Experimental detection of the diamino-pentazolium cation and theoretical exploration of derived high energy materials

In this work, we realized the detection of diamino-pentazolium cation (DAPZ+) in the reaction solution experimentally and proved it to be meta-diamino-pentazole based on the transition state theory. Quantum chemical methods were used to predict its spectral properties, charge distribution, stability and aromaticity. Considering that DAPZ+ has excellent detonation properties, it was further explored by assembling it with N5-, N3- and C(NO2)3- anions, respectively. The results show a strong interaction between DAPZ+ and the three anions, which will have a positive effect on its stability. Thanks to the high enthalpy of formation and density, the calculated detonation properties of the three systems are exciting, especially [DAPZ+][N5-] (D: 10,016 m·s-1; P: 37.94 GPa), whose actual detonation velocity may very likely exceed CL-20 (D: 9773 m·s-1). There is no doubt that this work will become the precursor for the theoretical exploration of new polynitrogen ionic compounds.

2,2'-Azobis(1,5'-bitetrazole) with a N10 Chain and 1,5'-Bitetrazolate-2N-oxides: Construction of Highly Energetic Nitrogen-Rich Materials Based on C-N-Linked Tetrazoles

A series of high-nitrogen compounds, including a unique molecule 2,2'-azobis(1,5'-bitetrazole) with a branched N10 chain and 1,5'-bitetrazolate-2N-oxides, were synthesized successfully based on C-N-linked 1,5'-bistetrazoles using azo coupling of N-amine bonds and N-oxide introduction strategies. All compounds were characterized by NMR spectroscopy, IR spectroscopy, elemental analysis, and differential scanning calorimetry, in which the structures of five compounds were further determined by single-crystal X-ray diffraction analysis (2, T-N10B, 3a, 3b, and THX). The nitrogen contents of these five compounds range from 63.62 (THX) to 83.43% (T-N10B), which are much higher than that of CL-20 (38.34%). The heat of formation for the prepared compounds was calculated by using the Gaussian 09 program, with T-N10B having the highest value of 5.13 kJ g-1, about 6 times higher than that of CL-20 (0.83 kJ g-1). The calculated detonation performances by EXPLO5 v6.05.04 show that THX has excellent detonation performance (D = 9581 m s-1, P = 35.93 GPa) and a remarkable specific impulse (Isp = 284.9 s).

Why can’t cyclo-pentazolate anion in Oxone solution be N-oxidized?

When cyclo-pentazolate anion (N5-) was treated with Oxone, a peak of m/z = 86 in the Liquid Chromatograph Mass Spectrometer (LC-MS) was detected, the same molecular weight as the pentazolate...

Improving stability of the hydrazinium pentazolate through cocrystallization

An energetic cocrystal of hydrazinium cyclo-pentazolate and pyrazine-1,4-dioxide (2:1), N2H5N5/PDO, was synthesized. The cocrystal, as characterized by single-crystal X-ray diffraction, IR, Raman, XRD, and elemental analysis, has higher density, lower...

Embryonal rhabdomyosarcoma of oropharynx in a 65-year-old male with indolent clinical presentation and unusual morphology

Introduction/Objective

Embryonal rhabdomyosarcoma (ERMS) is a malignant primitive mesenchymal tumor which commonly affects children and adolescence. Although head and neck area is a common location for ERMS, oropharynx is rarely involved. ERMS in adults often present with stage IV disease and show a relatively poor prognosis. Loss of heterozygosity in 11p15.5 is one of the common genetic findings in sporadic ERMS.

Methods/Case Report

A 65-year-old male with no significant medical history, presented with pharyngodynia and was found to have a polypoid mass originating from the pharyngeal surface of the soft palate and extends into the vallecula. He reported having this mass for a decade and having intermittent episodes of similar oropharyngeal symptoms which were usually resolved with antibiotics.

Results (if a Case Study enter NA)

Excisional biopsy shows a 2.4 cm polypoid mass with atypical cellular proliferation in submucosa. Tumor cells demonstrate ovoid to round nuclei and eosinophilic cytoplasm. No mitotic figure was found and Ki67 proliferation index was extremely low (<1%). Immunostains showed that the tumor cells are positive for Desmin and MyoD1. Scattered cells are positive for Myogenin. Due to the unusual clinical presentation and low proliferation activity, late onset of fetal rhabdomyoma was also considered in the differential diagnosis. The specimen was sent for chromosomal microarray which showed chromosomal gains and losses including loss of heterozygosity in chromosome 11. This finding together with cytologic atypia are mostly compatible with the diagnosis of ERMS. Post-biopsy MRI and PET-CT did not reveal any residual disease or distant metastasis. Patient has been followed up for 6 months after biopsy with no sign of recurrence.

Conclusion

Our case indicates that ERMS in adult can present with an indolent clinical process and low proliferating activity. Diagnosis can be challenging in this scenario. Chromosomal microarray is a useful tool to help confirm the diagnosis.

Fascinating 3D energetic [Ag2(N5)2(EDA)]n: filling the ethylenediamine molecules into [Ag(N5)]n framework

An interesting 3D energetic motif based on Ag(I) ion, cyclo-pentazolate anion (cyclo-N5-) and ethylenediamine (EDA), namely, [Ag2(N5)2(EDA)]n, was prepared through embedding the ethylenediamine molecules into [Ag(N5)]n structure. The architecture was...

