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The crystal structures of the complexes (SP-4-2)-cis-bis[8-(dimethylphosphanyl)quinoline-κ2 N,P]nickel(II) bis(perchlorate) nitromethane monosolvate, [Ni(C11H12NP)2](ClO4)2·CH3NO2 (1), and (SP-4-2)-cis-bis[8-(dimethylphosphanyl)quinoline-κ2 N,P]platinum(II) bis(tetrafluoroborate) acetonitrile monosolvate, [Pt(C11H12NP)2](BF4)2·C2H3N (2), are reported. In both complex cations, two phosphanylquinolines act as bidentate P,N-donating chelate ligands and form the mutually cis configuration in the square-planar coordination geometry. The strong trans influence of the dimethylphosphanyl donor group is confirmed by the Ni—N bond lengths in 1, 1.970 (2) and 1.982 (2) Å and, the Pt—N bond lengths of 2, 2.123 (4) and 2.132 (4) Å, which are relatively long as compared to those in the analogous 8-(diphenylphosphanyl)quinoline complexes. Mutually cis-positioned quinoline donor groups would give a severe steric hindrance between their ortho-H atoms. In order to reduce such a steric congestion, the NiII complex in 1 shows a tetrahedral distortion of the coordination geometry, as parameterized by τ4 = 0.199 (1)°, while the PtII complex in 2 exhibits a typical square-planar coordination geometry [τ4 = 0.014 (1)°] with a large bending deformation of the ideally planar Me2Pqn chelate planes. In the crystal structure of 2, three F atoms of one of the BF4 − anions are disordered over two sets of positions with refined occupancies of 0.573 (10) and 0.427 (10).

Several series of platinum(II), palladium(II), and nickel(II) complexes bearing 8-(diphenylphosphino)quinoline (PQH) or its 2-methyl or 2-phenyl derivatives (PQMe or PQPh) were synthesized, and their crystal structures and behaviors in solution were investigated. Most of the complexes [M(PQR)2]X2 (MII = PtII, PdII, or NiII; R = H, Me or Ph; X = monoanionic ions) characterized in this study have an approximately square-planar coordination geometry with two bidentate P,N-chelating or monodentate P-donating quinolylphosphine ligands in the cis(P,P) configuration. A large steric requirement from the Me or Ph substituent introduced at the 2-position of the quinoline ring gives the resulting complexes severe distortion. The PtII and PdII complex cations maintained the square-planar coordination geometry, but the MII center was displaced from the chelating ligand plane. This bending of the chelate coordination makes the M-N(quinoline) bond weaker, as demonstrated by the longer M-N bonds. In accord with the bond weakening, the partial dissociation of the PQH or PQMe chelates by substitution with halide anions were observed using UV-vis spectroscopy and X-ray crystallography. In contrast, the PQPh complexes were stable in solution toward the addition of halide anions; the intramolecular π-π stacking interaction between the coordinating quinolyl and the 2-substituted phenyl rings protects the MII center from nucleophilic attack. In the corresponding NiII complexes, the steric congestion arising from the mutually cis-positioned PQR ligands resulted in a large tetrahedral distortion around the NiII center. However, the intramolecular π-π stacking interaction was still effective in the PQPh complex, and this interaction can explain some unusual robustness and electrochemical properties of the NiII-PQPh complex.

The steric requirement resulting from the substituted methyl or phenyl group at the ortho-position of the coordinating quinoline-N atom in 8-(di­phenyl­phosphan­yl)quinoline enforces the square-planar coordination geometry of the di­chlorido­palladium(II) center to be highly distorted., The crystal structures of di­chlorido­palladium(II) complexes bearing 2-methyl- and 2-phenyl-8-(di­phenyl­phosphan­yl)quinoline, namely, di­chlorido­[8-(di­phenyl­phosphan­yl)-2-methyl­quinoline-κ2 N,P]palladium(II), [PdCl2(C22H18NP)] (1) and di­chlorido­[8-(di­phenyl­phosphan­yl)-2-phenyl­quinoline-κ2 N,P]palladium(II), [PdCl2(C27H20NP)] (2), were analyzed and compared to that of the 8-(di­phenyl­phosphan­yl)quinoline (PQH) analogue (3). In all three complexes, the phosphanyl­quinoline moiety acts as a bidentate P,N-donating chelate ligand. In the PQH complex (3), the PdII center has a typical planar coordination environment; however, both the methyl- and phenyl-substituted phosphanyl­quinoline (PQMe and PQPh, respectively) complexes (1) and (2) exhibit a considerable tetra­hedral distortion around the PdII center, as parameterized by the τ4 values of 0.1555 (4) and 0.1438 (4) for (1) and (2), respectively. The steric inter­action from the substituted group introduced at the 2-position of the quinoline ring enforces the cis-positioned Cl ligand to be displaced from the ideal coordination plane. Also, the ideally planar phosphanyl­quinoline five-membered chelate ring shows a large bending deformation by the displacement of the PdII center from the quinoline plane. In addition, in the phenyl-substituted complex (3), the coordinating quinolyl and the substituted phenyl rings are not co-planar to each other, having a dihedral angle of 33.08 (7)°. This twist conformation prohibits any inter­molecular π–π stacking inter­action between the quinoline planes, which is observed in the crystals of complexes (1) and (2).

