PIWIL1 promotes gastric cancer via a piRNA-independent mechanism.

Targeted cancer therapy aims to achieve specific elimination of cancerous but not normal cells. Recently, PIWI proteins, a subfamily of the PAZ-PIWI domain (PPD) protein family, have emerged as promising candidates for targeted cancer therapy. PPD proteins are essential for small noncoding RNA pathways. The Argonaute subfamily partners with microRNA and small interfering RNA, whereas the PIWI subfamily partners with PIWI-interacting RNA (piRNA). Both PIWI proteins and piRNA are mostly expressed in the germline and best known for their function in transposon silencing, with no detectable function in mammalian somatic tissues. However, PIWI proteins become aberrantly expressed in multiple types of somatic cancers, thus gaining interest in targeted therapy. Despite this, little is known about the regulatory mechanism of PIWI proteins in cancer. Here we report that one of the four PIWI proteins in humans, PIWIL1, is highly expressed in gastric cancer tissues and cell lines. Knocking out the PIWIL1 gene (PIWIL1-KO) drastically reduces gastric cancer cell proliferation, migration, metastasis, and tumorigenesis. RNA deep sequencing of gastric cancer cell line SNU-1 reveals that KO significantly changes the transcriptome, causing the up-regulation of most of its associated transcripts. Surprisingly, few bona fide piRNAs exist in gastric cancer cells. Furthermore, abolishing the piRNA-binding activity of PIWIL1 does not affect its oncogenic function. Thus, PIWIL1 function in gastric cancer cells is independent of piRNA. This piRNA-independent regulation involves interaction with the UPF1-mediated nonsense-mediated mRNA decay (NMD) mechanism. Altogether, our findings reveal a piRNA-independent function of PIWIL1 in promoting gastric cancer.

Heat shock protein DNAJA1 stabilizes PIWI proteins to support regeneration and homeostasis of planarian Schmidtea mediterranea.

PIWI proteins are key regulators of germline and somatic stem cells throughout different evolutionary lineages. However, how PIWI proteins themselves are regulated remains largely unknown. To identify candidate proteins that interact with PIWI proteins and regulate their stability, here we established a yeast two-hybrid (Y2H) assay in the planarian species Schmidtea mediterranea We show that DNAJA1, a heat shock protein 40 family member, interacts with the PIWI protein SMEDWI-2, as validated by the Y2H screen and co-immunoprecipitation assays. We found that DNAJA1 is enriched in planarian adult stem cells, the nervous system, and intestinal tissues. DNAJA1-knockdown abolished planarian regeneration and homeostasis, compromised stem cell maintenance and PIWI-interacting RNA (piRNA) biogenesis, and deregulated SMEDWI-1/2 target genes. Mechanistically, we observed that DNAJA1 is required for the stability of SMEDWI-1 and SMEDWI-2 proteins. Furthermore, we noted that human DNAJA1 binds to Piwi-like RNA-mediated gene silencing 1 (PIWIL1) and is required for PIWIL1 stability in human gastric cancer cells. In summary, our results reveal not only an evolutionarily conserved functional link between PIWI and DNAJA1 that is essential for PIWI protein stability and piRNA biogenesis, but also an important role of DNAJA1 in the control of proteins involved in stem cell regulation.

Delivering siRNA and Chemotherapeutic Molecules Across BBB and BTB for Intracranial Glioblastoma Therapy.

For aggressive brain glioblastoma, the therapy is significantly impaired by blood-brain barrier (BBB) and blood-tumor barrier (BTB). Choosing more than one target from the pool of tumor-stroma interactions is profoundly beneficial to therapeutic approaches. Thus, a multifunctional liposomal system based on anchoring two receptor-specific and penetrable peptides was designed for the combination delivery of BBB-impermeable siRNA and chemotherapeutic docetaxel to brain glioblastoma. Both macroscopic and microscopic specific distributions and targeting effect of the liposomes in the intracranial glioblastoma were confirmed. Superiority in therapeutic efficacies of the siRNA and DTX combination delivery system was revealed from encouraged VEGF gene silencing, tumor cell apoptosis, prolonged survival time, subdued glioblastoma cells in intracranial glioblastoma, and negligible system toxicities after systemic application. Furthermore, the liposomes made better modulation of glioblastoma microenvironment such as the down-regulation of CD31-positive tumor vessels and HIF-1α expression. The transport mechanism of the liposomes delivering the cargos across BBB via receptor-mediated transcytosis without destroying the integrity of BBB has been evaluated from in vitro and in vivo. Therefore, the dual peptides-modified liposomal system provides a safe and noninvasive approach for the delivery of siRNA and chemotherapeutic molecules across the BBB and BTB to target therapy of brain glioblastoma.