Co-utilization of lake sediment and blue-green algae for porous lightweight aggregate (ceramsite) production

Lake sediment and algal sludge with large output posed significant environmental risks. In this work, an idea of co-utilization of both solid wastes for the production of ceramsite (a sort of porous lightweight aggregates as building materials) was proposed and validated for the first time. The treatment process contained a dewatering step by a flocculation-pressure filtration method, and a sintered ceramsite preparation step. Effects of flocculant type and dosage on the dewatering performance were studied in the first step. An environmental-friendly amphoteric starch flocculant with a dosage of 12 mg/(g dried sample) was found to achieve the best dewatering performance. Effects of raw material mass ratio, sintering temperature and time in the second step were investigated. Under the optimal conditions (60 wt% of dewatered sediment; 20 wt% of dewatered algal sludge; 20 wt% of additives (fly ash: calcium oxide: kaolin = 2:1:2); sintering temperature: 1100 °C; time: 35 min), the obtained ceramsite met the Chinese National Standard as a qualified building material, with reliable environmental safety according to the leaching results for both heavy metals and microcystins. Both environmental and economic benefits of the proposed treatment were assessed. The process completely followed the rules of "reduction, harmlessness and resource utilization" for solid waste treatment and disposal; Meanwhile, the profit of the proposed ceramsite production could be more than 2.3 US dollar/m³. The co-utilization method in this work acted as a good example for the comprehensive management of solid wastes in water-rich areas.

[Na4(N5)4(H2O)2]•H2O•2MeOH: a honeycomb-like sodium-pentazolate-framework with helical chains

A new NaN5 framework [Na4(N5)4(H2O)2]•H2O•2MeOH was synthesized by changing the content of auxiliary ligand. It features an UNJ-type zeolite topology with double right-handed helix chains construct enclosed channels filled with...

Mass-forming chronic invasive fungal sinusitis; an uncommon mimicker of head & neck malignancy

Introduction/Objective

Invasive fungal sinusitis is a progressive infection affecting the nasal cavity and associated sinus spaces. Acute forms affect immunocompromised patients with debilitating systemic diseases while chronic forms usually occur in immunocompetent individuals.

Methods/Case Report

A 26-year-old immunocompetent male with daily Marijuana smoking consulted for acute swelling of the right eye with dull pain, photophobia, loss of vision and pressure of 4 day duration. He reported nasal congestion for approximately one year and over the previous 2 months developed exophthalmos. Imaging demonstrated a 4.9 x 4.3 x 4.1 cm invasive soft tissue mass in the right lamina papyracea with involvement of the paranasal sinus, right orbit, and intracranial space. The mass was presumed to represent a high-grade malignancy.

Biopsy was performed and demonstrated granulomatous invasive fungal sinusitis. The patient underwent right orbitotomy and right extranasal ethmoidectomy. He was begun on empiric amphotericin B. After culture and sequencing identification of Curvularia species, voriconazole was added. Follow up imaging studies after two month of treatment still demonstrated residual mass forming lesion with 10-20% decrease in size. The patient has regained his vision after 4 month of treatment and he is expected to complete a six months course. If the mass forming lesion persists, a second round of surgical debridement will be performed.

Results (if a Case Study enter NA)

N/A

Conclusion

Curvularia is a dematiaceous fungus most commonly associated with allergic sinusitis, but can rarely become invasive in immunocompetent individuals. Histopathologically large fungal elements are easily recognizable but specific identification requires culture or ribosomal DNA sequencing by PCR. Mass-forming chronic fungal sinusitis overlaps clinically and radiologically with head and neck malignancies. Our report brings attention to this uncommon clinical variant of invasive fungal sinusitis that affects immunocompetent individuals.

Amyloid deposition in oral cavity and larynx, a single institute experience

Introduction/Objective

Amyloidosis is characterized by extracellular accumulation of insoluble amyloid fibril. Amyloid deposition in the head and neck area is rare.

Methods/Case Report

In this study, we reviewed 34 specimens from 26 patients including: 18 specimens from the larynx and/or pharynx (13 patients) and 16 specimens from the oral cavity (13 patients). The clinical presentation, related laboratory results, and pathologic finding were reviewed.

Results (if a Case Study enter NA)

Within the 18 laryngeal specimens were: 10 glottic, 4 supraglottic, 3 nasopharyngeal or pharyngeal wall, and 1 subglottic. Of the 16 cases from oral cavity there were 9 lingual, 3 labial, 2 palatine, 1 tonsillar, and 1 alveolar ridge. Ten out of 13 patients with laryngeal amyloid deposition had protein electrophoresis performed and only 3 of the patients had monoclonal light chain detected. Among these three patients, one had multiple myeloma, one had lymphoplasmacytic lymphoma and one had the diagnosis of plasma cell dyscrasia. Interestingly, in the patients with oral cavity amyloidosis, 10 out of 11 patients tested had abnormal findings. Six of the patients had monoclonal light chain, two demonstrated monoclonal peak of IgG kappa, one with IgG lambda and one with IgA lambda. Among these 10 patients, 6 of them had biopsy-proved or history of multiple myeloma, one patient had marginal zone lymphoma, two patients had systematic amyloidosis. Only one patient did not have any malignancy or systematic involvement identified.

Conclusion

In our small cohort, the most common location of amyloid deposition in the larynx is glottis. When it involves the oral cavity, tongue is the most common location. Compared to the larynx, amyloid deposition in the oral cavity tends to be associated with hematopoietic malignancy or systematic involvement, although this finding needs to be confirmed by a larger scale of study.

