Color Doppler sonography of focal lesions of the skin and subcutaneous tissue.
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We evaluated with color Doppler sonography 71 visible and palpable nodules of the skin and subcutaneous tissue from 51 patients. The nodules were classified as avascular (type I), hypovascular with a single vascular pole (type II), hypervascular with multiple peripheral poles (type III), and hypervascular with internal vessels (type IV). Of the 32 malignant nodules, 9% showed a type I pattern, 50% had a type III pattern, and 41% had a type IV pattern; of the 39 benign nodules, 86% showed a type I pattern and 14% had a type II pattern. The sensitivity and specificity of hypervascularity in malignant lesions were 90% and 100%, respectively, whereas the sensitivity and specificity of hypovascularity in benign lesions were 100% and 90%, respectively. The authors conclude that color Doppler sonography is able to increase the specificity of ultrasonography in the evaluation of nodular lesions of the skin. (+info)
Cryosurgery for common skin lesions. Treatment in family physicians' offices.
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OBJECTIVE: To review the principles of use, common techniques, and effectiveness of cryosurgery for common skin lesions that can be treated by family physicians in their offices. QUALITY OF EVIDENCE: MEDLINE and the Cochrane Database controlled trials register (1998 version) were searched. Much of the evidence for the effectiveness of cryosurgery or cryotherapy is based on of cryosurgery for treating common warts, external genital warts, lentigines, and basal cell carcinomas. Many of the trials reviewed were conducted in specialty clinics and, therefore, the results might not apply accurately to family practice. MAIN MESSAGE: Evidence from case report and series suggests that cryosurgery is effective for actinic keratoses, seborrheic keratoses, dermatofibroma, keloids, molluscum contagiosum, and benign nevi. Randomized comparative trials show that, for external genital warts, cryosurgery is more effective than podophyllin treatment, better than or equal to trichloroacetic acid, but less effective than electrodesiccation or surgical removal. Prospective randomized trials of cryosurgery for common warts showed that weekly cryotherapy produced more rapid cures, but the overall cure rate depended on number of treatments. Two freeze-thaw cycles and paring before freezing improved the cure rate for plantar warts. (+info)
Morphological, histochemical, immunohistochemical, and ultrastructural characterization of tumors and dysplastic and non-neoplastic lesions arising in BK virus/tat transgenic mice.
(19/2324)
To study the role in AIDS pathogenesis of the human immunodeficiency virus type 1 (HIV-1) Tat protein, a transactivator of viral and cellular genes, we generated transgenic mice with a recombinant DNA containing BK virus (BKV) early region and the HIV-1 tat gene, directed by its own promoter-enhancer. DNA hybridization revealed that the transgene is stably maintained in all organs of transgenic mice as a tandem insertion in a number of copies ranging from 5 to 20 per cell. In addition, tat and BKV RNA were expressed in all tissues. Transgenic mice developed three types of lesions: 1) tumors, 2) hyperplastic and dysplastic lesions, and 3) non-neoplastic lesions. Tumors of different histotypes, such as lymphomas, adenocarcinomas of skin glands, leiomyosarcomas, skin squamous cell carcinomas, hepatomas, hepatocarcinomas, and cavernous liver hemangiomas, developed in 29% of transgenic animals. The majority of tumors were malignant, invasive, and producing metastases. Conversely, tumors of only two histotypes (lymphomas and adenocarcinomas of skin glands) appeared in control mice. Hyperplastic and dysplastic lesions were more frequent in transgenic than in control mice and involved the skin or its adnexes, the liver and the rectum, indicating multiple targets for the activity of the transgene. Pyelonephritis, frequently complicated with hydronephrosis, inflammatory eye lesions, and amyloid depositions represented the most frequent non-neoplastic lesions detected in transgenic mice. Many of the pathological findings observed in this animal model are comparable to similar lesions appearing in AIDS patients, suggesting a relevant role for Tat in the pathogenesis of such lesions during the course of AIDS. (+info)
Apc1638T: a mouse model delineating critical domains of the adenomatous polyposis coli protein involved in tumorigenesis and development.
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The adenomatous polyposis coli (APC) gene is considered as the true gatekeeper of colonic epithelial proliferation: It is mutated in the majority of colorectal tumors, and mutations occur at early stages of tumor development in mouse and man. These mutant proteins lack most of the seven 20-amino-acid repeats and all SAMP motifs that have been associated with down-regulation of intracellular beta-catenin levels. In addition, they lack the carboxy-terminal domains that bind to DLG, EB1, and microtubulin. APC also appears to be essential in development because homozygosity for mouse Apc mutations invariably results in early embryonic lethality. Here, we describe the generation of a mouse model carrying a targeted mutation at codon 1638 of the mouse Apc gene, Apc1638T, resulting in a truncated Apc protein encompassing three of the seven 20 amino acid repeats and one SAMP motif, but missing all of the carboxy-terminal domains thought to be associated with tumorigenesis. Surprisingly, homozygosity for the Apc1638T mutation is compatible with postnatal life. However, homozygous mutant animals are characterized by growth retardation, a reduced postnatal viability on the B6 genetic background, the absence of preputial glands, and the formation of nipple-associated cysts. Most importantly, Apc1638T/1638T animals that survive to adulthood are tumor free. Although the full complement of Apc1638T is sufficient for proper beta-catenin signaling, dosage reductions of the truncated protein result in increasingly severe defects in beta-catenin regulation. The SAMP motif retained in Apc1638T also appears to be important for this function as shown by analysis of the Apc1572T protein in which its targeted deletion results in a further reduction in the ability of properly controlling beta-catenin/Tcf signaling. These results indicate that the association with DLG, EB1, and microtubulin is less critical for the maintenance of homeostasis by APC than has been suggested previously, and that proper beta-catenin regulation by APC appears to be required for normal embryonic development and tumor suppression. (+info)
Clinical experience and results of a Sentinel Health Investigation related to indoor fungal exposure.