Owing to the intra­molecular steric hindrance between the mutually cis-positioned 8-(di­methyl­phosphan­yl)quinoline (Me2Pqn) ligands, the nickel(II) complex of cis-[Ni(Me2Pqn)2]2+ shows a remarkable tetra­hedral distortion of the NiII coordination geometry. In contrast, the corresponding platinum(II) complex of cis-[Pt(Me2Pqn)2]2+ exhibits a typical square-planar PtII coordination center, but large envelope-type distortions of the five-membered chelate planes are observed., The crystal structures of the complexes (SP-4-2)-cis-bis­[8-(di­methyl­phosphan­yl)quinoline-κ2 N,P]nickel(II) bis­(perchlorate) nitro­methane monosolvate, [Ni(C11H12NP)2](ClO4)2·CH3NO2 (1), and (SP-4-2)-cis-bis­[8-(di­methyl­phos­phan­yl)quinoline-κ2 N,P]platinum(II) bis­(tetra­fluoro­borate) aceto­nitrile monosolvate, [Pt(C11H12NP)2](BF4)2·C2H3N (2), are reported. In both complex cations, two phosphanyl­quinolines act as bidentate P,N-donating chelate ligands and form the mutually cis configuration in the square-planar coordination geometry. The strong trans influence of the di­methyl­phosphanyl donor group is confirmed by the Ni—N bond lengths in 1, 1.970 (2) and 1.982 (2) Å and, the Pt—N bond lengths of 2, 2.123 (4) and 2.132 (4) Å, which are relatively long as compared to those in the analogous 8-(di­phenyl­phosphan­yl)quinoline complexes. Mutually cis-positioned quinoline donor groups would give a severe steric hindrance between their ortho-H atoms. In order to reduce such a steric congestion, the NiII complex in 1 shows a tetra­hedral distortion of the coordination geometry, as parameterized by τ4 = 0.199 (1)°, while the PtII complex in 2 exhibits a typical square-planar coordination geometry [τ4 = 0.014 (1)°] with a large bending deformation of the ideally planar Me2Pqn chelate planes. In the crystal structure of 2, three F atoms of one of the BF4 − anions are disordered over two sets of positions with refined occupancies of 0.573 (10) and 0.427 (10).

The exact pathology of COVID-19 remains mostly unclear, and accurate epidemiological understanding and rapid testing are crucial to overcome this disease. Several types of nucleic acid tests (NAT) have been used in Japan, but information about the viral RNA load, determined by Ct values, of the patients is limited due to the small number of patients tested in each clinical institution and lack of standardization of the testing kits. We have been performing the qRT-PCR tests established by NIID, and the mean Ct value distribution of 62 cases, which are deemed “first-visit” patients, among the total of 88 positive cases tested in a 4-day window of early April, was 24.9 with SD=5.45. Recently approved antigen testing kits were also used in the same samples (62 positives) along with 100 negative cases, and it revealed the positive predictive value of 80.6% and negative predictive value of 100%, with an overall agreement rate of 92.6%. These results indicate that a certain number of patients with lower Ct values, existed in Japan when SARS-CoV-2 virus started to spread. The newly approved rapid antigen testing kit will be a useful tool to identify such populations rapidly.