Cell-free DNA from bile outperformed plasma as a potential alternative to tissue biopsy in biliary tract cancer

BACKGROUND

Biliary tract cancers (BTCs) are rare and highly heterogenous malignant neoplasms. Because obtaining BTC tissues is challenging, the purpose of this study was to explore the potential roles of bile as a liquid biopsy medium in patients with BTC.

PATIENTS AND METHODS

Sixty-nine consecutive patients with suspected BTC were prospectively enrolled in this study. Capture-based targeted sequencing was performed on tumor tissues, whole blood cells, plasma, and bile samples using a large panel consisting of 520 cancer-related genes.

RESULTS

Of the 28 patients enrolled in this cohort, tumor tissues were available in eight patients, and plasma and bile were available in 28 patients. Somatic mutations were detected in 100% (8/8), 71.4% (20/28), and 53.6% (15/28) of samples comprising tumor tissue DNA, bile cell-free DNA (cfDNA), and plasma cfDNA, respectively. Bile cfDNA showed a significantly higher maximum allele frequency than plasma cfDNA (P = 0.0032). There were 56.2% of somatic single-nucleotide variant (SNVs)/insertions and deletions (indels) shared between bile and plasma cfDNA. When considering the genetic profiles of tumor tissues as the gold standard, the by-variant sensitivity and positive predictive value for SNVs/indels in bile cfDNA positive for somatic mutations were both 95.5%. The overall concordance for SNVs/indels in bile was significantly higher than that in plasma (99.1% versus 78.3%, P < 0.0001). Moreover, the sensitivity of CA 19-9 combined with bile cfDNA achieved 96.4% in BTC diagnosis.

CONCLUSION

We demonstrated that bile cfDNA was superior to plasma cfDNA in the detection of tumor-related genomic alterations. Bile cfDNA as a minimally invasive liquid biopsy medium might be a supplemental approach to confirm BTC diagnosis.

[Expression profile of intervertebral disc degeneration-specific genes: a transcriptome sequencing-based analysis]

OBJECTIVE

To identify new therapeutic targets for intervertebral disc degeneration (IDD) by analyzing gene variations in IDD.

OBJECTIVE

We analyzed surgical samples of intervertebral disc from 4 patients with IDD and 3 patients with non-IDD using RNA sequencing (RNA-seq) technology to identify significant differentially expressed genes (DEGs) in IDD. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) databases were utilized for gene enrichment studies to acquire the key genes and signal pathways during IDD progression. The differential expressions of the identified genes in IDD were validated in clinical samples with qRT-PCR.

OBJECTIVE

The transcriptome profile revealed 512 significant DEGs, which were enriched in terms of keratinization, extracellular matrix (ECM) components, growth factor binding, and inflammatory chemotaxis in GO analysis. The top 10 terms of KEGG enrichment included amoebiasis, viral protein interaction with cytokine and cytokine receptor, ECM-receptor interaction, IL-17 signaling pathway, cytokine-cytokine receptor interaction, TNF signaling pathway, AGE-RAGE signaling pathway in diabetic complications, PI3K-Akt signaling pathway, chemokine signaling pathway and estrogen signaling pathway. Thirteen DEGs selected as the targets for qRT-PCR validation showed significant differential expressions in IDD (P < 0.001), and their expression trends were all consistent with the results of RNA-seq. Among these genes, 10 genes showed significant intergroup fold change (Log2FoldChange>1).

OBJECTIVE

ECM, growth factors, collagen components, inflammatory chemokines and such signal pathways as TNF-α and PI3K-Akt all have important contributions to IDD progression and may thus serve as new therapeutic targets for treatment of IDD.

Role of moderately hydrophobic chitosan flocculants in the removal of trace antibiotics from water and membrane fouling control

In this paper we describe the preparation and testing of a new class of chitosan-based flocculants for the treatment of surface waters containing antibiotic compounds. Three forms of moderately hydrophobic chitosan flocculants (MHCs) were prepared by chemically grafting hydrophobic branches with different lengths onto hydrophilic chitosan and these were evaluated by jar tests and a bench-scale continuous flow ultrafiltration (UF) membrane process with coagulation/sedimentation pre-treatment. Tests were conducted using both synthetic and real surface water in which norfloxacin and tylosin were added as representative antibiotics at an initial concentration of 0.1 μg/L. In jar tests, the MHCs achieved similar high removal efficiencies (REs) of turbidity and UV₂₅₄ absorbance, but much higher REs of the two antibiotics (71.7-84.7% and 68.7-76.6% for synthetic and river waters, respectively), compared to several commercial flocculants; the superior performance was attributed to an enhanced hydrophobic interaction and H-bonding between the flocculants and antibiotics. The presence of suspended kaolin particles and humic acid enhanced the antibiotic removal, speculated to be through MHC bridging of the kaolin/humic acid and antibiotic molecules. In the continuous flow tests involving flocculation/sedimentation-UF for 40 days, an optimal MHC achieved a much greater performance than polyaluminium chloride in terms of the overall removal of antibiotics (RE (norfloxacin) of ∼90% and RE (tylosin) of ∼80%) and a greatly reduced rate of membrane fouling; the latter resulting from a more porous and looser structure of cake layer, caused by a surface-modification-like effect of residual MHC on the hydrophobic PVDF membrane. The results of this study have shown that MHCs offer a significant advance over the use of existing flocculants for the treatment of surface water.

