Ewing sarcoma with very late metastasis in the skull: a case report.

BACKGROUND: Ewing sarcoma is a malignant bone tumor; however, its prognosis has improved since the development of modern chemotherapy. Although Ewing sarcoma outcomes have improved, issues related to late complications, secondary malignant neoplasms, and late recurrence or metastasis have emerged. CASE PRESENTATION: We report a case of Ewing sarcoma that recurred in the occipital bone 21 years after primary tumor treatment. A 45-year-old Japanese woman with a history of Ewing sarcoma 21 years prior, was referred to our hospital due to a severe headache. A tumor was detected in the left occipital bone, and the biopsy revealed Ewing sarcoma. Metastasis was suspected because the patient had been treated for Ewing sarcoma of the left clavicle 21 years prior. There have been several cases of local recurrence or metastasis, occurring 15-20 years after the onset of the initial disease. To our knowledge, very late metastasis of Ewing sarcoma in the skull has not been reported. CONCLUSION: We report a rare case of very late metastasis of Ewing sarcoma in the skull with a review of the literature. Delayed metastasis secondary to Ewing sarcoma can occur in the lung, which is the most common site for metastasis, as well as other regions of the body, such as the cranium.

Cerebrovascular Treatment with Superselective Balloon Test Occlusion for Multiple Cerebral Aneurysms Associated with Middle Cerebral Artery Anomaly: A Case Report.

A 38-year-old woman presented with impaired consciousness and anisocoria due to a subarachnoid hemorrhage and an intracerebral hemorrhage of the left temporal lobe. Examination revealed severe tortuosity in the left middle cerebral artery and three sequential bead-like aneurysms. She underwent a craniotomy in the acute phase to stop rebleeding at the rupture site and remove the intracerebral hematoma. During the chronic phase, endovascular treatment with superselective balloon test occlusion (ssBTO) was performed for the remaining aneurysms. Preoperative ssBTO was useful in evaluating collateral circulation and assessing the curability of the treatment.

Bacterial Avenalumic Acid Biosynthesis Includes Substitution of an Aromatic Amino Group for Hydride by Nitrous Acid Dependent Diazotization.

The diazo group is an important functional group that can confer biological activity to natural products owing to its high reactivity. Recent studies have revealed that diazo groups are synthesized from amino groups using nitrous acid in secondary metabolites of actinomycetes. However, genome database analysis indicated that there are still many diazo group-biosynthesizing enzymes for unknown biosynthetic pathways. Here, we discovered an avenalumic acid biosynthesis gene cluster in Streptomyces sp. RI-77 by genome mining of enzymes involved in diazo group formation. Through heterologous expression, the gene cluster was revealed to direct avenalumic acid (AVA) biosynthesis via 3-aminoavenalumic acid (3-AAA). In vitro enzyme assays showed that AvaA6 and AvaA7 catalyzed the diazotization of 3-AAA using nitrous acid and substitution of the diazo group for hydride to synthesize AVA, respectively. This study revealed an unprecedented pathway for amino group removal via diazotization.

Prediction of Post-operative Long-Term Outcome of the Motor Function by Multimodal Intraoperative Neuromonitoring With Transcranial Motor-Evoked Potential and Spinal Cord-Evoked Potential After Microsurgical Resection for Spinal Cord Tumors.

Objective: To examine the effect of multimodal intraoperative neuromonitoring on the long-term outcome of motor function after microsurgical resection for spinal cord tumors. Materials and Methods: Consecutive fourteen patients with spinal tumors who were surgically treated at the University of Fukui Hospital between 2009 and 2020 [M:F = 10:4, ages ranging from 22 to 83 years (mean ± SD = 58 ± 21 years)] were included in this study. There were eight intra-axial tumors and six extra-axial tumors. There were four patients with hypertension, two patients with diabetes mellitus, and four patients with hyperlipidemia. Three patients were under antithrombotic medication, two were under steroid medication, four were current smokers, and four were current drinkers. Manual muscle test (MMT) of the upper and lower extremities of the patients was examined before surgery, 2 weeks after surgery, and at the final follow-up. The mean follow-up period was 38 ± 37 months. McCormick scores were examined before surgery and at the final follow-up. Microsurgical resection of the tumor was underwent through the posterior approach under transcranial motor-evoked potential (TcMEP) monitoring. The MEP of 46 extremities was recorded during the surgery. Gross total resection was achieved in 13 of 14 surgeries. Spinal cord-evoked potential (Sp-SCEP) monitoring was performed in eight of 14 patients. Results: The length of peritumoral edema was significantly longer in patients with deterioration of McCormick scores than in patients with preservation of McCormick scores (p = 0.0274). Sp-SCEP could not predict the deterioration. The ratio of MEP at the beginning of the surgery to that at the end of the surgery was the only significant negative factor that predicts deterioration of motor function of the extremity at the final follow-up (p = 0.0374, odds ratio [OR] 1.02E-05, 95% CI 9.13E+01-7.15E+18). A receiver operating characteristic (ROC) analysis revealed that the cutoff value of the ratio of MEP to predict the deterioration at the final follow-up was 0.23 (specificity 100%, specificity 88%, positive predictive value 100%, and negative predictive value 88%) to predict deterioration at the final follow-up. Conclusions: Ratio MEP was the most significant negative factor to predict the deterioration of motor weakness at spinal tumor surgery. The setting of the cutoff value should be more strict as compared to the brain surgery and might be different depending on the institutions.