Synthesis, antitumor evaluation and molecular docking studies of [1,2,4]triazolo[4,3-b][1,2,4,5]tetrazine derivatives.

A series of [1,2,4]triazolo[4,3-b][1,2,4,5]tetrazine derivatives have been synthesized and evaluated for their antitumor activities. These compounds exhibited potent antiproliferative activities against MCF-7, Bewo and HL-60 cells and c-Met kinase inhibitory activities. Three compounds were highly effective against MCF-7, Bewo and HL-60 cells with IC50 values in 1.09-2.24µM. Molecular docking was further performed to study the inhibitor-c-Met kinase interactions, and the results show that compound 4j was potently bound to the c-Met kinase with three hydrogen bonds. The further research on acute toxicity and in vivo antitumor activity of compound 4j to ICR (Institute of Cancer Research) mice were carried out, and found 4j with a certain toxicity but good efficacy in vivo. Based on the preliminary results, it is deduced that compound 4j with potent c-Met kinase inhibitory activity may be a potential anticancer agent.

Synthesis, antitumor evaluation and 3D-QSAR studies of [1,2,4]triazolo[4,3-b][1,2,4,5]tetrazine derivatives.

A series of [1,2,4]triazolo[4,3-b][1,2,4,5]tetrazine derivatives have been synthesized and their structures were confirmed by single-crystal X-ray diffraction. Compared to some reported structures of 1,6-dihydro-1,2,4,5-tetrazine, these compounds can't be considered as having homoaromaticity. Their antiproliferative activities were evaluated against MCF-7, Bewo and HL-60 cells in vitro. Two compounds were highly effective against MCF-7, Bewo and HL-60 cells with IC50 values in 0.63-13.12µM. Three-dimensional quantitative structure-activity relationship (3D-QSAR) studies of comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA) were carried out on 51 [1,2,4]triazolo[4,3-b][1,2,4,5]tetrazine derivatives with antiproliferative activity against MCF-7 cell. Models with good predictive abilities were generated with the cross validated q(2) values for CoMFA and CoMSIA being 0.716 and 0.723, respectively. Conventional r(2) values were 0.985 and 0.976, respectively. The results provide the tool for guiding the design and synthesis of novel and more potent tetrazine derivatives.

Enhance Cancer Cell Recognition and Overcome Drug Resistance Using Hyaluronic Acid and α-Tocopheryl Succinate Based Multifunctional Nanoparticles.

Multidrug resistance (MDR) presents a clinical obstacle to cancer chemotherapy. The main purpose of this study was to evaluate the potential of a hyaluronic acid (HA) and α-tocopheryl succinate (α-TOS) based nanoparticle to enhance cancer cell recognition and overcome MDR, and to explore the underlying mechanisms. A multifunctional nanoparticle, HTTP-50 NP, consisted of HA-α-TOS (HT) conjugate and d-α-tocopheryl polyethylene glycol succinate (TPGS) with docetaxel loaded in its hydrophobic core. The promoted tumor cell recognition and accumulation, cytotoxicity, and mitochondria-specific apoptotic pathways for the HTTP-50 NP were confirmed in MCF-7/Adr cells (P-gp-overexpressing cancer model), indicating that the formulated DTX and the conjugated α-TOS in the HTTP-50 NP could synergistically circumvent the acquired and intrinsic MDR in MCF-7/Adr cells. In vivo investigation on the MCF-7/Adr xenografted nude mice models confirmed that HTTP-50 NP possessed much higher tumor tissue accumulation and exhibited pronouncedly enhanced antiresistance tumor efficacy with reduced systemic toxicity compared with HTTP-0 NP and Taxotere. The mechanisms of the multifunctional HTTP-50 NP to overcome MDR and enhance antiresistance efficacy may be contributed by CD44 receptor-targeted delivery and P-gp efflux inhibition, and meanwhile to maximize antitumor efficacy by synergism of DTX and mitocan of α-TOS killing tumor cells.

Nitratireductor soli sp. nov., isolated from phenol-contaminated soil.