Nitrogen-Free Cationic Starch Flocculants: Flocculation Performance, Antibacterial Ability, and UF Membrane Fouling Control

In light of growing concerns about the formation of nitrogen-based disinfection byproducts (N-DBP) and the possible contribution from the use of quaternary-ammonium-containing flocculants, there is growing interest in the alternative use of quaternary phosphonium salts, which have been reported to have a lower DBP formation potential, stronger cationic properties, lower cytotoxicity, and greater stability. In this study, the performance of N-free quaternary-phosphonium-modified starch flocculants (S-BTP), synthesized through a facile one-step method using commercially available raw materials, in the treatment of bacteria-laden waters (E. coli as the model bacteria) was assessed in both jar tests and a bench-scale continuous-flow flocculation-sedimentation-ultrafiltration process. In jar tests, the effects of the cationic degree of substitution (DS) and dosage of the flocculant, solution pH, and presence of model contaminants on treatment performance were studied. One particular flocculant (S-BTP3), with a DS of 19.3%, displayed high removal efficiencies of E. coli, turbidity, and UV₂₅₄ from water, comparable with those of ammonium-based analogues and conventional alum, via a combination of charge attraction, polymer bridging, and antibacterial effects. S-BTP3 also possessed better bactericidal properties (99.4% of E. coli killed) than alum (41.4% killed) and did not cause the release of intracellular substances into the treated water. In the continuous-flow flocculation-sedimentation-UF tests, S-BTP3 was superior to alum in the flocculation and antibacterial performance, and in mitigating UF membrane fouling. The results have clearly demonstrated the multiple benefits of the use of N-free cationic starch flocculants in water treatment as an alternative to conventional chemicals.

H9N2 influenza virus isolated from minks has enhanced virulence in mice

H9N2 is one of the major subtypes of influenza virus circulating in poultry in China, which has a wide host range from bird to mammals. Two H9N2 viruses were isolated from one mink farm in 2014. Phylogenetic analysis showed that internal genes of the H9N2 viruses have close relationship with those of H7N9 viruses. Interestingly, two H9N2 were separated in phylogenetic trees, indicating that they are introduced to this mink farm in two independent events. And further mice studies showed that one H9N2 caused obvious weight loss and 20% mortality in infected mice, while another virus did not cause any clinical sign in mice infected at the same dose. Genetic analysis indicated that the virulent H9N2 contain a natural mutation at 701N in PB2 protein, which was reported to contribute to mammalian adaptation. However, such substitution is absent in the H9N2 avirulent to mice. Circulation of H9N2 in mink may drive the virus to adapt mammals; continual surveillance of influenza virus in mink was warranted.

[Clinical analysis of 384 cases of benign paroxysmal positional vertigo]

Objective:To study the disease characteristics in cases with benign paroxysmal positional vertigo(BPPV).Method:The characteristics and clinical features of 384 cases with BPPV were retrospectively analyzed,and all cases were treated with repositioning maneuver.The treatment outcomes were observed and analyzed during the follow-up period. Result:①Of the 384 cases,331(86.20%) cases were PC-BPPV, 47(12.24%) cases were HC-BPPV and 3(0.78%) cases were AC-BPPV, 3(0.78%) cases were combined semicircular canal BPPV. ②All cases underwent repositioning maneuver, PC-BBPV cases first efficiency was 93.66%, long-term (six months) efficiency was 96.68%; HC-BBPV cases first efficiency was 91.49%, long-term (six months) efficiency was 95.74%;AC-BPPV cases first efficiency and long-term efficiency were 66.67%;combined semicircular canal BPPV cases first efficiency and long-term efficiency were 66.67%.③Among 331 cases with PC-BBPV, cases diagnosed duct stones accounted for 96.37%,cases diagnosed crest stones accounted for 3.63%. Among 47 cases with HC-BBPV, cases diagnosed duct stones accounted for 78.72%，cases diagnosed crest stones accounted for 21.28%.④During the follow-up of six months,the recurrence rate was 12.76%(49/384). Conclusion:①In BPPV cases of Guangxi,the ratio of male and female,age of onset and the incidence of BPPV in each semicircular canal are consistent with other literatures.Geographical and ethnic factors do not affect the above results.②Repositioning maneuver is an simple and effective treatment for cases with BPPV.③There is higher recurrence rate in cases with BPPV after repositioning maneuver.

Dihydroartemisinin attenuates lipopolysaccharide-induced osteoclastogenesis and bone loss via the mitochondria-dependent apoptosis pathway

Dihydroartemisinin (DHA) is a widely used antimalarial drug isolated from the plant Artemisia annua. Recent studies suggested that DHA has antitumor effects utilizing its reactive oxygen species (ROS) yielding mechanism. Here, we reported that DHA is inhibitory on lipopolysaccharide (LPS)-induced osteoclast (OC) differentiation, fusion and bone-resorption activity in vitro. Intracellular ROS detection revealed that DHA could remarkably increase ROS accumulation during LPS-induced osteoclastogenesis. Moreover, cell apoptosis was also increased by DHA treatment. We found that DHA-activated caspase-3 increased Bax/Bcl-2 ratio during LPS-induced osteoclastogenesis. Meanwhile, the translocation of apoptotic inducing factor (AIF) and the release of cytochrome c from the mitochondria into the cytosol were observed, indicating that ROS-mediated mitochondrial dysfunction is crucial in DHA-induced apoptosis during LPS-induced osteoclastogenesis. In vivo study showed that DHA treatment decreased OC number, prevents bone loss, rescues bone microarchitecture and restores bone strength in LPS-induced bone-loss mouse model. Together, our findings indicate that DHA is protective against LPS-induced bone loss through apoptosis induction of osteoclasts via ROS accumulation and the mitochondria-dependent apoptosis pathway. Therefore, DHA may be considered as a new therapeutic candidate for treating inflammatory bone loss.

