A mass spectrometry imaging method for visualizing synthetic polymers by using average molecular weight and dispersity as indices.

RATIONALE: Matrix-assisted laser desorption/ionization mass spectrometric imaging (MSI) is considered to be a powerful tool for visualizing the spatial distribution of synthetic polymers. However, a conventional method extracting an image of a specific m/z value is not suitable for polymers, which have a mass distribution. It is necessary to develop the visualization method to show the spatial distribution of entire polymer series. METHODS: The mass peaks included in polymer series were specified from the average mass spectrum of the entire MSI measurement region by using Kendrick mass defect analysis. The images of those mass peaks were extracted and the number average molecular weight (Mn ), the weight average molecular weight (Mw ) and dispersity (D) were calculated for each pixel. Finally, the spatial distribution of the polymer series was summarized to images using Mn , Mw and D as indices. RESULTS: The effects of the methods were investigated by (i) polymers with different mass distributions and (ii) polymers with different repeat units and end-groups. In both cases, the spatial distribution of specific polymer series including several dozens to hundreds of mass peaks was summarized into three images related to Mn , Mw and D, which are familiar indices in polymer analysis. The results are able to provide an overview of the spatial variation of each polymer more intuitively. CONCLUSIONS: The visualization of Mn , Mw and D will help provide an overview of the spatial distribution of polymer series combined with ion intensity distribution made by conventional methods. It can be also applied to other mass spectrometric imaging methods such as desorption electrospray ionization (DESI) or time-of-flight secondary ion mass spectrometry (TOF-SIMS).

Integrated qualitative analysis of polymer sample by pyrolysis-gas chromatography combined with high-resolution mass spectrometry: Using accurate mass measurement results from both electron ionization and soft ionization.

RATIONALE: Gas chromatography/mass spectrometry (GC/MS) is a powerful analytical tool used to separate and then identify volatile compounds through library database searches. However, as not all compounds are registered in these databases, it is not uncommon to detect unregistered components. Therefore, new analytical techniques were developed that utilize methods of identification beyond database searches alone. METHODS: Acquire data by using electron ionization (EI) and soft ionization (SI) with high-resolution mass spectrometry (HRMS). Use the EI mass spectra to library search for matches. Use the SI mass spectra for accurate mass analysis of the EI molecular ions. Conduct an isotope pattern analysis of the molecular ion to refine the possible candidate compositions. Use these compositions as a constraint for the accurate mass analysis of the EI fragment ions. If a given molecular ion formula is not correct, the EI fragment ions will not show good matches. Finally, all analytical results are integrated into a color-coded qualitative analysis report. RESULTS: The capabilities of this new integrated analytical method were assessed for a polymer resin sample that was measured by using pyrolysis-gas chromatography/high resolution time-of-flight mass spectrometry. A total of 161 compounds were detected in the total ion current chromatogram, and 154 of these compounds were identified as having only one chemical formula candidate with this new integrated qualitative analysis method. CONCLUSIONS: This new integrated qualitative analysis method gives analytical results independent of library search results. It can be applied to a variety of SI methods including chemical ionization, photoionization, field ionization, and low-energy EI.

Conditioning the cochlea to facilitate survival and integration of exogenous cells into the auditory epithelium.

The mammalian auditory epithelium (AE) cannot replace supporting cells and hair cells once they are lost. Therefore, sensorineural hearing loss associated with missing cells is permanent. This inability to regenerate critical cell types makes the AE a potential target for cell replacement therapies such as stem cell transplantation. Inserting stem cells into the AE of deaf ears is a complicated task due to the hostile, high potassium environment of the scala media in the cochlea, and the robust junctional complexes between cells in the AE that resist stem cell integration. Here, we evaluate whether temporarily reducing potassium levels in the scala media and disrupting the junctions in the AE make the cochlear environment more receptive and facilitate survival and integration of transplanted cells. We used sodium caprate to transiently disrupt the AE junctions, replaced endolymph with perilymph, and blocked stria vascularis pumps with furosemide. We determined that these three steps facilitated survival of HeLa cells in the scala media for at least 7 days and that some of the implanted cells formed a junctional contact with native AE cells. The data suggest that manipulation of the cochlear environment facilitates survival and integration of exogenously transplanted HeLa cells in the scala media.