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This is a review of exposure conditions, clinical presentation, and morbidity of children and adults with indoor fungal exposure such as toxic Stachybotrys chartarum. Indoor exposure was characterized using different methods including microscopic, culture, cytotoxicity screening tests, and chemical analyses. Clinical case histories and physical and laboratory findings are presented of children (age < 18 years, n = 22; mean age 9 years; 60% females) and adults (age >18 years, n = 125; mean age 39 years, 67% females) who consulted an environmental health specialty clinic. In the pediatric patients' exposure history, widespread fungal contamination of water-damaged building materials with known toxic or allergic fungi was identified. Primarily disorders of the respiratory system, skin, mucous membranes, and central nervous system were reported. Some enumeration and functional laboratory abnormalities, mainly of the lymphatic blood cells, were observed, although no statistically significant differences were found. IgE or IgG fungi-specific antibodies, used as exposure markers, were positive in less than 25% of all tested cases. In an evaluation of a symptomatic girl 11 years of age (sentinel case investigation) living in an apartment with verified toxigenic fungi (i.e., S. chartarum), several health indicators showed improvement after exposure cessation. (+info)
Cutaneous T-cell lymphoma presenting as benign dermatoses.
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Cutaneous T-cell lymphoma, also known as mycosis fungoides, is a malignancy of the T helper (CD4+) cells. Diagnosis is difficult early in the course of this disease because it mimics several benign skin disorders, including eczema, psoriasis and contact dermatitis. Cutaneous T-cell lymphoma is also difficult to identify histologically, and multiple biopsies may be necessary to confirm the diagnosis. Treatment may require a combination of topical and systemic agents. Patients with limited skin disease have a good prognosis, but the prognosis is less hopeful in those with extracutaneous involvement. As the disease progresses, the normal T-cell population is eliminated, and the patient becomes significantly immunosuppressed. Infection is the primary cause of mortality in patients with cutaneous T-cell lymphoma. (+info)
Cladribine activity in adult langerhans-cell histiocytosis.
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Langerhans-cell histiocytosis (LCH) results from the accumulation of tissue histiocytes derived from the same progenitor cells as monocytes. Because cladribine is potently toxic to monocytes, we conducted a phase II trial of cladribine. Cladribine was administered to 13 LCH patients at 0.14 mg/kg per day by 2-hour intravenous infusion for 5 consecutive days, every 4 weeks for a maximum of six courses. Median age was 42 years (range, 19 to 72) and median pretreatment disease duration was 99 months (range, 6 to 252). One patient was untreated, one had received prior prednisone only, one prior radiation only, six prior radiation and chemotherapy, and four prior surgery, radiation, and chemotherapy. Seven patients had cutaneous involvement, six multifocal osseous, six pulmonary, two each with soft tissue and nodal involvement, and four had diabetes insipidus. Of 13 patients, 12 were evaluable for response and all for toxicity. After a median of three courses (range, 1 to 6), seven (58%) patients achieved complete responses (two pathologic and five clinical) and two (17%) patients achieved partial responses; overall response rate, 75%. Median response follow-up duration was 33 months (range, 1 to 65). Seven patients experienced grade 3 to 4 neutropenia. Only one patient had a documented infection, dermatomal herpes zoster. At a median follow-up of 42 months (range, 5 to 76), 12 patients remain alive and one patient has died. Thus, cladribine has major activity in adult LCH and warrants further investigation in both pediatric and adult LCH as a single agent and in combination with other drugs. (+info)
Immunohistological analysis of in situ expression of mycobacterial antigens in skin lesions of leprosy patients across the histopathological spectrum. Association of Mycobacterial lipoarabinomannan (LAM) and Mycobacterium leprae phenolic glycolipid-I (PGL-I) with leprosy reactions.
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The presence of mycobacterial antigens in leprosy skin lesions was studied by immunohistological methods using monoclonal antibodies (MAbs) to Mycobacterium leprae-specific phenolic glycolipid I (PGL-I) and to cross-reactive mycobacterial antigens of 36 kd, 65 kd, and lipoarabinomannan (LAM). The staining patterns with MAb to 36 kd and 65 kd were heterogeneous and were also seen in the lesions of other skin diseases. The in situ staining of PGL-I and LAM was seen only in leprosy. Both antigens were abundantly present in infiltrating macrophages in the lesions of untreated multibacillary (MB) patients, whereas only PGL-I was occasionally seen in scattered macrophages in untreated paucibacillary lesions. During treatment, clearance of PGL-I from granulomas in MB lesions occurred before that of LAM, although the former persisted in scattered macrophages in some treated patients. This persistence of PGL-I in the lesions paralleled high serum anti-PGL-I antibody titers but was not indicative for the presence of viable bacilli in the lesions. Interestingly, we also observed a differential expression pattern of PGL-I and LAM in the lesions of MB patients with reactions during the course of the disease as compared with those without reactions. In conclusion, the in situ expression pattern of PGL-I and LAM in MB patients may assist in early diagnosis of reactions versus relapse. (+info)