Effects of rifampicin on osteogenic differentiation and proliferation of human mesenchymal stem cells in the bone marrow

This study was designed to investigate the effect of different concentrations of rifampicin on osteogenic differentiation and proliferation of mesenchymal stem cells (MSCs) in human bone marrow. Rifampicin treatment at 0, 4, 8, 16, 32, 64, and 128 mg/mL was applied throughout the whole process, from stromal cells purified from human bone marrow to differentiated bone cells. The effect of rifampicin on MSC proliferation was determined using the MTT assay. The effect of rifampicin on the expressions of type I collagen (COL1A1), osteopontin/bone Gla protein (OPN/BGP), and alkaline phosphatase (ALP) in human osteoblast cells were determined by real-time polymerase chain reaction, and the expressions of COL1A1, OPN/BGP, and the runt-related transcription factor (RUNX2) were determined by Western blot. Results showed that the proliferation of MSCs was significantly inhibited when the rifampicin concentration exceeded 32 mg/mL. In addition, increased rifampicin concentrations inhibited the formation of calcium nodules, OPN/BGP, and COL1A1 in osteoblasts after 28 days of induction. The RNA expressions of OPN/BGP, COL1A1, and ALP were significantly downregulated compared to those of the control group in osteoblasts after induction. The protein expressions of RUNX2, COL1A1, and OPN/BGP were also significantly downregulated compared to those of the control group after induction. In conclusion, rifampicin at exorbitant concentration exerts adverse effects on the proliferation of MSCs in human bone marrow and the differentiation of osteoblasts.

An introduction to clinical practice guideline for Chinese undergraduates in stomatology

The Society of Dental Education, Chinese Stomatological Association has formulated the Standards of Clinical Practice for Chinese Undergraduate Students Majoring in Stomatology, on the basis of extensively soliciting the views of experts in various fields. The aim of this standard is to guide clinical teaching and improve teaching quality in schools of stomatology in China. The standards include eight parts: the standard of clinical practice for oral and maxillofacial surgery, for cariology and endodontics, for periodontics, for the oral mucosa diseases, for preventive dentistry, for pedodontology, for prosthodontics and for oral imageology. Each part includes introduction to subjects, the clinical practice time period, the purpose and requirements of practice, the disease types of practice and items of clinical operation, the index of the lowest workload of practice and the major methods of assessment. These standards are not only the basic requirements and guiding principles for clinical teaching, but also the major criteria for assessing the clinical teaching quality of stomatological colleges/schools of China.

MicroRNA-196a promotes cervical cancer proliferation through the regulation of FOXO1 and p27Kip1

Background:

The phosphoinositide 3-kinase (PI3K)/Akt signalling pathway appears to be a key regulator in cervical carcinogenesis. However, the downstream regulatory mechanism of PI3K/Akt signalling remains largely unknown.

Methods:

The expression of miR-196a in cervical cancer cell lines and cervical cancer tissues was examined using real-time PCR. The effects of miR-196a on PI3K/Akt signalling and cellular proliferation were evaluated by bromodeoxyuridine labelling, 3-(4,5-Dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazoliumbromide, colony formation assays and luciferase assays.

Results:

The expression level of miR-196a was markedly increased in cervical cancer tissues and cell lines compared with normal cervical tissue and normal cervical squamous cells. Upregulation of miR-196a was correlated with advanced tumour stage and poor overall and recurrence-free survival in cervical cancer patients. Upregulation of miR-196a enhanced G1/S-phase transition and the proliferative ability of cervical cancer cells, whereas suppression of miR-196a had the opposite effect. Using bioinformatics and biological approaches, we showed that FOXO1 and p27^Kip1, two key effectors of PI3K/Akt signalling, were direct targets of miR-196a.

Conclusions:

Our findings suggest that miR-196a has an important role in promoting human cervical cancer cell proliferation and may represent a novel therapeutic target of microRNA-mediated suppression of cell proliferation in cervical cancer.

Morphologies of fibroblast cells cultured on surfaces of PHB films implanted by hydroxyl ions

Polyhydroxybutyrate (PHB) films were implanted with 40 keV hydroxyl ions with fluences ranging from 1 x 10(12) to 1 x 10(15) ions/cm2, respectively. The as-implanted PHB films were characterized by scanning electron microscopy (SEM), electron spectroscopy for chemical analysis (ESCA) and water contact angle measurements. The surface structures and properties of the as-implanted PHB films were closely related with hydroxyl ion fluence. They were further investigated by inoculating 3T6 fibroblasts cells on their surfaces. Morphologies of the 3T6 fibroblast cells cultured on surfaces of the as-implanted PHB films were observed by SEM. Characterization of the cultural 3T6 cells was analyzed qualitatively. The preliminary experimental results reveal that the bioactivity of the PHB films modified by hydroxyl ion implantation was improved at different levels, and the fluence of 1 x 10(13) ions/cm2 is optimal for PHB film.

