Minimally invasive surgical approach to model hypertrophic scarring in the rabbit ear.

BACKGROUND: Current strategies for hypertrophic scar prevention and treatment are limited. OBJECTIVE: To facilitate these efforts, a minimally invasive hypertrophic scar model was created in a rabbit ear for the first time based on previous methods used to induce ischemia. METHODS: Six New Zealand white rabbits (12 ears total) were studied. First, ischemia was achieved by ligating the cranial artery, cranial vein and central artery, while preserving the caudal artery, caudal vein and central vein, respectively. The relative level of ischemia induced at time of surgery, both baseline and maximum perfusion, was assessed with a fluorescent light-assisted angiography and demonstrated lower rates of perfusion in the ischemic ears. Following vascular injury, a 2-cm full thickness linear wound was created on the ventral ear and closed with 4 - 0 Nylon sutures under high tension. For each rabbit, one ear received a combination of ischemia and wounding with suture tension (n = 6), while the other ear was non-ischemic with wounding and suture tension alone (n = 6). RESULTS: Four weeks post-operatively, ischemic ears developed scar hypertrophy (histological scar thickness: 1.1 ± 0.2 mm versus 0.5 ± 0.1 mm, p < 0.05). CONCLUSION: Herein, we describe a novel, prototypical minimally invasive rabbit ear model of hypertrophic scar formation that can allow investigation of new drugs for scar prevention.

The extracellular matrix dictates regional competence for tumour initiation.

The skin epidermis is constantly renewed throughout life1,2. Disruption of the balance between renewal and differentiation can lead to uncontrolled growth and tumour initiation3. However, the ways in which oncogenic mutations affect the balance between renewal and differentiation and lead to clonal expansion, cell competition, tissue colonization and tumour development are unknown. Here, through multidisciplinary approaches that combine in vivo clonal analysis using intravital microscopy, single-cell analysis and functional analysis, we show how SmoM2-a constitutively active oncogenic mutant version of Smoothened (SMO) that induces the development of basal cell carcinoma-affects clonal competition and tumour initiation in real time. We found that expressing SmoM2 in the ear epidermis of mice induced clonal expansion together with tumour initiation and invasion. By contrast, expressing SmoM2 in the back-skin epidermis led to a clonal expansion that induced lateral cell competition without dermal invasion and tumour formation. Single-cell analysis showed that oncogene expression was associated with a cellular reprogramming of adult interfollicular cells into an embryonic hair follicle progenitor (EHFP) state in the ear but not in the back skin. Comparisons between the ear and the back skin revealed that the dermis has a very different composition in these two skin types, with increased stiffness and a denser collagen I network in the back skin. Decreasing the expression of collagen I in the back skin through treatment with collagenase, chronic UV exposure or natural ageing overcame the natural resistance of back-skin basal cells to undergoing EHFP reprogramming and tumour initiation after SmoM2 expression. Altogether, our study shows that the composition of the extracellular matrix regulates how susceptible different regions of the body are to tumour initiation and invasion.

Benefits of medially based perichondrio-adipo-dermal flap in cartilage sparing prominent ear surgery.

BACKGROUND: Cartilage-cutting and cartilage-sparing techniques are the two types of otoplasty procedures. Because of the significant risk of haematoma, skin necrosis, and ear deformity, cartilage-cutting techniques have been questioned. As a result; suture-based cartilage-sparing procedures such as Mustarde and Furnas suture procedures have grown in popularity. However, these techniques have a tendency for deformity recurrence due to cartilage memory and suture fatigue, as well as the possibility of suture extrusion and pinpricking sensation of the sutures. METHODS: In this study, we used a medially based adipo-dermal flap including perichondrium which is elevated from the back of the auricle to cover and support a cartilage-sparing otoplasty, thirty-four patients (14 female and 20 male) were operated using this technique. The medially based perichondrio-adipo-dermal flap is advanced anteriorly and fixed to the helical rim under cover of the distal skin flap. This procedure sought to cover the suture line preventing suture extrusion and support in the repair of the deformity preventing its recurrence. RESULTS: The average operative time was 80min, ranging from 65 to 110min. The patients passed the early postoperative period uneventfully except for 2 patients; one patient (2.9%) developed haematoma, and the other patient developed a small area of necrosis on the new antihelical fold. In late the postoperative period recurrence of the deformity developed in one patient. No patients developed suture extrusion or granuloma. CONCLUSION: The treatment to repair prominent ears is easy and safe, with benefits such as a natural-looking antihelical fold and minimal tissue stress. The medially or proximally based adipo-dermal flap may help to lower recurrence rates and suture extrusion.