Strain ZZ-1(T), a Gram-negative, rod-shaped bacterium, motile by flagella, was isolated from phenol-contaminated soil. Strain ZZ-1(T) was found to grow at 15-37 °C (optimum 25-30 °C), at pH 6.0-10.0 (optimum pH 7.5) and with 0-8.0% (w/v) NaCl (optimum 0.5%). The isolate was found to be able to reduce nitrate to nitrite, but not to nitrogen. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain ZZ-1(T) is a member of the genus Nitratireductor, and shows high sequence similarities to Nitratireductor pacificus MCCC 1A01024(T) (98.5%) and lower (<97%) sequence similarities to all other Nitratireductor species. Chemotaxonomic analysis revealed that strain ZZ-1(T) possesses Q-10 as the predominant ubiquinone and Summed feature 8(C(18:1) ω6c and/or C(18:1) ω7c; 66.6%), C(19:0) ω8c cyclo (23.3%), C(18:0) (3.4%), iso-C(17:0) (2.3%) and C(17:0) (1.0%) as the major fatty acids. The polar lipids of strain ZZ-1(T) were determined to be diphosphatidylglycerol, phosphatidylcholine, phospholipids, aminolipids, a glycolipid and an aminophospholipid. The DNA G+C content was determined to be 64.1 mol%. Based on the draft genome sequence, the DNA-DNA hybridization estimate value between strain ZZ-1(T) and N. pacificus MCCC 1A01024(T) was 46.5 ± 3.0% and ANI was 75.9 %. The combination of phylogenetic analysis, phenotypic characteristics, chemotaxonomic data and DNA-DNA hybridization supports the conclusion that strain ZZ-1(T) represents a novel species of the genus Nitratireductor, for which the name Nitratireductor soli sp. nov. is proposed. The type strain is ZZ-1(T) (=JCM 30640(T) = MCCC 1K00508(T)).

Efficient CO2 capture by tertiary amine-functionalized ionic liquids through Li(+)-stabilized zwitterionic adduct formation.

Highly efficient CO2 absorption was realized through formation of zwitterionic adducts, combining synthetic strategies to ionic liquids (ILs) and coordination. The essence of our strategy is to make use of multidentate cation coordination between Li(+) and an organic base. Also PEG-functionalized organic bases were employed to enhance the CO2-philicity. The ILs were reacted with CO2 to form the zwitterionic adduct. Coordination effects between various lithium salts and neutral ligands, as well as the CO2 capacity of the chelated ILs obtained were investigated. For example, the CO2 capacity of PEG150MeBu2N increased steadily from 0.10 to 0.66 (mol CO2 absorbed per mol of base) through the formation of zwitterionic adducts being stabilized by Li(+).

[Risk Assessment of Antibiotics in Agricultural Environment].

Antibiotics are widely used in animal husbandry, planting, and aquaculture in agricultural industries. A large amount of the parent antibiotics used are released into the environment through discharge via feces and urine, posing potential risks to human health and ecosystems. It is thus very important to understand how antibiotics in the agricultural environment threaten the ecological environment and human health. Accordingly, risk assessment of antibiotics in the environment has become the research focus in recent years. The aim of this study was to review the risk assessment methods of antibiotics. The results showed that the ecological environment risk has mainly been assessed by the risk quotient (RQ). Predicted no-impact concentrations (PNECs) are an important indicator for ecological environment risk assessment, but a definite value is still controversial. The hazard quotient (HQ) is generally used to assess health risks. At present, it is necessary to clarify the selection of antibiotic exposure pathways and toxicological thresholds. However, neither of these two methods have currently considered either mixed pollution or the risk of antibiotic metabolites. Further analysis indicated that the ecological risks of antibiotics in the water environment and feces/manure/soil environment were widespread, which had an impact on both the soil and water environment. The types of antibiotics with high risk were different for various cultivated types. The factors including test species, testing conditions, calculation methods, and soil types all affected the detection of PNECs. Human health risk caused by dietary intake of antibiotics was minimal, but it cannot be ignored given the seafood consumption in coastal areas. Moreover, quinolones have both high ecological and human health risks in the agricultural environment. Based on the amount of antibiotics in agriculture and the residual concentration or toxicity of antibiotics in the related environment, this study proposed a priority-control list of antibiotics in the agricultural environment and summarized the main problems in the current antibiotic risk assessment. It will provide helpful support for the scientific optimization of antibiotic risk assessment and the effective control of antibiotics in agricultural environments.

