Reactive Molecular Dynamics Simulations of the Thermal Decomposition Mechanism of 1,3,3-Trinitroazetidine.

1,3,3-Trinitroazetidine (TNAZ) has a molecular formula of C3 H4 N4 O6 and the characteristics of low melting point, low impact sensitivity and good thermal stability. It is suitable for melt casting and pressed charges, and it has broad prospects for applications in low-sensitivity ammunition. In this study, the thermal decomposition of TNAZ crystals at high temperature was calculated by molecular dynamics simulation with the ReaxFF/lg reactive force field. The change in the potential energy of TNAZ, the formation of small-molecule products and clusters, and the initial reaction path of TNAZ were analysed. The kinetic parameters of different reaction stages in TNAZ thermal decomposition were obtained. The primary thermal decomposition reaction of TNAZ was found to be as follows: N-NO2 and C-NO2 bonds broke; a H atom on the quaternary ring was transferred to the nitro group; and the C-HNO2 and N-HNO2 bonds broke. The main decomposition products of TNAZ were thus NO2 , NO, N2 , H2 O, CO2 and HNO2 , as well as macromolecular clusters. The size of the cluster structure was related to the reaction temperature, and the higher the temperature was, the smaller the cluster size was.

Cardiac Point-of-Care Ultrasound in Pediatric Neurocritical Care: A Case Series.

BACKGROUND: Pediatric brain injury is accompanied by hemodynamic perturbations complicating the optimization of cerebral physiology. Point-of-care ultrasound (POCUS) uses dynamic real-time imaging to complement the physical examination and identify hemodynamic abnormalities in preload, contractility, and afterload conditions, but the contribution of cardiac POCUS in the context of pediatric brain injury is unclear. METHODS: We reviewed cardiac POCUS images integrated in clinical care to examine those with neurological injury and hemodynamic abnormalities. RESULTS: We discuss three children with acute brain injury and myocardial dysfunction identified using cardiac POCUS by bedside clinicians. CONCLUSIONS: Cardiac POCUS may have an important role in caring for children with neurologic injury. These patients received personalized care informed by POCUS data in attempts to stabilize hemodynamics and optimize clinical outcomes.

Cloning and functional characterization of a caffeic acid O-methyltransferase from Trigonella foenum-graecum L.

A cDNA encoding an O-methyltransferase (namely FGCOMT1) was identified from the medicinal plant Trigonella foenum-graecum L. The FGCOMT1 enzyme is a functional caffeic acid O-methyltransferase (COMT) and is localized in the cytosol. Kinetic analysis indicated that FGCOMT1 protein exhibited the highest catalyzing efficiency towards 5-hydroxy ferulic acid and caffeic acid as substrates, but did not possess the abilities to methylate either quercetin or tricetin in vitro. Furthermore, transformation of Arabidopsis loss-of-function Atomt1 mutant with a FGCOMT1 cDNA partially complements accumulation of sinapoyl derivatives but did not function to produce the major methylated flavonol isorhamnetin in seeds. The results from this study indicated that FGCOMT1 is a COMT with substrate preference to monomeric lignin precursors but is not involved in the flavonoid methylation in T. foenum-graecum L.

Metabolic engineering of isoflavone genistein in Brassica napus with soybean isoflavone synthase.

Genistein, 4',5,7-trihydroxyisoflavone, is an isoflavonoid compound predominantly restricted to legumes and known to possess phyto-oestrogenic and antioxidative activities. The key enzyme that redirects phenylpropanoid pathway intermediates from flavonoids to isoflavonoids is the isoflavone synthase (IFS). Brassica napus is a non-legume oilseed crop with vegetative tissues producing phenylpropanoids and flavonoids, but does not naturally accumulate isoflavones due to the absence of IFS. To demonstrate whether exogenous IFS is able to use endogenous substrate to produce isoflavone genistein in oilseed crop, the soybean IFS gene (GmIFS2) was incorporated into B. napus plants. The presence of GmIFS2 in B. napus was shown to direct the synthesis and accumulation of genistein derivatives in leaves up to 0.72 mg g(-1) DW. In addition, expression levels for most B. napus genes in the phenylpropanoid pathway were altered. These results suggest that the heterologous GmIFS2 enzyme is functionally active at using the B. napus naringenin as a substrate to produce genistein in oilseed rape.

