145 research outputs found

    An Update on Automatic Positioning, Inspection, and Signal Processing Techniques in the RFC/NDE Inspection System

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    This paper updates several techniques developed for the Retirement For Cause (RFC) Nondestructive Evaluation (NDE) Inspection System eddy current inspection module. Techniques to be discussed include: (1) Scallop Centering — development of an automatic scallop centering routine makes scallop inspections reliable.; (2) Soft Survey Mode — improvements have been made for fast peak detection.; (3) Method 2 Select Mode — a fine flaw detection technique based on the acquired waveform.; (4) Antirotation Window Inspection — a frequency select mode has been established for detecting flaws in antirotation windows.; (5) Scaling of Flaw Depth — a scaling factor has been developed, based on Phase I Reliability Test data, which converts flaw signal amplitude into estimated flaw depth

    Reduced Apaf-1 expression in human cutaneous melanomas

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    Malignant melanoma is a life-threatening skin cancer due to its highly metastatic character and resistance to radio- and chemotherapy. It is believed that the ability to evade apoptosis is the key mechanism for the rapid growth of cancer cells. However, the exact mechanism for failure in the apoptotic pathway in melanoma cells is unclear. p53, the most frequently mutated tumour suppressor gene in human cancers, is a key apoptosis inducer. However, p53 mutation is only found in 15–20% of melanoma biopsies. Recently, it was found that Apaf-1, a downstream target of p53, is inactivated in metastatic melanoma. Specifically, loss of heterozygosity (LOH) of the Apaf-1 gene was found in 40% of metastatic melanoma. To determine if loss of Apaf-1 expression is indeed involved in melanoma progression, we employed the tissue microarray technology and examined Apaf-1 expression in 70 human primary malignant melanoma biopsies by immunohistochemistry. Our data showed that Apaf-1 expression is significantly reduced in melanoma cells compared with normal nevi (χ2=6.02, P=0.014). Our results also revealed that loss of Apaf-1 was not associated with the tumour thickness, ulceration or subtype, patient's gender, age and 5-year survival. In addition, our in vitro apoptosis assay revealed that overexpression of Apaf-1 can sensitise melanoma cells to anticancer drug treatment. Taken together, our data indicate that Apaf-1 expression is significantly reduced in human melanoma and that Apaf-1 may serve as a therapeutic target in melanoma

    High-Level Expression of Wild-Type p53 in Melanoma Cells is Frequently Associated with Inactivity in p53 Reporter Gene Assays

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    Background: Inactivation of the p53 pathway that controls cell cycle progression, apoptosis and senescence, has been proposed to occur in virtually all human tumors and p53 is the protein most frequently mutated in human cancer. However, the mutational status of p53 in melanoma is still controversial; to clarify this notion we analysed the largest series of melanoma samples reported to date. Methodology/Principal Findings: Immunohistochemical analysis of more than 180 melanoma specimens demonstrated that high levels of p53 are expressed in the vast majority of cases. Subsequent sequencing of the p53 exons 5–8, however, revealed only in one case the presence of a mutation. Nevertheless, by means of two different p53 reporter constructs we demonstrate transcriptional inactivity of wild type p53 in 6 out of 10 melanoma cell lines; the 4 other p53 wild type melanoma cell lines exhibit p53 reporter gene activity, which can be blocked by shRNA knock down of p53. Conclusions/Significance: In melanomas expressing high levels of wild type p53 this tumor suppressor is frequently inactivated at transcriptional level

    Surgery and radiotherapy in the treatment of cutaneous melanoma

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    Adequate surgical management of primary melanoma and regional lymph node metastasis, and rarely distant metastasis, is the only established curative treatment. Surgical management of primary melanomas consists of excisions with 1–2 cm margins and primary closure. The recommended method of biopsy is excisional biopsy with a 2 mm margin and a small amount of subcutaneous fat. In specific situations (very large lesions or certain anatomical areas), full-thickness incisional or punch biopsy may be acceptable. Sentinel lymph node biopsy provides accurate staging information for patients with clinically unaffected regional nodes and without distant metastases, although survival benefit has not been proved. In cases of positive sentinel node biopsy or clinically detected regional nodal metastases (palpable, positive cytology or histopathology), radical removal of lymph nodes of the involved basin is indicated. For resectable local/in-transit recurrences, excision with a clear margin is recommended. For numerous or unresectable in-transit metastases of the extremities, isolated limb perfusion or infusion with melphalan should be considered. Decisions about surgery of distant metastases should be based on individual circumstances. Radiotherapy is indicated as a treatment option in select patients with lentigo maligna melanoma and as an adjuvant in select patients with regional metastatic disease. Radiotherapy is also indicated for palliation, especially in bone and brain metastases
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