Multilocular thymic cyst detected during COVID­19 treatment in an HIV­positive adult man: A case report and literature review.

A multilocular thymic cyst (MTC) is a rare mediastinal tumor with multiloculated cyst-like structures in the anterior mediastinum. This tumfor is associated with inflammatory diseases, including human immunodeficiency virus (HIV) infection. The present study reports a case of MTC detected during coronavirus disease 2019 (COVID-19) treatment in an adult who was tested HIV positive. An anterior mediastinal tumor was incidentally detected on computed tomography in a 52-year-old man with a 20-year history of HIV infection on the 9th day of COVID-19. The patient was asymptomatic with no notable physical findings. Magnetic resonance imaging revealed a 28-mm bilocular cyst. Robot-assisted thoracoscopic tumor resection was performed. Pathological examination showed that the cyst was lined with squamous or cuboidal epithelium, and the cystic lesion wall was mainly composed of thymic tissue with follicular hyperplasia. Based on these findings, the patient was diagnosed with MTC. To date, only 15 MTC cases have been reported in patients with HIV, and the majority of cases showed HIV infection-related symptoms such as lymphoid interstitial pneumonia and parotid gland enlargement. The present case was atypical for an HIV-related MTC because it did not involve HIV infection-related symptoms, suggesting the possibility for an alternative etiology such as COVID-19. Further reports on MTC development in patients with COVID-19 are required to elucidate the relationship between MTC and COVID-19.

Treatment of refractory localized pulmonary nocardiosis caused by Nocardia mexicana with a combination of medication and surgery.

Pulmonary nocardiosis is a rare disease that is often difficult to cure because of its tendency to recur. Here, we report a case of refractory localized pulmonary nocardiosis caused by Nocardia mexicana. A 60-year-old Japanese woman had recurring pulmonary nocardiosis four times previously and each time she was treated with antibiotics for a sufficient duration; nevertheless, the disease continued to recur, probably because of resistance to antibiotics. As a fifth treatment, we performed middle lobe resection and pre- and post-operative antimicrobial therapy for 6 months. The combination of medication and surgery was useful for treating refractory localized pulmonary nocardiosis.

Clinical outcomes after tracheostomy in patients with coronavirus disease 2019: a single-center experience in Japan.

PURPOSE: Many patients with coronavirus disease 2019 require mechanical ventilation and tracheostomy. However, the timing and indications for tracheostomy are controversial. This study assessed 11 patients with coronavirus disease 2019 who underwent tracheostomy with clinical information and retrospective analyses. METHODS: A single-center retrospective observational study was performed on patients with coronavirus disease 2019 who underwent tracheostomy between 2020 and 2021. RESULTS: Failure to wean was the most common indication for tracheostomy, followed by extracorporeal membrane oxygenation decannulation and the need for secretion management. After tracheostomy, six patients (54.5%) were liberated from the ventilator. The time from intubation to tracheostomy (21.1 ± 9.14 days) was correlated with the duration of ventilator dependency (36.83 ± 20.45 days, r2 = 0.792, p = 0.018). The mean Acute Physiological and Chronic Health Evaluation II score was significantly lower in the ventilator-liberated group (23 ± 2.77) than in the non-ventilator-liberated group (31 ± 6.13, p = 0.0292). Furthermore, patients with Acute Physiological and Chronic Health Evaluation II scores of < 27 points achieved ventilator liberation and a long-term survival (p = 0.0006). CONCLUSIONS: This study describes the outcomes of a cohort of patients who underwent tracheostomy after intubation for coronavirus disease 2019. The Acute Physiological and Chronic Health Evaluation II score predicted whether or not the patient could achieve ventilator liberation.

Gatekeeper Residue Replacement in a Phosphite Transporter Enhances Mutational Robustness of the Biocontainment Strategy.

