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Biomedical subjects

L From

Publications and source records attributed to L From.

At least 37 records · Page 2Linked to original sources
PubMed1993

Lymphocyte and macrophage subsets in active and inactive lesions of lichen planus.

Lichen planus (LP) is a mucocutaneous disease for which the etiology and pathogenesis are poorly understood. We performed an immunohistochemical study on formalin-fixed tissue sections of 10 cases of LP using subsets of antibodies to lymphocytes (LCA, CD3, OPD4-CD4, L26, LN1 and Leu-7), and monocyte-macrophages [lysozyme, KP1-Mac, Factor XIIIa (FXIIIa) and S-100 protein]. Six cases showed typical histological features of active LP, two cases showed features of active and inactive LP, and two cases showed only inactive LP. In active LP, scattered T cells (CD3+ and pan T cells) were present in the epidermis, whereas large numbers of CD3+ T cells were present at the dermoepidermal junction and in the dermis. Approximately 40% of the T cells at the dermoepidermal junction were of the helper/inducer subset, whereas approximately 80% of those in the dermis were CD4 positive (helper/inducer T cells). Occasional B cells were present in the dermis only. Increased numbers of S-100-positive Langerhans cells, macrophages expressing lysozyme, and FXIIIa dendritic cells were present in the epidermis and dermis. The inactive lesions showed the presence of a few epidermal Langerhans cells and a mild infiltrate of T cells (helper/inducer subset). These results suggest that in addition to different subsets of T cells and macrophages, including Langerhans cells, dermal dendritic cells expressing Factor XIIIa and lysozyme-positive histiocytes play an important role in lichen planus. They may participate in the destruction and subsequent regeneration of the basal layer of the epidermis, or alternatively may be activated as a result of destruction of the basement membrane in LP.

CD4-Positive T-Lymphocytes↗
PubMed1992

Use of host factors to identify people at high risk for cutaneous malignant melanoma .

OBJECTIVE: To determine which host characteristics are risk factors for cutaneous malignant melanoma in order to aim prevention and early detection programs at people at high risk. DESIGN: Case-control study. SETTING: Southern Ontario. SUBJECTS: The 583 case subjects were aged 20 to 69 years and had had malignant melanoma newly diagnosed between Oct. 1, 1984, and Sept. 30, 1986. The 608 control subjects were randomly selected from a list of residents in the study area and were stratum matched for age, sex and municipality. INTERVENTION: Through in-person interviews the interviewer ascertained exposure to putative external risk factors and assessed skin colour and number of nevi on the arm, and the subject reported his or her natural hair colour at age 20 years, eye colour, skin reaction to repeated sun exposure, and freckle and whole-body nevus densities. RESULTS: Although all the host factors mentioned were significantly associated with melanoma risk when considered separately, only hair colour, skin reaction to repeated sun exposure, and self-reported freckle and nevus densities remained significant after backward logistic regression analysis. The odds ratio for melanoma was estimated to be 10.7 in people who had many nevi compared with those who had none (95% confidence interval [CI] 6.6 to 17.4), 4.0 in people who had red hair compared with those who had black hair (95% CI 1.9 to 8.2), 1.9 in people who had many freckles compared with those who had none or few (95% CI 1.3 to 2.8) and 1.4 respectively in people who burned and had a subsequent increase in tan and those who burned and had no increase in tan after repeated sun exposure compared with those who did not burn [corrected]. CONCLUSIONS: Four risk factors for malignant melanoma have been identified. Prospective evaluation of their predictive value should be done. In the meantime, however, these factors should be used to identify people apparently at high risk for malignant melanoma, who can then be targeted for early detection and prevention programs.

Adult↗
PubMed1992

The association of cutaneous malignant melanoma and fluorescent light exposure.

Data are presented from an interview case-control study (583 cases and 608 controls), performed in southern Ontario, Canada, from October 1984 to September 1986, on the association of cutaneous malignant melanoma with exposure to fluorescent light. Males showed a significant trend with cumulative years of occupational exposure and with various indices of exposure to domestic fluorescent light. The risk was more pronounced for lesions on the arms and for superficial spreading melanomas. There was no consistent association in females. These effects were similar when adjusted for other major risk factors for melanoma, including the amount of time spent outdoors occupationally. Comparisons of melanoma cases interviewed before or after diagnosis revealed no evidence of rumination bias. Comparisons of sample data from the same cases and controls by interview and mail questionnaire showed reasonable levels of reliability with no evidence of recall bias. A small sample of subjects was also selected for exposure validation with employers; this revealed very accurate recall of occupational exposure. On the basis of these results, previous epidemiologic studies, and clinical and animal evidence, the authors conclude that fluorescent light exposure remains a potential risk factor for melanoma.

