Spindle epithelial tumor with thymus-like elements (SETTLE): a surgical case diagnosed preoperatively using fine-needle aspiration cytology

Summary Spindle epithelial tumor with thymic-like elements (SETTLE) is an extremely rare tumor that occurs primarily in the thyroid gland. Histologically, SETTLE is characterized by the presence of spindle-shaped epithelial cells and glandular structures. However, it is known that diagnosis via fine-needle aspiration cytology can be challenging. SETTLE predominantly occurs in younger individuals and has a less favorable prognosis compared to differentiated thyroid carcinoma. Therefore, ensuring accurate diagnosis and appropriate treatment is crucial. We encountered a case of spindle epithelial tumor with thymus-like differentiation in a 10-year-old patient for whom the preoperative diagnosis was successfully established through fine-needle aspiration cytology, which facilitated appropriate surgical resection. Comprehensive histopathological examination and immunohistochemical analysis are essential to ensure appropriate management and surveillance of SETTLE. Learning points A rare thyroid tumor, spindle epithelial tumor with thymic-like elements (SETTLE), was diagnosed preoperatively and treated surgically. SETTLE presents with characteristic histological features that must be recognized for accurate diagnosis. In addition, diagnosis through cytology is often challenging. The primary treatment for SETTLE is surgical intervention as radiotherapy and pharmacological treatments are generally not expected to be highly effective. Radical resection is the only effective treatment, making the selection of the surgical procedure according to the stage of the disease essential

Measurement of the Lifetime Difference in D0 Meson Decays

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研究速報 : 磁気ディスクアルミニウム基板加工用弗素樹脂多孔質真空チャックの開発 : 第1報 チャックとしての基礎特性

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The Market Structure and Pricing Process of Saw Timber of Locally Produced Broad Leaved Trees (I) : In Nara and Wakayama Prefectures

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Transfer RNAs used in this study.

<p>In order to reconstruct the early stages of the CUG identity alteration in <i>C. albicans</i>, <i>S. cerevisiae</i> leucine tRNAs containing the anticodons UAG or CAG were expressed in C. <i>albicans</i>. A) The respective tRNA genes were cloned into plasmid pUA12, which is based on the <i>C. albicans</i> pRM1 vector. B) A leucine tRNA gene containing the near-cognate anticodon (5′-UAG-3′) for the CUG codon was used as a low decoding efficiency tRNA (pUA13). C) Two tRNA_CAG^Leu genes, containing anticodons cognate for the CUG codon were used for higher CUG decoding efficiency, one contained G₃₃ (pUA14; medium decoding efficiency) and the other contained U₃₃ (pUA15; high decoding efficiency), in the anticodon-loop. D) The <i>S. cerevisiae</i> tRNA_AGA^Ser gene was used as negative control (pUA16).</p

Ambiguous CUG decoding induced mating.

<p>A) In pUA15 transformed cells, the number of opaque cells was very high. This phenotype is most likely explained by up-regulation of the white-opaque master regulator <i>WOR1</i> gene (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0000996#pone-0000996-g006" target="_blank">Figure 6</a>). Since <i>C. albicans</i> white cells (most common form) are mating incompetent and opaque cells (rare cells) are mating competent, we have verified whether pUA15 opaque cells formed conjugation tubes and mating figures in liquid culture. Both were readily observed using optical microscopy (white arrows). B) In order to confirm that mating occurred, the DNA content of pUA15 cells was analyzed by flow cytometry. Since <i>C. albicans</i> is diploid, 4N cells were expected. Surprisingly, higher ploidies (6N, 8N) were also observed suggesting that the cultures had significant number of aneuploid and poliploid cells. C) White to opaque transition and mating induced by CUG ambiguity occurs due to MTL homozygosity. Since mating requires transition from the heterozygotic mating locus (MTL a/α) found in white cells, to the homozygotic configuration (MTLa/a or MTLα/α) found in opaque cells, detection of αα/αα cells supported the hypothesis that CUG ambiguity induced mating.</p

