Search PubMed⌕ Search

Biomedical subjects

A C Chu

Publications and source records attributed to A C Chu.

At least 91 records · Page 5Linked to original sources
PubMed1984

Comparative clinical trial of bifonazole solution versus selenium sulphide shampoo in the treatment of pityriasis versicolor.

38 patients were entered into a controlled randomised trial, comparing two forms of topical treatment for pityriasis versicolor. Diagnosis was made on clinical criteria and confirmed by direct microscopic examination of Parker Quink/KOH preparations. 20 patients were treated with bifonazole solution daily for 2 weeks. 18 patients were treated with 2.5% selenium sulphide shampoo daily for one week and weekly for six weeks. Mycological examination showed that Malassezia furfur was present in all patients prior to treatment. At the end of the trial, 1 patient (5%) treated with bifonazole and 4 patients (22%) of those treated with selenium sulphide shampoo showed the presence of the fungus in the skin. This study demonstrates that bifonazole solution is an effective and well-tolerated form of treatment for pityriasis versicolor. A 2-week course of bifonazole solution was as effective as a 7-week course of selenium sulphide shampoo in eradicating the disease and had a lower relapse rate at 4 weeks.

Administration, Topical↗
PubMed1984

Characterization of immature T cell subpopulations in neonatal blood.

A series of monoclonal antibodies directed against T cell differentiation antigens was used to identify circulating T cells in normal human neonates. Twenty-five cord blood samples, taken after cesarean or vaginal delivery, and 16 venous blood samples from normal adult controls were examined using monoclonal antibodies in an indirect immunofluorescence technique. The percentage of circulating OKT3 positive (pan-T cell) cells was significantly lower in the neonatal blood (52.8%) compared with the adult controls (74.9%) (P less than .001). Of the cord mononuclear cells, 58% showed reactivity with OKT10 (common thymocyte antigen) compared with only 7% in adult controls (P less than .001). The helper:suppressor T cell ratio was lower in cord blood (1:2) as compared with 1:3 for adult blood (P less than .005) as observed in these studies. These figures reflect the presence of a significant population (25%) of immature T cells in cord blood that expresses simultaneously both helper (OKT4) and suppressor (OKT8) phenotypes. Twenty-four percent of the T cells in cord blood also expressed OKT6 antigen (cortical thymocyte), a feature not found in adult blood. Double-labeling studies characterized a previously undescribed blood T cell phenotype, which was simultaneously OKT6 and OKT3 (pan-T cell) positive; of the cells reactive with OKT3, 43% also were positive with OKT6. This study reveals the presence of immature populations of T cells in normal human neonatal blood exhibiting phenotypes characteristic of normal developing thymocytes and a previously undescribed cell phenotype.

Adult↗
PubMed1983

Thymopoietin-like substance in human skin.

A heterologous antithymopoietin (anti-TP) antibody was used to determine whether a TP-like molecule is present in the epidermis, since such factors have been postulated to play a part in known T cell-epidermal cell interaction. Examination of cytocentrifuge smears of freshly separated human epidermal cells stained by indirect immunofluorescence revealed that 8-14% of these cells possessed cytoplasmic reactivity with the anti-TP antibody. Similarly, 2-5% of human epidermal cells, maintained in tissue culture for 2-8 weeks, showed cytoplasmic staining with the anti-TP antibody. Double-labeling immunofluorescence studies, with the anti-TP antibody and a monoclonal antibody specifically reactive with Langerhans cells (OKT6), demonstrated that cells possessing this TP-like substance were not Langerhans cells. In situ studies of 4-microns frozen sections of normal human skin indicated that the cell population which possesses the TP-like substance is the basal layer of keratincoytes in the epidermis.

Fluorescent Antibody Technique↗
PubMed1983

Recognition of immature T-cell phenotypes in neonatal blood using monoclonal antibodies.

The monoclonal antibody reactivity of cord blood mononuclear cells to six monoclonal reagents, OKT3, OKT4, OKT6, OKT8, OKT10, and OKT11, was evaluated using an indirect immunofluorescence technique. An immature population of cells was found; 24% of T cells in cord blood expressed OKT6 and 58% expressed OKT10. A previously undescribed phenotype, OKT3+/OKT6+, was discovered using double-labeling studies. In addition, the OKT4+:OKT8+ ratio in cord blood was 1:2, compared with 1:3 in the normal adult controls tested in this study. This is explained by the presence of a population of OKT4+/OKT8+ cells circulating in the neonate. Double-labeling studies of the cord blood samples demonstrated that all of the OKT3+ cells were simultaneously OKT11+ and that 17% of the cells were OKT11+ only. This is in accordance with the findings in normal adult peripheral T cells. Therefore, circulating neonatal T cells express an immature phenotype more characteristic of thymocytes and an altered OKT4+:OKT8+ ratio as compared with adult controls. We also describe a new phenotype OKT3+/OKT6+ present on the cord mononuclear cells.

