide derivatives. The synthetic routes of titled compounds were shown in Scheme 1. The key intermediates 3 (the different heterocyclic thioethers) were synthesised from benzyl bromides 1 and heterocyclic thiols 2 in the presence of triethylamine in acetonitrile. Benzyl bromide 1 was added dropwise into the mixture at room temperature.26 Then intermediates 3 were oxidised by meta-chloroperoxybenzoic acid in dichloromethane to obtain the different types of compounds. We first synthesised 4a-4l (containing benzo thiazole), 5a-5l (containing benzoxazole), the preliminary screening of P. aeruginosa biofilm activity showed that compounds with benzoxazole have good inhibitory effects. Furthermore, we considered chloro-substitution as an important halogen group for QS activity, a series of 6a-6l (containing 5-chlorobenzoxazole) and 7a-7f (containing 6-chlorobenzooxazole) were synthesised. To investigate whether the chloro-substitution on the benzoxazole ring was the key active site, we synthesised the series 8a-8f (containing 5-methylbenzoxazole) and 9a-9f (containing 5-methoxybenzoxazole).
The user safety assessment of a selenized yeast feed additive
Published in Cutaneous and Ocular Toxicology, 2022
Gerry P. Dillon, Colm A. Moran
No reactions were noted in the animals treated at any test item concentration investigated in the preliminary tolerance study. Consequently, the highest concentration of 50% was selected for the induction and challenge phases of the main study. In the induction phase, no response was seen to either the test item at 50% concentration or the negative control item (corn oil) in animals of the test and control groups following 6-h topical exposure. The results of the induction phase are included in the supplementary information tables (Table S2). The test item at 50% was further used at the challenge phase, as no irritation was noted during the induction phase. No response was observed to the test item at this selected concentration, in either test or control group animals 24 and 48 h following a 6h topical exposure (See Table S3 in supplementary information). No reaction was observed to the negative control item. The validity of the test system has been verified with the periodic testing of the positive control. A sensitisation reaction was observed in 60% of animals in the reliability check with the positive control (2-Mercaptobenzothiazole 97%). This result was in excess of the 15% positivity threshold, and therefore the test system was considered valid. The results of the induction and challenge studies indicate that the test item, SP3000, does not elicit a sensitisation response in the guinea pig, as there was no evidence of a reaction at the challenge phase following a period of induction exposure to the test item.
Synthesis, physiochemical property and antimicrobial activity of novel quaternary ammonium salts
Published in Journal of Enzyme Inhibition and Medicinal Chemistry, 2018
Xianrui Xie, Wei Cong, Feng Zhao, Hongjuan Li, Wenyu Xin, Guige Hou, Chunhua Wang
In the antifungal activity assay of the target compounds, four strains of common fungi in clinical practice and agriculture (Canidia albicans, Cytospora mandshurica, Physalospora piricola, Aspergillus niger) were tanken as the target fungi. As shown in Tables 1 and 2, to our delight, most compounds bearing with the long-chain alkyl group (dodecyl, e.g. 5d, 6d, 7d, 10d, 13d and 16d) displayed fairly good antifungal activities. The most noticeable compound was 13d (MIC: ca. 6.25 μg/mL against Canidia albicans, ca. 1.56 μg/mL against Cytospora mandshurica, ca. 3.125 μg/mL against Physalospora piricola, Aspergillus niger, Table 1; MBC: ca. 6.25 μg/mL against Cytospora mandshurica, other MBC values were equal to corresponding MIC values, Table 2), with a 2-mercaptobenzothiazole substituent in C12QAS, exhibited more potent activities than positive controls (BZK and CA). In addition, POT-C12QAS (2) derivative 7d (MIC: ca. 6.25 μg/mL against Canidia albicans, ca. 3.125 μg/mL against Cytospora mandshurica, ca. 1.56 μg/mL against Physalospora piricola, ca. 6.25 μg/mL against Aspergillus niger, Table 1; MBC values were equal to corresponding MIC values, Table 2) also displayed almost the same antifungal activities as positive controls (BZK and CA). These encouraging results indicated that either POTT (7d) or 2-mercaptobenzothiazole (13d) substituent in C12QAS could enhance the antifungal activities. More than that, both of which might develop into promising antifungal agents in clinic or agriculture.