Highly efficient SO2 absorption and its subsequent utilization by weak base/polyethylene glycol binary system.

A binary system consisting of polyethylene glycol (PEG, proton donor)/PEG-functionalized base with suitable basicity was developed for efficient gas desulfurization (GDS) and can be regarded as an alternative approach to circumvent the energy penalty problem in the GDS process. High capacity for SO(2) capture up to 4.88 mol of SO(2)/mol of base was achieved even under low partial pressure of SO(2). Furthermore, SO(2) desorption runs smoothly under mild conditions (N(2), 25 °C) and no significant drop in SO(2) absorption was observed after five-successive absorption-desorption cycles. On the other hand, the absorbed SO(2) by PEG(150)MeIm/PEG(150), being considered as the activated form of SO(2), can be directly transformed into value-added chemicals under mild conditions, thus eliminating the energy penalty for SO(2) desorption and simultaneously realizing recycle of the absorbents. Thus, this SO(2) capture and utilization (SCU) process offers an alternative way for GDS and potentially enables the SO(2) conversion from flue gas to useful chemicals as a value-added process.

Comparison of two stitches versus one stitch for emergency cervical cerclage to prevent preterm birth in singleton pregnancies.

OBJECTIVE: To compare the efficacy of two stitches versus one stitch in women with emergency cervical cerclage. METHODS: A retrospective case-control study of 26 women with singleton pregnancies who underwent emergency cervical cerclage before 26 weeks. A comparison was made between patients with two stitches versus one stitch at the time of cervical cerclage placement. The primary outcome was gestational age (GA) at delivery and preterm birth (PTB) before 37, 34, 32, 28, and 24 weeks. RESULTS: Average GA at delivery in the two-stitches group was significantly greater than in the one-stitch group (32.71 ± 5.54 weeks vs 27.99 ± 4.70 weeks, P = 0.028). There were significant decreases in the incidence of spontaneous PTB at <34 weeks and less than 32 weeks in the two-stitches group (P = 0.034; P = 0.013, respectively). The neonatal intensive care unit (NICU) admissions rate and length of stay in the NICU in the two-stitches group were significantly reduced (P = 0.035 and P = 0.018, respectively). However, there was no significant difference in neonatal mortality between the two groups. CONCLUSION: Compared with emergency cervical cerclage placement with one stitch, the procedure with two stitches can prolong the pregnancy and improve the neonatal prognosis more effectively.

A comparative study on the application of different endoscopic diagnostic methods in the differential diagnosis of benign and malignant bile duct strictures.

Objective: To compare the diagnostic value of cytobrush, ERCP-guided biopsy, SpyGlass direct visual impression and SpyGlass-guided biospy (SpyBite) in the differential diagnosis of benign and malignant bile duct strictures. Methods: The data of 1,008 patients who were clinically diagnosed with indeterminate biliary strictures and underwent ERCP-guided biopsy, cytobrush, SpyGlass direct visual impression or SpyBite at the First Affiliated Hospital of Nanchang University between January 2010 and December 2019 were collected and analyzed retrospectively. The final diagnose was determined by surgical pathological specimen or follow-up (Malignant stricture can be identified if the stricture showed malignant progression during one year of follow-up). The differential diagnostic value of the above endoscopic diagnostic methods was evaluated by means of sensitivity, specificity, accuracy, positive predictive value, negative predictive value, etc. and safety was evaluated by the incidence rate of adverse events. Results: In terms of sensitivity, standard biopsy group (48.6%) and SpyBite group (61.5%) were significantly higher than cytobrush group (32.0%), and visual impression group (100%) was significantly higher than any other group. As far as specificity was concerned, cytobrush group (99.0%), standard biopsy group (99.3%) and the SpyBite group (100%) were significantly higher than visual impression (55.6%), but there was no statistical difference among the three groups above. As far as accuracy was concerned, standard biopsy group (65.3%), and SpyBite group (80.0%) were significantly higher than cytobrush group (44.4%), and SpyBite group (80.0%) was significantly higher than visual impression group (54.8%). In terms of safety, visual impression group and SpyBite group were significantly higher than cytobrush group and standard biopsy group in post-ERCP cholangitis. Conclusion: SpyBite combined with SpyGlass-guided visual impression was better for differential diagnosis of benign and malignant bile duct strictures in terms of sensitivity and accuracy compared with conventional endoscopic diagnostic methods such as cytobrush and standard biopsy. Furthmore, the incidence rates of adverse events after SpyGlass examination was similar to those after conventional endoscopic diagnostic methods except for higher cholangitis, which could be controlled by antibiotics and might be avoided by adequate biliary drainage.