Adult↗
PubMed1982

In-situ T lymphocyte identification in cutaneous tissue sections of benign and malignant dermatoses.

An indirect immunoperoxidase technique employing a specific anti-human T lymphocyte antiserum has been used to identify T lymphocytes in cutaneous tissue sections of various benign and malignant dermatoses. Skin biopsies from patients with histologically confirmed lichen planus, discoid lupus erythematosus, psoriasis, actinic keratosis, squamous cell carcinoma, Bowen's disease, keratoacanthoma, malignant melanoma, inflamed serborrhoeic warts, sarcoidosis, follicular lymphoma and multicentric reticulohistiocytosis were examined. T lymphocytes were found to be the predominant cell type in the cutaneous infiltrates of the majority of these dermatoses. However, only few T lymphocytes were identified in sarcoidosis where they tended to be restricted to the periphery of the epithelioid cell granulomas. Similarly, in the cutaneous infiltrates of follicular lymphoma and in a patient with multicentric reticulohistiocytosis, few T lymphocytes were identified.

Carcinoma, Squamous Cell↗
PubMed1982

Biochemical characterization of a differentiation antigen shared by human epidermal langerhans cells and cortical thymocytes.

Previous immunofluorescent studies have shown that differentiation antigens recognized by the monoclonal antibody (OKT6) are present on the external membranes of human epidermal Langerhans cells, cortical thymocytes and some cultured T cell lines. In the present investigation, the biochemical characteristics of the OKT6 recognized antigens derived from these three sources were compared. Following immunoprecipitation with OKT6, a single band with an approximate molecular weight of 52,000 daltons was identified by sodium dodecyl sulfate polyacrylamide gel electrophoresis (under both reducing and nonreducing conditions) in the detergent lysate of radioiodinated normal epidermal cells. A molecule with the same apparent molecular weight was immunoprecipitated from thymocytes and cultured MOLT-3 (T cell-acute lymphoblastic leukemia) cells. However, a low molecular weight protein of approximately 10,000 daltons was coprecipitated from these MOLT-3 cells. No electrophoretically identifiable antigens were precipitated from peripheral lymphocytes or monocytes with OKT6. These observations further distinguish Langerhans cells from classical monocytes, indicate that these cells express a membrane antigen otherwise characteristic of cortical thymocytes, and suggest the potential usefulness of the monoclonal antibody, OKT6, in further investigations of the functions and ontogeny of Langerhans cells.

Animals↗
PubMed1981

Juvenile xanthogranuloma with recurrent subdural effusions.

A 2-year-old girl with extensive cutaneous xanthogranuloma and recurrent subdural effusions has been investigated. Differentiation from histiocytosis X depended upon light and electron microscopical studies of the cutaneous infiltrate and cells obtained from the cerebrospinal fluid. The recurrent subdural effusions responded well to cranial irradiation. Although juvenile xanthogranuloma is generally a benign cutaneous disorder, a spectrum of naevoid proliferative changes involving systemic organs may occur.

Child, Preschool↗
PubMed1981

Evaluation of acid alpha-naphthyl acetate esterase activity as a marker of T lymphocytes in benign and neoplastic cutaneous infiltrates.

Activity of the enzyme acid alpha-naphthyl acetate esterase (ANAE) in T lymphocytes and histiocytes in cutaneous tissue sections of patients with histologically confirmed lichen planus, chronic discoid eczema and mycosis fungoides was compared with results obtained using an in situ immunohistochemical technique employing an antiserum against the human T lymphocyte surface antigen (HTLA). In lichen planus and chronic discoid eczema, most of the cells in the cutaneous infiltrate exhibited both positive ANAE activity and the presence of HTLA. In mycosis fungoides, cells identified as T lymphocytes by the presence of HTLA often showed no ANAE activity. ANAE activity appears to be a useful marker of T lymphocytes in benign cutaneous infiltrates but is less reliable in labelling abnormal T cells.

Carboxylic Ester Hydrolases↗