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Biomedical subjects

A Moreland

Publications and source records attributed to A Moreland.

8 recordsLinked to original sources

An SNP map of human chromosome 22.

The human genome sequence will provide a reference for measuring DNA sequence variation in human populations. Sequence variants are responsible for the genetic component of individuality, including complex characteristics such as disease susceptibility and drug response. Most sequence variants are single nucleotide polymorphisms (SNPs), where two alternate bases occur at one position. Comparison of any two genomes reveals around 1 SNP per kilobase. A sufficiently dense map of SNPs would allow the detection of sequence variants responsible for particular characteristics on the basis that they are associated with a specific SNP allele. Here we have evaluated large-scale sequencing approaches to obtaining SNPs, and have constructed a map of 2,730 SNPs on human chromosome 22. Most of the SNPs are within 25 kilobases of a transcribed exon, and are valuable for association studies. We have scaled up the process, detecting over 65,000 SNPs in the genome as part of The SNP Consortium programme, which is on target to build a map of 1 SNP every 5 kilobases that is integrated with the human genome sequence and that is freely available in the public domain.

Cell Line↗

Investigation of the potential use of immunosuppressive agent gliotoxin in organ transplantation.

Gliotoxin is an immunosuppressive secondary metabolite produced by several pathogenic fungi. It has previously been shown to prevent graft-versus-host disease in transplantation of allogeneic mouse bone marrow and to reduce the immunogenicity of human fetal pancreas. We here report on the effect of gliotoxin on the prevention of rejection of allografts in two distinct models. Bathing mouse thyroid tissue in gliotoxin solution for 16 hr prolonged graft survival following transplantation into allogeneic recipients. In contrast the perfusion of rat kidneys with gliotoxin followed by 1 hr of incubation before orthotopic transplantation had little success with preventing allograft rejection. This disparity is most likely due to the incubation in the renal model not allowing sufficient time for the elimination of antigen presenting cells in the donor organ. However, the success with the thyroid grafts demonstrates the potential of gliotoxin as an immunomodulating agent in organ transplantation and warrants further investigation in other systems.

Animals↗

HLA typing in polymorphous light eruption.

Human leukocyte antigen typing of 41 white patients with polymorphous light eruption (limited concept) showed no significant differences when compared with the typing of 51 white control subjects. We previously found that actinic prurigo, an idiopathic photodermatosis particularly associated with Amerindians, has a positive association with antigens A24 and Cw4 and a negative association with A3. We suggest, on the basis of both laboratory and clinical findings, that polymorphous light eruption (limited concept) and actinic prurigo are two different and distinct diseases.

Adolescent↗

Oral acanthosis nigricans: report of a case and comparison of oral and cutaneous pathology.

Malignant acanthosis nigricans is usually associated with adenocarcinomas of the digestive tract. The lesions of acanthosis nigricans commonly run a parallel course to the associated malignancy, producing hyperpigmented, roughened plaques on the skin and, sometimes, verruca-like papules on the oral mucosa. The clinical differences between cutaneous and oral acanthosis nigricans are mirrored by the marked differences in the histopathology. Because oral acanthosis nigricans is uncommon, recognizing histologic features may be difficult. The oral lesions have a true acanthosis and epithelial papillary hyperplasia while the cutaneous forms show slight irregular acanthosis that alternates with areas of epidermal atrophy and dermal papillomatosis.

Acanthosis Nigricans↗

T helper-suppressor cell imbalance in pyoderma gangrenosum, with relapsing polychondritis and corneal keratolysis.

We found decreased T helper/inducer and increased T suppressor/cytotoxic cells in a 45-year-old woman with pyoderma gangrenosum. Serum immunoglobulin levels were normal, suggesting that these T suppressor cells did not function primarily to regulate antibody synthesis. The patient had diminished cutaneous delayed hypersensitivity responses, reacting to only one of six antigens tested, but responded in vitro to three of three antigens. Because of their various regulatory functions, excess T suppressor cells, or a lack of T helper cells, could be a common factor underlying many of the humoral and cell-mediated immune derangements, as well as the neutrophil abnormalities, that have been found in pyoderma gangrenosum. Our patient also had relapsing polychondritis and corneal keratolysis, consistent with the systemic nature of the disorder. The T-cell imbalance persisted even as the ulcer improved. Since monoclonal antibodies against T cell subpopulations are readily available, measuring these cell types as part of the immunological workup of patients with pyoderma gangrenosum might yield valuable clues concerning the pathogenesis of this disorder.

Corneal Ulcer↗

Negative immunoperoxidase staining for lysozyme in nodular subepidermal fibrosis.

Nodular subepidermal fibrosis (NSF) is a clinical entity, the histogenetic origins of which remain unclear. More than 200 such lesions were examined with light microscopy and subdivided into four types based on their relative degree of cellularity. Five examples of each subtype were stained for lysozyme with the peroxidase-antiperoxidase technique. None of the 20 lesions contained cells with lysozyme. We conclude that the basic cell type in NSF is not lysozyme-containing macrophage; it is a different cell, perhaps one of mesenchymal origin.

Histiocytoma, Benign Fibrous↗