Biocontainment is a key methodology to reduce environmental risk through the deliberate release of genetically modified microorganisms. Previously, we developed a phosphite (HPO32-)-dependent biocontainment strategy, by expressing a phosphite-specific transporter HtxBCDE and phosphite dehydrogenase in bacteria devoid of their indigenous phosphate (HPO42-) transporters. This strategy did not allow Escherichia coli to generate escape mutants (EMs) in growth media containing phosphate as a phosphorus source using an assay with a detection limit of 1.9 × 10-13. In this study, we found that the coexistence of a high dose of phosphate (>0.5 mM) with phosphite in the growth medium allows the phosphite-dependent E. coli strain to generate EMs at a frequency of approximately 5.4 × 10-10. In all EMs, the mutation was a single amino acid substitution of phenylalanine to cysteine or serine at position 210 of HtxC, the transmembrane domain protein of the phosphorus compound transporter HtxBCDE. Replacement of the HtxC F210 residue with the other 17 amino acids revealed that HtxC F210 is crucial in determining substrate specificity of HtxBCDE. Based on the finding of the role of HtxC F210 as a "gatekeeper" residue for this transporter, we demonstrate that the replacement of HtxC F210 with amino acids resulting from codons that require two simultaneous point mutations to generate phosphate permissive HtxC mutants can reduce the rate of EM generation to an undetectable level. These findings also provide novel insights into the functional classification of HtxBCDE as a noncanonical ATP-binding cassette transporter in which the transmembrane domain protein participates in substrate recognition.

Pulmonary leiomyoma with iceberg tumor growth pattern: A case report.

Pulmonary leiomyoma is a rare disease, accounting for ~2% of cases of benign lung tumors. Pulmonary leiomyomas can be classified as tracheobronchial or pulmonary parenchymal, or as having an iceberg growth pattern, wherein the tumor extends into both the bronchial and pulmonary cavities. In the present report, a 41-year-old man complaining of sputum and discomfort during swallowing was referred to the National Center for Global Health and Medicine, because of an abnormal shadow on chest radiography and computed tomography (CT). Since the follow-up CT showed that the tumor in the third right lung segment had increased and progressed along the intra-bronchus over time, thoracoscopic right upper lobectomy was performed and leiomyoma was pathologically diagnosed. After resection, the symptoms of airway irritation improved. Since respiratory symptoms and radiographical findings are nonspecific with tracheobronchial and pulmonary parenchymal types of pulmonary leiomyoma, the identification of symptoms and determination of the extent of the lesion are necessary for treatment. In cases of iceberg growth pattern, in which the tumor extends into both the bronchial and pulmonary cavities, surgical resection should be considered.

Case of a lung collision tumor consisting of squamous cell carcinoma of the lung and diffuse large B-cell lymphoma.

Among the reports of malignant collision tumors, collision tumors consisting of lung cancer and malignant lymphoma are extremely rare. We report case of a lung collision tumor consisting of squamous cell carcinoma of the lung and diffuse large B-cell lymphoma.

Liver herniation mimicking a thoracic tumor with restoration of the liver surface structure on closure of the hernia orifice under thoracoscopic surgery.

Non-congenital, non-traumatic spontaneous diaphragmatic liver hernia in adults is extremely rare and sometimes misdiagnosed as a thoracic tumor. Almost all previous reports with a definitive diagnosis reported preservation; thus, differential diagnosis is extremely important for planning optimal management of such clinical conditions. An abnormal shadow in the right lower lung field was detected on chest radiography in a 61-year-old woman. Further imaging study revealed a 33-mm diameter mass adjacent to the right diaphragm. Thoracoscopic surgery was performed as diagnostic treatment. We found a pale hemispherical herniated liver on the central tendon of the diaphragm. After repositioning the herniated liver, the orifice was closed with a non-absorbable suture, and the surface of the liver returned to being a perfectly smooth surface. With this result, we believe that repair of diaphragmatic liver hernia through a minimally invasive procedure has great benefits for patients.

[A CASE OF PRIMARY MUCOSA-ASSOCIATED LYMPHOID TISSUE (MALT) LYMPHOMA OF THE URINARY BLADDER].

