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Biomedical subjects

B R Nelson

Publications and source records attributed to B R Nelson.

At least 37 records · Page 2Linked to original sources
PubMed1994

Increased expression of stromelysin-3 in basal cell carcinomas.

We examined the expression of two groups of matrix metalloproteinases (MMPs), stromelysin and interstitial collagenase, in human skin cancer by northern blot analysis and in situ hybridization. Stromelysin-3 (ST-3) mRNA was overexpressed more than tenfold in 17 of 19 (89%) specimens of basal cell carcinoma (BCC) but in only three of 13 (23%) cutaneous squamous cell carcinomas (SCCs). Stromelysin-1 and -2 (ST-1/2) mRNA was overexpressed in three of 19 (16%) BCC and three of 13 (23%) SCC. Collagenase mRNA was overexpressed in nine of 19 (47%) BCC and three of 13 (23%) SCC. No mRNA for ST-3, ST-1/2, or collagenase was detected by northern analysis in 21 specimens of adjacent normal skin. Because of these findings, we examined the specific location of the ST-3 mRNA in BCC specimens by in situ hybridization. ST-3 mRNA was particularly abundant in the characteristic stroma adjacent to the invasive basaloid tumor islands of the BCC and absent in the malignant cells. Moreover, ST-3 mRNA was expressed and induced by phorbol ester treatment in adult dermal fibroblasts but not in keratinocytes. In vitro studies have shown that MMPs are involved in the degradation of extracellular matrix molecules. Our finding of ST-3 mRNA overexpression in 17 of 19 (89%) BCC specimens is consistent with a role for this molecule in local invasion of stroma by BCC. Our in situ hybridization data suggested that while ST-3 is not expressed by malignant basal cells themselves, these tumor cells may induce the expression of ST-3 in adjacent nonmalignant stromal elements such as fibroblasts.

Blotting, Northern↗
PubMed1994

Increased expression of matrix metalloproteinase-3 (stromelysin-1) in cultured fibroblasts and basal cell carcinomas of nevoid basal cell carcinoma syndrome.

Nevoid basal cell carcinoma syndrome (NBCCS), an autosomal dominant disorder, is characterized by the development of numerous cutaneous basal cell carcinomas (BCCs). To better characterize this disorder, we examined the expression of matrix metalloproteinase-3 (MMP-3; also known as stromelysin-1) in BCC tumor specimens, adjacent normal skin, and fibroblasts isolated from the normal-appearing skin of NBCCS patients. Three of three BCC tumors obtained from NBCCS patients overexpressed MMP-3 mRNA. In contrast, only 25% of BCC specimens in patients without NBCCS demonstrated overexpression of MMP-3 mRNA. Moreover, fibroblasts isolated and cultured from all nine uninvolved skin specimens of NBCCS patients overexpressed MMP-3 mRNA. MMP-3 mRNA was not detected or was detected at very low levels in normal skin and fibroblast cultures isolated from normal skin in nonsyndrome patients.

Amino Acid Isomerases↗
PubMed1994

Unusual basal cell carcinomas.

The typical features of basal cell carcinoma are well recognized. However, manifestations of uncommon and unusual basal cell carcinomas are less well known. In this review, unusual basal cell carcinomas are described based on their clinical characteristics, histologic appearance, behavior, and treatment.

Age Factors↗
PubMed1994

Clinical improvement following dermabrasion of photoaged skin correlates with synthesis of collagen I.