Proteomic analysis requires protein tags that enable high-throughput handling; however, versatile tags that can be used in in vitro expression systems are currently lacking. In this study, we developed an insoluble protein tag, INSOL-tag, derived from human transcription factor MafG. The INSOL-tagged target protein is expressed in a eukaryotic in vitro expression system and recovered as a pellet following centrifugation at 19,000 × g for 20 min. Comparisons of the target protein recovery rates of GST-tag and INSOL-tag using 111 cytoplasmic proteins revealed a fourfold increase in the yield of INSOL-tagged proteins. Using 267 cancer antigens purified with INSOL-tag, we subsequently developed an INSOL-CTA array method, for profiling autoantibodies in sera of cancer patients. The detection limit of the array was approximately 11.1 pg IgG, and the correlation with ELISA was high (R2 = .993, .955). Moreover, when autoantibody profiling of digestive cancer patient sera was performed, antigen spreading was observed. These data suggest that INSOL-tag is a versatile tag that can insolubilize a wide range of target proteins. It is therefore expected to become a powerful tool in comprehensive protein preparation for protein arrays, antibody production, and mass spectrometry.

Targeted proteomics approaches are of value for deep and accurate quantification of protein abundance. Extending such methods to quantify large numbers of proteins requires the construction of predefined targeted assays. We developed a targeted proteomics platform-in vitro proteome-assisted multiple reaction monitoring (MRM) for protein absolute quantification (iMPAQT)-by using >18,000 human recombinant proteins, thus enabling protein absolute quantification on a genome-wide scale. Our platform comprises experimentally confirmed MRM assays of mass tag (mTRAQ)-labeled peptides to allow for rapid and straightforward measurement of the absolute abundance of predefined sets of proteins by mass spectrometry. We applied iMPAQT to delineate the quantitative metabolic landscape of normal and transformed human fibroblasts. Oncogenic transformation gave rise to relatively small but global changes in metabolic pathways resulting in aerobic glycolysis (Warburg effect) and increased rates of macromolecule synthesis. iMPAQT should facilitate quantitative biology studies based on protein abundance measurements.

Highlights: •Nobiletin is a polymethoxylated flavone that is abundant in citrus peels. •Nobiletin is a major constituent of the Citrus unshiu peel extract. •Nobiletin suppresses induction of NO and reduces iNOS expression in hepatocytes. •Nobiletin reduces the iNOS promoter activity and the DNA-binding activity of NF-κB. -- Abstract: Background: Nobiletin is a polymethoxylated flavone that is abundant in the peels of citrus fruits, such as Citrus unshiu (Satsuma mandarin) and Citrus sinensis. The dried peels of C. unshiu (chinpi) have been included in several formulae of Japanese Kampo medicines. Nobiletin may suppress the induction of inducible nitric oxide synthase (iNOS), which synthesizes the inflammatory mediator nitric oxide (NO) in hepatocytes. Methods: A C. unshiu peel (CUP) extract was prepared. Primary cultured rat hepatocytes were treated with the CUP extract or nobiletin in the presence of interleukin 1β (IL-1β), which induces iNOS expression. NO production and iNOS gene expression were analyzed. Results: High-performance liquid chromatography analyses revealed that the nobiletin content in the CUP extract was 0.14%. Nobiletin dose-dependently reduced the NO levels and decreased iNOS expression at the protein, mRNA and antisense transcript levels. Flavone, which does not contain any methoxy groups, also suppressed iNOS induction. Nobiletin reduced the transcriptionalmore » activity of iNOS promoter-luciferase constructs and the DNA-binding activity of nuclear factor κB (NF-κB) in the nuclei. Conclusions: The suppression of iNOS induction by nobiletin suggests that nobiletin may be responsible for the anti-inflammatory effects of citrus peels and have a therapeutic potential for liver diseases.« less

Locations of floods are not always known. Persons nearby for whom there is a possibility of danger due to flooding need information with which to predict flooding and to find refuge quickly and accurately. A Webbased Flood Monitoring System (FMS) using Google Earth and 3D GIS has been developed by employing Google Earth pro v. 6.0 and ArcGIS 10.0 (ESRI). The FMS provides a viewer for Windows PCs and smart phones. This viewer provides information consisting of digital elevation data from a 2 m Digital Surface Model (DSM) integrating 1:2500 digital topographic maps from the Geographical Survey Institute of Japan with official river information from the Ministry of Land, Infrastructure, Transport and Tourism of Japan and local river offices. It includes flood simulations and hazard maps from local governments. Users are able to download KML file data and/or Shape file data for private use. In addition, a reporting system for preregistered users who want immediate information has been prepared for alert and flood information.

