The Cofactor Specificity of NQO2

NQO1 and NQO2 are closely related quinone reductases, which are FAD-linked enzymes that catalyze the 2-electron reduction of quinones. Whereas NQO1 has a well-defined role in cellular detoxification of quinones, NQO2’s function is less clear; it uses the conventional cofactors NADH/NADPH inefficiently compared to smaller nicotinamide cofactors, which are often present in low cellular amounts. This unique cofactor specificity suggests that NQO2 may have non-enzymatic functions, such as a role in intracellular signalling. The goals of this research project include: 1) examining whether cofactor specificity is conserved in amniote NQO2 enzymes and 2) re-constructing ancient enzymes along the evolutionary pathway of NQO1 and NQO2 to determine the molecular origins of cofactor specificity differences. The reductive half-reactions of H.sapiens, A.platyrhynchos, and A.mississippiensis NQO2 with NADH were investigated using stopped-flow apparatus. With increasing NADH concentration, the observed rate constant for NQO2 reduction for all three amniotes increased before reaching saturation. This indicates that the enzyme-substrate complex for NQO2 reduction exists in rapid equilibrium, leading to the conclusion of non-productive NADH binding across all amniote NQO2s. To examine the evolution of NQO1 and NQO2, a phylogenetic tree was created using amino acid sequences of numerous species. While the characterization of ancient enzyme kinetics is still ongoing, the successful expression of various ancestral proteins confirmed our analysis of the phylogeny and predicted sequences

Overproduction of Aromatic Amino Acids from Cyanobacteria

L-phenylalanine, L-tyrosine and L-tryptophan are aromatic amino acids that are widely used in industrial, agricultural and pharmaceutical applications. Currently, heterotrophic microorganisms are fed require an organic source of carbon to produce amino acids, photosynthetic bacteria are investigated. Mutagenesis by methyl methanesulfonate followed by selection on aromatic amino acid analogues produced mutants that are able to overproduce aromatic amino acids. Two mutant strains were investigated: TA1, which is a better L-phenylalanine overproducer, and 5FT1, which overproduces L-tryptophan. To test the influence of growth conditions on amino acid production, we grew mutant strains of Synechocytis sp. 6803 under enhanced CO2 or glucose-rich conditions. We quantified the amount of each aromatic amino acid synthesized intracellularly and transported to extracellular medium by high performance liquid chromatography. We analysed the transient production of the aromatic amino acids to see if it is a growth related process. If it is growth related, the recommended growth method would be a fed batch reactor or a turbidostat to keep the cells at the exponential phase. If it is not growth related, we would recommend to use a batch reactor to allow cells reach stationary phase and harvest after maximum production

Adrenomedullin delivery in microsphere-scaffold composite for remodeling of the alveolar bone following tooth extraction: an experimental study in the rat

BACKGROUND: Alveolar ridge resorption, as a significant problem in implant and restorative dentistry, has long been considered as an inevitable outcome following tooth extraction. Recently, adrenomedullin (ADM) is reported to be able to stimulate the proliferation and migration of various cells including osteoblasts. The purpose of this study was to investigate the influence of local ADM application in the tooth extraction socket in vivo. METHODS: Chitosan micropheres were developed by an emulsion-ionic cross-linking method for ADM delivery. Poly (L -lactic-co-glycolic) acid (PLGA) and nano-hydroxyapatite (nHA) were used to prepare scaffolds to contain the micrspheres with ADM. In vivo experiment was evaluated by transplanting the composite into the rat socket right after the incisor extraction. After 4, 8, 12 weeks implantation, radiographic and histological tests were carried out to evaluate the effect of released ADM on the alveolar bone. RESULTS: The microspheres had a spherical structure and a relative rough and uniform surface, and the particle size was under a normal distribution, with the average diameter of 38.59 μm. The scaffolds had open and interconnected pores. In addition, the high porosity of the composite was 88.93%. Radiographic and histological examination revealed that the PLGA/nHA/CMs/ADM composite could accelerate the alveolar bone remodeling and reduce the residual ridge resorption compared with the PLGA/nHA/CMs scaffold. CONCLUSIONS: The results of this study suggest that local application of ADM has the potential to preserve the residual alveolar ridge and accelerate the alveolar bone remodeling

Agent with Warm Start and Active Termination for Plane Localization in 3D Ultrasound