Adult↗
PubMed1992

Lymphocyte markers on formalin-fixed tissue in Jessner's lymphocytic infiltrate and lupus erythematosus.

Clinical and histological differentiation between Jessner's lymphocytic infiltration of the skin (JLI) and lupus erythematosus (LE) may be difficult. Previous immunohistochemical studies using monoclonal antibodies on frozen sections have shown that the majority of inflammatory cells in JLI and LE are T lymphocytes, whereas B lymphocytes are few or absent. We have performed an immunohistochemical study on formalin-fixed, paraffin-embedded tissue sections from seven patients with JLI and five with LE using monoclonal antibodies MT1 (pan T-cells), OPD4 (helper/inducer T-cells CD4), MT2 (mantle zone B and some T-cells), MB2 (pan B-cells), L26 (pan B-cells), and LN1 (germinal centre B-cells). In both diseases, the-majority of the inflammatory cells were T lymphocytes (MT1 positive), confirming the results others have obtained on frozen material. OPD4 positive cells were detected in varying numbers in all cases. However, the percentage of B lymphocytes tended to be higher in JLI than LE. LN1 was the most useful B-cell marker in distinguishing JLI from LE. However, a combination of MT2 and LN1 gave the most significant difference. We conclude that immunohistochemical analysis using a panel of monoclonal antibodies to T and B lymphocytes may be useful in differentiating JLI from LE, although there is still considerable overlap.

Adult↗
PubMed1992

Hypertrophic lichen planus of the oral mucosa.

Hypertrophic lichen planus is a variant of the condition not previously recognised as occurring in the mouth. Four cases are described that have been followed clinically for 18, 9, 6 and 3 years. The histopathology is described.

Adult↗
PubMed1991

Lymphadenosis benigna cutis resulting from Borrelia infection (Borrelia lymphocytoma).

Swelling and erythema of the right pinna developed in a 7-year-old girl. Six months later a biopsy specimen showed a dense, diffuse lymphoplasmacytic infiltrate involving most of the dermis except for a thin Grenz zone. The appearance was consistent with lymphocytoma cutis. She had been bitten by a tick on the right ear in Switzerland 6 weeks before the onset of the lesion. Serologic tests by enzyme-linked immunosorbent assay for Borrelia burgdorferi, done 6 and 11 months after the bite, yielded optical density readings of 1.04 and 0.65, respectively; indirect immunofluorescence yielded titers of 1:256 and 1:128. A Borrelia-like organism was identified by a modified Steiner stain; immunohistochemistry was noncontributory. The spirochetal origin of lymphadenosis benigna cutis is briefly reviewed.

Antibodies, Bacterial↗
PubMed1991

Lysozyme in abnormal dermal elastic fibers of cutaneous aging, solar elastosis and pseudoxanthoma elasticum.

Staining of elastic fibres with antilysozyme antibodies has been noted previously. In this study, we examined the staining pattern of dermal elastic fibres in aging, solar elastosis, and lesional skin of pseudoxanthoma elasticum (PXE) using an antibody to lysozyme and the indirect-peroxidase technique. To assess the effects of aging, sun-protected skin (buttock) from a younger and an older group of patients was used. Sun damage was studied in skin specimens from varying sun-exposed body regions (trunk; head and neck). No staining was seen in sun-protected skin from younger individuals, whereas sun-protected skin from older persons had scattered positive fibres. Solar elastotic material was intensely positive and the number of positive fibres appeared to correlate with the amount of sun damage. Abnormal elastic fibres in PXE also stained positively, but less intensely, than fibres in solar elastosis. This study shows that changes in the elastic fibres due to degenerative processes or genetic factors results in altered antigenic expression of the fibres. This may be an epiphenomenon secondary to changes in proteoglycans, which are known to occur with solar elastosis and PXE, or may represent an adaptive phenomenon to maintain the elastic properties of the altered fibres or to decrease their antigenicity.

Adolescent↗
PubMed1991

Immunohistochemical demonstration of actinically damaged elastic fibers in keratoacanthomas: an aid in diagnosis.