A 68-year-old female presented with macroscopic hematuria. Cystoscopy revealed a wide-based submucosal mass. Computed tomography revealed a 3.5 × 2.5-cm solitary mass situated from the trigone to the left lateral bladder wall and the left hydroureter and hydronephrosis. T2-weighted magnetic resonance imaging (MRI) revealed low intensity, and diffusion-weighed MRI showed increased diffusion without invasion. The bladder tumor was immediately resected transurethrally. Histological diagnosis of the tissue obtained by transurethral resection was extranodal marginal zone B cell lymphoma of MALT. Positron emission tomography-CT showed no lesions other than the bladder tumor. The patient was diagnosed with stage-IE lymphoma of the bladder (Ann Arbor classification). Radiotherapy was performed at the bladder and pelvis (30 Gy) with six courses of rituximab (375 mg/m2). No local or distant recurrence after a 48-month follow-up was noted.

Complete thoracoscopic surgery for extensive emphysema in the right upper and middle lobes caused by right B5 bronchial atresia.

Bronchial atresia is a rare congenital condition that may lead to infectious complications. Almost all patients with this condition are diagnosed early in life with normal lungs, making them particularly suitable candidates for thoracoscopic surgery. A 30-year-old man was referred to our hospital due to an abnormal shadow on chest radiography taken 7 years prior. Despite being diagnosed with B5 bronchial atresia, he refused to undergo surgical resection. Seven years later, he developed right chest pain. Computed tomography showed B5 bronchial occlusion, mucoid impaction and emphysematous changes. Treatment with thoracoscopic right middle lobectomy and S3 partial resection using four ports resulted in good lung expansion after discharge. This study highlights that thoracoscopic surgical resection should be considered in patients with bronchial atresia.

Solitary pleural tuberculoma diagnosed by thoracoscopic surgical resection.

Tuberculoma is a manifestation of pleural tuberculosis. Although the clinical manifestation of tuberculoma has been widely reported, the pathogenesis of this condition still remains unclear. An abnormal shadow was detected on the chest radiograph of a 44-year-old man with a history of pulmonary tuberculosis. Computed tomography revealed a well-defined, elliptical 44 mm nodule located in the right posterior thoracic cavity. Thoracoscopic surgery was performed to rule out malignant tumors. Although loose adhesions were observed throughout the thoracic cavity, a nodule was found between the visceral pleura and parietal pleura. En bloc resection was performed, and the patient was pathologically diagnosed with tuberculoma. An acid-fast bacterium culture was negative, and the patient's recovery was uneventful without chemotherapy. Surgical resection should be considered to rule out malignancy, because tuberculomas are difficult to distinguish from malignant pleural tumors.

MPL exon 10 mutations other than canonical MPL W515L/K mutations identified by in-house MPL exon 10 direct sequencing in essential thrombocythemia.

MPL exon 10 mutations are one of the driver mutations in essential thrombocythemia (ET) or myelofibrosis (MF). We have established an in-house MPL mutation analysis system, covering the entire region of MPL exon 10 by direct sequencing. Since 2009, MPL exon 10 mutation analysis has been performed for diagnosis of myeloproliferative neoplasms (MPN) without JAK2 V617F or CALR exon 9 mutations. So far, 11 cases of MPL exon 10 mutation have been found in 51 patients with suspected MPN. In patients with ET, we detected five non-canonical MPL mutations including one novel mutation, MPL R514_P518delinsK, and one canonical MPL W515L mutation. Notably, three ET patients without canonical MPL mutations had thrombotic events. Meanwhile, in primary or secondary MF, only canonical MPL W515L/K mutations were found. Further cases need to be examined to elucidate the full MPL mutation profile in MPN. However, our data indicate that analysis of the whole of MPL exon 10 is warranted for the diagnosis of MPL mutations, especially in ET, and that the use of Japanese commercial laboratory tests that only detect canonical MPL W515L/K mutations may miss a significant percentage of MPL exon 10 mutations, which could delay the administration of anti-thrombotic therapy.