Expression of <i>S. cerevisiae</i> tRNA^leu in <i>C. albicans.</i>

<p>A) Aminoacylation <i>in vivo</i> in <i>C. albicans</i> of <i>S. cerevisiae</i> tRNA_UAG/CAG^Leu and tRNA_AGA^Ser was monitored by Acidic Page and Northern Blot analysis. For this, total tRNAs were extracted under acidic conditions from pUA13, pUA14, pUA15, and pUA16 clones and fractionated on an acidic polyacrylamide gel, as described in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0000996#s4" target="_blank">materials and methods</a>. These gels separated deacylated (-AA) from aminoacylated tRNAs (+AA), which were detected using a tDNA_Leu/Ser probe labeled with [³²P]. B) Transformation efficiencies of plasmids encoding tRNA^Leu, which decoded the <i>C. albicans</i> serine CUG codons as leucine, was significantly lower that that of control plasmids (pUA12 and pUA16), indicating that the leucine tRNAs were slightly toxic. C) However, clones that survived the transformation procedure adapted readily to CUG ambiguity and showed growth rates similar to control clones (pUA12).</p

Ambiguous CUG decoding induced karyotype rearrangements and ploidy-shift.

<p>A) In ambiguous cell lines (pUA15) polyploidy was predominant and very high ploidy was often detected (>32N). Aneuploidy was also observed (6N). B) However, after plating cells several consecutive times on fresh agar chromosome numbers were reduced indicating that most cells returned to low ploidy (2N or 4N). Ploidy reduction after mating normally occurs by chromosome loss in <i>C. albicans</i> and it is likely that such mechanism also played a role in ploidy reduction in pUA15 transformed cells. C) CUG ambiguity also promoted extensive rearrangements of the R-chromosome (highlighted in white circles). Chromosomes were separated by PFGE on 0.6% agarose gels under the following conditions: 120–300 s for 24h at 80 V, then 420–900 s for 48 h at 80 V. The numbers 1–7 and R identify <i>C. albicans</i> chromosomes.</p

Reconstruction model for the <i>Candida</i> genetic code alteration.

<p>The ancestor of <i>Candida</i> decoded the CUG codon as leucine using a single leucine tRNA (tRNA^Leu). This situation changed dramatically with appearance 272±25My of a mutant serine tRNA that acquired a 5′-CAG-3′anticodon (tRNA_CAG^Ser). The latter competed with the tRNA^Leu for decoding of CUG codons, inserting both leucine and serine, at high level, at CUG positions, on a proteome wide scale. Such ambiguity decreased over time due to disappearance of the tRNA^Leu gene, however charging of the tRNA_CAG^Ser with leucine and serine prevented complete change of identity of the CUG codon from leucine to serine. In order to elucidate why CUG ambiguity was preserved in <i>C. albicans</i> and clarify whether CUG identity could be partially reverted from serine back to leucine, we have reconstructed the early stages of CUG identity change (high level of ambiguity) in <i>C. albicans</i> using <i>S. cerevisiae</i> tRNAs that decode CUG codons as leucine.</p

Increased CUG ambiguity up-regulated morphogenesis genes.

<p>Cells of pUA15 clones showed significant up-regulation of the <i>WOR1</i> (7.0±2.5) gene and hyphal-specific genes <i>CaHWP1</i> (41.76±9.96) and <i>HGC1</i> (2.64±1.12). Since <i>WOR1</i> increases the frequency of the white-opaque transition the very high percentage of opaque cells found in transformed clones may be a consequence of <i>WOR1</i> up-regulation. On the other hand, expression of the hypha-specific genes, <i>CaHWP1</i> and <i>CaHGC1,</i> supported the hypothesis that morphogenesis and hyphal growth triggered by CUG ambiguity resulted from expression of morphogenesis regulators. Induction of the <i>CaHWP1</i> gene was accompanied by repression of the <i>CaMCM1</i> (−1.84±0.44) gene, which controls cell morphology through the recruitment of other morphogenesis regulatory factors.</p