BACKGROUND AND DESIGN: The ability of superficial dermabrasion to improve clinical features of photoaged skin is well known, but the specific biological mechanisms involved are poorly understood. The so-called repair zone, as visualized by routine histologic examination, has been attributed to new collagen formation within the papillary dermis and may be responsible for clinical improvement following dermabrasion. We investigated molecular and histologic events occurring in dermabraded skin and correlated them with clinical improvement. Ten photoaged patients (mean age, 59 years) underwent facial dermabrasion to the level of the papillary dermis. Clinical severity of photoaging was graded in a blinded manner at baseline and 12 weeks after dermabrasion. Biopsy specimens obtained at baseline and 3 and 12 weeks after dermabrasion were analyzed histologically and by in situ hybridization for fibroblast procollagen I mRNA, immunohistologically and by Western blotting with a monoclonal antibody specific for the aminoterminal cleavage site of procollagen I. RESULTS: Masson's trichrome staining demonstrated an increase in collagen from baseline (as an upper dermal band in the dermabrasion "repair zone") at 3 and 12 weeks' postdermabrasion. Immunohistologic examination demonstrated papillary dermal fibroblast staining for procollagen I at baseline that increased by threefold at 3 weeks' postdermabrasion and by 1.5-fold at 12 weeks' postdermabrasion. Western blotting demonstrated an average-fold increase in pN collagen I of 4.2 +/- 1.5 at 3 weeks and of 2.7 +/- 0.7 at 12 weeks. By in situ hybridization, baseline levels of procollagen I mRNA in papillary dermal fibroblasts increased sixfold at weeks 3 and 12 postdermabrasion. Increase in procollagen I mRNA correlated with clinical improvement, ie, reduction in wrinkling. CONCLUSION: Superficial dermabrasion clinically improves photoaged skin, and this improvement correlates strongly with increased collagen I gene expression.

Aged↗
PubMed1994

Basic suture materials and suturing techniques.

There is a need for surgeons to be able to make a logical decision regarding which suture materials to use in a given clinical situation because the choice of wound-closure materials may make a difference in wound healing and the ultimate functional and cosmetic result obtained. This article will review the basic physical, handling, and tissue-reaction characteristics of commonly used suture materials. Basic suturing techniques are also reviewed. Knowledge of multiple suturing techniques provides versatility, individuality, and optimal closure of surgical wounds.

Absorption↗
PubMed1993

Merkel cell carcinoma.

Merkel cell carcinoma is a malignant neuroendocrine tumor with features of epithelial differentiation. Biologically aggressive, it may be difficult to diagnose and, particularly in its late stages, even more difficult to treat effectively. This article addresses what is known and what is still controversial about the histogenesis, diagnosis, and management of Merkel cell carcinoma and the structure and function of the Merkel cell from which it is believed to be derived. The incidence, clinical presentation and diagnosis, ultrastructure, immunocytochemistry, treatment, and prognosis of this tumor will be discussed.

Carcinoma, Merkel Cell↗
PubMed1993

Microcystic adnexal carcinoma.

Microcystic adnexal carcinoma is a rare cutaneous neoplasm characterized by invasive, relentless, and destructive local growth. The incidence of perineural invasion and tumor recurrence is high. We report two cases of microcystic adnexal carcinoma with typical clinical features. The use of formalin-fixed, paraffin-embedded horizontal Mohs sections is described in one case. We also review the current concepts and management of microcystic adnexal carcinoma.

Aged↗
PubMed1993

Histology and physiology of tissue expansion.

BACKGROUND: Tissue expansion is a concept based on the skin's natural ability to stretch in response to an underlying force. OBJECTIVE: The purpose of this article is to review the histological and physiological changes that occur within the soft tissue and underlying structures during tissue expansion. METHODS: An extensive search of the literature reviewing these changes is summarized herein. RESULTS: Conventional tissue expansion may result in epidermal hypertrophy, decreased dermal, muscle, and adipose thickness, and bone resorption. A vascular capsule and angiogenesis provides a highly vascular flap and improves flap viability. Few soft tissue changes occur during rapid tissue expansion. The ability of the skin to increase in surface area during conventional tissue expansion is primarily because of biological tissue creep. Rapid expansion may result from mechanical tissue creep. CONCLUSION: Many soft tissue changes occur during tissue expansion. Most of these changes return to the pre-expansion state over time following discontinuation of the expansion process.

Animals↗
PubMed1992

Squamous cell carcinoma of the skin (excluding lip and oral mucosa).

