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Biomedical subjects

D I McLean

Publications and source records attributed to D I McLean.

At least 37 records · Page 2Linked to original sources
PubMed1995

Sunlight exposure, pigmentation factors, and risk of nonmelanocytic skin cancer. II. Squamous cell carcinoma.

INTRODUCTION AND DESIGN: Squamous cell carcinoma of the skin (SCC), a common cancer in white populations, is related to sunshine exposure; however, relatively little information is available on how timing and character of exposure affect the relationship. The purpose of this study was to investigate the nature of the relationship of SCC to individual solar UV exposure after control for phenotype and pigmentary factors. All newly diagnosed cases of SCC were in men aged 25 through 79 years, ascertained in the province of Alberta from January 1, 1983, through December 31, 1984, who were approached for participation; 80% completed a standardized etiologic interview that was conducted in their homes by a trained interviewer. Control subjects were chosen at random from the Alberta Health Care Insurance Plan subscribers list, matched only by sex (male) and age (within a 5-year age group). The response rate among controls was 71%. RESULTS: Subjects with pale skin and red hair had an elevated risk of SCC. Subjects whose mother was of southern European ancestry had a reduced risk of SCC. After accounting for pigmentary factors, no association was seen between risk of SCC and cumulative lifetime sun exposure. However, a strong trend toward increasing risk was seen with increasing chronic occupational sun exposure in the 10 years prior to diagnosis. CONCLUSION: The results suggest that recent sun exposure (in the 10 years prior to diagnosis) may be important in accounting for individual risk of SCC.

Adult↗
PubMed1993

A computerized autofluorescence and diffuse reflectance spectroanalyser system for in vivo skin studies.

A microcomputer-controlled spectroanalyser system has been set up to study optical properties of normal and abnormal human skin in vivo. The system can measure both tissue autofluorescence and diffuse reflectance at selected skin locations. The sample holder allows adjustment of the incident angle of the illumination light and the pick-up angle of the collected light providing the means to examine different depths of skin tissue. Using this system, we detected measurable skin autofluorescence with a maximum at about 470 nm when excited with 380 nm UV radiation. In this work, we also show that the absorption and scattering properties of the skin tissue (which can be determined from the measured diffuse reflectance spectrum) affect the shape of the autofluorescence spectrum. We believe that the combination of autofluorescence and diffuse reflectance measurements will lead to better understanding of the optical properties of normal and abnormal skin tissue.

Computer Systems↗
PubMed1991

Melanocytic nevus density in Asian, Indo-Pakistani, and white children: the Vancouver Mole Study.

Melanocytic nevus density in 378 Asian and 68 Indo-Pakistani school children 6 to 18 years of age was compared with that in 1146 white children of the same age range. At all ages, the number of melanocytic nevi 2 mm or larger per square meter of body surface area was substantially lower in Asians and Indo-Pakistanis than in white persons. Among white persons characteristics associated with a higher risk of cutaneous melanoma in adults, that is, light skin color, a propensity to burn rather than tan in the sun, and a history of numerous or severe sunburns, are also associated with the highest melanocytic nevus density in children. Examination of these same host pigmentation and sunburn factors among Asian children revealed no association with nevus density.

Adolescent↗
PubMed1990

Trends in basal cell carcinoma, squamous cell carcinoma, and melanoma of the skin from 1973 through 1987.

Major increases have occurred in the incidence of basal cell carcinoma and squamous cell carcinoma of the skin, as well as in cutaneous malignant melanoma during the period 1973 through 1987 in British Columbia. The greatest increases in basal and squamous cell carcinomas are on the head and neck. This indicates that exposure to sunlight is the major causative factor. The greatest increase in melanoma is on the trunk in men and on the lower limbs in women. The dramatic increases in nonmelanoma skin cancers in British Columbia, a relatively low sunlight area, suggest that major prevention programs are needed in areas that are not considered "sunspots."

Adolescent↗
PubMed1990

Cyclosporine in nonpsoriatic dermatoses.

This article reviews the indications, efficacy, and possible mechanisms of action of cyclosporine in the treatment of nonpsoriatic dermatoses. These dermatoses can be categorized according to their responsiveness to cyclosporine therapy as excellent, moderate, variable, and nonresponsive. The advantages and disadvantages of cyclosporine are discussed and guidelines are proposed for its use in nonpsoriatic dermatoses.

Cyclosporins↗
PubMed1990

Anatomic distribution of acquired melanocytic nevi in white children. A comparison with melanoma: the Vancouver Mole Study.