[Effect analysis of individualized operation for congenital preauricular fistula].

Objective:To investigate the effect and influencing factors of individualized operation for congenital preauricular fistula in children. Methods:The clinical data of 98 cases （109 ears） of congenital preauricular fistula treated in Department of Otolaryngology，Fuzhou Children's Hospital of Fujian Medical University from July 2016 to December 2020 were retrospectively analyzed. According to the characteristics and infection of preauricular fistula，they were divided into common type and variant type，static period of inflammation and period of infection.Individual surgical methods such as classical fistula resection, double fusiform incision and fistula location resection were used respectively.The efficacy，complication and influencing factors of different surgical methods were analyzed. Results:The operation time of classical fistula resection was shorter, and the difference was statistically significant（t = －2.905 and－3.005 respectively, all P<0.05）. According to the stages and types of fistulas, the selection of individualized surgical methods had achieved good results. There was no significant difference in incision complications and fistula recurrence among different surgical methods （all P>0.05）. Conclusion:Once infection occurs in congenital preauricular fistula, surgical resection should be performed as soon as possible after infection control, or as early as possible after infection maximum control if infection cannot completely subside. Surgical incision design should be individualized, complete resection of fistulas and lesions, minimally invasive and aesthetic.

Perforación timpánica y colesteatoma, una patología de niños y adultos / Tympanic perforation and cholesteatoma, a pathology of children and adults

INTRODUCCIÓN. La patología de oído es una enfermedad frecuente en nuestro medio, asociada a infecciones a repetición del oído, con la presencia de perforación timpánica y colesteatoma, que determinará la presencia de lesiones mucho más acentuadas en cuanto a la evolución auditiva o complicaciones locales o sistémicas. OBJETIVO. Determinar la asociación existente entre la presencia de colesteatoma y perforación timpánica en pacientes con otitis media crónica. MATERIALES Y MÉTODOS. Estudio epidemiológico analítico retrospectivo. Población de 4 733 y muestra de 75 pacientes para casos y 75 para controles basados en historias clínicas tomadas del sistema informático AS 400, que acudieron a la consulta externa de torrinolaringología del Hospital de Especialidades Carlos Andrade Marín en el periodo de enero de 2018 a diciembre de 2019; Criterios de inclusión para grupo de casos: Hombres y mujeres de 20 a 65 años de edad, diagnóstico de otitis media crónica, diagnóstico de colesteatoma ótico. Criterios de inclusión para grupo controles: Hombres y mujeres de 20 a 65 años de edad, no presentar diagnóstico de colesteatoma. RESULTADOS. Se observó una relación fuerte entre el poseer perforación timpánica y el desarrollo de colesteatoma con un valor de OR 33,14 con un IC al 95% de 31,94 ­ 34,34, con lo que se comprobó la hipótesis del estudio. Se determinó que la perforación timpánica es un factor de riesgo asociado con el desarrollo de colesteatoma en pacientes con otitis media crónica, la prevalencia de colesteatoma en relación a la edad estuvo en un 72% en pacientes de 41 a 65 años, con mayor predominancia en mujeres en un 57,3%. DISCUSIÓN. La presencia de perforación timpánica de acuerdo a lo observado es un factor de riesgo para el desarrollo de colesteatoma, ligado en su mayoría a cuadros de Otitis Media Crónica. CONCLUSIONES. Se confirmó que la perforación timpánica, es un factor de riesgo en el desarrollo del colesteatoma en los pacientes que tienen otitis media crónica, lo que demuestra la necesidad de manejo actualizado y continuo en pacientes con esta patología de oído. Se requieren estudios con muestras más amplias para determinar otros factores de riesgo como sexo, nivel de educación y edad que podrían influir en el desarrollo de colesteatoma.

