Publications by authors named "Lawrence S Chan"

Article Synopsis
  • The COVID-19 pandemic raised significant healthcare issues and highlighted how the human immune system responds to viral infections and vaccinations.
  • This paper discusses two patients who experienced granulomatous skin lesions after receiving the COVID-19 vaccine, noting one had generalized granuloma annulare (GA) and the other had localized GA.
  • Both patients responded well to treatment with systemic corticosteroids, and the paper reviews related literature on skin diseases associated with COVID-19, focusing on potential mechanisms for these granulomatous skin eruptions.
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Occupational sun exposure is a well-known risk factor for the development of melanoma and nonmelanoma skin cancer (NMSC), especially among US military personnel who may have inadequate access to sun protection, are located in geographic regions with increased sun exposure, and work with potential carcinogens. Herein, we describe a case of a military service member who developed skin cancer at an early age potentially due to occupational sun exposure. We also provide a review of the literature to examine the risk factors and incidence of melanoma and NMSC in US military personnel and veterans, as well as provide recommendations for skin cancer prevention, screening, and intervention in the military population.

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Psoriasis is a chronic disorder characterized by a complex interplay between keratinocytes and inflammatory mediators. In a previous study, we evaluated diacerein's ability to diminish interleukin (IL)-1's proinflammatory effects on cultured primary human keratinocytes. In this study, we evaluated diacerein's ability to diminish the inflammatory effects of a cytokine mixture (CM) consisting of IL-17A, IL-22, oncostatin M, IL-1A, and tumor necrosis factor (TNF)-alpha on cultured primary human keratinocytes.

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IL-4 plays an important role in the pathogenesis of atopic dermatitis (AD) by dysregulating many key factors at the transcriptional level. In this study, a microRNA array technique and IL-4 transgenic mice were used to demonstrate that IL-4 dysregulates microRNAs involved in inflammation, angiogenesis, lymphangiogenesis and apoptosis. Of the 372 common microRNAs examined, 26 and one microRNAs were found to be up- and down-regulated, respectively.

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Senear-Usher Syndrome, or pemphigus erythematosus, is an autoimmune skin blistering disorder with an overlapping clinical presentation of pemphigus foliaceus and lupus erythematosus. Lesions typically involve the scalp, face, and upper chest or back. This case study focuses on a patient who presentedwith progressive scalp ulcers, hyperpigmentation, and eroded plaques with overlying hemorrhagic crust.

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Skin barrier defects play an important role in atopic dermatitis (AD) pathogenesis. Loricrin, an important barrier protein suppressed in human AD, is down-regulated by IL-4 in keratinocytes. However, the molecular mechanism is unknown.

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We investigated IL-1-induced regulation of genes related to inflammation and atherogenesis in human keratinocytes and endothelial cells, and if 'diacerein', an oral IL-1 inhibiting drug currently approved for use in osteoarthritis, would reverse IL-1's effects on these cells. Primary human keratinocytes and coronary artery endothelial cells were treated with either IL-1α or IL-1β, with and without diacerein. Using PCR-array, we assessed differential gene-expression regulated by IL-1 and diacerein.

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Autoimmune paraneoplastic and neoplasm-associated skin syndromes are characterized by autoimmune-mediated cutaneous lesions in the presence of a neoplasm. The identification of these syndromes provides information about the underlying tumor, systemic symptoms, and debilitating complications. The recognition of these syndromes is particularly helpful in cases of skin lesions presenting as the first sign of the malignancy, and the underlying malignancy can be treated in a timely manner.

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Skin barrier defects play an important role in atopic dermatitis (AD). Involucrin, an important barrier protein suppressed in human AD, is downregulated by interleukin-4 (IL-4). However, the molecular mechanism for IL-4 downregulation of involucrin has not been delineated, and especially how Stat6, a transcriptional activator, represses involucrin expression is unknown.