Haemorrhagic shearing lesions associated with diffuse axonal injury: application of T2 star-weighted angiography sequence in the detection and clinical correlation.

PURPOSE: To assess the diagnostic value of T2 star-weighted angiography (SWAN) sequence for diffuse axonal injury (DAI) by virtue of correlation analysis between the number, volume and regional distribution of haemorrhagic lesions determined with SWAN sequence and clinical variables. METHODS: Twenty-eight DAI patients were included in our study and were divided into subgroups in compliance with dichotomized clinical variables separately. Global and regional number, volume and distribution of haemorrhagic lesions were compared between groups by non-parametric Mann-Whitney U test (two tailed) and independent samples t test. Spearman's rank correlation analysis was performed to compare the dichotomized clinical variables with the global and regional number and volume of lesions. RESULTS: Patients with lower Glasgow Coma Scale (GCS) score (≤8, n = 16) or prolonged coma (>4 days, n = 15) or abnormal pupillary light reflex (PLR, n = 15) had a greater global number (p ≤ 0.01) and apparent volume (p ≤ 0.01) of haemorrhagic lesions. In our study, haemorrhage extent in most brain regions, such as frontal white matter (FW), parietotemporaloccipital white matter (PTOW), corpus callosum (CC), thalamus (THAL), brain stem (BS), were greater in the lower GCS group, in the prolonged coma group and in the abnormal PLR group (p ≤ 0.05). Significant correlations were found between haemorrhage extent in global range and the dichotomized clinical variables (p ≤ 0.01). Correlations were also found between haemorrhage extent in most regions, such as FW, PTOW, CC, THAL and BS, and the dichotomized clinical variables (p ≤ 0.05). The number of involved regions was much more higher in the lower GCS group and the prolonged coma group (p < 0.0001). CONCLUSION: More accurate and objective assessment of injury can be obtained in DAI patients via SWAN sequence.

CD19+CD5+ B cells in primary IgA nephropathy.

The source of IgA and the mechanism for deposition of IgA in the mesangium remain unknown for primary IgA nephropathy. Because CD19(+)CD5(+) B cells are important producers of IgA and contribute to several autoimmune diseases, they may play an important role in IgA nephropathy. In this study, flow cytometry, quantitative PCR, and confocal microscopy were used to assess the frequency, distribution, Ig production, CD phenotypes, cytokine production, and sensitivity to apoptosis of CD19(+)CD5(+) B cells in the peripheral blood, peritoneal fluid, and kidney biopsies of 36 patients with primary IgA nephropathy. All patients with IgA nephropathy were significantly more likely to have CD19(+)CD5(+) B cells in the peripheral blood, peritoneal fluid, and kidney biopsies than were five control subjects and 10 patients with active systemic lupus erythematosus. The 33 patients who had IgA nephropathy and responded to treatment demonstrated a significant decrease in CD19(+)CD5(+) B cells in the peripheral blood, peritoneal fluid, and kidney (all P < 0.01). In the three patients who had IgA nephropathy and did not respond to treatment, the frequency of CD19(+)CD5(+) B cells did not change. CD19(+)CD5(+) B cells isolated from patients with untreated IgA nephropathy expressed higher levels of IgA, produced more IFN-gamma, and were more resistant to CD95L-induced apoptosis than cells isolated from control subjects and patients with lupus; these properties reversed with effective treatment of IgA nephropathy. In conclusion, these results strongly suggest that CD19(+)CD5(+) B cells play a prominent role in the pathogenesis of primary IgA nephropathy.

All roads lead to Rome: pathways of NKT cells promoting asthma.