A simple method to distinguish residual elotuzumab from monoclonal paraprotein in immunofixation assays for multiple myeloma patients.

Negative immunofixation electrophoresis (IFE) of serum and/or urine is a diagnostic marker for determining a complete response (CR) after immunotherapy for multiple myeloma (MM). However, residual therapeutic antibodies such as elotuzumab (IgG-κ), can compromise IFE evaluation when the affected immunoglobulins belong to the same IgG-κ subclass. We thus sought to develop a simple and rapid method to treat patient serum before IFE to distinguish the residual elotuzumab. Serum samples from patients receiving elotuzumab were treated with a predetermined amount of soluble signaling lymphocyte activation molecule F7 (SLAMF7) protein and then subjected to conventional IFE testing. We tested our method in samples from 12 patients. The IgG-κ band in IFE disappeared or shifted after elotuzumab treatment in four patients with no bone marrow minimal residual disease and normalized free light chain, whereas seven patients with any sign of residual MM showed a remaining IgG-κ band after treatment. One-hour incubation of samples with 6-9 molar excess soluble SLAMF7 before IFE was sufficient to distinguish residual elotuzumab in 11 of 12 samples. This simple method does not require special reagents, can be performed in most clinical laboratories, and enables differentiation between patients with a CR and those requiring further treatment.

Ectopic intrapulmonary follicular adenoma diagnosed by surgical resection.

Ectopic intrapulmonary thyroid tissue is extremely rare and considerably difficult to diagnose without surgery. Ectopic thyroid tissue, described as a mediastinal tumor, and intrapulmonary lesions are infrequent. An abnormal shadow was detected upon chest X-ray in a 60-year old woman with a history of benign thyroid goiter. A computed tomography scan revealed a solitary nodule measuring 27 mm in diameter in the left lower lobe, the diameter of which had increased by 5 mm since initial observation eight years ago. A thoracoscopic wedge resection was performed and the lesion was determined to be a non-invasive, soft-tissue tumor. It was pathologically diagnosed as an ectopic thyroid follicular adenoma. The course of the tumor was uneventful. A diagnosis of ectopic intrapulmonary thyroid should be made cautiously and only after ruling out metastasis of a follicular adenoma or thyroid carcinoma. This diagnosis of ectopic thyroid tissue was made possible by the surgical approach.

Intratumoral gene expression of dihydrofolate reductase and folylpoly-c-glutamate synthetase affects the sensitivity to 5-fluorouracil in non-small cell lung cancer.

BACKGROUND: Various factors related to the sensitivity of non-small cell lung carcinoma (NSCLC) to 5-fluorouracil (5-FU) have been reported, and some of them have been clinically applied. In this single-institutional prospective analysis, the mRNA expression level of five folic acid-associated enzymes was evaluated in surgical specimens of NSCLC. We investigated the correlation between the antitumor effect of 5-FU in NSCLC using an anticancer drug sensitivity test and the gene expression levels of five enzymes. MATERIALS AND METHODS: Forty patients who underwent surgery for NSCLC were enrolled, and the antitumor effect was measured using an in vitro anticancer drug sensitivity test (histoculture drug response assay) using freshly resected specimens. In the same sample, the mRNA expression levels of five enzymes involved in the sensitivity to 5-FU were measured in the tumor using real-time PCR. The expression levels and the result of the sensitivity test were compared. RESULTS: No correlation was found between dihydropyrimidine dehydrogenase (DPD), orotate phosphoribosyltransferase (OPRT), or DPD/OPRT expression and the antitumor effects of 5-FU. On the other hand, a correlation was found between thymidylate synthase (TS), folylpoly-c-glutamate synthetase (FPGS), and dihydrofolate reductase (DHFR) expression and 5-FU sensitivity. CONCLUSION: Expression of FPGS and DHFR may be useful for predicting the efficacy of 5-FU-based chemotherapy for NSCLC.

Application of peptides with an affinity for phospholipid membranes during the automated purification of extracellular vesicles.