INTRODUCTION. Ear pathology is a frequent disease in our environment, associated with repeated ear infections, with the presence of tympanic perforation and cholesteatoma, which will determine the presence of much more accentuated lesions in terms of auditory evolution or local or systemic complications. OBJECTIVE. To determine the association between the presence of cholesteatoma and tympanic perforation in patients with chronic otitis media. MATERIALS AND METHODS. Retrospective analytical epidemiological study. Population of 4 733 and sample of 75 patients for cases and 75 for controls based on clinical histories taken from the AS 400 computer system, who attended the Otorhinolaryngology outpatient clinic of the Carlos Andrade Marín Specialties Hospital in the period from January 2018 to December 2019; Inclusion criteria for case group: Men and women aged 20 to 65 years, diagnosis of chronic otitis media, diagnosis of otic cholesteatoma. Inclusion criteria for controls group: men and women aged 20 to 65 years, no diagnosis of cholesteatoma. RESULTS. A strong relationship was observed between having tympanic perforation and the development of cholesteatoma with an OR value of 33,14 with a 95% CI of 31,94 - 34,34, thus proving the study hypothesis. It was determined that tympanic perforation is a risk factor associated with the development of cholesteatoma in patients with chronic otitis media, the prevalence of cholesteatoma in relation to age was 72% in patients aged 41 to 65 years, with greater predominance in women in 57,3%. DISCUSSION. The presence of tympanic perforation according to what was observed is a risk factor for the development of cholesteatoma, mostly linked to Chronic Otitis Media. CONCLUSIONS. It was confirmed that tympanic perforation is a risk factor in the development of cholesteatoma in patients with chronic otitis media, which demonstrates the need for updated and continuous management in patients with this ear pathology. Studies with larger samples are required to determine other risk factors such as sex, education level and age that could influence the development of cholesteatoma.

Necrosis of the Ear Following Skin Cancer Resection.

We report 2 patients who underwent Mohs micrographic surgery (MMS) and operative closure on the ear. Both cases were complicated by necrosis resulting in the formation of auricular defects. These cases highlight the importance of the auricular vasculature and the associated watershed regions during operative planning for MMS as well as the complications that can arise with vascular compromise. This case report also provides a review of the auricular vasculature with special attention to these vulnerable watershed regions.

Tympanic membrane perforations: a critical analysis of 1003 ears and proposal of a new classification based on pathogenesis.

PURPOSE: To present a large series ears with tympanic membrane perforations (TMP), to describe their characteristics, and to propose a new classification system based on the pathogenesis of TMP. METHODS: This cross-sectional study was conducted at a tertiary university hospital with 1003 ears (792 consecutive patients with TMP in at least 1 ear). Otoendoscopy and audiometry were performed. Perforation measurements and their locations were digitally assessed. TMP with no suggestive signs of previous retraction were classified as Group 1, and those with possible previous retraction were classified as Group 2. Signs of retraction previous to the TMP, symptom length, perforation size and location, status of the contralateral ear, and hearing status were compared. RESULTS: Group 1 comprised 63.5% of the included ears. Compared to Group 2, Group 1 presented a higher rate of central perforations (99% vs. 53%), a shorter duration of symptoms, smaller perforations (mean area: 18.5% vs. 41.4%), a higher rate of perforations in the anterior quadrants, better hearing levels (mean tritonal gap: 23.9 dB vs. 29.2 dB), and a lower rate of abnormal contralateral ears (28% vs. 66%). CONCLUSION: The classification of TMP into two groups based on signs of previous retractions is feasible and indicates two different levels of disease severity. While the group without previous signs of retraction comprises ears with more limited disease, membranes with previous retraction seem to show more severe disease and, consequently, a less functional middle ear.

Anti-allergic property of 4,8-sphingadienine stereoisomers in vivo and in vitro model.

4,8-Sphingadienines (SD), metabolites of glucosylceramides (GlcCer), are sometimes determined as key mediators of the biological activity of dietary GlcCer, and cis/trans geometries of 4,8-SD have been reported to affect its activity. Since regulating excessive activation of mast cells seems an important way to ameliorate allergic diseases, this study was focused on cis/trans stereoisomeric-dependent inhibitory effects of 4,8-SD on mast cell activation. Degranulation of RBL-2H3 was inhibited by treatment of 4-cis-8-trans- and 4-cis-8-cis-SD, and their intradermal administrations ameliorated ear edema in passive cutaneous anaphylaxis reaction, but 4-trans-8-trans- and 4-trans-8-cis-SD did not. Although the activation of mast cells depends on the bound IgE contents, those stereoisomers did not affect IgE contents on RBL-2H3 cells after the sensitization of anti-TNP IgE. These results indicated that 4-cis-8-trans- and 4-cis-8-cis-SD directly inhibit the activation of mast cells. In conclusion, it was assumed that 4,8-SD stereoisomers with cis double bond at C4-position shows anti-allergic activity by inhibiting downstream pathway after activation by the binding of IgE to mast cells.

