smoking and the risk of venous thromboembolism (VTE) is an as-yet-unsolved clinical question. 10,11 Because VTE events occur after censoring the data to evaluate deaths caused by cancer or CVD, data regarding VTE events have not been counted and thus excluded from analysis. However, when VTE events are analyzed as the only outcome, heavy smoking is associated with provoked VTE. 12 Prevalence of Tobacco SmokingThe estimated global prevalence of tobacco smoking in 2010 was 36.6% for men and 7.5% for women. 13 In Japan, smoking prevalence rates in 2017 were 29.4% for men and 7.2% for women. 14 Although the average smoking rate in Japan has declined by half during the past 30 years, the rate among middle-aged men remains high, at approximately 40%. 14 This fact indicates that a high incidence of smokingrelated CVDs will continue for several more decades in Japan.
The microphthalmia (mi) locus encodes a member of the basic-helix-loop-helix-leucine zipper (bHLH-Zip) protein family of transcription factors (MITF). We have reported that expression of several genes was impaired in cultured mast cells (CMCs) of mi/mi mice due to a defective transactivation ability of mutant MITF (mi-MITF). We also found that mi/mi CMCs did not express a receptor (MC1R) for α-melanocyte-stimulating hormone. The overexpression of the wild-type (+/+) MITF but not mi-MITF normalized the expression of the MC1R in mi/mi CMCs, indicating the involvement of +-MITF in the MC1R gene expression. Next, we analyzed the promoter region of the MC1R gene by the transient cotransfection assay. The luciferase construct under the control of the MC1R promoter and the cDNA-encoding +-MITF or mi-MITF were cotransfected into NIH/3T3 fibroblasts. The cotransfection of +-MITF but not mi-MITF increased the luciferase activity. There were five CANNTG motifs recognized by bHLH-Zip-type transcription factors in the cloned promoter region. We found +-MITF bound two of five CANNTG motifs, and both motifs were essential for the transactivation of the MC1R gene by +-MITF. These results indicated that +-MITF directly transactivated the MC1R gene through these two motifs.
Reported herein is an unusual case of intrahepatic cholangiocarcinoma with lymphoepithelioma-like appearance in a 64-year-old man who was found to have an intrahepatic mass without cirrhosis. The tumor had two distinct histological patterns with dense lymphoplasmacytic infiltrate. The first was similar to nasopharyngeal undifferentiated carcinoma; the second pattern was a well-differentiated adenocarcinoma. Transition between the two components was observed in the same duct. Immunohistochemistry indicated that the tumor was immunoreactive with AE1/AE3 and cytokeratin (CK) 7, but negative for CEA and CK20. Stromal inflammatory infiltrate primarily consisted of plasma cells and lymphocytes. Immunohistochemical examination and in situ hybridization for EBV showed no integration of the virus in the tumor cells. Intrahepatic lymphoepithelioma-like carcinoma is rare, and most are associated with EBV. Only three cases were not associated with EBV. The authors would like to add one more example of the tumors not associated with EBV.
We evaluated the clonality of seborrheic keratoses using a polymorphism due to the random inactivation of one of two X chromosomes in females. Thirty-eight seborrheic keratoses obtained from the skin of females with polymorphism of the human androgen receptor (HUMARA) locus were examined by a fluorescent polymerase chain reaction procedure, which allowed accurate measurement of the peak intensities of each HUMARA allele. The epithelial portion of seborrheic keratosis and normal control epidermis adjacent to the seborrheic keratosis were removed by laser capture microdissection. As biopsied specimens of seborrheic keratoses contained small amounts of normal epidermis, the effect of digestion by a restriction enzyme (HhaI) recognizing the nonmethylated active sites was compared between seborrheic keratoses and normal control epidermis in only five seborrheic keratosis cases. Disappearance or significant reduction in intensity of one of two HUMARA alleles was observed after HhaI digestion in seborrheic keratoses, but not in the normal control epidermis. Although the skewing of the polymorphism was not corrected by the normal control epidermis in the remaining 33 seborrheic keratosis cases, one of two HUMARA peaks practically disappeared after HhaI digestion in 20 of 33 seborrheic keratosis cases. In total, 25 of 38 seborrheic keratoses were considered to be monoclonal. The histologic type of seborrheic keratoses did not affect clonality.
The receptor encoded by the W (c-kit) locus (W receptor) is expressed on the surface of cultured mast cells (CMC) derived from normal (+/+) mice, whereas its ligand encoded by the Sl locus (Sl ligand) is expressed on the surface of fibroblast cell lines derived from murine embryos. Involvement of W receptors and Sl ligands in attachment of CMC to fibroblasts was investigated. CMC were cocultured with fibroblasts; nonattaching CMC were removed and the remaining CMC were counted. CMC derived from mice of the W/W genotype did not express the extracellular domain of W receptors, and attachment of W/W CMC to +/+ fibroblasts was significantly impaired. Fibroblasts derived from embryos of the Sl/Sl genotype did not express Sl ligands, and the attachment of +/+ CMC to Sl/Sl fibroblasts was also impaired. The Wv and W42 alleles are point mutations at the intracellular tyrosine kinase domain. Attachment of either Wv/Wv, W/Wv, or W/W42 CMC to +/+ fibroblasts was comparable with that of +/+ CMC. Moreover, the addition of monoclonal antibody against the extracellular domain of W receptors inhibited the attachment of +/+ CMC to +/+ fibroblasts. Thus, the extracellular domain of W receptors appeared to be necessary for attachment of CMC to fibroblasts.
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