Extracellular vesicles (EVs), such as exosomes, have garnered increasing interest because of their potential clinical applications that range from diagnostics to therapeutics. The development of an automated and reproducible EV purification platform would therefore aid the introduction of EV biomarkers and therapies into the clinic. Here, we demonstrate that K8- as well as K-16 peptides (containing 8 and 16 lysine residues with dissociation constants of 102 nM and 11.6 nM for phosphatidylserine, respectively) immobilized on magnetic beads can capture small EVs (< 0.2 µm) from culture supernatants of MCF7 human breast cancer cells. Importantly, the bound EVs could be dissociated from the beads under mild conditions (e.g. 0.5 M NaCl), and the isolated EVs had the typical shapes of EVs under SEM and TEM with a mean particle size of 99 nm. Using the peptide-immobilized beads, we adapted a pre-existing bench top instrument for magnetic separation to perform automated EV purification with higher purity and yield than that obtained using the standard ultracentrifugation method.

Live-cell imaging of macrophage phagocytosis of asbestos fibers under fluorescence microscopy.

BACKGROUND: Frustrated phagocytosis occurs when an asbestos fiber > 10 µm in length is engulfed imperfectly by a macrophage, and it is believed to be associated with chromosomal instability. Few studies have focused on dynamic cellular imaging to assess the toxicity of hazardous inorganic materials such as asbestos. One reason for this is the relative lack of fluorescent probes available to facilitate experimental visualization of inorganic materials. We recently developed asbestos-specific fluorescent probes based on asbestos-binding proteins, and achieved efficient fluorescent labeling of asbestos. RESULTS: Live-cell imaging with fluorescent asbestos probes was successfully utilized to dynamically analyze asbestos phagocytosis. The fluorescently labeled asbestos fibers were phagocytosed by RAW 264.7 macrophages. Internalized fibers of < 5 µm in length were visualized clearly via overlaid phase contrast and fluorescence microscopy images, but they were not clearly depicted using phase contrast images alone. Approximately 60% of the cells had phagocytosed asbestos fibers after 2 h, but over 96% of cells remained alive even 24 h after the addition of asbestos fibers. Immediate cell death was only observed when an asbestos fiber was physically pulled from a cell by an external force. Notably, at 24 h after the addition of asbestos fibers an approximately 4-fold increase in the number of binucleated cells was observed. Monitoring of individual cell divisions of cells that had phagocytosed asbestos suggested that binucleated cells were formed via the inhibition of cell separation, by asbestos fibers of > 10 µm in length that were localized in the proximity of the intercellular bridge. CONCLUSIONS: Fluorescently labeled asbestos facilitated visualization of the dynamic biological processes that occur during and after the internalization of asbestos fibers, and indicated that (i) frustrated phagocytosis itself does not lead to immediate cell death unless the asbestos fiber is physically pulled from the cell by an external force, and (ii) macrophages that have phagocytosed asbestos can divide but sometimes the resulting daughter cells fuse, leading to the formation of a binucleated cell. This fusion only seemed to occur when a comparatively long asbestos fiber (> 10 µm) was shared by two daughter cells.

Insulin sensor cells for the analysis of insulin secretion responses in single living pancreatic ß cells.

Investigation of the functions of insulin-secreting cells in response to glucose in single-living cells is essential for improving our knowledge on the pathogenesis of diabetes. Therefore, it is desired to develop a new convenient method that enables the direct detection of insulin secreted from single-living cells. Here, insulin-sensor-cells expressing a protein-based insulin-detecting probe immobilized on the extracellular membrane were developed to evaluate the insulin-secretion response in single-living pancreatic ß cells. The protein-based insulin-detecting probe (NαLY) was composed of a bioluminescent protein (nano-luc), the αCT segment of the insulin receptor, L1 and CR domains of the insulin receptor, and a fluorescent protein (YPet). NαLY exhibited a bioluminescence resonance energy transfer (BRET) signal in response to insulin; thus, cells of Hepa1-6 line were genetically engineered to express NαLY on the extracellular membrane. The cells were found to act as insulin-sensor-cells, exhibiting a BRET signal in response to insulin. When the insulin-sensor-cells and pancreatic ß cells (MIN6 cell line) were cocultured and stimulated with glucose, insulin-sensor-cells nearby pancreatic ß cells showed the spike-shaped BRET signal response, whereas the insulin-sensor-cells close to one pancreatic ß cell did not exhibit such signal response. However, all the insulin-sensor-cells showed a gradual increase in BRET signals, which were presumably attributed to the increase in insulin concentrations in the culture dish, confirming the function of these insulin-sensor-cells. Therefore, we demonstrated that heterogenetic insulin secretion in single-living pancreatic ß cells could be measured directly using the insulin sensor cells.