The inclusion of elastic fibers within the epithelium of keratoacanthomas is a phenomenon suggested to be an aid in differentiating this lesion from squamous cell carcinoma. Antilysozyme antibodies have recently been noted to stain actinically damaged elastic fibers but not those from sunprotected skin. In this study, 54 keratoacanthomas and 46 squamous cell carcinomas were stained with a histochemical elastic tissue stain and polyclonal antibody to lysozyme using an immunoperoxidase technique. Elastic fibers were demonstrated in keratoacanthomas (37/54, 68%) significantly more often than squamous cell carcinomas (12/46, 26%) (p less than 0.001) using both techniques. This study confirms that the inclusion of elastic fibers occurs significantly more often in keratoacanthomas than squamous cell carcinomas. These elastic fibers were also actinically damaged, suggesting a role for sun damage in the evolution of keratoacanthoma.

Adult↗
PubMed1991

Poorly differentiated skin tumors. Beyond hematoxylin-and-eosin staining.

Although many tumors may be diagnosed by light microscopy alone, a few require further investigation. Selective use of antibodies by immunohistochemical techniques solves most diagnostic problems. The explosive discovery of many new antibodies often raises more questions than it answers, and electron microscopy still plays a significant role when used judiciously. It is important to recognize that every new antibody must be adequately assessed in the clinical situation and that its specificity, or lack thereof, is appreciated by both clinician and pathologist. With every new antibody, we increase our knowledge of basic disease processes. In the future, antibodies will be part of the pathologist's armamentarium for predicting disease outcomes. Not only will the cell of origin be identified but proliferation rates and production of various factors that influence metastatic potential will be delineated.

Humans↗
PubMed1990

Absence of estrogen receptors in dysplastic nevi and malignant melanoma.

Benign nevi, dysplastic nevi, and primary and metastatic malignant melanomas were evaluated for the presence of sex hormone binding and estrogen receptor protein. We have confirmed the observation of Ellis et al. that some pigmented lesions possess sex hormone-binding proteins. We could not demonstrate a true estrogen receptor in any benign nevi, dysplastic nevi, primary melanomas, or metastatic melanomas. Thus the ability to bind estrogen or progesterone does not correlate with the presence of a true estrogen receptor. Lack of nuclear estrogen receptors suggests that the influence of estrogen on the pathophysiology of melanoma or of benign melanocytic nevi may not be significant.

Dysplastic Nevus Syndrome↗
PubMed1990

The association of cutaneous malignant melanoma with the use of sunbeds and sunlamps.

Data are presented from a large case-control study (583 cases, 608 controls) to estimate the association of melanoma with the use of sunbeds and sunlamps. Odds ratios of 1.88 and 1.45 were found for ever having used a sunbed or sunlamp in males and females, respectively, which was statistically significant in males and of borderline significance in females. These effects persisted when adjustments were made for age and a variety of potential confounders. The effect was slightly stronger for lentigo maligna and for lesions of the face, head, neck, and arms. The risk was greater and significant for both sexes for domestic use of sunbeds/sunlamps, and increased with duration and amount of use. A comparison of 43 cases interviewed before a diagnosis of melanoma had been made with the other 540 cases suggests that recall bias was not responsible for the association. The authors conclude that use of artificial tanning devices appears to be a risk factor for melanoma.

Adult↗
PubMed1989

Palisaded encapsulated neuroma: an immunohistochemical study.

Ten palisaded neuromas of the skin were studied immunohistochemically for the presence of S-100 protein, epithelial membrane antigen, neurofilaments, glial fibrillary acidic protein, and positivity with the Leu-7 monoclonal antibody. In all cases, the fascicles of tumor cells were positive for S-100 protein and negative for epithelial membrane antigen; the tumor capsules were negative for the former in all cases but positive for the latter in seven of ten cases. In three lesions, epithelial membrane antigen-positive cells formed sheaths around fascicles of tumor cells. Axons were demonstrated by anti-neurofilament antibody in seven lesions. None of the lesions stained for glial fibrillary acidic protein. All of them showed positivity with the Leu-7 antibody, which stained both tumor spindle cells as well as membranous profiles consistent with myelin sheaths. These results indicate that the tumor is composed of cells of schwannian differentiation whereas the capsule and sheaths surrounding intratumoral fascicles are of perineurial origin. They also indicate the presence of axons, some of which are myelinated. Our findings support the concept of a close relationship between palisaded and traumatic neuroma.

Adult↗
PubMed1989

Palisaded encapsulated neuromas. A clinicopathologic study.