NKT cells are the prominent manipulator in asthma development. Asthmatic NKT cells migrate from thymus, spleen, liver and bone marrow into blood vessels, and then concentrate in airway bronchi mucosa. This recruitment is dependent on high expression of CCR9 and engagement of CCL25/CCR9. NKT cells promote asthma in two different pathways. One is an indirect pathway. NKT cells contact with CD3(+) T cells and induce them secreting large quantity of Th2 cytokines (IL-4, IL-13), which requires the participation of dentritic cells and the synergic signaling of CCL25/CCR9 and CD226. The other is a direct pathway. Circulating asthmatic NKT cells selectively highly express Th1 cytokines (IFN-gamma). Once reached airway epithelium, most NKT cells shift to Th2-bias, highly expressing IL-4, IL-13, but not IFN-gamma. Both pathways lead to airway hyperresponsiveness and inflammation, asthma development. Comparing to the well documented suppressive regulatory T cells, CD4(+)CD25(+) T cells, NKT cells perform as a novel active regulator in asthma. These recent understanding of NKT cells performance in the development of asthma might unveil new therapy targets and management strategies for asthma.

High-spatial-resolution isotropic three-dimensional fast-recovery fast spin-echo magnetic resonance dacryocystography combined with topical administration of sterile saline solution.

OBJECTIVE: This study aims to investigate the clinical performance of three-dimensional (3D) fast-recovery fast spin-echo (FRFSE) magnetic resonance dacryocystography (MRD) with topical administration of sterile saline solution for the assessment of the lacrimal drainage system (LDS). METHODS: A total of 13 healthy volunteers underwent both 3D-FRFSE MRD and two-dimensional (2D)-impulse recovery (IR)-single-shot fast spin-echo (SSFSE) MRD after topical administration of sterile saline solution, and 31 patients affected by primary LDS outflow impairment or postsurgical recurrent epiphora underwent 3D-FRFSE MRD and conventional T1- and T2-weighted sequences. All patients underwent lacrimal endoscopy or surgery, which served as a standard of reference for confirming the MRD findings. RESULTS: 3D-FRFSE MRD detected more visualized superior and inferior canaliculi and nasolacrimal duct than 2D-IR-SSFSE MRD. Compared with 2D-IR-SSFSE MRD, 3D-FRFSE MRD showed more visualized segments per LDS, although the difference was not statistically significant. Significant improvements in the inferior canaliculus and nasolacrimal duct visibility grades were achieved using 3D-FRFSE MRD. 3D-FRFSE MRD had 100% sensitivity and 63.6% specificity for detecting LDS obstruction. In 51 out of the 62 LDSs that were assessed, a 90% agreement was noted between the findings of 3D-FRFSE MRD and lacrimal endoscopy in detecting the obstruction level. CONCLUSION: 3D-FRFSE MRD combined with topical administration of sterile saline solution is a simple and noninvasive method of obtaining detailed morphological and functional information on the LDS. Overall, 3D-FRFSE MRD could be used as a reliable diagnostic method in many patients with epiphora prior to surgery.

EBV-induced human CD8+ NKT cells suppress tumorigenesis by EBV-associated malignancies.