Production of l-Theanine by Escherichia coli in the Absence of Supplemental Ethylamine.

l-Theanine is a nonproteinogenic amino acid present almost exclusively in tea plants and is beneficial for human health. For industrial production, l-theanine is enzymatically or chemically synthesized from glutamine/glutamate (or a glutamine/glutamate derivative) and ethylamine. Ethylamine is extremely flammable and toxic, which complicates and increases the cost of operational procedures. To solve these problems, we developed an artificial biosynthetic pathway to produce l-theanine in the absence of supplemental ethylamine. For this purpose, we identified and selected a novel transaminase (NCBI:protein accession number AAN70747) from Pseudomonas putida KT2440, which catalyzes the transamination of acetaldehyde to produce ethylamine, as well as γ-glutamylmethylamide synthetase (NCBI:protein accession number AAY37316) from Pseudomonas syringae pv. syringae B728a, which catalyzes the condensation of l-glutamate and ethylamine to produce l-theanine. Expressing these genes in Escherichia coli W3110S3GK and enhancing the production capacity of acetaldehyde and l-alanine achieved successful production of l-theanine without ethylamine supplementation. Furthermore, the deletion of ggt, which encodes γ-glutamyltranspeptidase (EC 2.3.2.2), achieved large-scale production of l-theanine by attenuating its decomposition. We show that an alanine decarboxylase-utilizing pathway represents a promising route for the fermentative production of l-theanine. Our study reports efficient methods to produce l-theanine in the absence of supplemental ethylamine.IMPORTANCE l-Theanine is widely used in food additives and dietary supplements. Industrial production of l-theanine uses the toxic and highly flammable precursor ethylamine, raising production costs. In this study, we used Escherichia coli to engineer two biosynthetic pathways that produce l-theanine from glucose and ammonia in the absence of supplemental ethylamine. This study establishes a foundation for safely and economically producing l-theanine.

Complete Biosynthetic Pathway of Alazopeptin, a Tripeptide Consisting of Two Molecules of 6-Diazo-5-oxo-l-norleucine and One Molecule of Alanine.

DON (6-diazo-5-oxo-l-norleucine), a diazo-containing amino acid, has been studied for more than 60 years as a potent antitumor agent, but its biosynthesis has not been elucidated. Here we reveal the complete biosynthetic pathway of alazopeptin, the tripeptide Ala-DON-DON, which has antitumor activity, by gene inactivation and in vitro analysis of recombinant enzymes. We also established heterologous production of N-acetyl-DON in Streptomyces albus. DON is synthesized from lysine by three enzymes and converted to alazopeptin by five enzymes and one carrier protein. Most interestingly, transmembrane protein AzpL was indicated to catalyze diazotization using 5-oxolysine and nitrous acid as substrates. Site-directed mutagenesis of AzpL indicated that the hydroxy group of Tyr-93 is important for the diazotization. These findings expand our knowledge of the enzymology of N-N bond formation.

Novel desferrioxamine derivatives synthesized using the secondary metabolism-specific nitrous acid biosynthetic pathway in Streptomyces davawensis.

Recently, a novel nitrous acid biosynthetic pathway composed of two enzymes was discovered to be involved in the biosynthesis of cremeomycin for the formation of its diazo group. In this pathway, CreE oxidizes L-aspartic acid to nitrosuccinic acid and CreD liberates nitrous acid from nitrosuccinic acid. Bioinformatic analysis showed that various actinobacteria have putative secondary metabolite biosynthesis gene clusters containing creE and creD homologs, suggesting that this pathway is widely used for the biosynthesis of various natural products. Here, we focused on creE and creD homologs (BN159_4422 and BN159_4421) in Streptomyces davawensis. In vitro analysis of recombinant BN159_4422 and BN159_4421 proteins showed that these enzymes synthesized nitrous acid from L-aspartic acid. Secondary metabolites produced by this gene cluster were investigated by comparing the metabolic profiles of the wild-type and ΔBN159_4422 strains. When these strains were co-cultured with Tsukamurella pulmonis TP-B0596, three compounds were specifically produced by the wild-type strain. These compounds were identified as novel desferrioxamine derivatives containing either of two unique five-membered heterocyclic ring structures and shown to have iron-binding properties. A putative desferrioxamine biosynthetic gene cluster was found in the S. davawensis genome, and inactivation of a desD homolog (BN159_5485) also abolished the production of these compounds. We propose that these compounds should be synthesized by the modification of desferrioxamine B and a shorter chain analog using nitrous acid produced by the CreE and CreD homologs. This study provides an important insight into the diverse usage of the secondary metabolism-specific nitrous acid biosynthetic pathway in actinomycetes.