The botulinum neurotoxin light chain (BoNT-LC) is a zinc-dependent metalloprotease that cleaves neuronal SNARE proteins such as SNAP-25, VAMP2, and Syntaxin1. This cleavage interferes with the neurotransmitter release of peripheral neurons and results in flaccid paralysis. SNAP, VAMP, and Syntaxin are representative of large families of proteins that mediate most membrane fusion reactions, as well as both neuronal and non-neuronal exocytotic events in eukaryotic cells. Neuron-specific SNARE proteins, which are target substrates of BoNT, have been well studied; however, it is unclear whether other SNARE proteins are also proteolyzed by BoNT. Herein, we define the substrate specificity of BoNT-LC/B, /D, and /F towards recombinant human VAMP family proteins. We demonstrate that LC/B, /D, and /F are able to cleave VAMP1, 2, and 3, but no other VAMP family proteins. Kinetic analysis revealed that all LC have higher affinity and catalytic activity for the non-neuronal SNARE isoform VAMP3 than for the neuronal VAMP1 and 2 isoforms. LC/D in particular exhibited extremely low catalytic activity towards VAMP1 relative to other interactions, which we determined through point mutation analysis to be a result of the Ile present at residue 48 of VAMP1. We also identified the VAMP3 cleavage sites to be at the Gln 59-Phe 60 (LC/B), Lys 42-Leu 43 (LC/D), and Gln 41-Lys 42 (LC/F) peptide bonds, which correspond to those of VAMP1 or 2. Understanding the substrate specificity and kinetic characteristics of BoNT towards human SNARE proteins may aid in the development of novel therapeutic uses for BoNT.

Production of proteins is an important issue in protein science and pharmaceutical studies. Numerous protein expression systems using living cells and cell-free methods have been developed to date. In these systems, a promising strategy for improving the success rate of obtaining soluble proteins is the attachment of various tags into target proteins based on empirical rules. This paper presents a method for the production of data-driven designed tags (DDTs) based on highly frequent sequence property patterns in an experimentally assessed protein solubility dataset in a wheat germ cell-free system. We constructed seven proteins combined with 12 kinds of DDTs (six for enhancing solubility and six for insolubility) at the N-terminal region as tags. Then we investigated their behavior using SDS-PAGE. Results show that three and four proteins respectively showed a trend toward solubilization and insolubilization, which indicates the possibility that the theoretically designed sequence can control protein solubility.

In automobiles, a suspension bush, a set of aluminum parts connected to each other via rubber, is mounted into the suspension members to link the body to the wheels, and realizes hard and soft mounts contributing both to the stabilization during high speed driving and to absorbing the shock from the road. However, decohesion of the aluminum part from the rubber occurs occasionally, arising from the interface corrosion of aluminum, which deteriorates the performance of the vehicle directly. In this study, effects of alloy composition and processing route on this kind of corrosion will be investigated. Also, development of a new corrosion test that shortens the time for the test will be attempted.

背景．癌性腹膜炎を伴う非小細胞肺癌に対してゲフィチニブが奏効したが，内服開始375日後に急性肺障害·間質性肺炎を発症した症例を経験した．ゲフィチニブ内服1年以降の発症はまれであり報告する．症例．患者は急性肺障害発症時72歳の男性．2004年7月癌性胸膜炎を伴う右肺腺癌と診断し，シスプラチン，ビノレルビン併用療法を5コース行った．その後S-1，シスプラチン併用療法を6コース行った．2007年4月癌性腹膜炎を併発し，腹水内の癌細胞にEGFR遺伝子変異（exon 19 deletion）を認めたため，2007年5月よりゲフィチニブ250 mg/日を開始した．2008年5月下旬より息切れを自覚，6月上旬の外来受診時，胸部X線で左肺野に網状陰影を認めた．胸部CTで左肺に非区域性びまん性にすりガラス陰影を認め，牽引性気管支拡張を伴っており，急性間質性肺炎と診断した．メチルプレドニゾロン1 g/日を3日間行ったが，診断後4日目に死亡した．

症例は52歳男性．右肺癌にて手術予定であったが，血小板数，プロトロンビン時間，活性化部分トロンボプラスチン時間は正常であるものの，鼻出血しやすいこと，また甥がvon Willebrand病の患者であることが判明した．精査にて出血時間5分30秒と延長，von Willebrand因子6％以下，血液凝固第VIII因子65.3％に低下しており，von Willebrand病と診断した．血液凝固第VIII因子とvon Willebrand因子の複合体製剤（Confact F）の投与により，出血時間は2分と短縮した．手術は気管支形成（楔状切除）を伴う右上葉切除および右下葉S6の一部の合併切除を行った．周術期を通して，Confact Fを投与した結果，出血はコントロール可能であった．