[Laryngeal Papillomatosis: A Statistical Analysis of 60 Cases].

Laryngeal papillomatosis is the most common benign neoplasm of the larynx. Juvenile onset laryngeal papillomatosis tends to recur. In patients with adult onset laryngeal papillomatosis, laryngeal cancer rarely develops. This paper reports a clinical analysis of 60 patients with laryngeal papillomatosis who were treated at our clinic between January 1971 and September 2009. We analyzed the sex ratio, age at the onset of papilloma, type of developing papilloma (single or multiple type), site of developing papilloma, recurrence rate, and therapeutic modalities. Furthermore, the clinical characteristics of the patients with malignant transformation were examined. The patients were classified according to their age at the onset of the papilloma and the type of developing papilloma. The patients were grouped into a juvenile-onset group and an adult-onset group according to their age at the onset of the papilloma. They were also classified into single-type or multiple-type according to whether the initial papilloma appeared singly or multiply. The male to female sex ratios were 1.2 in the juvenile-onset group and 5.1 in the adult-onset group. Among the patients who developed papilloma at an age of under 10 years old, most of the juvenile cases had experienced onset by 4 years of age. Furthermore, the frequency of multiple-type papilloma was significantly higher in the juvenile-onset group, compared with the adult-onset group. The vocal fold was the most frequent site of the papilloma. The recurrence rate in the juvenile-onset group was significantly higher than that of the adult-onset group. A stratified analysis according to the type of papilloma occurrence, however, showed no significant difference in recurrences between the juvenile-onset and adult-onset groups. A stratified analysis according to the age at the onset of papilloma showed that the recurrence rate of multiple-type papilloma was significantly higher than that of single-type papilloma in the adult-onset group. Among multiple therapeutic modalities, vaporization by carbon dioxide laser was the most frequently used. Adjuvant therapy was performed in 6 cases who suffered from multiple relapses. The injection of interferon was performed in 5 cases, and the local injection of cidofovir was performed in 1 case. Malignant transformation of the papilloma was confirmed in 3 cases. The periods between the onset of papilloma and the malignant transformation were 40 years, 14 years, and 3 years. The present study indicates that patients with laryngeal papilloma developing at multiple sites have a significantly higher rate of relapse, even in the adult-onset group. There was no tendency in the period observed between the onset of papilloma and malignant transformation. From the standpoint of recurrence and malignant transformation, patients with papillomatosis should be carefully followed up for a long period of time.

[Surgical approach of lateral temporal bone resection for treatment of head and neck cancer with invasion surrounding the jugular foramen].

We herein present a review of the surgical approach of lateral temporal bone resection (LTBR) in the treatment of 5 cases of head and neck cancers invading the jugular foramen between 2008 to 2013. The patients comprised 3 males and 2 females with ages ranging from 25 to 76 and observation times were between 13 and 22 months. In this study we reviewed the method of operation and treatment. Four patients are alive, but one patient died from the primary disease. Complications occurred including postoperative facial nerve palsy and hearing loss. Although the LTBR with jugular foramen approach can cause postoperative facial nerve palsy and hearing loss, this method would be recommended as a safe surgical procedure for its wide surgical field. We therefore propose that this LTBR technique is useful for patients with head and neck cancer extending to the jugular foramen.

Long-term postoperative vocal function after thyroplasty type I and fat injection laryngoplasty.