Reed et al described the clinical and light-microscopic findings of palisaded encapsulated neuromas in 1972, but few cases have been reported since. We have studied 81 consecutive tumors. Clinically, these were solitary, asymptomatic, 2- to 6-mm, flesh-colored papules, usually located on the face of middle-aged patients. The correct diagnosis was rarely made; the lesion was most often mistaken for a basal cell epithelioma, melanocytic nevus, or other benign tumor. Light microscopy revealed single or multiple encapsulated dermal lobules composed of interlacing Schwann cells. Variable numbers of fine axons and myelin sheath remnants were present. Palisading of nuclei was not a prominent feature. Electron microscopy demonstrated substantial numbers of class C fibers (mostly nonmyelinated) only partially enveloped by Schwann cell cytoplasm. Pathologically, palisaded encapsulated neuromas are distinctive true neuromas resembling those seen in the multiple mucosal neuroma syndrome. Electron-microscopic findings are similar to those seen in peripheral nerve regeneration, suggesting that palisaded encapsulated neuromas may be traumatic in origin, and could represent regeneration following local minor injury to the skin.

Adult↗
PubMed1987

Cutaneous ultrastructural changes and photosensitivity associated with amiodarone therapy.

Amiodarone, an antiarrhythmic agent, is known to cause photosensitivity and cutaneous hyperpigmentation. Five patients taking this drug for periods of 1 to 48 months were studied. Skin biopsy specimens taken from a sun-exposed site were assessed by light microscopy, electron microscopy, and direct immunofluorescence. Three patients allowed comparative studies to be done on a biopsy specimen from non-sun-exposed skin. Light microscopy findings, including special stains, were not diagnostic of amiodarone-associated cutaneous changes. Electron microscopy, however, displayed distinctive intracytoplasmic inclusions in many cell types, some of which have not been reported previously. These inclusions represent phospholipid membranes associated with amiodarone or its metabolites as the result of a drug-induced lipidosis. Previous reports had postulated the inclusions were lipofuscin. Sun exposure may accelerate the formation of these intracellular deposits because they are more prominent in sun-exposed skin. Four of the above five cases, plus two additional patients, had symptoms compatible with a photosensitivity. Porphyrin assays were normal. Of the six patients phototested, three showed acute reactions to ultraviolet A (UVA) and ultraviolet B (UVB) and significant delayed reactions to UVA and/or UVB. The patients who had normal phototesting were on the drug for shorter periods than those with positive tests.

Adult↗
PubMed1987

Lymphomatoid granulomatosis.

The clinical and pathologic appearance of seven patients with lymphomatoid granulomatosis who had skin lesions when first seen is reviewed. Six patients subsequently developed systemic disease. Although the gross morphology of the skin lesions is variable, the pathology is distinctive. An adequate deep biopsy shows the characteristic lymphohistiocytic infiltrate with variable numbers of atypical cells. Angiodestruction is less evident in the skin compared to other organs. The infiltrate surrounds and invades not only vessels but also nerves and epidermal appendages. The skin biopsy specimen can be differentiated from the lymphomatous infiltrates and Wegener's granulomatosis. Two of the patients who developed systemic disease were diagnosed by skin biopsy but clinicians failed to institute therapy, preferring to wait for other organ involvement. In addition, two patients developed lymphoma, one of which was confirmed at autopsy and one on subcutaneous and bone marrow biopsy 5 years after the initial skin diagnosis. Lymphomatoid granulomatosis can be diagnosed by performing a skin biopsy. Appropriate chemotherapy may result in a high percentage of complete remissions and therefore the dermatopathologist can play an important role in the early diagnosis of this potentially fatal disease.

Adult↗
PubMed1987

Observer perception of skin color in a study of malignant melanoma.

Observer perceptions of skin color with a 15-step skin tone panel were evaluated during an as yet unpublished case-control study of malignant melanoma. Skin color is a risk factor for melanoma, and the skin tone panel was introduced in an effort to reduce its misclassification. Reflectances of the 15 artificial skin tones were measured at four wavelengths with a reflectance spectrophotometer. Six observers each evaluated the skin color of eight study subjects twice under three lighting conditions, and the results were transformed to reflectance values. Components of variance analysis demonstrated that between-subject variability contributed 63% or more of the variance at wave-lengths of 400-600 nm, while observers, light source, observation time, and error contributed 30% or less. At 700 nm, only 25.5% of the variance was due to subjects, indicating lower levels of reliability. Similarly, the correlation of visual and spectrophotometric assessment of skin reflectance was higher at 400-600 nm (r = 0.63-0.71) than at 700 nm (r = 0.41). Thus, the value of the skin tone panel-based assessments depends upon knowledge of which wavelengths most closely relate to the physiologic risk factor. For instance, reflectance at 650-700 nm is a better measure of skin melanin content than reflectance at lower wavelengths. Since the role of melanin as a risk factor remains in doubt, the utility of this technique has yet to be demonstrated. However, data from the case-control study and from this validity and reliability study will allow us to develop an analytic approach that minimizes misclassification of skin color as a confounder.

Analysis of Variance↗