The presence of acquired benign nevi is a risk factor for cutaneous melanoma, yet relatively little is known about the etiology of nevi. We have conducted a study of the prevalence of melanocytic nevi among 1146 white Vancouver (Canada) schoolchildren aged 6 to 18 years. Numbers of nevi per square meter of body surface area increase with age in children of both sexes. Male adolescents have more nevi than female adolescents on the head and neck as well as on the trunk, while prevalence in females is higher on the upper and lower limbs. This distribution parallels that of cutaneous melanoma in British Columbia adults. Nevi are more common in children on intermittently exposed body sites than on constantly or minimally sun-exposed sites. This suggests that exposure to strong intermittent sunlight in childhood (a risk factor for cutaneous melanoma) may also be important in the etiology of acquired benign nevi.

Adolescent↗
PubMed1990

Suntan, sunburn, and pigmentation factors and the frequency of acquired melanocytic nevi in children. Similarities to melanoma: the Vancouver Mole Study.

The association between prevalence of benign melanocytic nevi and a number of skin cancer risk factors was examined among 913 white Vancouver (Canada) school children aged 6 to 18 years. Subjects with light skin, with a propensity to burn rather than tan in the sun, and with numerous or severe sunburns in the previous 5 years had significantly higher nevus counts than individuals without these characteristics. Subjects who acquired deeper tans tended to have fewer nevi than those who did not tan. Finally, children who freckled had higher nevus counts than those who did not freckle. These findings in children are similar to those seen in studies of malignant melanoma among adults and suggest that strategies to reduce melanoma incidence should begin with young children.

Adolescent↗
PubMed1989

Nuclear DNA, serum sialic acid and measured depth in malignant melanoma for predicting disease recurrence and survival.

In a previous multivariate analysis of 151 malignant melanoma patients we identified measured depth of primary lesion (Breslow) and serum N-acetyl-neuraminic acid (NANA) concentration as significant independent predictors of recurrence. Our present study examines the contribution of flow cytometric DNA analysis to prediction of recurrence and survival. Fixed, paraffin-embedded specimens of primary lesions were evaluated from 63 of the previously studied patients. These were prepared for DNA analysis. Of the 28 primaries identified as aneuploid 17 later recurred, while this was true for only 9 of the 35 diploid tumors. On multivariate analysis measured depth was again the most significant predictor of recurrence (p less than 0.001). Additional independent predictors were DNA ploidy (p = 0.02) and NANA (p = 0.05). For survival the independent predictors were measured depth (p = 0.003) and NANA (p = 0.05). Measured depth, DNA ploidy and NANA can be used to construct a model predicting the recurrence risk for stage-I melanoma.

Cell Nucleus↗
PubMed1984

Multiple melanomas occurring in a patient with xeroderma pigmentosum.

Xeroderma pigmentosum (XP) is associated with an increased frequency of cutaneous malignancies including malignant melanoma. We report a patient who developed eleven primary melanomas and numerous highly atypical nevi in addition to the basal cell carcinomas and squamous cell carcinomas more commonly seen in patients with XP.

Adult↗
PubMed1984

Tumors of ceruminous glands.

Tumors of the ceruminous glands may involve the auricular and preauricular skin and thus should be included in the differential diagnosis of neoplasms involving these areas. A rational decision as to the management of ceruminous gland tumors depends on the precise histologic classification of these tumors and the extent of involvement. We present seven patients with tumors of the ceruminous glands: ceruminous adenoma in one, ceruminous adenocarcinoma in three, and adenoid cystic carcinoma in three. The literature is reviewed with respect to signs and symptoms, pathology, and therapy.

Adenocarcinoma↗
PubMed1979

On the prognostic importance of white depressed areas in the primary lesion of superficial spreading melanoma.

The lesions of 163 patients with superficial spreading melanoma (SSM) were examined for the presence of white, depressed areas; and lesions with and without these areas of "regression" were compared. There was no statistically significant correlation with the histological level of invasion (Clark-Mihm), sex or age of the patient, location of the melanoma, or presence of local, intransit or regional lymph node metastases. It is apparent from examining the recurrence rate and patient survival, that white depressed areas in an SSM are not of prognostic importance. There was a striking correlation of the presence of white depressed areas with the size of the area covered by the malignant melanoma (p less than or equal to 0.001).

Adult↗
PubMed1978

Growth rate of cultured human fibroblasts increased by glucocorticoids.

Selected glucocorticoids have been demonstrated to increase the growth rate of human skin fibroblasts in culture, over a physiologically significant concentration range. At the same concentrations and identical conditions, the glucocorticoid compounds tested inhibited the growth rate of mouse L-929 cells. We have discussed currently acceptable theories of glucocorticoid mechanism of action that permit this dichotomous effect, the main point being that inhibition can no longer be regarded as the only response of fibroblasts to glucocorticoids. Conclusions drawn from observations of cell cultures affected by addition of glucocorticoids must have considered the source of the cells, as response may vary with source and biologic state of the cells in culture.

Adult↗