OBJECTIVES: We evaluated the differences in the long-term functional results of medialization thyroplasty type I (MT) and autologous fat injection laryngoplasty (FIL) in patients with unilateral vocal fold paralysis. METHODS: Forty-one patients underwent MT, and 73 patients underwent FIL. The voice functions before and after both surgeries were examined by aerodynamic, pitch and intensity, and acoustic analyses. The postoperative voice examinations were performed 12 months (median) after the MT, and 4 years (median) after the FIL. The differences between the preoperative and postoperative parameters were examined with a paired t-test for each group separately. For each variable, a comparison of the effects of surgery was conducted with an analysis of covariance model, with the change between the preoperative and postoperative values as the dependent variable and the preoperative value as the covariate. RESULTS: In both groups, all parameters significantly improved after surgery. In particular, there was a significant difference for the postoperative acoustic analyses. However, the aerodynamic analysis after FIL improved more significantly in comparison to that after MT because of the respiratory handicap. CONCLUSIONS: We found that MT and FIL provided almost the same effectiveness, and that both surgeries were reliable in improving the vocal function in patients with vocal fold paralysis.

Development of a new electron ionization/field ionization ion source for gas chromatography/time-of-flight mass spectrometry.

We have developed a combined EI/FI source for gas chromatography/orthogonal acceleration time-of-flight mass spectrometry (GC/oaTOFMS). In general, EI (electron ionization) and FI (field ionization) mass spectra are complementary: the EI mass spectrum contains information about fragment ions, while the FI mass spectrum contains information about molecular ions. Thus, the comparative study of EI and FI mass spectra is useful for GC/MS analyses. Unlike the conventional ion sources for FI and EI measurements, the newly developed source can be used for both measurements without breaking the ion source vacuum or changing the ion source. Therefore, the combined EI/FI source is more preferable than the conventional EI or FI ion source from the viewpoint of the reliability of measurements and facility of operation. Using the combined EI/FI source, the complementarity between EI and FI mass spectra is demonstrated experimentally with n-hexadecane (100 pg): characteristic fragment ions for the n-alkane such as m/z 43, 57, 71, and 85 are obtained in the EI mass spectrum, while only the parent peak of m/z 226 (M+) without any fragment ions is observed in the FI mass spectrum. Moreover, the field desorption (FD) measurement is also demonstrated with poly(ethylene glycol)s M600 (10 ng) and M1000 (15 ng). Signals of [M+H]+, [M+Na]+ and [M+K]+ are clearly detected in the FD mass spectra.

[Voice reconstruction of the recurrent laryngeal nerve after nerve resection].

Our treatment of choice in voice reconstruction for recurrent laryngeal nerve (RLN) resection is concurrent nerve reconstruction. If this is not possible, we secondarily inject fat. We studied postoperative voice function and the feasibility of this voice reconstruction treatment strategy. Subjects were 39 patients with advanced thyroid cancer having the primary lesion resected together with RLN between 2001 and 2007. Of these 39, 9 underwent concurrent reconstruction by directly anastomosing the ansa cervicalis to the peripheral RLN. Fat was secondarily injected in 25 and 5 did not undergo any reconstruction. We found that: 1) Postoperative maximum phonation time (MPT), mean flow rate (MFR) and pitch perturbation quotient (PPQ) in the direct anastomosis group were significantly better than in the nonreconstruction group (p < 0.05). 2) Postoperative MPT, MFR, and PPQ in the fat injection group were significantly better than in the nonreconstruction group (p < 0.05). 3) MPT in the fat injection group was significantly better than in the direct anastomosis group one month postoperatively (p = 0.007), although this finding was reversed six months postoperatively (p = 0.08). 4) MFR in the fat injection group tended to be better than the direct anastomosis group one month postoperatively (p = 0.1), although this finding was reversed six months postoperatively (p = 0.1). We thus recommend concurrent voice reconstruction by direct anastomosis in conjuction with nerve resection.

New coupling of planar chromatography with direct analysis in real time mass spectrometry.