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An otherwise healthy 43-year-old man presented with seven papules that had all erupted within the previous 6 months from an epidermal nevus on his left lower extremity. He reported that one of the new growths was painful and bled with minor trauma. Physical examination revealed a linear blaschkoid cobblestoned dark brown plaque that extended from the disto-lateral left thigh 30 cm to the mid-calf.

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Wound healing in a pre-existing Th2-dominated skin milieu was assessed by using an epidermal specific interleukin-4 (IL-4) transgenic (Tg) mouse model, which develops a pruritic inflammatory skin condition resembling human atopic dermatitis. Our results demonstrated that IL-4 Tg mice had delayed wound closure and re-epithelialization even though these mice exhibited higher degrees of epithelial cell proliferation. Wounds in IL-4 Tg mice also showed a marked enhancement in expression of inflammatory cytokines/chemokines, elevated infiltration of inflammatory cells including neutrophils, macrophages, CD3+ lymphocytes, and epidermal dendritic T lymphocytes.

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IL-4 plays an important role in the pathogenesis of atopic dermatitis (AD), a common chronic inflammatory skin disease. We have generated IL-4 transgenic (Tg) mice by over-expressing IL-4 in the epidermis. These mice spontaneously develop chronic pruritic inflammatory skin lesions, which meet the clinical and histological diagnostic criteria for human AD.

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Interleukin-19 (IL-19) plays an important role in asthma by stimulating T helper type 2 (Th2) cytokine production. Interestingly, IL-4, a key Th2 cytokine, in turn up-regulates IL-19 expression in bronchial epithelial cells, so forming a positive feedback loop. In atopic dermatitis (AD), another Th2 disease closely related to asthma, IL-19 is up-regulated in the skin.

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Atopic dermatitis (AD), a common chronic inflammatory skin disease, is characterized by inflammatory cell skin infiltration. The JAK-STAT pathway has been shown to play an essential role in the dysregulation of immune responses in AD, including the exaggeration of Th2 cell response, the activation of eosinophils, the maturation of B cells, and the suppression of regulatory T cells (Tregs). In addition, the JAK-STAT pathway, activated by IL-4, also plays a critical role in the pathogenesis of AD by upregulating epidermal chemokines, pro-inflammatroy cytokines, and pro-angiogenic factors as well as by downregulating antimicrobial peptides (AMPs) and factors responsible for skin barrier function.

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Atopic dermatitis (AD) is a common chronic inflammatory skin disease. Although the pathogenesis of AD is not fully understood, we and others have shown that IL-4 plays a key role. In this study we aimed to identify keratinocyte genes regulated by IL-4 that may play important roles in the pathophysiology of AD.

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Objective: To investigate the presence and extent of inflammatory lymphangiogenesis in AD and determine the role of IL-4 in lymphatic proliferation in both K14-IL-4 Tg mouse model of AD and cultured human epidermal cells.

Methods: Skin tissues from Tg mice were collected for immunostaining against PDPN, LYVE-1, CD11b and VEGF-C. The regulation of specific lymphatic biomarkers and growth factors were determined using qPCR and Western Blot analyses.

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Atopic dermatitis (AD), a chronic, pruritic, inflammatory skin disease, is histopathologically characterized by epidermal hyperplasia and infiltration of T cells, mast cells, and eosinophils. Clinical study and basic research have established that IL-4 plays an important role in the pathogenesis of AD. In this report, using HaCat cells, we show that CCL26, a chemokine for eosinophils, is up-regulated by IL-4 at both the mRNA and protein levels.

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Mucous membrane pemphigoid, a heterogeneous group of autoimmune blistering diseases, affects primarily the mucous membranes. Although oral and ocular mucosae can both be affected in a given patient, patients with involvement restricted to oral mucosae tend to have a benign outcome, whereas those with ocular disease commonly face treatment resistance, resulting in scarring and blindness. Diagnosis requires direct immunofluorescence microscopy to demonstrate a linear deposition of immunoglobulin (Ig) G or IgA, or complement component 3 (C3), at the epithelial basement membrane.

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