Biography:

In the past Michael D. Tharp has collaborated on articles with Caitlin G. Haydek. One of their most recent publications is 18 - Urticaria y angioedema. Which was published in journal .

More information about Michael D. Tharp research including statistics on their citations can be found on their Copernicus Academic profile page.

Michael D. Tharp's Articles: (5)

Original ArticleClinical ResearchValidation and Banding of the ItchyQuant: A Self-Report Itch Severity Scale

Because of the significant emotional and psychosocial impact of chronic pruritus, it is important to accurately assess and measure itch severity. This study aims to validate and apply clinically meaningful bands to the ItchyQuant, an illustrated self-report numeric rating scale (NRS) for itch severity. A total of 76 adults with chronic pruritus were recruited. Participants rated their itch on the ItchyQuant, on a traditional 11-point NRS, and with verbal categorizations (no, mild, moderate, or severe). There was a significant, high correlation between the ItchyQuant and NRS (>0.92, P < 0.0001), demonstrating concurrent validity. Significantly more patients (47.2%) preferred the ItchyQuant than the NRS (23.6%) or had no preference (29.2%), P = 0.0015. Significantly more patients found the ItchyQuant easier to use (45.8%) than the NRS (20.8%) or had no preference (33.3%), P = 0.008. The set of clinically meaningful bands with the highest weighted kappa coefficient of agreement (κ = 0.69) was as follows: 0 (no itch), 1–3 (mild itch), 4–7 (moderate itch), 8–10 (severe itch). The ItchyQuant is a clinically meaningful measure of itch severity, demonstrating face and concurrent validity, that many patients prefer and find easier to use when compared with a traditional NRS. We suggest that the ItchyQuant can be added to the existing armamentarium of itch severity scales. We plan to investigate the ItchyQuant further in cognitively challenged populations.

Original ArticleIn Vitro Functional Reactivities of Cutaneous Mast Cells From Patients With Mastocytosis

Cutaneous mast cells from 3 patients with mastocytosis were evaluated for their morphologic characteristics and in vitro functional reactivities to different secretory agonists. By electron microscopy, mastocytosis mast cells appeared larger than normal skin mast cells, frequently had atypical, highly indented or bibbed nuclei, and each contained numerous, elongated cytoplasmic projections. Suspensions of mastocytosis mast cells were obtained from lesional skin biopsy specimens, and their response to both immunologic and nonimmunologic secretagogues was compared with mast cells from normal skin. Lesional skin mast cells had a net histamine release of 12.3% (± 1.3 SEM) and 31.1% (± 6.0 SEM) following stimulation with the purified human anaphylotoxin C3a and mouse monoclonal antihuman IgE antibodies, respectively. This specific release was similar to the responses observed in normal skin mast cells (11.5% ± 4.5 SEM and 16.7% ± 2.1 SEM, respectively. Mast cells from cutaneous lesions of mastocytosis also responded to the nonimmunologic secretagogues, morphine sulfate and calcium ionophore A23187 with a specific histamine release of 15.I% (± 1.2 SEM) and 39.8% (± 8.7 SEM), respectively. The results of this study demonstrate that mast cells from lesions of mastocytosis are morphologically atypical, but have a histamine content similar to normal skin mast cells and retain their functional reactivities to clinically relevant secretory stimuli.

Ultrastructural morphometric analysis of lesional skin: Mast cells from patients with systemic and nonsystemic mastocytosis†

AbstractLesional skin mast cells from some patients with mastocytosis appear morphologically atypical; however, these subjective differences have not been quantified. Herein we describe an objective method for analyzing cutaneous mastocytosis mast cells by a combination of morphometric analysis and electron microscopy. By this technique, lesional mast cells from patients with adult systemic mastocytosis had a significantiy larger mean cytoplasmic area (53.3 μm2), nuclear size (20.4 μm2), and granule diameter (0.81 μm) when compared with mast cells from adults with nonsystemic mastocytosis (36.3 μm2, 15.4 μm2, and 0.67 μm, respectively) and normal age-matched control subjects (34.4 μm2, 14.1 μm2, and 0.67 μm, respectively). Lesional skin mast cells from infants with nonsystemic mastocytosis were very similar to adult nonsystemic mastocytosis mast cells but differed by several parameters from mast cells in adults with systemic involvement. This study demonstrates that there are quantitative differences between lesional skin mast cells from patients with systemic mastocytosis and those with nonsystemic disease.

IgE and Immediate Hypersensitivity

Immediate hypersensitivity reactions occur following stimulation of tissue mast cells. Activation of these cells leads to a series of biochemical events that result in the release of preformed and newly formed mediators. Although these reactions are often initiated by the interaction of multivalent antigens, it is now recognized that mast cells also are stimulated by a number of non-IgE-associated mechanisms. This article focuses on the tissue mast cell, its response to different stimuli, and the role of its released mediators in immediate hypersensitivity reactions.

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