Acute exacerbation of pleuroparenchymal fibroelastosis with lower lobe usual interstitial pneumonia: An autopsy case.

An 87-year-old man presented with dyspnea. Computed tomography revealed progressive subpleural consolidation in the apex, reticular shadows in the lower lobes, and bilateral ground glass opacifications. He died of respiratory failure on day 3. The post-mortem examination showed exudative stage diffuse alveolar damage and pulmonary edema. Intraalveolar collagenous fibrosis and subpleural elastosis were observed in the upper lobes, accompanied by interlobular septal and pleural thickening and lung architecture remodeling in the lower lobes. He was diagnosed with acute exacerbation of pleuroparenchymal fibroelastosis with lower lobe usual interstitial pneumonia, which can be fatal.

Venous Stent Placement for Malignant Vena Cava Syndrome in a Patient with Liposarcoma.

BACKGROUND Reports of venous stenting for inferior vena cava (IVC) syndrome (IVCS) due to sarcoma are limited, and the treatment's efficacy and safety are not clear. CASE REPORT A 36-year-old woman with myxoid liposarcoma was admitted to the Department of Respiratory Medicine for treatment of bilateral lower-leg edema and to be evaluated for acute liver dysfunction. She was 13 years old when she was diagnosed with myxoid liposarcoma. Over the next 18 years, she had 4 tumor resections and 1 round of radiation therapy. She had been on chemotherapy for 4 years and then pazopanib at the age of 35. The edema did not improve after admission despite treatment with diuretics. Computed tomography revealed a huge liposarcoma occupying the right thoracic cavity and a compressed IVC, which caused the edema. Although doxorubicin was administered as fifth-line treatment, there was no response. Since there was no additional chemotherapy regimen, her prognosis was considered to be less than 6 months. She could not be discharged to her home since she was unable to walk due to the edema; therefore, IVC stenting was performed to improve her dysmotility. After IVC stenting, the lower-leg edema improved without any adverse events, enabling her to walk and eventually return home. CONCLUSIONS In patients with IVCS caused by rare malignancies such as myxoid liposarcoma, an IVC stent can be safely implanted and can help to alleviate symptoms. IVC stenting can improve symptoms and allow for home care, resulting in improved quality of life.

Chronic Expanding Haematoma Causing Stenosis of the Right Ventricular Outflow Tract and Pulmonary Hypertension.

A chronic expanding haematoma (CEH) is an encapsulated mass that gradually increases in size from repeated internal bleeding and neovascularization. We herein report a 69-year-old man who was admitted with dyspnoea on exertion after undergoing thymic carcinoma resection 17 years ago. Chest computed tomography showed a heterogeneous mass in the anterior mediastinum and compression of the right ventricle, and pulmonary artery. Right cardiac catheterisation revealed pulmonary hypertension that was relieved after resection of the diagnosed CEH mass. This report highlights the mechanism underlying anterior mediastinal CEH-induced stenotic compression of the right ventricle-pulmonary artery outflow and subsequent pulmonary hypertension.

siRNA screening identifies METTL9 as a histidine Nπ-methyltransferase that targets the proinflammatory protein S100A9.

Protein methylation is one of the most common post-translational modifications observed in basic amino acid residues, including lysine, arginine, and histidine. Histidine methylation occurs on the distal or proximal nitrogen atom of its imidazole ring, producing two isomers: Nτ-methylhistidine or Nπ-methylhistidine. However, the biological significance of protein histidine methylation remains largely unclear owing in part to the very limited knowledge about its contributing enzymes. Here, we identified mammalian seven-ß-strand methyltransferase METTL9 as a histidine Nπ-methyltransferase by siRNA screening coupled with methylhistidine analysis using LC-tandem MS. We demonstrated that METTL9 catalyzes Nπ-methylhistidine formation in the proinflammatory protein S100A9, but not that of myosin light chain kinase MYLK2, in vivo and in vitro. METTL9 does not affect the heterodimer formation of S100A9 and S100A8, although Nπ-methylation of S100A9 at His-107 overlaps with a zinc-binding site, attenuating its affinity for zinc. Given that S100A9 exerts an antimicrobial activity, probably by chelation of zinc essential for the growth of bacteria and fungi, METTL9-mediated S100A9 methylation might be involved in the innate immune response to bacterial and fungal infection. Thus, our findings suggest a functional consequence for protein histidine Nπ-methylation and may add a new layer of complexity to the regulatory mechanisms of post-translational methylation.