Online mass spectrometry of exhaled breath with a modified ambient ion source.

Exhaled breath (EB) may contain metabolites that are closely related to human health conditions. Real time analysis of EB is important to study its true composition, however, it has been difficult. A robust ambient ionization mass spectrometry method using a modified direct analysis in real time (DART) ion source was developed for the online analysis of breath volatiles. The modified DART ion source can provide a confined region for direct sampling, rapid transmission and efficient ionization of exhaled breath. With different sampling methods, offline analysis and near real-time evaluation of exhaled breath were also achieved, and their unique molecular features were characterized. High resolution MS data aided the putative metabolite identification in breath samples, resulting in hundreds of volatile organic compounds being identified in the exhalome. The method was sensitive enough to be used for monitoring the breath feature changes after taking different food and over-the-counter medicine. Quantification was performed for pyridine and valeric acid with fasting and after ingesting different food. The developed method is fast, simple, versatile, and potentially useful for evaluating the true state of human exhaled breath.

High Resolution Capillary Isoelectric Focusing Mass Spectrometry Analysis of Peptides, Proteins, And Monoclonal Antibodies with a Flow-through Microvial Interface.

Capillary isoelectric focusing directly coupled to high resolution mass spectrometry (cIEF-MS) provides information on amphoteric molecules, including isoelectric point and accurate mass, which enables structural interrogation of biopolymer pI variants. The coupling of cIEF with MS was facilitated by a flow-through microvial interface, made by stainless steel with high chemical resistance and mechanical robustness. Two on-column electrolyte configurations of cIEF-MS were demonstrated using peptide and protein pI markers. The pI resolution was 0.02 pH unit in the pH range of 5.5 to 7.0, with no anticonvective reagent (glycerol) added. High resolution Orbitrap detector provides mass spectra for midsized proteins (<30 kDa), enabling deconvolution with high accuracy for IEF-focused low abundance species. Charge heterogeneity of therapeutic monoclonal antibodies (mAb) is one of the most important attributes in the biopharmaceutical industry, and it is routinely monitored by IEF and fractionation-based methods. As a proof of concept, the commercial formulation of infliximab was directly analyzed using cIEF-MS for separation and online identification of mAb charge variants. The main intact antibody species along with two basic and one acidic variants were observed, and their accurate molecular weights ( Mw) recorded by MS detector readily revealed the structural differences of these variants. Variants with 0.1 unit in pI difference and 1 Da difference in molecular weight were readily resolved. The deconvoluted intact Mw values showed ppm level accuracy compared to theoretical predictions.

Direct Analysis in Real Time Mass Spectrometry for Characterization of Large Saccharides.

Polysaccharide characterization posts the most difficult challenge to available analytical technologies compared to other types of biomolecules. Plant polysaccharides are reported to have numerous medicinal values, but their effect can be different based on the types of plants, and even regions of productions and conditions of cultivation. However, the molecular basis of the differences of these polysaccharides is largely unknown. In this study, direct analysis in real time mass spectrometry (DART-MS) was used to generate polysaccharide fingerprints. Large saccharides can break down into characteristic small fragments in the DART source via pyrolysis, and the products are then detected by high resolution MS. Temperature was shown to be a crucial parameter for the decomposition of large polysaccharide. The general behavior of carbohydrates in DART-MS was also studied through the investigation of a number of mono- and oligosaccharide standards. The chemical formula and putative ionic forms of the fragments were proposed based on accurate mass with less than 10 ppm mass errors. Multivariate data analysis shows the clear differentiation of different plant species. Intensities of marker ions compared among samples also showed obvious differences. The combination of DART-MS analysis and mechanochemical extraction method used in this work demonstrates a simple, fast, and high throughput analytical protocol for the efficient evaluation of molecular features in plant polysaccharides.

Comparison of short term curative effects of open door laminoplasty with different plate density for the treatment of multi segment cervical spondylotic myelopathy / 中国骨伤

<p><b>OBJECTIVE</b>To compare the short term curative effect of posterior open door laminoplasty between continuous placement of shaping plate and intermittent placement in treating multilevel cervical spondylotic myelopathy.</p><p><b>METHODS</b>From January 2012 to March 2015, 43 patients with multi segment cervical spondylotic cervical were treated with posterior open door laminoplasty, 21 patients with continuous placement of shaping plate(continuous group), 22 patients with intermittent placement of shaping plate(intermittent group). Operative time, intraoperative blood loss, JOA score, VAS score, postoperative spinal sagittal diameter and cervical curvature, postoperative cervical activity, complications, hospitalization expenses etc. were observed.</p><p><b>RESULTS</b>The patients of two groups were followed up with an average of (23.2±8.1) months and (23.3±8.0) months in continuous group and intermittent group, respectively. There was no significant difference in operative time, intraoperative blood loss, hospitalization time between two groups(>0.05). JOA and VAS scores of all patients at final follow up were obviously improved than preoperative(<0.05). Postoperative spinal sagittal diameter at 3 days and final follow up were obviously improved(<0.05), and there was no significant difference between postoperative at 3 days and final follow up(>0.05). Cervical activity of all patients at final follow up was decreased than preoperative(<0.05), but there was no significant difference between two groups(>0.05). There was no significant difference in postoperative complication and there was significant difference in hospitalization expenses between two groups.</p><p><b>CONCLUSIONS</b>Posterior open door laminoplasty with continuous or intermittent placement of shaping plate have similar clinical effects in ameliorating nerve function for the treatment of multilevel cervical spondylotic myelopahty. However, the hospitalization expenses of intermittent group is obviously reduced, and the medical resources can be saved.</p>

Clinical study of cervical anterior and posterior decompression and internal fixation in the revision of anterior cervical fixation failure / 中国骨伤

<p><b>OBJECTIVE</b>To investigate the clinical effects and prevent the complications of posterior and anterior decompression and internal fixation in the revision of cervical anterior internal fixation failure.</p><p><b>METHODS</b>From 2008 January to 2011 December, 17 patients with cervical anterior internal fixation failure were treated with posterior and anterior decompression and internal fixation. There were 12 males and 5 females, aged from 26 to 68 years old with an average of 44.1 years. The lower screw loosening was found in 6 cases, the upper screw loosening in 5 cases, titanium mesh caving in 3 cases, the upper screw breakage in 2 cases, the lower screw breakage in 1 case. Informations of bone fusion were observed by X-ray, CT, MRI. Clinical effects were evaluated by modified JOA score.</p><p><b>RESULTS</b>All the revision operations were successfully completed. One case with poor blood coagulation function before operation resulted in postoperative hematoma and occurred neurological symptoms; after hematoma removal and fresh frozen plasma infusion later, neurological symptoms of the patient disappeared. All patients were followed up from 6 to 38 months with an average of (22.4±10.0) months. Postoperative at 2 weeks, 3 months, and final follow-up, JOA score had obviously improved and respectively was 13.1±1.6, 13.4±1.6, 14.2±1.5. All internal fixation locations were good after revision,and obtained bone fusion at 10 months after operation, with an average fusion time of 6 months.</p><p><b>CONCLUSION</b>The combined posterior and anterior decompression and internal fixation in the revision of cervical anterior internal fixation failure is safe, can achieve thoroughly decompression, maintain the cervical curvature, reconstruct the three column stability, and it may be used for the patients of cervical anterior fixation failure.</p>