Rapid Characterization of Polymer Materials Using Arc Plasma-Based Dissociation-Mass Spectrometry.

Fingerprinting spectra of polymer materials containing information of monomers' molecular weight and detailed structure, constituents, and sequences were obtained by a direct analytical process using arc plasma-based dissociation (APD)-mass spectrometry. The thermal arc plasma generated using a simple arc discharge device induces the dissociation of the polymeric backbone, producing mass spectra with strong regularity within seconds. The molecular weight of the repeating unit was revealed by equal intervals between peak series and protonated monomer ions in the mass spectra. Meanwhile, lots of secondary fragment ions were produced to provide abundant structural information. For polyethers, it is even possible to decipher (read) the "sequence" directly from their spectra. Polymers composed of isomers or only differing in their initiator moieties were easily distinguished with their characteristic APD mass spectra. The spectra were highly reproducible according to the results of similarity calculation. Unlike pyrolysis mass spectrometry, in the APD device, polymers in liquid, solid, powder, and crude samples can be analyzed directly without any pretreatment, and the regular spectra are easier to interpret. Compared with other direct analytical methods, more structural informative spectra can be acquired owing to the high energy, high temperature, and unique chemical reactivity of arc plasma. Thus, this technique is promising to be a valuable tool in rapid elucidation of polymer materials.

Arc Plasma-Based Dissociation Device: Fingerprinting Mass Spectrometric Analysis Realized at Atmospheric Condition.

Fingerprinting mass spectrometric analysis at atmospheric conditions has been realized using an arc plasma-based dissociation (APD) device. Because of its high energy, high temperature, and unique chemical reactivity, the thermal plasma can induce dissociation of neutral molecules or ions produced by atmospheric ion sources. Both even/odd electron (fragment) ions would be generated to provide fingerprinting structural information and molecular weight of the compounds simultaneously. Meanwhile, elimination and aromatization were observed as special dissociation patterns in this device, which can be applied in the differentiation of isomers. The good compatibility with atmospheric ion sources is demonstrated by coupling the device with nanoelectrospray ionization (nano-ESI) and zero volt paper spray ionization (PSI), respectively. With erythromycin as the tuning standard, informative dissociation spectra of various compounds can be reproducible, making it possible to establish an arc plasma-based dissociation spectra database. This device allows fingerprinting mass spectrometric analysis, with no need for harsh vacuum conditions and is promising for making a breakthrough in making up the deficiency of atmospheric ionization techniques.

TRPM2-AS inhibits the growth, migration, and invasion of gliomas through JNK, c-Jun, and RGS4.

Gliomas are a group of brain cancers with high mortality and morbidity. Understanding the molecular mechanisms is important for the prevention or treatment of gliomas. The present study was to investigate the effects and mechanisms of long noncoding RNA TRPM2-AS in gliomas proliferation, migration, and invasion. We first compared the levels of TRPM2-AS in 111 patients with glioma to that of the normal control group by a quantitative polymerase chain reaction. The results indicated a significant increase of TRPM2-AS in patients with glioma (2.43 folds of control, p = .0135). MTT methods, wound healing assays, transwell analysis, and clone formation analysis indicated the overexpression of TRPM2-AS promoted the proliferation, migration, and invasion of U251 and U87 cells, while downregulation of TRPM2-AS inhibited the cell proliferation, migration, and invasion significantly (p < .05). To further uncover the mechanisms, bioinformatics analysis was conducted on the expression profiles, GSE40687 and GSE4290, from the Gene Expression Omnibus database. One hundred fifty-six genes were differentially expressed in both datasets (FC > 2.0; p = .05). Among these differentially expressed genes, the level of RGS4 messenger RNA was drastically regulated by TRPM2-AS. Further western-blot analysis indicated the increase of RGS4 protein expression and decrease of p-JNK/JNK and p-c-Jun/c-Jun ratio after TRPM2-AS overexpression. On the other hand, inhibition of TRPM2-AS by small interfering RNA suppressed the expression of RGS4 and promoted the ratios of p-JNK/JNK and p-c-Jun/c-Jun. The present work indicated the mechanisms of the participation of TRPM2-AS in the progression of gliomas might, at least partly, be related to JNK, c-Jun, and RGS4. Our work provided new insights into the underlying mechanisms of glioma cellular functions.

[Optimal dose of local anesthetic mixture in ultrasound-guided infraclavicular brachial plexus block via coracoid approach: analysis of 160 cases].

OBJECTIVE: To investigate the optimal dose of local anesthetic mixture in ultrasound-guided infraclavicular brachial plexus block via coracoid approach. METHODS: 160 patients scheduled for surgery of the hand or forearm were randomly divided into 4 equal groups (Groups A, B, C, and D). To receive 8, 7, 6, or 5 ml of anesthetic mixture of 0.75% ropivacaine and 2% lidocaine for radial nerve, axillary nerve, median nerve, ulnar nerve, median cutaneous nerve of arm, median antebrachial cutaneous nerve, and lateral antebrachial cutaneous nerve respectively ultrasound-guided infraclavicular brachial plexus block via coracoid approach. The time for anesthesia taking effect, anesthesia maintenance time, and quality of sensory block were observed. RESULTS: Anesthesia took effect about 4 minutes after injection in these 4 groups without significant differences among then (all P > 0.05). The good analgesic effect rates of Groups A, B, and C were all 100%, all significantly higher than that of Group D (87.5%, P = 0.027). The block maintenance times of Groups A, B, and C were (377 +/- 111) min, (369 +/- 135) min, and (351 +/- 112) min respectively, all significantly longer than that of Group D [(296 +/- 101) min, P = 0.024]. No anesthesia-related complication was found in these 4 groups. CONCLUSION: Ultrasound-guided infraclavicular brachial plexus block via coracoid approach can reduce the volume of local anesthetic mixture. The dose of 6 ml local anesthetic mixture for each nerve fascicle, totally 18 ml, provides good analgesic effect and does not seem to affect the time for anesthesia taking effect.