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M J Petersen

Publications and source records attributed to M J Petersen.

44 records · Page 3Linked to original sources
PubMed1986

Circulating activated (DR-positive) T lymphocytes in a patient with autoeczematization.

A patient with classical hypostatic dermatitis-related autoeczematization was found to have an elevated ratio of helper to suppressor T lymphocytes and increased circulating activated T cells in the absence of detectable levels of circulating interferon. Despite the high levels of activated T cells, peripheral blood mononuclear leukocytes did not produce interferon spontaneously in culture. These findings suggest that autoeczematization is a form of cell-mediated autoimmunity and that activated T cells and interferon production may be unrelated in vivo.

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PubMed1984

Development of a nude mouse model to study human sebaceous gland physiology and pathophysiology.

Study of human sebaceous gland physiology and pathophysiology is limited by lack of an adequate animal model. This study was designed to develop an animal model using human face skin grafted onto the nude mouse to study human sebaceous glands. Full-thickness human face skin was grafted onto 60 adult male nude mice. 4 wk after grafting, androgens, which are known to stimulate sebaceous glands, were administered to test the system. Androgens were administered to 21 animals by implanted catheters that were filled with testosterone (T) or dihydrotestosterone (DHT). Empty catheters were implanted in 15 control animals. Graft biopsies and blood for androgen levels were obtained at time 1 (pre-catheter) and time 2 (26 d after catheter implantation). Three assessments were made on each biopsy: sebaceous gland volume, using an image analyzing computer; sebaceous cell size; and sebaceous gland labeling index. 29 mice completed the study through time 2. In the androgen-treated group, T levels (nanogram per milliliter) five times increased to 4.92 +/- 0.35, and DHT levels (nanogram per milliliter) increased 50 times to 16.70. In the androgen-treated group, sebaceous gland volume (micron 3 X 10(-3) increased from 896 +/- 194 to 3,233 +/- 754 (P less than 0.001), sebaceous cell area (micron 2) increased from 167 +/- 12 to 243 +/- 19 (P less than 0.001), and labeling index (percentage) increased from 2.7 +/- 0.7 to 6.4 +/- 0.9 (P less than 0.01). In the control group, sebaceous gland volume fell from 1,070 +/- 393 to 417 +/- 99 (NS), sebaceous cell size remained the same, and the labeling index fell from 5.1 +/- 1.9 to 3.2 +/- 1.1. After androgen administration, Halowax N-34, a known comedogen, or its vehicle, was applied to 15 grafts for 2-6 wk. Twice as many microcomedones were seen in the Halowax-treated grafts, compared with vehicle-treated grafts at the end of this time period. No visible comedones were produced. This study demonstrated that: (a) human sebaceous glands can be successfully transplanted and studied on the nude mouse; (b) after androgen stimulation, sebaceous gland volume, cell size, and labeling index increase; (c) microcomedones can be produced in the human skin grafts by the application of a comedogenic substance. Thus, this model demonstrates significant potential for the future study of human sebaceous gland physiology and pathology.

Acne Vulgaris↗
PubMedDate not supplied

Could X-ray microbeams inhibit angioplasty-induced restenosis in the rat carotid artery?

BACKGROUND: Parallel, thin (<100 microm) planes of synchrotron-generated X rays, have been shown to spare normal tissues and preferentially damage tumors in animal models. The aim of the present study was to assess the effect of such microbeams directed unidirectionally on angioplasted rat carotid arteries. METHODS AND MATERIALS: Three groups of Sprague-Dawley rats were studied: (a) rats with normal, untreated arteries, (b) rats treated by balloon angioplasty, but not irradiated, and (c) rats treated with balloon angioplasty and exposed to single fraction, unidirectional, parallel, microbeams an hour after angioplasty. The microbeam array, 15 mm widex7.6 mm high, consisting of 27-microm-wide beam slices, spaced 200 microm center-to-center laterally traversed the damaged artery. The in-depth in-beam dose was 150 Gy, the "valley" dose (dose midway between microbeams resulting mainly from X-ray scattering) was 4.5 Gy on average, and the "integrated" (averaged) dose was 26 Gy. RESULTS: Microbeam irradiation, as given in the present study, was tolerated, but was insufficient to significantly suppress the neointimal hyperplasia. DISCUSSION: The microbeam dose used is considered low. Dose escalation would be necessary to reach conclusive results regarding the X-ray microbeam efficacy to control restenosis.

Angioplasty, Balloon↗
PubMedDate not supplied

Biologic aspects of expression of stably integrated transgenes in cells of the skin in vitro and in vivo.

The observation that transgenes can be stably integrated into the genome of fibroblasts using recombinant retroviruses enhanced interest in using these cells as a vector for gene therapy. This enthusiasm has lessened during the past 8 years, not because skin has lost the features that make it attractive for gene therapy, but rather because stable transgene expression in vivo has not been achieved. All investigators who have used genetically modified fibroblasts to study in vivo aspects of gene therapy have shown a decrease in transgene expression with time. This contrasts with transgene expression in similarly transduced fibroblasts in vitro, where expression is not lost or is lost very slowly. We have initiated an approach to bring further understanding to the biology of transgene expression by fibroblasts carrying stably integrated transgenes in an in vivo setting. Experiments described permit the following conclusions. Expression by and survival of genetically modified fibroblasts a) requires a persistent matrix scaffold in in vivo settings; b) is prolonged if the matrix is allowed to mature in vitro; c) is enhanced if the matrix is partially sequestered behind a coating of normal fibroblasts; and d) can be substantively prolonged in vivo by immortalizing the cells. These observations support the notion that prolonged expression of transgenes by fibroblasts can be achieved in vivo and that gene therapy utilizing fibroblasts and other cells of the skin has clinical utility.

Clone Cells↗
PubMedDate not supplied

Eosinophilic fasciitis occurring four weeks after the onset of dialysis in a renal failure patient.

BACKGROUND: Eosinophilic fasciitis is a rare, scleroderma-like disease that usually affects the extremities of young to middle-aged males. The disease may cause flexion contractures and limit joint mobility and is associated with peripheral eosinophilia. The fascia, by definition, is infiltrated with mononuclear cells and typically with eosinophils. Eosinophilic fasciitis may be separated from another sclerodermatous disorder, linear scleroderma, by its response to systemic corticosteroids. The etiology is unclear but eosinophilic fasciitis has numerous disease associations. However, it has not previously been associated with renal failure and hemodialysis. OBJECTIVE: This article reports a case of eosinophilic fasciitis occurring four weeks following the onset of hemodialysis. METHODS: The clinical and histologic features confirmed the diagnosis of eosinophilic fasciitis. He was treated with systemic corticosteroids with good response. CONCLUSION: This is the first reported patient who developed eosinophilic fasciitis in close temporal relationship with the start of hemodialysis. While eosinophilic fasciitis may be coincidental with a common disorder, namely, renal failure, it is interesting to note that hemodialysis patients often have immune-regulation abnormalities and peripheral eosinophilia.

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