完全内臓逆位に合併した肺癌の切除例を経験したので報告する．症例は72歳男性．検診で右上肺野に異常陰影を指摘された．胸腹部CTにて胸腹部内臓の完全逆位を認め，さらに右肺上葉に3.5×3cm大の結節陰影を認めた．気管支鏡検査で扁平上皮癌と診断した．左気管支用のダブルルーメン気管支内チューブを用いて，分離肺換気を行い，右肺上葉切除術を行った．右肺は上・下葉に分葉し，肺動静脈は正常の鏡像を呈していた．

症例は67歳男性．既往歴として3年前に胃癌で内視鏡的胃粘膜切除術を受けている．FDG-PET検診で右肺門部に集積を認めた．CT検査で右下葉気管支に接して約2cmの腫瘤を認め，FDG-PETの集積部位と一致していた．腫瘤の増大を認め，悪性を否定できず，手術を行った．腫瘤は肺動脈に強固に癒着し剥離不可能であり，右下葉切除術と縦隔リンパ節郭清術を行った．低分化腺癌のリンパ節転移と病理診断した．郭清した上縦隔と気管分岐部リンパ節に転移を認めなかった．摘出した右肺下葉の検索にても癌病変を指摘できなかったが，腫瘍の免疫染色ではThyroid transcription factor-1陽性，Cytokeratin7陽性，Cytokeratin20陰性であった．原発性肺癌の肺門リンパ節転移の可能性が示唆された．

A 29-year-old man presented with a mass in the left lower lung field on a chest radiograph obtained during a medical checkup. Computed tomography revealed a tumor adjacent to the diaphragm. A sessile tumor measuring 10.5 x 8.5 x 4.5 cm arising from the parietal pleura was resected. The tumor was accompanied by several little tumors on the nearby diaphragm. Pathologically, the major tumor consisted of typical spindle-shaped cells with myxoid degeneration. There was no increased cellularity, cellular pleomorphism, or a high mitotic count. In immunohistochemical studies, the spindle cells showed positive staining for CD34 and were negative for bcl-2. The smaller tumors also consisted of myxoid degeneration. We diagnosed benign solitary fibrous tumor of the pleura with satellite tumors. We must be aware of the possibility of satellite tumors when we treat patients with a benign solitary fibrous tumor.

Asymmetric Anionic Polymerization of 1-Phenyldibenzosuberyl and 1-(2-Pyridyl)dibenzosuberyl Methacrylates and Chiral Recognition Ability of the Obtained Polymers

Satellite imagery of LANDSAT, SPOT, JERS-1 is used to estimate a water depth. Analgorithm for water depth mapping is used of Lyzenga algorithm. As bathymetry method for satellite imagery, we used a linear-regression method to obtain correlation R2 between water depth and estimated depth. The main purpose is to obtain the maximum R2 for each sensor and to obtain a contribution band for correlation. In this study, we analyze the relation between absolute water depth and remotely sensed data by linearregression, specially, STEPWISE method of SAS cluster. JERS-1/OPS is new sensors by NASDA, and which is used for the first analysis for bathymetry.

Stereospecific and asymmetric (helix-sense-selective) polymerization of 1-phenyldibenzosuberyl methacrylate (PDBSMA) was performed with radical and anionic initiators. A highly isotactic polymer having triad isotacticity greater than 97% was obtained by radical polymerization with (i-PrOCOO)2 at 40°C. The radical polymerization of PDBSMA in (+)- and (-)-menthol gave (-)-and (+)-polymers, respectively, whose optical activity is ascribed to the prevailing one-handed helical conformation of a polymer chain. The radical copolymerization of PDBSMA with a small amount of an optically active monomer, (+)-phenyl-2-pyridyl-o-tolylmethyl methacrylate, afforded an optically active copolymer with the prevailing one-handed helical structure of PDBSMA sequences. Asymmetric anionic polymerization of PDBSMA was carried out with the complex of N, N′-diphenylethylenediamine monolithium amide and a chiral ligand, (+)-1-(2-pyrrolidinylmethyl)pyrrolidine in toluene at −78°C. The obtained polymer was highly isotactic and optically active due to nearly 100% one-handed helical structure.