Tacrolimus action pathways in an ointment base for hypertrophic scar prevention in a rabbit ear model

Abstract Background: Tacrolimus is used to prevent unaesthetic scars due to its action on fibroblast activity and collagen production modulation. Objectives: To evaluate the action pathways, from the histopathological point of view and in cytokine control, of tacrolimus ointment in the prevention of hypertrophic scars. Methods: Twenty-two rabbits were submitted to the excision of two 1-cm fragments in each ear, including the perichondrium. The right ear received 0.1% and 0.03% tacrolimus in ointment base twice a day in the upper wound and in the lower wound respectively. The left ear, used as the control, was treated with petrolatum. After 30 days, collagen fibers were evaluated using special staining, and immunohistochemistry analyses for smooth muscle actin, TGF-β and VEGF were performed. Results: The wounds treated with 0.1% tacrolimus showed weak labeling and a lower percentage of labeling for smooth muscle actin, a higher proportion of mucin absence, weak staining, fine and organized fibers for Gomori's Trichrome, strong staining and organized fibers for Verhoeff when compared to controls. The wounds treated with 0.03% tacrolimus showed weak labeling for smooth muscle actin, a higher proportion of mucin absence, strong staining for Verhoeff when compared to the controls. There was absence of TGF-β and low VEGF expression. Study limitations: The analysis was performed by a single pathologist. Second-harmonic imaging microscopy was performed in 2 sample areas of the scar. Conclusions: Both drug concentrations were effective in suppressing TGF-β and smooth muscle actin, reducing mucin, improving the quality of collagen fibers, and the density of elastic fibers, but only the higher concentration influenced elastic fiber organization.

Application of least absolute shrinkage and selection operator logistic regression for the histopathological comparison of chondrodermatitis nodularis helicis and hyperplastic actinic keratosis.

BACKGROUND: The distinction between chondrodermatitis nodularis helicis (CNH) and hyperplastic actinic keratosis (HAK) on the ear can pose a diagnostic challenge. We aimed to identify histopathological characteristics that could distinguish between CNH and HAK on routine sections using penalized least absolute shrinkage and selection operator (LASSO) logistic regression analysis. METHODS: Cases of CNH (n = 80) and HAK (n = 28) were analyzed for selected histopathological characteristics. Fisher's exact test and LASSO regression were performed. RESULTS: In univariate analyses, the following were significantly associated with CNH: ulceration, acanthosis, granular layer in the majority of the lesion, hypergranulosis at the periphery of the lesion, hyperkeratosis at the periphery of the lesion, hyperparakeratosis at the periphery of the lesion, fibrosis, increased blood vessels, vertically oriented blood vessels, and fibrin. A LASSO model excluding atypia found that fibrin, fibrosis, presence of granular layer, ulceration, and vertically oriented blood vessels were most predictive of CNH. Keratinized strap cells were not a significant predictor. CONCLUSION: We have identified features that may aid in differentiating these entities and demonstrated that a LASSO regression model can identify predictors that may improve diagnostic accuracy. Our results indicate that the highest diagnostic accuracy in this dilemma is dependent on obtaining biopsy specimens with visible dermis.

Coordinated action of microsomal prostaglandin E synthase-1 and prostacyclin synthase on contact hypersensitivity.