The underlying mechanism of the protective and suppressive role of NKT cells in human tumor immunosurveillance remains to be fully elucidated. We show that the frequencies of CD8(+) NKT cells in patients with EBV-associated Hodgkin's lymphoma or nasopharyngeal carcinoma are significantly lower than those in healthy EBV carriers. These CD8(+) NKT cells in tumor patients are also functionally impaired. In human-thymus-severe combined immunodeficient (hu-thym-SCID) chimeras, EBV challenge efficiently promotes the generation of IFN-gamma-biased CD8(+) NKT cells. These cells are strongly cytotoxic, drive syngeneic T cells into a Th1 bias, and enhance T-cell cytotoxicity to EBV-associated tumor cells. Interleukin-4-biased CD4(+) NKT cells are predominately generated in unchallenged chimeras. These cells are noncytotoxic, drive syngeneic T cells into a Th2 bias, and do not affect T-cell cytotoxicity. In humanized xenogeneic tumor-transplanted hu-thym-SCID chimeras, adoptive transfer with EBV-induced CD8(+) NKT cells significantly suppresses tumorigenesis by EBV-associated malignancies. EBV-induced CD8(+) NKT cells are necessary and sufficient to enhance the T-cell immunity to EBV-associated malignancies in the hu-thym-SCID chimeras. CD4(+) NKT cells are synergetic with CD8(+) NKT cells, leading to a more pronounced T-cell antitumor response in the chimeras cotransferred with CD4(+) and CD8(+) NKT cells. Thus, immune reconstitution with EBV-induced CD8(+) NKT cells could be a useful strategy in management of EBV-associated malignancies.

CCL19 and CXCL13 synergistically regulate interaction between B cell acute lymphocytic leukemia CD23+CD5+ B Cells and CD8+ T cells.

Interacting with T cells, cytokine-producing B cells play a critical protective role in autoimmune diseases. However, the interaction between malignant B and T cells remains to be fully elucidated. In a previous study, we have reported that ligation of CCL19-CCR7 and CXCL13-CXCR5 activates paternally expressed gene 10 (PEG10), resulting in an enhancement of apoptotic resistance in B-cell acute lymphocytic leukemia (B-ALL) CD23+CD5+ B cells. Here, we report that B-ALL CD23+CD5+ B cells produce IL-10 at high level, which can be further elevated by costimulation with CCL19 and CXCL13. CCL19/CXCL13-activated B-ALL CD23+CD5+ B cells, in turn, increase IL-10 expression in syngeneic CD8+ T cells in a B cell-derived IL-10-dependent manner and requiring a cell-cell contact. IL-10 secreted from B-ALL CD23+CD5+ B cells in vitro impairs tumor-specific CTL responses of syngeneic CD8+ T cells. The impairment of cytotoxicity of syngeneic CD8+ T cells is escalated by means of CCL19/CXCL13-induced up-regulation of IL-10 from B-ALL CD23+CD5+ B cells. Moreover, using a short hairpin RNA to knockdown PEG10, we provide direct evidence that increased expression of PEG10 in B-ALL CD23+CD5+ B cells is involved in malignant B-T cell interaction, contributing to the up-regulation of IL-10 expression, as well as to the impairment of cytotoxicity of syngeneic CD8+ T cells. Thus, malignant B-ALL CD23+CD5+ B cells play an immunoregulatory role in controlling different inflammatory cytokine expressions. IL-10 may be one of the critical cellular factors conferring B-ALL CD23+CD5+ B cells to escape from host immune surveillance.

Enhanced secretion and uptake of beta-glucuronidase improves adeno-associated viral-mediated gene therapy of mucopolysaccharidosis type VII mice.

Previous treatment of mucopolysaccharidosis type VII mice (Sly syndrome) with AAV vectors has resulted in increased levels of beta-glucuronidase (GUS) enzyme in some tissues with reduction of glycosaminoglycan storage granules and improved health. By adding coding sequences for secretion (Igkappa) and uptake (HIV-1 TAT) signals to the GUS gene delivered by AAV, and treating mice both intrathecally and intravenously as newborns, we have increased the GUS enzyme levels in more tissues and have improved the health of the mice so much that they are able to breed. The levels of GUS in the serum were above normal in some mice, which caused reduction of storage in the spleen, a nontransduced tissue. The heart and aorta showed therapeutic levels of GUS enzyme. AAV GUS DNA was found in brain and liver, which showed no storage. Phenotypically the treated mice were more active and showed less stunted skeletal growth. The pups born to these mice were not affected by the gene therapy, as shown by mutant levels of GUS enzyme in their tissues and the absence of AAV GUS DNA. However, they were resistant to intravenous treatment with AAV GUS due to the mother's antibodies, but not to intrathecal treatment.