Andrographolide induces cell cycle arrest and apoptosis in human rheumatoid arthritis fibroblast-like synoviocytes.

The pseudo-tumoral expansion of fibroblast-like synoviocytes is a hallmark of rheumatoid arthritis (RA), and targeting rheumatoid arthritis fibroblast-like synoviocytes (RAFLSs) may have therapeutic potentials in this disease. Andrographolide, a diterpenoid compound isolated from the herb Andrographis paniculata, has been reported to have potent anti-inflammatory activity. In the present study, we aimed to investigate the effects of andrographolide on human RAFLSs and the underlying molecular mechanism(s). RAFLSs were isolated from patients with RA and treated with or without various concentrations (i.e., 10, 20, and 30 µM) of andrographolide for 48 h. 3-[4,5-Dimethyl-2-yl]-2,5-diphenyl tetrazolium bromide assay revealed that andrographolide treatment decreased the proliferation of RAFLSs in a dose-dependent manner. Cell cycle analysis using propidium iodide (PI) staining showed a G0/G1 cell cycle arrest in andrographolide-treated RAFLSs. Immunoblotting analysis of key cell cycle regulators demonstrated that andrographolide treatment caused a dose-dependent increase in the expression of cell-cycle inhibitors p21 and p27 and a concomitant reduction of cyclin-dependent kinase 4. Exposure to andrographolide-induced apoptosis of RAFLSs measured by annexin V/PI double staining, which was coupled with promotion of cytochrome C release from mitochondria and activation of caspase-3. Moreover, andrographolide-treated RAFLSs displayed a significant decrease in the Bcl-2/Bax ratio compared to untreated cells. In conclusion, our data demonstrate that andrographolide exerts anti-growth and pro-apoptotic effects on RAFLSs, thus may have therapeutic potential for the treatment of RA.

Highly efficient SO2 absorption/activation and subsequent utilization by polyethylene glycol-functionalized Lewis basic ionic liquids.

Up to now, flue-gas desulfurization (FGD) is one of the most effective techniques to control SO(2) emission from the combustion of fossil fuels. The conventional technology for FGD poses serious inherent drawbacks such as formation of byproducts and volatilization of solvents. In this work, polyethylene glycol (PEG)-functionalized Lewis basic ionic liquids (ILs) derived from DABCO were proved to be highly efficient absorbents for FGD due to its specific features such as high thermal stability, negligible vapor pressure, high loading capacity. Notably, PEG(150)MeDABCONTf(2) gave an extremely high SO(2) capacity (4.38 mol mol(-1) IL), even under 0.1 bar SO(2) partial pressure (1.01 mol mol(-1) IL), presumably owing to the strong SO(2)-philic characterization of the PEG chain. Furthermore, the absorbed SO(2) could be easy to release by just bubbling N(2) at room temperature, greatly reducing energy requirement for SO(2) desorption. In addition, SO(2)/CO(2) selectivity (110) of PEG(150)MeDABCONTf(2) is two times larger than the non-functionalized imidazolium IL (45). On the other hand, through activation of SO(2) with the tertiary nitrogen in the cation, Lewis basic ILs such as PEG(150)MeDABCOBr proved to be efficient catalysts for the conversion of SO(2) to some value-added chemicals such as cyclic sulfites without utilization of any organic solvent or additive. Thus, this protocol would pave the way for the development of technological innovation towards efficient and low energy demanded practical process for SO(2) absorption and subsequent transformation.

Equimolar CO2 capture by N-substituted amino acid salts and subsequent conversion.

Steric bulk controls CO(2) absorption: N-substituted amino acid salts in poly(ethylene glycol) reversibly absorb CO(2) in nearly 1:1 stoichiometry. Carbamic acid is thought to be the absorbed form of CO(2); this was supported by NMR and in situ IR spectroscopy, and DFT calculations. The captured CO(2) could be converted directly into oxazolidinones and thus CO(2) desorption could be sidestepped.