The striking impression obtained from reviewing the cancer literature is how difficult it is to analyze the data for answers to many important biologic, behavioral, prognostic, and therapeutic questions about squamous cell carcinoma of the skin. This article addresses current concepts, controversies, and management of cutaneous squamous cell carcinoma (excluding the lip and oral mucosa).

Carcinoma, Squamous Cell↗
PubMed1992

Soft tissue reconstruction with skin grafting.

Free skin grafts for soft tissue reconstruction can be classified into three types: full-thickness skin grafts, split-thickness skin grafts, and composite grafts. The indications, techniques, donor site considerations, and postoperative complications of each type of skin graft are reviewed.

Dermatologic Surgical Procedures↗
PubMed1992

Carbon dioxide laser treatment of actinic cheilitis. Clinicohistopathologic correlation to determine the optimal depth of destruction.

BACKGROUND: The carbon dioxide laser is an effective modality for the treatment of actinic cheilitis, but the number of passes required is unknown. After each pass different visual tissue qualities are observed. OBJECTIVE: Our purpose was to identify and characterize histologically the tissue zones seen after laser impact and thereby to determine the optimal depth of destruction of diseased tissue. METHODS: Twenty-three biopsy specimens from 14 patients were obtained from zones of different tissue qualities after one and three passes with the laser. Specimens were histologically examined for the presence or absence of diseased epithelium and degree of thermal necrosis. RESULTS: Complete destruction of the epithelial layer was observed in all specimens irrespective of the number of laser passes. The amount of dermal homogenization increased with multiple passes. CONCLUSION: Treatment to the first or second surgical zone is effective for actinic cheilitis.

Adult↗
PubMed1992

The paramedian scalp reduction with posterior Z-plasty. A technique to minimize the "slot" defect.

BACKGROUND: One consistent and undesired sequela resulting from scalp reductions has been the "slot" or "trough" defect, referring to the scar following the final reduction. Attempts to correct this have not been entirely satisfactory. OBJECTIVE: To present an approach to minimize the "slot" defect that consists of staged modified paramedian scalp reductions combined with a large posterior Z-plasty during the final reduction. METHODS: A paramedian crescent-shaped ellipse was marked onto the patient's scalp parallel and adjacent to the existing fringe hair. Subsequent reductions were performed in a similar manner approximately 2 months apart. The final reduction consisted of mobilization and transposition of the large flaps used in the posterior Z-plasty. RESULTS: Patients who underwent the staged modified paramedian reductions combined with a posterior Z-plasty had significant minimization and adequate camouflage of the undesirable "slot." CONCLUSION: Combining a large posterior Z-plasty with a paramedian reduction minimizes the slot defect.

Alopecia↗
PubMed1991

Treatment of keratoacanthomas with intralesional methotrexate.

Multiple modalities exist for the treatment of keratoacanthoma. Excisional surgery is currently the treatment of choice for the majority of keratoacanthomas. This can result in functional and cosmetic defects when large or strategically located lesions are treated. An effective nonsurgical treatment would be desirable in such cases. Intralesional therapy, particularly with 5-fluorouracil, has been shown to be effective in the treatment of keratoacanthomas. Systemic methotrexate has been tried, with variable success. We report an open, noncontrolled study of nine consecutive patients with unusually large or strategically located solitary keratoacanthomas treated successfully with intralesional methotrexate. All lesions responded promptly, with complete resolution after a mean of 3.0 weeks and a mean of 1.7 injections. No side effects occurred, and scarring was minimal. We concluded that intralesional methotrexate is a simple and effective modality for the treatment of select keratoacanthomas and may offer greater efficacy, a more rapid response, decreased pain, and lower cost compared with intralesional 5-fluorouracil.

Adult↗
PubMed1991

Incisional slit grafting.

Incisional slit grafting, a new and greatly improved technique in hair transplantation, is described. Incisional slit grafting utilizes larger numbers of smaller grafts than does traditional punch grafting. No tissue is removed from the recipient bed. The vascular supply is conserved, resulting in an increased graft yield. The clumping and stalking effect associated with traditional round grafting is eliminated largely, and a more natural frontal hairline is achieved.

Alopecia↗