The botulinum neurotoxin light chain (BoNT-LC) is a zinc-dependent metalloprotease that cleaves neuronal SNARE proteins such as SNAP-25, VAMP2, and Syntaxin1. This cleavage interferes with the neurotransmitter release of peripheral neurons and results in flaccid paralysis. SNAP, VAMP, and Syntaxin are representative of large families of proteins that mediate most membrane fusion reactions, as well as both neuronal and non-neuronal exocytotic events in eukaryotic cells. Neuron-specific SNARE proteins, which are target substrates of BoNT, have been well studied; however, it is unclear whether other SNARE proteins are also proteolyzed by BoNT. Herein, we define the substrate specificity of BoNT-LC/B, /D, and /F towards recombinant human VAMP family proteins. We demonstrate that LC/B, /D, and /F are able to cleave VAMP1, 2, and 3, but no other VAMP family proteins. Kinetic analysis revealed that all LC have higher affinity and catalytic activity for the non-neuronal SNARE isoform VAMP3 than for the neuronal VAMP1 and 2 isoforms. LC/D in particular exhibited extremely low catalytic activity towards VAMP1 relative to other interactions, which we determined through point mutation analysis to be a result of the Ile present at residue 48 of VAMP1. We also identified the VAMP3 cleavage sites to be at the Gln 59-Phe 60 (LC/B), Lys 42-Leu 43 (LC/D), and Gln 41-Lys 42 (LC/F) peptide bonds, which correspond to those of VAMP1 or 2. Understanding the substrate specificity and kinetic characteristics of BoNT towards human SNARE proteins may aid in the development of novel therapeutic uses for BoNT.

Src family kinases (SFKs) are the earliest known family of tyrosine kinases and are widely thought to play essential roles in cellular signal transduction. Although numerous functional analyses have been performed, no study has analyzed the specificity of all SFKs on an equal platform. To gain a better understanding of SFK phosphorylation, we designed a high-throughput in vitro kinase assay on the subproteome scale using surface plasmon resonance. We reacted each of the 11 human SFKs with 519 substrate proteins, and significant phosphorylation was detected in 33.6% (1921) of the total 5709 kinase-substrate combinations. A large number of novel phosphorylations were included among them. Many substrates were shown to be phosphorylated by multiple SFKs, which might reflect functional complementarity of SFKs. Clustering analysis of phosphorylation results grouped substrates into 10 categories, while the similarity of SFK catalytic specificity exhibited no significant correlation with that of amino acid sequences. In silico predictions of SRC-specific phosphorylation sites were not consistent with experimental results, implying some unknown SRC recognition modes. In an attempt to find biologically meaningful novel substrates, phosphorylation data were integrated with annotation data. The extensive in vitro data obtained in this study would provide valuable clues for further understanding SFK-mediated signal transduction.

Appropriate resources and expression technology necessary for human proteomics on a whole-proteome scale are being developed. We prepared a foundation for simple and efficient production of human proteins using the versatile Gateway vector system. We generated 33,275 human Gateway entry clones for protein synthesis, developed mRNA expression protocols for them and improved the wheat germ cell-free protein synthesis system. We applied this protein expression system to the in vitro expression of 13,364 human proteins and assessed their biological activity in two functional categories. Of the 75 tested phosphatases, 58 (77%) showed biological activity. Several cytokines containing disulfide bonds were produced in an active form in a nonreducing wheat germ cell-free expression system. We also manufactured protein microarrays by direct printing of unpurified in vitro-synthesized proteins and demonstrated their utility. Our 'human protein factory' infrastructure includes the resources and expression technology for in vitro proteome research.

We present a case of non-Hodgkin's lymphoma after chemotherapy for a cancer of unknown origin. A 68-year-old man was hospitalized for hoarseness. Computed tomography(CT)scans showed a swelling of the superior mediastinal lymph node and a tumor of the right lobe of thyroid gland. Resection of the superior mediastinal lymph node and right hemithyroidectomy were performed. Pathological findings of the lymph node showed adenosquamous cell carcinoma, but no malignant lesion was found in the thyroid gland. Post-operative systemic survey failed to identify the origin of the adenosquamous cell carcinoma. Six courses of chemotherapy consisting of carboplatin and docetaxel were carried out. Seven months later, CT and positron emission tomography revealed swelling of the mediastinal lymph nodes and a tumor in the left abdominal tumor. An open biopsy of the abdominal tumor demonstrated non-Hodgkin's lymphoma, mature B cell type, follicular lymphoma, grade 1. Radiotherapy was done for the malignant lymphoma, and radiochemotherapy for the mediastinal lymph nodes. Seven months later, the patient died of systemic metastases of the adenosquamous cell carcinoma.

An abnormal anatomic structure of the thoracic inlet causing stenosis of the trachea is rare. This case report illustrates a man presenting tracheal stenosis caused by retrosternal ossification, and discusses its clinical significance and possible pathogenesis.