Intermolecular double-quantum coherence MR microimaging of pig tail with unique image contrast

Image contrast in intermolecular double-quantum coherence (iDQC) imaging of a pig tail was investigated on a 7.05-T microimaging scanner. In addition to TR (repetition time) and TE (echo time), the time interval tau between radio frequency pulses during iDQC evolution and the areas under the iDQC-encode gradients in the iDQC imaging sequence were also used to manipulate image contrast. When suitable imaging parameters were selected, images with unique contrast, such as those with certain regions of the sample highlighted, were obtained without using contrast agents. The effects of iDQC-encode gradient on image contrast were studied quantitatively, and the unique contrast imposed by the related diffusion weighting was also shown. Experimental results demonstrated that the iDQC images have contrast fundamentally different from the conventional single-quantum coherence images.

A new molecular simulation software package--Peking University Drug Design System (PKUDDS) for structure-based drug design

We present a comprehensive molecular simulation program package, the Peking University Drug Design System (PKUDDS), which runs on personal computers. PKUDDS has been developed mainly for computer-aided drug design using the methods of two-dimensional quantitative structure-activity relationships, three-dimensional quantitative structure-activity relationships, molecular docking, and database screening. This study presents an overview of its functionality, especially of methods developed in our group. PKUDDS uses genetic algorithms in molecular docking, conformational analysis, and quantitative structure-activity relationships as the most useful optimization technique. A user-friendly graphical interface provides easy access to many functions of PKUDDS. We report some examples of our considerable research using PKUDDS.

Analysis of multiple samples using multiplex sample NMR: selective excitation and chemical shift imaging approaches

Two improved approaches for the rapid analysis of multiple samples using multiplex sample NMR are described. In the first approach, frequency-selective 90 degrees radio frequency pulses and large pulsed field gradients are applied to excite and detect multiple samples in rapid succession. This method is advantageous for samples with relatively long longitudinal (T1) relaxation times. In the second approach, chemical shift imaging is applied to acquire both the spectral and spatial information of multiple samples simultaneously. Chemical shift imaging is more time-consuming than selective excitation; however, it is advantageous for detecting samples with short T1's and for signal averaging. Both approaches demonstrate the potential of multiplex sample NMR for carrying out high-throughput NMR detection.

Activity of the botanical aphicides 1,5-diphenyl-1-pentanone and 1,5-diphenyl-2-penten-1-one on two species of Aphididnae

1,5-Diphenyl-1-pentanone (A) and 1,5-diphenyl-2-penten-1-one (B) are natural products extracted for the first time from Stellera chamaejasme. Laboratory bioassay showed that the two products have strong contact activity and very good anti-feedant activity against Aphis gossypii and Schizaphis graminum. Both products showed dose-dependent relationships for both forms of activity against the two aphids, the contact activity of B being about twice that of A. Both products were inferior to methomyl in contact activity but superior in anti-feedant activity against the two aphids. This is the first report of aphicidal activity in these two compounds, which may represent a new class of aphicide.

Cysteine-independent polymerization of metallothioneins in solutions and in crystals

Polymerization of metallothioneins is one of the usually encountered puzzles during the research process of metallothioneins' structure and function. Our work focuses on the cysteine independently occurred polymerization from metallothioneins monomers in different milieus, while it leaves out the aggregation caused by the oxidation of cysteine, because the latter circumstance is the result of purification lapsus. After the purification of metallothioneins monomers, a dynamic light-scattering technique is used to detect the polymerized states of rabbit liver metallothionein I and II in different buffers, which is the first systematical detection of polymerized states of metallothioneins in solutions. The effects of different compositions of each buffer are discussed in details. Steric complementarity, hydrophobic, and electrostatic interaction characteristics are studied, following the modeling of monomers and relevant polymers of rat metallothionein II, rabbit liver metallothionein I and II. These theoretical calculations are the first complete computer simulations on different factors affecting metallothioneins' polymerization. A molecular recognition mechanism of metallothioneins' polymerization in solutions is proposed on the bases of experimental results and theoretical calculations. Preliminary X-ray studies of two crystal forms of rabbit liver metallothionein II are compared with the crystal structure of rat metallothionein II, and the polymerized states in crystal packing are discussed with the knowledge of polymerization of metallothioneins in solutions. The hypothesis, which is consistent with theoretical calculations and experimental results, is expected to construct a connection between the biochemical characteristics and physiological functions of metallothioneins, and this research may give some enlightenment to the topics of protein polymerizations.

[Adenosine in treatment of rats with spinal cord injury]

OBJECTIVE

To observe the changes of endogenous extracellular adenosine after spinal cord injury (SCI) to rats and the effect of exogenous adenosine on extracellular calcium after SCI and post-injury neurological function.

METHODS

A ventral compression injury model of T13 spinal cord was used, and the extracellular fluids were collected consecutively every 20 minutes after injury by using microdialysis. Adenosine in the samples was analyzed using high-pressure liquid chromatography (HPLC) with u.v. detection. The rats received different doses of 2-chloroadenosine (2-CADO), a nonspecific agonist of adenosine receptors, by intrathecal injection 15 minutes before injury. The extracellular fluid was collected every 10 minutes immediately after injury and the calcium was measured using atomic absorption spectrophotometer. Neurological function score, inclined plane angle, and histology were observed 24 hours after injury.

RESULTS

A significant increase of adenosine was found immediately after spinal cord injury. The concentration of adenosine peaked at one hour after injury and dropped down to the basal level. There was a positive relation between the increase of adenosine and the severity of SCI. High dose of 2-CADO can significantly significantly inhibit the decrease of extracellular calcium and improve the neurological function of injured rats.

CONCLUSIONS

Adenosine could involve the pathological process of secondary spinal cord injury and might play a protective role in SCI.

