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Biomedical subjects

C Calhoun

Publications and source records attributed to C Calhoun.

10 recordsLinked to original sources
PubMed2002

Alterations in cytokine regulation in aged epidermis: implications for permeability barrier homeostasis and inflammation. I. IL-1 gene family.

Acute disruption of the cutaneous permeability barrier with either solvents or tape-stripping stimulates a homeostatic metabolic response in the subjacent nucleated layers of the epidermis that results in a rapid restoration of normal permeability barrier function. When the aged epidermal permeability barrier is stressed, it reveals a diminished capacity for recovery, in comparison to young epidermis, analogous to other organs in the aged when stressed. Although the signals that regulate this homeostatic response by the epidermis have not yet been resolved, acute permeability barrier disruption stimulates release of prestored IL-1alpha, and increased production of potentially regulatory cytokines, including IL-1alpha and TNFalpha in the epidermis. In these studies, we addressed the hypothesis that cytokine dysregulation explains the permeability barrier abnormality in aged epidermis, assessing the regulation of IL-1 and TNF signaling in aged vs young mice. To determine whether the IL-1 family of cytokines plays a key role in the permeability barrier abnormality of the aged, permeability barrier recovery rates were compared in transgenic mice lacking the functional IL-1 type 1 receptor vs wild-type mice at various ages. Knockout of the IL-1 type 1 receptor exacerbates the defect in permeability barrier homeostasis that is seen in age-matched, wild-type counterparts. Furthermore, the sluggish permeability barrier recovery in aged epidermis is associated with, and at least in part attributable to, altered expression of the IL-1 family of cytokines and receptors both under basal conditions and after acute barrier perturbations. Whereas modulations in cytokine expression with epidermal permeability barrier perturbation are qualitatively similar in aged epidermis, they greatly differ quantitatively. In contrast, examination of TNFalpha mRNA and protein basally, and following barrier perturbation revealed no alterations in aged epidermis. Together, these results show that selective alterations in the IL-1 family of cytokines occur with aging and that defects in IL-1 signaling may contribute to the epidermal permeability barrier abnormality of aged skin.

Animals↗
PubMed2001

Mistakes that heterosexual people make when trying to appear non-prejudiced: the view from LGB people.

In two studies, lesbians, gay men and bisexuals were queried concerning mistakes that well-meaning heterosexual people have made when interacting with them. In qualitative, open-ended research, we determined that the most common mistakes concerned heterosexuals' pointing out that they know someone who is gay, emphasizing their lack of prejudice, and relying on stereotypes about gays. Following up with a quantitative, close-ended questionnaire, we determined that the mistakes respondents experienced most often involved heterosexuals (a) relying on stereotypes and (b) ignoring gay issues; the most annoying mistakes were heterosexuals (a) using subtle prejudicial language and (b) not owning up to their discomfort with gay issues. We used two theoretical perspectives, shared reality theory and the contact hypothesis, to analyze the quantitative responses. Implications for intergroup relationships between heterosexual people and gay people are discussed.

Adult↗
PubMed1996

Incidence of maxillofacial involvement in arthrogryposis multiplex congenita.

PURPOSE: This study determined the incidence of maxillofacial involvement in patients diagnosed with arthrogryposis multiplex congenita (AMC). PATIENTS AND METHODS: Twenty-three patients were evaluated by the pediatric physical medicine and rehabilitation, orthopedic surgery, and pediatric oral and maxillofacial surgery departments. Any patient in whom the diagnosis of AMC was in doubt was excluded from the study. All patients with limited mandibular function underwent computed tomography (CT) examination of their temporomandibular joints (TMJ). The results of physical therapy were followed. RESULTS: Five of the 23 patients diagnosed with AMC were found to have maxillofacial involvement, eg, presence of cleft palate, Robin-like sequence, high-arched palate, open-bite deformity, facial muscle weakness, esophageal dysfunction, and limited mandibular opening. No TMJ abnormalities were found by CT scan. Physical therapy was used for treatment of the limited opening, but relapse occurred quicky after therapy was discontinued. CONCLUSION: The incidence of maxillofacial findings is similar to that of most other reports. Treatment involves surgical correction of abnormal anatomy when possible (ie, cleft repair), symptomatic management (ie, esophageal dysfunction), and physical therapy.

Adolescent↗
PubMed1996

Barrier disruption stimulates interleukin-1 alpha expression and release from a pre-formed pool in murine epidermis.

Previous studies have shown that barrier disruption increases epidermal mRNA levels of interleukin-1 alpha (IL-1 alpha). We used immunohistochemistry to examine IL-1 alpha expression in hairless mouse skin under basal conditions and following barrier abrogation. In untreated mice, IL-1 alpha was present in the dermis and nucleated epidermal layers in a diffuse, generalized pattern. In essential fatty acid deficient mice IL-1 alpha was present in all epidermal layers and the dermis, with prominent staining in the stratum corneum. After acute barrier disruption with tape-stripping, IL-1 alpha increased in the epidermis and dermis within 10 min, remained elevated at 2 and 4 h, and decreased to near basal levels by 24 h. Moreover, intense, perinuclear, basal cell staining appeared at 10 min, persisting until 4 h after barrier disruption. Since the increase in IL-1 alpha immunostaining after acute barrier abrogation precedes the increase in mRNA, we hypothesized that the IL-1 alpha might derive from a pre-formed pool. Prolonged occlusion of normal skin, a treatment that specifically reduces epidermal mRNA levels of IL-1 alpha, decreased basal immunostaining for IL-1 alpha and blunted the increase in IL-1 alpha usually seen following barrier disruption. Moreover, tape-stripping of skin, maintained ex vivo at 4 degrees C, resulted in increased IL-1 alpha immunostaining within the upper nucleated epidermal layers, as well as release of mature IL-1 alpha into the medium, as measured by Western blotting and enzyme-linked immunosorbent assay. In addition, the stratum corneum attached to the tape contained IL-1 alpha. These studies show that acute barrier disruption induces both the immediate release and dispersion of IL-1 alpha from a pre-formed, epidermal pool, as well as increased IL-1 alpha synthesis; both mechanisms are consistent with a role for IL-1 alpha in the regulation of proinflammatory and homeostatic processes in the skin.

Animals↗