Microsomal prostaglandin (PG) E synthase-1 (mPGES-1) and prostacyclin (PGI2) synthase (PGIS) are PG terminal synthases that work downstream of cyclooxygenase and synthesize PGE2 and PGI2, respectively. Although the involvement of PG receptors in acquired cutaneous immune responses was recently shown, the roles of these PG terminal synthases remain unclear. To identify the pathophysiological roles of mPGES-1 and PGIS in cutaneous immune systems, we applied contact hypersensitivity (CHS) to mPGES-1 and PGIS knockout (KO) mice as a model of acquired immune responses. Mice were treated with 1-fluoro-2,4-dinitrobenzene (DNFB) and evaluated for ear thickness and histopathological features. The results showed that the severity of ear swelling in both gene-deficient mice was much lower than that in wild-type (WT) mice. Histological examination of DNFB-treated ears showed that inflammatory cell infiltration and edema in the dermis were also less apparent in both genotypic mice. LC-MS analysis further showed that the increment in PGE2 levels in DNFB-treated ear tissue was reduced in mPGES-1 KO mice, and that 6-keto PGF1α (a stable metabolite of PGI2) was not detected in PGIS KO mice. Furthermore, we made bone marrow (BM) chimera and found that transplantation of WT mouse-derived BM cells restored the impaired CHS response in mPGES-1 KO mice but did not restore the response in PGIS KO mice. These results indicated that mPGES-1 in BM-derived cells and PGIS in non-BM-derived cells might play critical roles in DNFB-induced CHS. mPGES-1-derived PGE2 and PGIS-derived PGI2 might coordinately promote acquired cutaneous immune responses.

The Face of COVID-19: Facial Pressure Wounds Related to Prone Positioning in Patients Undergoing Ventilation in the Intensive Care Unit.

In the setting of COVID-19 (coronavirus disease 2019)-associated moderate and severe acute respiratory distress, persistently hypoxemic patients often require prone positioning for >16 hours. We report facial pressure wounds and ear necrosis as a consequence of prone positioning in patients undergoing ventilation in the intensive care unit in a tertiary medical center in New York City.

Mutation analysis of TCOF1 gene in Chinese Treacher Collins syndrome patients.

BACKGROUND: Treacher Collins syndrome (TCS) is a rare autosomal dominant or recessive disorder, that involves unique bilateral craniofacial malformations. The phenotypes of TCS are extremely diverse. Interventional surgery can improve hearing loss and facial deformity in TCS patients. METHOD: We recruited seven TCS families. Variant screening in probands was performed by targeted next-generation sequencing (NGS). The variants identified were confirmed by Sanger sequencing. The pathogenicity of all the mutations was evaluated using the guidelines of the American College of Medical Genetics and Genomics (ACMG) and InterVar software. RESULTS: Three frameshift variants, two nonsense variants, one missense variant, and one splicing variant of TCOF1 were identified in the seven TCS probands. Five variants including c.1393C > T, c.4111 + 5G>C, c.1142delC, c.2285_2286delCT, and c.1719delG had not been previously reported. Furthermore, we report the c.149A > G variant for the first time in a Chinese TCS patient. We provided prenatal diagnosis for family 4. Proband 7 chose interventional surgery. CONCLUSION: We identified five novel variants in TCOF1 in Chinese patients with TCS, which expands the mutation spectrum of TCOF1 in TCS. Bone conduction hearing rehabilitation can improve hearing for TCS patients and prenatal diagnosis can provide fertility guidance for TCS families.

In Silico, In Vitro, and In Vivo Antitumor and Anti-Inflammatory Evaluation of a Standardized Alkaloid-Enriched Fraction Obtained from Boehmeria caudata Sw. Aerial Parts.

In the context of the cancer-inflammation relationship and the use of natural products as potential antitumor and anti-inflammatory agents, the alkaloid-enriched fraction of Boehmeriacaudata (BcAEF) aerial parts was evaluated. In vitro antiproliferative studies with human tumor cell lines showed high activity at low concentrations. Further investigation on NCI-H460 cells showed an irreversible effect on cell proliferation, with cell cycle arrest at G2/M phase and programmed cell death induction. Molecular docking studies of four alkaloids identified in BcAEF with colchicine's binding site on ß-tubulin were performed, suggesting (-)-C (15R)-hydroxycryptopleurine as the main inductor of the observed mitotic death. In vivo studies showed that BcAEF was able to reduce Ehrlich tumor volume progression by 30 to 40%. Checking myeloperoxidase activity, BcAEF reduced neutrophils migration towards the tumor. The in vivo anti-inflammatory activity was evaluated by chemically induced edema models. In croton oil-induced ear edema and carrageenan (CG)-induced paw edema models, BcAEF reduced edema around 70 to 80% together with inhibition of activation and/or migration of neutrophils to the inflammatory area. All together the results presented herein show BcAEF as a potent antitumor agent combining antiproliferative and anti-inflammatory properties, which could be further explored in (pre)clinical studies.