Automated docking of peptides and proteins by using a genetic algorithm combined with a tabu search

A genetic algorithm (GA) combined with a tabu search (TA) has been applied as a minimization method to rake the appropriate associated sites for some biomolecular systems. In our docking procedure, surface complementarity and energetic complementarity of a ligand with its receptor have been considered separately in a two-stage docking method. The first stage was to find a set of potential associated sites mainly based on surface complementarity using a genetic algorithm combined with a tabu search. This step corresponds with the process of finding the potential binding sites where pharmacophores will bind. In the second stage, several hundreds of GA minimization steps were performed for each associated site derived from the first stage mainly based on the energetic complementarity. After calculations for both of the two stages, we can offer several solutions of associated sites for every complex. In this paper, seven biomolecular systems, including five bound complexes and two unbound complexes, were chosen from the Protein Data Bank (PDB) to test our method. The calculated results were very encouraging-the hybrid minimization algorithm successfully reaches the correct solutions near the best binded modes for these protein complexes. The docking results not only predict the bound complexes very well, but also get a relatively accurate complexed conformation for unbound systems. For the five bound complexes, the results show that surface complementarity is enough to find the precise binding modes, the top solution from the tabu list generally corresponds to the correct binding mode. For the two unbound complexes, due to the conformational changes upon binding, it seems more difficult to get their correct binding conformations. The predicted results show that the correct binding mode also corresponds to a relatively large surface complementarity score. In these two test cases, the correct solution can be found in the top several solutions from the tabu list. For unbound complexes, the interaction energy from energetic complementarity is very important, it can be used to filter these solutions from the surface complementarity. After the evaluation of the energetic complementarity, the conformations and orientations close to the crystallographically determined structures are resolved. In most cases, the smallest root mean square distance (r.m.s.d.) from the GA combined with TA solutions is in a relatively small region. Our program of automatic docking is really a universal one among the procedures used for the theoretical study of molecular recognition.

[Long-term outcome of selective posterior rhizotomy for spastic cerebral palsy]

OBJECTIVE

To investigate the long term outcome and complication of selective posterior rhizotomy for spastic cerebral palsy.

METHOD

26 patients with cerebral palsy who had received SPR were followed up for four years.

RESULT

In the 9 patients who could walk and stand up from squatting position independently, 7 could stand steadily on one foot after operation. In the 12 who patients could walk and stand up from squatting position dependently, 7 could walk independently in the room after operation. In 5 patients couldn't walk and stand up from squatting position, 3 patients could walk dependently in the room after operation. Complications occurred in 3 patients.

CONCLUSION

Selective posterior rhizotomy is effective in the treatment of spastic cerebral palsy. Strictly selecting candidates for the operation and good rehabilitation training before and after operation should be emphasized for good results.

Synergetic protective effects of combined blockade by two kinds of autolesion mediator receptor on neurological function after cervical cord injury

OBJECTIVE

To investigate the effects of combined blockade by platelet activating factor (PAF) receptor antagonist BN52021 in combination with opiate receptor antagonist naloxone on neurological function and neurological tissue damage after cervical cord injury.

METHODS

Spinal cord contusion at C6 segment was made with Allen method in cats, which were randomly divided into four groups: saline control group; BN52021 group; naloxone group; and combined treatment group with BN52021 and naloxone. Alteration of cervical cord blood flow, blood barrier permeability of the spinal cord, cervical cord tissue pathology and neurological functional scores were studied after experimental cervical cord injury.

RESULTS

The animals treated with BN52021 or naloxone had significantly better functional scores than saline controls 6 weeks after injury (P < 0.05). Moreover, the combined treatment showed significantly better neurologic recovery than either naloxone or BN52021 treated animals (P < 0.05). The other indexes in combined treatment animals were also superior to those in naloxone or BN52021 treated animals.

CONCLUSIONS

Combined blockade by two kinds of autolesion mediator receptor can more effectively inhibit secondary damage production and development after cervical cord injury and improve neurologic function.

Diagnosis and treatment of acute central cervical cord injury

OBJECTIVE

To clarify the diagnosis and management of acute central cervical cord injury.

METHODS

Eighty-nine patients with acute cervical central cord injury were retrospectively reviewed. Sixty-three patients were treated conservatively and 26 were treated surgically. There were two acute deaths. Eighty-seven patients were followed up for 3 months to 15 years.

RESULTS

Their average neurological score (ASIA) was increased from 41.7 at admission to 83.1 at follow-up.

CONCLUSIONS

Acute central cervical cord injury should be differentiated from complete spinal cord injury, cervical myelopathy, cruciate paralysis and C8 nerve root injury. When compression of nerve tissue or cervical instability is identified, operative intervention should be indicated. The prognosis is less optimistic in the patients with severe primary injury and at old age.

[Isolation and characterization of a insecticidal protein from Pseudomonas pseudoalcaligenes]

A insecticidal protein was purified by gel-filtration chromatography on Sephadex G-100 and anion-exchange chromatography on DEAE-Sephadex A-50 from the suspension of Pseudomonas pseudoalcaligenes culture. Certain biophysical and biochemical properties were also studied. The molecular weight of the subunit of the insecticidal protein is 25,100 and pI is 5.16. Amino acid composition analysis showed that it is an acidic protein.