Standard plane localization is crucial for ultrasound (US) diagnosis. In prenatal US, dozens of standard planes are manually acquired with a 2D probe. It is time-consuming and operator-dependent. In comparison, 3D US containing multiple standard planes in one shot has the inherent advantages of less user-dependency and more efficiency. However, manual plane localization in US volume is challenging due to the huge search space and large fetal posture variation. In this study, we propose a novel reinforcement learning (RL) framework to automatically localize fetal brain standard planes in 3D US. Our contribution is two-fold. First, we equip the RL framework with a landmark-aware alignment module to provide warm start and strong spatial bounds for the agent actions, thus ensuring its effectiveness. Second, instead of passively and empirically terminating the agent inference, we propose a recurrent neural network based strategy for active termination of the agent's interaction procedure. This improves both the accuracy and efficiency of the localization system. Extensively validated on our in-house large dataset, our approach achieves the accuracy of 3.4mm/9.6{\deg} and 2.7mm/9.1{\deg} for the transcerebellar and transthalamic plane localization, respectively. Ourproposed RL framework is general and has the potential to improve the efficiency and standardization of US scanning.Comment: 9 pages, 5 figures, 1 table. Accepted by MICCAI 2019 (oral

Case report: A rare case of sintilimab-induced gastric stenosis and literature review

Sintilimab is a fully human IgG4 monoclonal antibody against programmed death-1 (PD-1) used to treat classical Hodgkin’s lymphoma and various solid tumors. With increasing use of sintilimab, some rare adverse reactions have been reported. Here, we report a case of a 50-year-old woman with squamous non-small cell lung cancer (NSCLC) (metastasis to pericardium and pleura) who received two cycles of 200 mg sintilimab immunotherapy combined with albumin-bound paclitaxel and carboplatin chemotherapy and one cycle of sintilimab monotherapy. She was diagnosed with Sjogren’s syndrome (with symptoms of fever, dry mouth, dysphagia, and eating difficulty) after three cycles’ treatment and received standard steroidal therapy. Prior to admission, the patient experienced severe stomach discomfort with vomiting and was hospitalized. Upper gastrointestinal iodine angiography showed significant gastric stenosis as well as lower esophageal stenosis. Subsequent ultrafine gastroscopy revealed ulceration at the stenotic site and an absence of normal peristalsis of the gastric wall. Pathological examination of the lesions showed reactive changes, including ulceration, fibrosis, and inflammatory cell infiltration. After multidisciplinary consultation, it was considered that the patient’s gastric stenosis with inflammatory fibrosis changes was due to a sintilimab-induced immune hyperinflammatory reaction. The patient had been treated with standard steroidal therapy since suffering from Sjogren’s syndrome, but the gastric stenotic changes were not relieved. The patient then received regular bouginage of esophago-cardiac stenosis under gastroscopy to physically reexpand the fibrous hyperplasia and stenotic site, enabling normal eating function. To our knowledge, this is the first case of gastric stenosis in a patient with squamous NSCLC after using sintilimab and may help clinicians better understand potential immune-related adverse events due to sintilimab and improve assessment and management

Germline Predisposition and Copy Number Alteration in Pre-stage Lung Adenocarcinomas Presenting as Ground-Glass Nodules

Objective: Synchronous multiple ground-glass nodules (SM-GGNs) are a distinct entity of lung cancer which has been emerging increasingly in recent years in China. The oncogenesis molecular mechanisms of SM-GGNs remain elusive.Methods: We investigated single nucleotide variations (SNV), insertions and deletions (INDEL), somatic copy number variations (CNV), and germline mutations of 69 SM-GGN samples collected from 31 patients, using target sequencing (TRS) and whole exome sequencing (WES).Results: In the entire cohort, many known driver mutations were found, including EGFR (21.7%), BRAF (14.5%), and KRAS (6%). However, only one out of the 31 patients had the same somatic missense or truncated events within SM-GGNs, indicating the independent origins for almost all of these SM-GGNs. Many germline mutations with a low frequency in the Chinese population, and genes harboring both germline and somatic variations, were discovered in these pre-stage GGNs. These GGNs also bore large segments of copy number gains and/or losses. The CNV segment number tended to be positively correlated with the germline mutations (r = 0.57). The CNV sizes were correlated with the somatic mutations (r = 0.55). A moderate correlation (r = 0.54) was also shown between the somatic and germline mutations.Conclusion: Our data suggests that the precancerous unstable CNVs with potentially predisposing genetic backgrounds may foster the onset of driver mutations and the development of independent SM-GGNs during the local stimulation of mutagens