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Biomedical subjects

D M MacDonald

Publications and source records attributed to D M MacDonald.

At least 199 records · Page 11Linked to original sources
PubMed1981

The antigenicity of trichophyton rubrum: In situ studies by an immunoperoxidase technique in light and electron microscopy.

The antigenic sites of cultured and invading Trichophyton rubrum can be located by using an immunoperoxidase technique in light and electron microscopy. The cell wall is identified as a major antigenic determinant in both cultured and invading T. rubrum and, in the cultured dermatophyte, other intracellular structures are also shown to be antigenic. The keratin immediately surrounding invading hyphae shows positive staining, suggesting the diffusion of dermatophyte-derived antigens, possibly keratinolytic enzymes.

Antigens, Fungal↗
PubMed1980

Ultrastructural identification of T lymphocytes in tissue sections of mycosis fungoides.

An immunoelectronomicroscopic method has been employed to demonstrate in situ the T lymphocyte nature of the dermal and epidermal infiltrates to mycosis fungoides. A specific antiserum to the human T lymphocyte surface antigen (HTLA) was used in an indirect reaction with a peroxidase labeled anti-immunoglobulin. After histochemically revealing the peroxidase activity, T cells were easily identified by the deposition of electron dense material on the cytoplasmic membrane. Counterstaining with uranyl acetate and lead citrate enabled us morphologically to observe the maturity of infiltrating T lymphocytes and to identify Sézary cells and other cells such as eosinophils in the infiltrate. Our results confirm the T cell nature of the dermal infiltrate in mycosis fungoides and show that the epidermal infiltrate of cells forming Pautrier micro-abscesses are predominantly T lymphocytes.

Adolescent↗
PubMed1980

Evaluation of staining methods of resin embedded cutaneous tissue sections of mycosis fungoides.

Biopsies from lesional skin of patients with histologically confirmed mycosis fungoides were embedded in resin and semi-thin ( I micrometer) sections were submitted to a variety of staining procedures, including Toluidine blue, Richardson's Huber, Giemsa, Paragon and Tribasic stains. The stained sections were examined with the light microscope and the quality of cellular morphological detail afforded by the different stains was assessed. The Toluidine blue, Richardson's and Paragon stains were found to be technically easy to perform and gave the best representation of nuclear and cytoplasmic detail Of these, the authors favoured Richardson's stain. The technique of processing the tissue, and staining a mounting procedures are detailed.

Adolescent↗
PubMed1980

Pagetoid reticulosis: a disease of histiocytic origin.

A patient with Pagetoid reticulosis has been investigated using standard transmission electron microscopy and an immunohistochemical technique for identifying T lymphocytes in situ in light and electron microscopy. Our results indicate that the majority of the cells in the underlying dermal infiltrate are T lymphocytes but that only very few T lymphocytes are found in the extensive epidermal infiltrate. Ultrastructurally the majority of the abnormal cells in the epidermis are of histiocytic origin.

Histiocytes↗
PubMed1980

Cutaneous cryptococcosis.

A 31-year-old woman with long-standing renal disease, treated with systemic steroids and azathioprine, developed progressive skin ulceration and subcutaneous nodules. A diagnosis of cryptococcosis was established after histological examination of a cutaneous lesion and confirmed by culture of the organism from the biopsy specimen. A detailed description of the histology and ultrastructure of the cutaneous lesion is presented. Treatment with parenteral amphotericin B and 5-fluorocytosine resulted in dramatic resolution of the skin lesions.

Adult↗
PubMed1979

Ultrastructure of the human mucocutaneous end organ.

The ultrastructure of the human mucocutaneous end organ is described. The corpuscle is divided into sublobular units comprising axon terminals surrounded by generally concentric lamellar processes which are derived from laminar cells whose nuclei are situated towards the periphery of the sublobules. Interlamellar substance which contains elastic tissue, collagen and coarse periodicity crossbanded structures intervenes between lamellar processes. Specialized zones of contact resembling desmosomes are found at intervals seemingly connecting adjacent lamellar processes and axons with lamellar processes. The ultrastructural features of this end organ are similar to that of the Meissner corpuscle despite minor differences of the light microscopical appearance, which supports the view that differences in sensory end organs are merely variations on a common organizational basis.

Aged↗
PubMed1979

Identification in situ of T lymphocytes in the dermal and epidermal infiltrates of mycosis fungoides.

Frozen tissue sections from the lesions of five patients with histologically proven mycosis fungoides were examined using a specific antihuman T-cell antiserum and an indirect peroxidase staining technique. The dermal and epidermal infiltrates were shown to comprise predominantly cells bearing the specific T-cell antigen, HTLA. Two of the patients exhibited characteristic Pautrier microabscesses whose cells were exclusively T lymphocytes.

Adult↗
PubMed1979

PUVA-induced repigmentation of vitiligo: a histochemical (split-DOPA) and ultrastructural study.

Repigmentation induced by oral photochemotherapy (8-MOP + UV-A) in four patients with vitiligo has been studied by histochemical and ultrastructural techniques. Hypertrophic melanocytes were demonstrated both in the middle and deep portions of the hair follicles in the centre of islands of repigmentation and also in the epidermis of the expanding repigmenting border. Mitosis of melanocytes was absent in these areas. Ultrastructural study showed that the melanocytes of repigmented areas were hyperactive. The melanosomes were larger than those of surrounding healthy skin, although the mode of packaging was unaltered. These observations suggest that melanocytes repigmenting vitiliginous skin under the influence of oral photochemotherapy are derived from a melanocytic reservoir localized in the hair follicles.

Adult↗