[The relationship between alteration of mitochondrial enzyme activities and mitochondrial function after cervical cord injury]

To investigate the relationship between mitochondrial enzyme activities and mitochondrial function after cervical cord injury, cervical cord model was prepared using Allen method in cats. Changes in mitochondrial Na+, K(+)-ATPase, Ca2+, Mg(2+)-ATPase, superoxide dismutase (SOD) activities, contents of malondialdehyde (MDA) and mitochondrial function in cervical cord were observed by different biochemical methods. The results showed that mitochondrial Na+, K(+)-ATPase, CA2+, Mg(2+)-ATPase, SOD activities decreased; mitichondral respiratory control rate (RCR), P/O ratio and oxidative phosphorylation rate (OPR) were also depressed is compared with control group (P < 0.05), but MDA level significantly increased compared to control group (P < 0.01). The results demonstrate that there is close correlation, between mitochondrial ATPase. SOD activities and mitochondral function, suggesting that mitochondrial pathophysiological alteration plays important roles in the secondary damage after cervical cord injury.

[Changes of NGF in injured spinal cord following treatment with a single large dose of methylprednisolone sodium succinate]

Nerve growth factor (NGF) was detected by ABC-ELISA in rat normal spinal cord, spinal cord with mild contusion of 25gcm, and that with mild contusion plus a single intramuscular injection of large dose of methylprednisolone sodium succinate (MPSS) (80 mg/kg). The mean preinjury NGF level in spinal cord was 10.2 +/- 2.8ng/g. Following injury, NGF level in spinal cord began to increase progressively. NGF level in spinal cord without treatment was attenuated to 30.32 +/- 0.32, 89.51 +/- 2.14, 66.02 +/- 1.51, 50.32 +/- 1.23 and 46.23 +/- 1.42ng/g at 4, 7, 14, 21 and 28 days respectively, while in cord spinal with MPSS treatment it was 121.98 +/- 4.05, 119.56 +/- 1.45, 80.39 +/- 1.50, 68.31 +/- 0.77 and 59.86 +/- 0.97 ng/g at 4, 7, 14, 21 and 28 days, respectively. This result suggests that a single large dose of MPSS enhances NGF level in injured spinal cord with a peak at day 4. The implication of this article is that the changes of NGF level in spinal cord are relevant to spinal cord self-recovery.

Responses of inferior collicular neurons of the FM bat, Eptesicus fuscus, to pulse trains with varied pulse amplitudes

Under free field stimulation conditions, we studied the responses of inferior collicular neurons of the FM bat, Eptesicus fuscus, to pulse trains with varied pulse amplitudes. Each pulse train consisted of 7 pulses of 4 ms delivered at 24 ms interpulse-intervals (i.e. 42 pulses/s). For a control pulse train, all pulse amplitudes were equal to a neuron's best amplitude which, when delivered in single pulses, elicited maximal number of impulses from the neuron. The amplitudes of individual pulses of the remaining pulse trains were linearly increased or decreased at a slope of 0, 14, 28, 42, 56 and 69 dB/s. All 56 inferior collicular neurons discharged to pulse trains were of two main types. Type I (N43, 77%) neurons discharged to each pulse within a train while type II (N11, 20%) neurons discharged to the first pulse of a train stimulus only. Discharge patterns of the remaining (N2, 3%) neurons changed between type I and type II when stimulated with different pulse trains. The number of impulses discharged by a neuron varied with different pulse trains. In addition, the number of impulses discharged to each pulse by type I neurons also varied among individual pulses within the train. Only 14 neurons (25%) discharged maximally to the control pulse train. Responses of the remaining neurons to other pulse trains were either 30%-120% larger than (N17, 30%) or within 30% (N25, 45%) of the control pulse train response. Furthermore, half of 56 neurons selectively discharged to a most preferred pulse train with a response magnitude which was at least 50% larger than the response to the least preferred pulse train. Possible mechanisms underlying the different discharge patterns are discussed in terms of a neuron's recovery cycle, minimum threshold and inhibitory period relative to the temporal characteristics (pulse repetition rate and amplitude) of the pulse trains.

Neurons in the inferior colliculus, auditory cortex and pontine nuclei of the FM bat, Eptesicus fucus respond to pulse repetition rate differently

Single-neuron responses to pulse repetition rate in the inferior colliculus, auditory cortex and pontine nuclei of the FM bat, Eptesicus fuscus were studied under free-field stimulation conditions. The best frequency (BF) and minimum threshold (MT) of each neuron were first determined with a 4 ms pulse broadcast from a specific point (response center) of the bat's frontal auditory space at which the neuron had maximal spatial sensitivity. The neuron's intensity-rate function was then studied with a 4 ms BF pulse delivered at 10 dB increments above its MT in order to determine the best intensity to which the neuron discharged maximally. The neuron's discharge pattern and number of impulses to 32 trials of 300 ms train stimuli, which consisted of different number of 4 ms BF and best intensity pulses (1, 2, 3, 8, 12, 19, 24, 29 pulses/train) and delivered at an interpulse interval of 1000, 250, 170, 100, 40, 25, 15, 12 and 10 ms (i.e. at a pulse repetition rate of 1, 4, 6, 10, 25, 40, 67, 83, 100 pulses/s), were sequentially recorded. All neurons recorded from the inferior colliculus, auditory cortex and pontine nuclei discharged phasically (1-3 impulses) but they responded to the pulse repetition rate in different manners. More than 63% of 38 inferior collicular and 65 pontine neurons studied discharged impulses to each pulse within a train stimulus when the pulse repetition rate was up to 40 pulses/s.(ABSTRACT TRUNCATED AT 250 WORDS)