Case report: Amisulpride therapy induced reversible elevation of creatine kinase-MB and bradycardia in schizophrenia.

Introduction: Schizophrenia is regarded as one of the most severe, disabling, and costly mental illnesses. Hence, early effective prevention and treatment are critical to the prognosis of patients. Amisulpride, a first-line atypical antipsychotic medication that acts as a blocker of the D2 and D3 dopamine receptors, is used in varying doses for the treatment of both positive and negative symptoms of schizophrenia. Reversible amisulpride-induced elevation of the myocardial enzyme spectrum with bradycardia is a rare condition. Case presentation: We report a 26-year-old patient diagnosed with first-episode schizophrenia. This patient was treated with amisulpride (400 mg/d), but no clinical benefits were obtained. Meanwhile, amisulpride caused elevation of the myocardial enzyme spectrum with asymptomatic bradycardia. After stopping the medication, these parameters normalized. Conclusion: We described a rare side reaction of amisulpride. Psychiatrists should take this side effect seriously in the clinical setting. The mechanism of this adverse reaction warrants further investigation and debate. When this side effect occurs during treatment, reducing the dosage of amisulpride and subsequently discontinuing medication, along with monitoring the electrocardiogram and serum myocardial enzymes, may be the most appropriate treatment protocol.

[Preparation of rivastigmine liposome and its pharmacokinetics in rats after intranasal administration].

To prepare rivastigmine liposome, rivastigmine was loaded into liposome via ammonium sulfate gradient method. Its pharmacokinetic profile in rats was evaluated after intranasal administration. The size, zeta potential, entrapped efficiency and release of rivastigmine from the liposome in vitro were determined. Plasma concentration of rivastigmine was determined by high performance liquid chromatography-tandem mass spectrometry (HPLC/MS) using antipyrine as internal standard. The pharmacokinetic parameters were calculated by DAS 2.0. The entrapped efficiency of rivastigmine liposome was (33.41 +/- 6.58) %, with the mean diameter of 154-236 nm and zeta potential of (-10.47 +/- 2.41) mV. The release behavior of rivastigmine was fitting the first order equation in vitro. The pharmacokinetic studies indicated that the C(max), T(max) and AUC(0-infinity), of rivastigmine liposome were (1.50 +/- 0.15) mg x L(-1), 15 min and (89.06 +/- 8.30) mg x L(-') x min, respectively. Rivastimine liposome was absorbed rapidly, and could reach a certain concentration in rat plasma after intranasal delivery.

[Production of porcine blastocysts expressed EGFP by handmade cloning].

Production of transgenic animals via somatic cell nuclear transfer (SCNT) has been widely used worldwide. However, the application of SCNT is impeded by overall high costs and low efficiency. Here, we reported a modification of the existing technology in order to overcome some of the disadvantages associated with SCNT. Firstly, a marker gene, enhanced green fluorescent gene (EGFP), was transfected into pig fetal fibroblast cells, and was subsequently screened by fluorescent expression to ensure donor cells expressing EGFP. Porcine embryos expressing EGFP were then produced by a method called handmade cloning (HMC), a simplified method for micromanipulation. To demonstrate the concept, we collected a total of 378 fresh swine oocytes, from which 266 with the nucleus removed, obtained a total of 127 viable recombinant oocytes after fusion with EGFP-expressing cells. In vitro incubation of the 127 recombinant oocytes for approximately 144 hours resulted in successful generation of 65 viable embryos, with an average success rate of 52.1±8.3%. Compared with the traditional SCNT, the method of HMC is not only easy to operate, but also increases the rate of recombinant embryo significantly. Furthermore, the modified method no longer relies on expensive instrument like micromanipulator, facilitating the industrialization of transgenic animal production.

1-[3-(4-Methoxy-phen-yl)-6-methyl-1,6-dihydro-1,2,4,5-tetra-zin-1-yl]propanone.

In the title compound, C(13)H(16)N(4)O(2), the central tetra-zine ring adopts an unsymmetrical boat conformation with the two C atoms as flagpoles. This compound can be considered as having homoaromaticity.

1-Benzoyl-3,6-diphenyl-1,4-dihydro-1,2,4,5-tetra-zine.

In the title compound, C(21)H(16)N(4)O, the central tetra-zine ring adopts an unsymmetrical boat conformation with the two N atoms as the bow and stern. The crystal packing is stabilized by inter-molecular N-H-O hydrogen bonds.