Single-stage video-assisted thoracoscopic surgery: Right upper lobectomy and left lower lobectomy for synchronous bilateral lung cancers.

INTRODUCTION: Single-stage bilateral radical surgery for synchronous bilateral multiple lung cancers (SBMLCs) has strong advantages; however, it is considered highly invasive. We have therefore adopted video-assisted thoracoscopic surgery (VATS) as a minimally invasive surgical maneuver for bilateral lung resection. Although there have been a few reports concerning bilateral lung resection, the safety and appropriate operative indications remain unclear, especially for bilateral VATS-lobectomy. A case of single-stage bilateral radical lobectomy with a good result is reported. PRESENTATION OF CASE: A 58-year-old man was found to have abnormal opacities in the right upper zone and left lower zone at a health checkup. Double primary bilateral lung cancers was suspected, and surgical resection was considered. Consequently, right upper lobectomy with D2 lymph node dissection and left lower lobectomy with D2 lymph node dissection as radical resection were performed under VATS. The lesions were finally diagnosed to be double primary adenocarcinomas of the right upper lobe (pT1N0M0, stage IA) and left lower lobe (pT1N0M0, stage IA). The patient's postoperative course was uneventful, and he was discharged on postoperative day 6. The patient is doing well with no evidence of recurrence for 9 years. CONCLUSION: While careful consideration of the surgical options is needed, if properly done, bilateral VATS-lobectomy for SBMLC has advantages for selected patients.

Differential Counting of Asbestos Using Phase Contrast and Fluorescence Microscopy.

Considering the increasing use of various asbestos substitutes, asbestos risk management in many industries may require accurate techniques for detecting and distinguishing asbestos from non-asbestos fibers. Using fluorescently labeled asbestos-binding proteins, we previously developed a novel method for detection and counting of asbestos fibers under fluorescence microscopy (FM). This method can provide speedy, on-site detection and identification of the asbestos fibers and has higher sensitivity than phase contrast microscopy (PCM). However, current asbestos exposure limits are derived from risk assessments based on epidemiological studies that were conducted using PCM fiber counts. Therefore, the sensitivity of asbestos testing should be maintained at PCM level to properly assess compliance with these limit values. Here, we developed and tested a novel application of FM as a differential counting method that complements PCM analysis and is fully compatible with the PCM-based epidemiological data. In the combined PCM-FM method, the fluorescent asbestos-binding probe is applied prior to filter clearing. The method makes it possible to easily switch between two microscopic techniques while analyzing the same fields of view: PCM is used for counting fibers, and FM for differentiating asbestos from non-asbestos fibers. Using airborne dust samples from demolition sites in Japan, we compared PCM-FM with scanning electron microscopy (SEM)-based differential counting method. Statistical analysis indicated a slight conservative bias of PCM-FM method, combined with relatively high variability across the full range of fiber concentrations in our sample set. Using correlative microscopy, we also evaluated the specificity of FM staining, which is a potential cause of variability between the two methods. The energy-dispersive X-ray analysis indicated that ~95% of fluorescently stained fibers in the demolition site samples were correctly identified as asbestos. While further research is needed to fully clarify the causes of variability between FM- and SEM-based differential counting, PCM-FM could be used for rapid and selective detection of asbestos fibers in field samples.