The coupling of planar chromatography with direct analysis in real time time-of-flight mass spectrometry (DART-TOF-MS) was shown for the first time. Cutting the plate within a track led to substance zones positioned on the plate edge which were directly introduced into the DART gas stream. Mass signals were obtained instantaneously within seconds. Detectability was shown in the very low ng-range per zone on the example of isopropylthioxanthone. The coupling was perfectly suited for identification and qualitative purposes, but it was initially critical for quantification of results. Analytical response (R2 0.8202) and repeatability were strongly dependent from proper manual positioning of the HPTLC plate into the electronic or vibronic excited-state gas stream of the ion source. This drawback was overcome by using stable isotope-labeled standards shown on the example of caffeine. This way, analytical response (R2 0.9892) and repeatability (RSD < +/- 5.4%, n=6) were improved to a high extent. Spatial resolution by an in-house-built plate holder system was shown to be better than 3 mm. The decay of the signal was observed. The efficacy of this new coupling was compared to a plunger-based extraction device for HPTLC/electrospray ionisation-MS. The latter device showed detectability down to the pg-range, e.g. the limit of quantification for isopropylthioxanthone was found to be 100 pg. Repeatability was comparable (RSD +/- 6.7%), however, without the need of internal standard correction. Analytical response was slightly better and showed a determination coefficient R2 of 0.9983. Similar data were obtained for caffeine as well. Spatial resolution was 2 mm or 4 mm depending on the plunger head used. The comparison showed that HPTLC/DART-TOF-MS is a useful coupling method regarding qualitative aspects and it has the potential to cope also with the difficulties of quantification if isotope-labeled standards were used or if a plate holder system is employed as initially shown.

Nitrogenous synergists induced potentiometric response to metal ions with polymeric liquid membranes containing thenoyltrifluoroacetone as an ionophore.

The effects of nitrogenous synergists on the potentiometric responses to divalent transition metal ions were investigated concerning polymeric liquid membranes containing thenoyltrifluoroacetone (Htta) as an ionophore. The tested synergists were pyridine (py) and 4,4'-dioctyl-2,2'-bipyridyl (C8bpy). The potentiometric responses to metal ions, such as Cd2+, Co2+, Ni2+ and Zn2+, were induced by adding the synergists into the liquid membrane systems. The coexistence of Htta and a synergist was necessary for generating the membrane potential. The tta- anion adsorbed at the liquid membrane/solution interface and the complex formation between the synergist and a given metal ion appeared to participate in preferential uptake of metal ions.

Diastereomer method for determining ee by (1)H NMR and/or MS spectrometry with complete removal of the kinetic resolution effect.

[structure: see text] Using chiral auxiliaries, 2-methoxy-2-(1-naphthyl)propionic acid (MalphaNP acid) (S)-(+)-1 and its deuterium-labeled enantiomer (R)-(-)-1-d(n)() (n = 3 or 6), we have developed a new diastereomer method for determining enantiomeric excess (% ee) of chiral alcohols by (1)H NMR and/or MS spectrometry, where the kinetic resolution effect is completely excluded. The data of % ee determined by this method agree well with those calculated by weight, the average error being ca. +/-1.08% ee.

Accurate mass measurement using multiple sprayer nano-electrospray mass spectrometry combined with nano-scale high-performance liquid chromatography on a magnetic sector instrument.

A new technique for accurate mass measurement utilizing multiple sprayer nano-electrospray ionization mass spectrometry (nano-ESI-MS) combined with nano-scale high-performance liquid chromatography (nano-HPLC) on a magnetic sector instrument is described. Both metal-coated glass capillaries and fused-silica capillaries were used as nano-ESI sprayers. A metal-coated glass capillary was used for the introduction of the Ref. compound solution, and a metal-coated fused-silica capillary was used for connection to the nano-HPLC column. By shifting each sprayer's position relative to the sampling orifice, spectra were obtained of both the sample components as eluted from the column and reference compounds. Several standard compounds were examined and satisfactory accurate masses were obtained. Problems arising from differences in ionization efficiency between the sample and reference compounds were not observed.