The effects of valsartan on scar maturation in an experimental rabbit ear wound model.

INTRODUCTION: In our study, we aimed to search and compare the effects of valsartan and enalapril on the pathological scar formation on the basis of histomorphological parameters. MATERIALS AND METHODS: Nine New Zealand albino male rabbits, which were divided into three groups, were included in the study. A previously described rabbit ear wound model was used. Enalapril was administered 0.75 mg/kg/day on the first group and valsartan was administered 10 mg/kg/day on the second group for 40 days. The third group was the control group. Results were evaluated on the 40th day with scar elevation index calculation and histological studies. Histological studies were done by using Hematoxylin-eosin, Masson trichrome and Sirius Red stains. RESULTS: Enalapril and valsartan groups were both significantly effective on the prevention of pathological scar formation when compared to the control group in terms of fibroblast count, capillary count, type 1/3 collagen ratio, collagen organization, and epithelial thickness. There was no significant difference between the enalapril and control group on the scar elevation index. Valsartan group was more efficient than the enalapril group on the reduction of fibroblast count and epithelial thickness. CONCLUSION: Both Valsartan and Enalapril are found to be effective for the prevention of pathological scar formation.

Retrofractamide C Derived from Piper longum Alleviates Xylene-Induced Mouse Ear Edema and Inhibits Phosphorylation of ERK and NF-κB in LPS-Induced J774A.1.

Many studies have reported the biological activities of retrofractamide C (RAC). However, few studies have investigated the anti-inflammatory effect of RAC. In the present study, we investigated the anti-inflammatory effect of RAC using lipopolysaccharide (LPS)-induced J774A.1 cells and a xylene-induced mouse ear edema model. Treatment with RAC decreased LPS-induced nitric oxide (NO) and prostaglandin E2 (PGE2) secretion and inducible NO synthase (iNOS) and cyclooxygenase 2 (COX2) protein expression. It also downregulated the LPS-induced production of interleukin-1ß (IL-1ß) and interleukin-6 (IL-6) but not tumor necrosis factor α (TNF-α). In the LPS-induced signaling pathway, RAC inhibited the phosphorylation of extracellular signal-regulated kinase (ERK) and nuclear factor kappa light chain enhancer of activated B cells (NF-κB) but not c-Jun N-terminal kinase (JNK) or p38. In a xylene-induced mouse ear edema model, RAC treatment alleviated edema formation and inflammatory cell infiltration. In conclusion, the present study indicates that RAC has the potential to have anti-inflammatory effects and could be a prospective functional food.

Costello syndrome model mice with a HrasG12S/+ mutation are susceptible to develop house dust mite-induced atopic dermatitis.

Costello syndrome is an autosomal dominant disorder that is caused by germline HRAS mutations. Patients with Costello syndrome present craniofacial abnormalities, cardiac defects, and cancer predisposition, as well as skin abnormalities, including papillomas, keratosis pilaris, and eczematous dermatitis. However, the mechanisms underlying the dermatological abnormalities remain unclear. Here, we demonstrated that knock-in mice expressing an Hras G12S mutation (HrasG12S/+ mice) are susceptible to develop atopic dermatitis (AD)-like skin lesions, including eczema, pruritus, elevated serum IgE levels, acanthosis, and the infiltration of mast cells, basophils, and type-2 innate lymphoid cells in the dermis, after stimulation with house dust mite allergens (Dermatophagoides farinae, Dfb). Reduced skin barrier function, increased proliferation of phosphorylated ERK (p-ERK)-positive epidermal cells, and increased Th2-type cytokines as well as epithelial cell-derived cytokines, including IL-33, were observed in the skin tissue of HrasG12S/+ mice compared with Hras+/+ mice. Cultured HrasG12S/+ keratinocytes exhibited increased IL-33 expression after Dfb stimulation. PD0325901, an MEK inhibitor, ameliorated AD-like symptoms in HrasG12S/+ mice, showing decreased proliferation of p-ERK-positive epidermal cells and decreased expression of IL-33. Our findings indicate that the epidermis of HrasG12S/+ mice stimulated by Dfb strongly induced IL-33 expression and type-2 innate lymphoid cells, resulting in AD-like skin lesions. These results suggest that the epidermis of HrasG12S/+ mice are prone to development of eczematous dermatitis stimulated with house dust mite allergens.